Methodology
Last reviewed: August 2026
Scope
This review covers 48 tests and test categories commonly included in "longevity", "executive health", or "biological age" testing packages marketed to healthy, asymptomatic adults: 25 blood-based markers, 9 imaging/scan modalities, 7 cancer and disease screening tests, and 7 emerging/consumer categories.
Scope was widened in August 2026. It previously excluded disease-specific screening on the grounds that it is well codified elsewhere — but that turned out to be the wrong cut, because those tests are not sold separately. PSA, tumour marker panels, FIT, mammography, chest X-ray and resting ECG arrive inside the same executive package, on the same invoice, with no indication that they are graded on a completely different body of evidence from the longevity markers beside them. They are now reviewed on their own page, against the same rubric. Screening outside that menu — prenatal, paediatric, occupational surveillance — remains out of scope.
The grading rubric
Each test receives one grade reflecting its evidence base for the use case actually being sold — i.e. testing/screening an asymptomatic or average-risk adult for longevity/risk-stratification purposes, not for diagnosing a symptomatic patient (which is often better-evidenced and out of scope here).
| Grade | Definition |
|---|---|
| Strong | Multiple randomised controlled trials and/or large, consistent prospective cohorts and meta-analyses demonstrate association with hard clinical outcomes (mortality, MI, stroke, fracture), and major guideline bodies (e.g. USPSTF, ACC/AHA, ESC/EAS, KDIGO) endorse use in a defined population. Acting on an abnormal result has a demonstrated path to changed management and improved outcomes. |
| Moderate | Consistent observational and/or genetic (Mendelian randomisation) evidence links the marker to hard outcomes, with a plausible causal mechanism, and guideline bodies support selective or risk-stratified use — but a dedicated RCT showing that testing (and acting on the result) improves outcomes is limited, mixed, or not yet population-general. |
| Weak | Evidence is associative/cross-sectional only, guideline bodies explicitly do not recommend routine use in asymptomatic adults, or randomised trial data are neutral/negative despite biological plausibility (a classic case of a "confounded" biomarker). |
| Emerging | Biologically plausible and an active area of research, but longitudinal human outcome data are too immature to grade for clinical use. Commercial availability has outpaced the evidence base. Not recommended as a basis for individual decisions at this time. |
Each grade is a human judgement made against this published rubric, and the reasoning is written out on every page so it can be checked and disputed. AI tools assist with research and drafting (see Limitations); they do not set grades. Some newer sites publish scores generated entirely by language models, with no human review. This site works the other way round.
How interventions are graded
Since August 2026 the site also grades five categories of intervention — diet, exercise, recovery practices, supplements and other modalities — on the same four-step scale. Both are judged on outcomes, reached by different routes. A diagnostic test is graded on whether testing, and acting on the result, improves outcomes. Finding something early only counts if what follows changes things for the better. An intervention is graded directly on outcomes in healthy people: whether doing it measurably changes things worth caring about — heart attacks, strokes, fractures, diabetes, how well you sleep, how long you stay independent.
The grades carry the same meaning they do for tests. Strong means randomised trials or very large, consistent cohorts tie the intervention to those outcomes, and guideline bodies recommend it. Moderate means a real signal with honest limits: consistent associations, or trial endpoints that stop short of outcomes. Weak means the measured benefits are small, indirect or unproven — fine if you enjoy it, not something to schedule your life or budget around. Emerging means interesting biology, real products on shelves, and no proper human outcome trials yet.
Supplements are held to exactly the same bar as everything else. The capsule aisle is where longevity marketing is loudest and the evidence thinnest, so most supplement entries grade weak or emerging — not because we found proof of harm, but because the proof of benefit does not clear the bar we set for the rest of the site. When we cannot verify a claim against a real, retrievable study, we say so in the entry rather than padding the citation list.
Singapore guidance
Each test page also shows what Singapore’s national screening guidance says about that test. The source is the Screening Test Review Committee report 2026, Volume 1, published by the Academy of Medicine Singapore and the Ministry of Health in February 2026. It covers screening in adults without symptoms, which is the same ground as this site.
The committee sorts screening tests into three categories:
- Category 1: suitable for the general population, within a stated age range and at a stated interval.
- Category 2: not worth it for everyone, but useful for defined higher-risk groups. Whether to screen, from what age and how often is decided with a doctor.
- Category 3: not recommended, either because the evidence is too thin to judge, or because there is good evidence the test does not work or does more harm than good.
Two more states appear on the test pages. “Not one of the named screening tests” means the committee reviewed the condition but named a different test for it. “Not covered in the current review” means the condition is not in Volume 1 at all.
Not reviewed is not the same as not recommended. Volume 1 covers nine conditions, and Volume 2 has not been published yet. A test missing from Volume 1 has simply not been assessed; the committee has said nothing about it either way.
The wording on each page is a fixed summary of the committee’s position, with the table it comes from where there is one. One test, DEXA, is shown in two parts, because the committee treats bone density and body-fat measurement differently. The Singapore guidance and the evidence grade are separate axes and can disagree.
The committee’s complete list, including the national basics this site does not grade (blood pressure, BMI and waist, cervical screening, colonoscopy, low-dose CT), is set out on What Singapore recommends.
For bone density, the committee’s first step is a risk score rather than a scan. The OSTA calculator works it out and shows what the committee recommends for each band.
What a wrong answer costs
A screening test can be wrong in two directions, and the costly direction is often the false alarm. In the committee’s words, “a false positive may lead to unnecessary invasive testing, which comes with its own costs and risks of severe complications,” and the anxiety it causes “may persist to affect mood and daily functioning” even after further tests rule out anything serious. It also notes that false positives multiply “when multiple tests are performed without appropriate clinical considerations”, which is exactly how a large package works (STRC 2026 Volume 1, page 6).
Every test page therefore carries a fourth block, What it costs when it is wrong, with two fields and a sentence:
- Basis — which documented harm applies: specificity, a follow-up cascade, overdiagnosis, ionising radiation, or no published criterion found.
- Severity — material, minor, or not documented.
- A plain sentence naming the harm, or saying plainly that none was found.
The committee’s own Category 3 criteria are the backbone of this axis. A test is advised against partly because its sensitivity and specificity are poor, and partly because “the screening test, or follow-up tests arising from a positive screen, are associated with significant medical risks”. Where a test is Category 3 or Category 2 here, its harm basis follows from the committee’s reasoning about that category, and the page says so in those words.
Where the basis comes from matters, so the page tells you. A row marked as following from the committee’s criteria is not a false-positive study of that specific test, and the block says so. Only a row that names a study carries that study’s numbers.
No published harm criterion found is not a clean bill of health. It means the search came up empty for that test, which is the honest state of much of the literature and the majority of tests on this site. It is not a claim that the test is safe. We would rather print an empty finding than manufacture one.
The clearest recent evidence is DETECT-A, the first large prospective study of what follows a positive multi-cancer early detection blood test in people with no symptoms (PMID 38705577). That is directly relevant to multi-cancer early detection tests, the newest and most expensive test on this site.
Sourcing standard
- Every factual claim about a study's findings is backed by a real, checkable citation — author(s), journal, year, and a link to PubMed or the publisher where available.
- Where we could not verify a specific claim against a real, retrievable publication, we say so explicitly in the text rather than presenting an unsupported number.
- We preferentially cite landmark RCTs, large prospective cohorts, and consensus/guideline statements (USPSTF, ACC/AHA, ESC/EAS, Endocrine Society, KDIGO) over single small studies or press releases.
- Cost figures (SGD) are indicative ranges based on typical private-sector pricing in Singapore as of 2026 and will vary by provider, panel bundling, and whether a doctor's consultation is included. They are not sourced from a specific price list and should be confirmed directly with a lab or clinic.
Key citations (125 landmark studies)
Every PMID cited anywhere on this site — in the evidence cards on Blood Panels, Scans, and Emerging & Overhyped, and in the long-tail cost articles — is indexed here in one place, grouped by category. This lets a reader (or a clinician colleague) sanity-check the evidence base in one pass instead of hunting across pages.
| Test | Citation | PMID | Key finding |
|---|---|---|---|
| Blood panels | |||
| ApoB | Sniderman AD, et al. JAMA Cardiol. 2019. | 31642874 | ApoB outperforms LDL-C for cardiovascular risk prediction, especially at discordant lipid values. |
| Lp(a) | Kamstrup PR, et al. JAMA. 2009. | 19509380 | Elevated Lp(a) independently predicts myocardial infarction risk in the general population. |
| HOMA-IR | Matthews DR, et al. Diabetologia. 1985. | 3899825 | Original derivation of the HOMA-IR model from fasting glucose and insulin. |
| hs-CRP | Ridker PM, et al. N Engl J Med. 2008 (JUPITER). | 18997196 | Statin therapy reduced events in patients with elevated hs-CRP but normal LDL-C — the trial hs-CRP's "Moderate" grade rests on. |
| Vitamin D | Manson JE, et al. N Engl J Med. 2019 (VITAL). | 30415629 | 25,871 adults randomised to vitamin D3 2000IU/day vs. placebo: no significant reduction in cancer incidence or major CV events over 5 years. |
| Vitamin D | USPSTF Recommendation Statement. JAMA. 2021. | 33847711 | Evidence insufficient to assess benefit/harm of screening asymptomatic adults for vitamin D deficiency (Grade I). |
| Testosterone | Lincoff AM, et al. N Engl J Med. 2023 (TRAVERSE). | 37326322 | Cardiovascular safety of testosterone replacement in men with hypogonadism and pre-existing CV risk — the largest RCT of its kind. |
| Thyroid (TSH) | US Preventive Services Task Force. Ann Intern Med. 2004. | 14734336 | Insufficient evidence to recommend routine thyroid screening in asymptomatic, non-pregnant adults. |
| Ferritin / haemochromatosis | USPSTF Recommendation Statement. Ann Intern Med. 2006. | 16880462 | Recommends against routine genetic screening for hereditary haemochromatosis in asymptomatic adults (Grade D). Note: USPSTF marked this topic "inactive" in 2018 — not superseded by a contradicting statement, simply not re-reviewed since. |
| Omega-3 index | Harris WS, von Schacky C. Prev Med. 2004. | 15208005 | Proposes the omega-3 index itself as a candidate cardiovascular risk marker. |
| Homocysteine | Lonn E, et al. N Engl J Med. 2006. | 16531613 | B-vitamin therapy lowered homocysteine but did not reduce cardiovascular events — the classic "confounded biomarker" case. |
| uACR | Matsushita K, et al. Lancet. 2010. | 20483451 | Albuminuria predicted all-cause and cardiovascular mortality independently of eGFR across 21 cohorts and >1.2 million people. |
| Cystatin C | Shlipak MG, et al. N Engl J Med. 2013. | 24004120 | Cystatin C-based eGFR strengthened the link between kidney function and death, reclassifying many people labelled CKD by creatinine alone. |
| CRP / fibrinogen | Kaptoge S, et al. N Engl J Med. 2012. | 23034020 | Adding CRP or fibrinogen to a conventional cardiovascular risk model produced only a slight improvement in prediction. |
| Lp-PLA2 | Thompson A, et al. Lancet. 2010. | 20435228 | Lp-PLA2 was associated with coronary risk at a magnitude comparable to conventional risk factors, across 32 prospective studies. |
| Food IgG panels | Stapel SO, et al. Allergy. 2008. | 18489614 | EAACI task force: food-specific IgG4 reflects exposure and tolerance, not intolerance — the test is explicitly not recommended. |
| Hepatitis B | Krist AH, et al. (USPSTF) JAMA. 2020. | 33320230 | USPSTF Grade B: screen adolescents and adults at increased risk of hepatitis B, including people born where prevalence is ≥2%. |
| HIV | Owens DK, et al. (USPSTF) JAMA. 2019. | 31184701 | USPSTF Grade A — the strongest classification issued — for HIV screening in everyone aged 15 to 65. |
| H. pylori | Chiang TH, et al. Gut. 2021. | 32792335 | Population-wide H. pylori screen-and-treat reduced both gastric cancer incidence and mortality on the Matsu Islands. |
| Scans & imaging | |||
| CAC score | Detrano R, et al. N Engl J Med. 2008 (MESA). | 18367736 | Coronary artery calcium score predicts coronary events across multiple ethnic groups, independent of traditional risk factors. |
| DEXA (body composition) | Kuk JL, et al. "Visceral fat is an independent predictor of all-cause mortality in men." | 16571861 | Visceral fat, measurable via DEXA, independently predicts all-cause mortality. |
| Carotid ultrasound | USPSTF Recommendation Statement. JAMA. 2021. | 34058106 | Recommends against screening asymptomatic adults for carotid artery stenosis. |
| Chest X-ray | Oken MM, et al. (PLCO) JAMA. 2011. | 22031728 | 154,901 adults randomised to annual chest radiograph or usual care: no reduction in lung cancer mortality at 13 years. |
| Resting ECG | Curry SJ, et al. (USPSTF) JAMA. 2018. | 29896632 | USPSTF Grade D against resting/exercise ECG screening in low-risk asymptomatic adults; Grade I at intermediate or high risk. |
| Thyroid ultrasound | Bibbins-Domingo K, et al. (USPSTF) JAMA. 2017. | 28492905 | USPSTF Grade D against screening for thyroid cancer in asymptomatic adults. |
| Thyroid ultrasound | Ahn HS, et al. N Engl J Med. 2014. | 25372084 | Korea's thyroid cancer diagnoses rose fifteen-fold after ultrasound screening spread, with no change in thyroid cancer mortality. |
| Cancer & disease screening | |||
| FIT / colorectal | Davidson KW, et al. (USPSTF) JAMA. 2021. | 34003218 | USPSTF Grade A for colorectal cancer screening at 50–75 and Grade B at 45–49, with annual FIT an accepted strategy. |
| PSA | Schröder FH, et al. (ERSPC) Lancet. 2014. | 25108889 | ERSPC at 13 years: PSA screening cut prostate cancer mortality, but ~27 extra men had to be diagnosed to prevent one death. |
| PSA | Grossman DC, et al. (USPSTF) JAMA. 2018. | 29801017 | USPSTF Grade C for PSA screening at 55–69 (individual decision) and Grade D at 70 and over. |
| Tumour markers (CA 125) | Menon U, et al. (UKCTOCS) Lancet. 2021. | 33991479 | UKCTOCS randomised 202,638 women to CA 125-based screening: more early-stage disease found, no significant mortality reduction. |
| EBV / nasopharyngeal | Chan KCA, et al. N Engl J Med. 2017. | 28792880 | Plasma EBV DNA screening of 20,174 Hong Kong men detected nasopharyngeal carcinoma earlier, with better progression-free survival. |
| Mammography | Nicholson WK, et al. (USPSTF) JAMA. 2024. | 38687503 | USPSTF Grade B for biennial screening mammography at 40–74, lowering the start age from 50. |
| Tonometry / glaucoma | Mangione CM, et al. (USPSTF) JAMA. 2022. | 35608574 | USPSTF Grade I: insufficient evidence to assess screening asymptomatic adults for primary open-angle glaucoma. |
| Multi-cancer detection | Klein EA, et al. Ann Oncol. 2021. | 34176681 | Multi-cancer early detection showed high specificity but sensitivity that falls sharply in early-stage disease. |
| Multi-cancer detection | Neal RD, et al. Cancers. 2022. | 36230741 | Design paper for NHS-Galleri, the randomised trial built to test whether multi-cancer early detection reduces mortality. |
| Emerging & overhyped | |||
| APOE genotyping | Mayeux R, et al. N Engl J Med. 1998. | 9468467 | APOE genotype's predictive value for Alzheimer's risk is population-level, not reliable for individual prognosis. |
| Gut microbiome testing | Porcari S, et al. (international consensus statement). Lancet Gastroenterol Hepatol. 2024. | 39647502 | Expert panel concludes evidence for clinical utility of commercial microbiome testing remains scarce; calls for standardised reporting. |
| Epigenetic clocks | "From population science to the clinic? Limits of epigenetic clocks as personal biomarkers." Epigenomics. 2025. | 41403206 | Technical and biological limitations mean epigenetic clocks are not yet fit for individual-level clinical decisions, even though they work at a population level. |
| Bundled/package panels | Krogsbøll LT, et al. Cochrane Database Syst Rev. 2019. | 30699470 | 15 RCTs, 250,000+ participants: general health checks in adults do not reduce all-cause, cardiovascular, or cancer mortality. |
| VO2 max | Mandsager K, et al. JAMA Netw Open. 2018. | 30646252 | Across 122,007 patients, cardiorespiratory fitness was inversely associated with mortality with no observed ceiling of benefit. |
| Grip strength | Leong DP, et al. (PURE) Lancet. 2015. | 25982160 | In 139,691 adults across 17 countries, each 5 kg drop in grip strength predicted higher mortality — more strongly than systolic blood pressure. |
| CGM (non-diabetic) | Cichosz SL, et al. Diabetes Technol Ther. 2025. | 39115921 | Glycemic variability indices from CGM separate healthy, prediabetic and type 2 diabetic groups — a real signal, not an outcome trial. |
| Interventions | |||
| DASH diet | Sacks FM, et al. Effects on blood pressure of reduced dietary sodium and the DASH diet. N Engl J Med 2001. | 11136953 | The original randomised trial in 459 adults found the fruit-and-vegetable-rich, low-fat dairy combination lowered systolic pressure by 5.5 mmHg overall and by 11.4 mmHg in those with hypertension, rivalling a starting blood-pressure tablet… |
| Fish intake | Mozaffarian D, Rimm EB. Fish intake, contaminants, and human health: evaluating the risks and the benefits. JAMA 2006. | 17047219 | A JAMA review weighing decades of evidence concluded that modest fish intake of one to two servings a week, particularly oily species, is associated with a 36 percent lower risk of coronary death and 17 percent lower total mortality, and… |
| Curcumin | Anand P et al., Mol Pharm, 2007 (curcumin bioavailability: problems and promises) | 17999464 | A landmark pharmacology review documents how poorly standard curcumin dissolves and gets absorbed, which is why enhanced formulations now fill the market. |
| DASH diet | Fung TT, et al. Adherence to a DASH-style diet and risk of coronary heart disease and stroke in women. Arch Intern Med 2008. | 18413553 | The original randomised trial in 459 adults found the fruit-and-vegetable-rich, low-fat dairy combination lowered systolic pressure by 5.5 mmHg overall and by 11.4 mmHg in those with hypertension, rivalling a starting blood-pressure tablet… |
| Sleeping 7–9 hours | Cappuccio FP, et al. Sleep duration and all-cause mortality: a systematic review and meta-analysis of prospective studies. Sleep. 2010;33:585–592. | 20469800 | A systematic review and meta-analysis of prospective cohorts (over 1.3 million participants) found short sleep, under about seven hours, carried a 12% higher all-cause mortality risk, with the pooled curve bottoming out at seven hours or a… |
| Stretching & mobility work | Herbert RD, et al. Stretching to prevent or reduce muscle soreness after exercise. Cochrane Database Syst Rev. 2011;(7):CD004577. | 21735398 | The Cochrane review of stretching trials found stretching before or after exercise produces small or no reductions in muscle soreness, with similar unimpressive results for injury prevention. |
| Grounding (earthing) | Chevalier G et al., J Environ Public Health, 2012 (earthing review) | 22291721 | The published base is thin. |
| Daily multivitamin | Gaziano JM, et al. Multivitamins in the prevention of cancer in men: the Physicians' Health Study II randomized controlled trial. JAMA. 2012;308:1871–1880. | 23162860 | The COSMOS-Mind trial reported multivitamin use slowed cognitive decline modestly over three years in older adults, a finding needing replication before it changes practice. |
| Mediterranean diet | Estruch R, et al. Primary prevention of cardiovascular disease with a Mediterranean diet. N Engl J Med. 2013;368:1279–1290. | 23432189 | The PREDIMED trial randomised about 7,400 people at high cardiovascular risk to a Mediterranean diet plus extra-virgin olive oil, the same diet plus nuts, or general low-fat advice. |
| Ashwagandha | Chandrasekhar K et al., Indian J Psychol Med, 2012 (RCT, stress) | 23439798 | Three separate placebo-controlled trials anchor the grade. |
| Berberine | Dong H et al., Planta Med, 2013 (SR/MA, berberine and blood lipids) | 23512497 | Meta-analyses covering dozens of small trials find real drops in HbA1c (a three-month average of blood sugar control), LDL cholesterol and triglycerides, mostly in people with type 2 diabetes or metabolic syndrome. |
| Sodium (salt) reduction | Aburto NJ, et al. Effect of lower sodium intake on health: systematic review and meta-analyses. BMJ 2013. | 23558163 | The hardest evidence is a randomised trial of about 21,000 older adults in rural China in which replacing ordinary salt with a potassium-enriched substitute cut strokes by 14 percent and premature deaths by 12 percent (Neal et al., NEJM… |
| Hydrogen-rich water | Song G et al., J Lipid Res, 2013 (RCT, hydrogen-rich water and lipids) | 23610159 | Bench science shows molecular hydrogen can neutralise certain harmful radicals, and a 2025 review maps dozens of small human trials across metabolic, liver and exercise settings. |
| Walking after meals | DiPietro et al., Diabetes Care 2013; three 15-min postmeal walks improved 24-h glycemic control (PMID 23761134) | 23761134 | The cleanest trial here is small. |
| Nut consumption | Bao Y, et al. Association of nut consumption with total and cause-specific mortality. N Engl J Med 2013. | 24256379 | Thirty years of follow-up in about 119,000 US health professionals found those eating nuts seven or more times a week had 20 percent lower all-cause mortality than those who never ate them, and nut eaters were actually leaner despite the… |
| Red-light therapy | Wunsch A, Matuschka K. A controlled trial to determine the efficacy of red and near-infrared light treatment in patient satisfaction, reduction of fine lines, wrinkles and skin roughness over time. Photomed Laser Surg. 2014;32:93–100. | 24286286 | A controlled trial of red and near-infrared light found measurable improvement in skin roughness and wrinkle ratings versus sham over 30 sessions, supporting the narrow cosmetic claim. |
| Plant-based diet | Yokoyama Y, et al. Vegetarian diets and blood pressure: a meta-analysis. JAMA Intern Med 2014. | 24566947 | A meta-analysis of 39 observational studies and clinical trials found vegetarian patterns associated with systolic pressure about 5 mmHg lower than omnivorous comparison groups (Yokoyama et al., JAMA Intern Med 2014). |
| N-acetylcysteine (NAC) | Zheng JP et al., Lancet Respir Med, 2014 (PANTHEON randomised trial, COPD) | 24621680 | The strongest human evidence lives in lung medicine. |
| Yoga | Cramer et al., American Journal of Hypertension 2014; systematic review and meta-analysis of yoga for hypertension (PMID 24795403) | 24795403 | Start with blood pressure, the best-studied endpoint here. |
| Exercise for brain health | Blondell et al., BMC Public Health 2014; systematic review and meta-analysis of prospective studies on physical activity, cognitive decline and dementia (PMID 24885250) | 24885250 | A meta-analysis of 47 prospective cohorts compared highly active adults with low-activity peers. |
| Sauna bathing | Laukkanen T, et al. Association between sauna bathing and fatal cardiovascular and all-cause mortality events. JAMA Intern Med. 2015;175:542–548. | 25705824 | The main evidence comes from the Kuopio Ischaemic Heart Disease cohort of middle-aged Finnish men, where men taking 4–7 sessions a week had substantially lower cardiovascular and all-cause mortality over two decades of follow-up than… |
| Grounding (earthing) | Oschman JL et al., J Inflamm Res, 2015 (review of grounding studies) | 25848315 | The published base is thin. |
| High-intensity interval training (HIIT) | Milanović Z, et al. Effectiveness of High-Intensity Interval Training (HIT) and Continuous Endurance Training for VO2max Improvements: A Systematic Review and Meta-Analysis. Sports Med. 2015;45:1469–1481. | 26243014 | A meta-analysis of 27 trials comparing HIIT with continuous endurance training found VO2max improved more with intervals for the same amount of total work. |
| Plant-based diet | Dinu M, et al. Vegetarian, vegan diets and multiple health outcomes: a systematic review with meta-analysis of observational studies. Crit Rev Food Sci Nutr 2017. | 26853923 | A meta-analysis of 39 observational studies and clinical trials found vegetarian patterns associated with systolic pressure about 5 mmHg lower than omnivorous comparison groups (Yokoyama et al., JAMA Intern Med 2014). |
| Collagen peptides | Shaw G, et al. Vitamin C-enriched gelatin supplementation before intermittent activity augments collagen synthesis. Am J Clin Nutr. 2017;105:136–143. | 27852613 | The trial most often cited by collagen sellers (Shaw et al.) showed raised circulating markers of collagen synthesis after vitamin-C-fortified gelatin taken before exercise. |
| Plant-based diet | Melina V, Craig W, Levin S. Position of the Academy of Nutrition and Dietetics: Vegetarian Diets. J Acad Nutr Diet 2016. | 27886704 | A meta-analysis of 39 observational studies and clinical trials found vegetarian patterns associated with systolic pressure about 5 mmHg lower than omnivorous comparison groups (Yokoyama et al., JAMA Intern Med 2014). |
| Cycling to work | Oja et al., British Journal of Sports Medicine 2017; specific sports and mortality, cohort of 80,306 British adults (PMID 27895075) | 27895075 | In the UK Biobank, 263,450 middle-aged adults reported how they travelled to work and were followed for around five years. |
| Cycling to work | Celis-Morales et al., BMJ 2017; active commuting and incident cardiovascular disease, cancer, and mortality, prospective cohort (PMID 28424154) | 28424154 | In the UK Biobank, 263,450 middle-aged adults reported how they travelled to work and were followed for around five years. |
| Creatine monohydrate | Kreider RB, et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. J Int Soc Sports Nutr. 2017;14:18. | 28615996 | The International Society of Sports Nutrition's position stand reviews hundreds of trials: creatine monohydrate at about 3–5 g a day reliably increases muscle phosphocreatine, training output and lean mass, with an extensive safety record… |
| Coffee intake | Gunter MJ, et al. Coffee Drinking and Mortality in 10 European Countries. Ann Intern Med 2017. | 28693038 | An umbrella review in the BMJ covering more than 200 meta-analyses found consumption of three to four cups a day carried the lowest observed risks for all-cause mortality and cardiovascular disease, with the clearest exception being… |
| Adequate protein intake | Morton RW, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength. Br J Sports Med. 2018;52:376–384. | 28698222 | A 2018 systematic review and meta-regression (26 trials, over 800 participants) found that added protein improved strength and lean mass gains from resistance training, with the effect strongest in trained adults and tapering with age. |
| Resveratrol | Berman AY, et al. The therapeutic potential of resveratrol: a review of clinical trials. NPJ Precis Oncol. 2017;1:35. | 28989978 | A review of completed resveratrol clinical trials found effects concentrated in small studies of inflammatory markers and endothelial function, inconsistent across doses and populations, with no trial showing reduced cardiovascular events,… |
| Coffee intake | Poole R, et al. Coffee consumption and health: umbrella review of meta-analyses of multiple health outcomes. BMJ 2017. | 29167102 | An umbrella review in the BMJ covering more than 200 meta-analyses found consumption of three to four cups a day carried the lowest observed risks for all-cause mortality and cardiovascular disease, with the clearest exception being… |
| Fish intake | Jayedi A, et al. Fish consumption and risk of all-cause and cardiovascular mortality: a dose-response meta-analysis. Public Health Nutr 2018. | 29317009 | A JAMA review weighing decades of evidence concluded that modest fish intake of one to two servings a week, particularly oily species, is associated with a 36 percent lower risk of coronary death and 17 percent lower total mortality, and… |
| Caloric restriction | Redman LM, et al. Metabolic Slowing and Reduced Oxidative Damage with Sustained Caloric Restriction. Cell Metab 2018. | 29576535 | CALERIE, a multicentre randomised controlled trial in 218 healthy adults of normal to slightly raised weight, asked volunteers to cut 25 percent of energy intake and achieved a sustained 12 percent, which brought meaningful weight loss… |
| Drinking less alcohol | Wood AM, et al. Risk thresholds for alcohol consumption: combined analysis of individual-participant data for 599 912 current drinkers in 83 prospective studies. Lancet. 2018;391:1513–1523. | 29676281 | A combined analysis of individual data from 83 prospective studies and close to 600,000 current drinkers found risk of stroke, coronary disease (outside light drinking), fatal hypertensive disease and several cancers rising monotonically… |
| Nut consumption | Estruch R, et al. Primary Prevention of Cardiovascular Disease with a Mediterranean Diet Supplemented with Extra-Virgin Olive Oil or Nuts. N Engl J Med 2018. | 29897866 | Thirty years of follow-up in about 119,000 US health professionals found those eating nuts seven or more times a week had 20 percent lower all-cause mortality than those who never ate them, and nut eaters were actually leaner despite the… |
| Coffee intake | Loftfield E, et al. Association of Coffee Drinking With Mortality by Genetic Variation in Caffeine Metabolism: Findings From the UK Biobank. JAMA Intern Med 2018. | 29971434 | An umbrella review in the BMJ covering more than 200 meta-analyses found consumption of three to four cups a day carried the lowest observed risks for all-cause mortality and cardiovascular disease, with the clearest exception being… |
| Omega-3 supplements (fish oil) | Manson JE, et al. Marine n-3 Fatty Acids and Prevention of Cardiovascular Disease and Cancer. N Engl J Med. 2019;380:23–32. | 30415637 | VITAL randomised 25,871 adults to 1 g a day of marine omega-3 or placebo and found no significant reduction in major cardiovascular events or cancer. |
| Fibre intake | Reynolds A, et al. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. The Lancet 2019. | 30638909 | A 2019 series of systematic reviews in The Lancet pooled 185 prospective studies and dozens of controlled trials and found 15 to 30 percent lower rates of death from any cause, coronary heart disease, type 2 diabetes and colorectal cancer… |
| Balance training | Sherrington et al., Cochrane Database of Systematic Reviews 2019; exercise for preventing falls in older people living in the community (PMID 30703272) | 30703272 | A Cochrane review pooled 108 randomised trials covering 23,407 community-dwelling adults. |
| Caloric restriction | Kraus WE, et al. 2 years of calorie restriction and cardiometabolic risk (CALERIE): exploratory outcomes of a randomised controlled trial. Lancet Diabetes Endocrinol 2019. | 31303390 | CALERIE, a multicentre randomised controlled trial in 218 healthy adults of normal to slightly raised weight, asked volunteers to cut 25 percent of energy intake and achieved a sustained 12 percent, which brought meaningful weight loss… |
| Ashwagandha | Lopresti AL et al., Medicine (Baltimore), 2019 (RCT, stress) | 31517876 | Three separate placebo-controlled trials anchor the grade. |
| Exercise for brain health | Livingston et al., Lancet 2020; Dementia prevention, intervention, and care: 2020 report of the Lancet Commission (PMID 32738937) | 32738937 | A meta-analysis of 47 prospective cohorts compared highly active adults with low-activity peers. |
| Ashwagandha | Langade D et al., J Ethnopharmacol, 2021 (RCT, sleep) | 32818573 | Three separate placebo-controlled trials anchor the grade. |
| Omega-3 supplements (fish oil) | Nicholls SJ, et al. Effect of High-Dose Omega-3 Fatty Acids vs Corn Oil on Major Adverse Cardiovascular Events: The STRENGTH Randomized Clinical Trial. JAMA. 2020;324:2268–2280. | 33190147 | VITAL randomised 25,871 adults to 1 g a day of marine omega-3 or placebo and found no significant reduction in major cardiovascular events or cancer. |
| Zone 2 cardio | Bull FC, et al. World Health Organization 2020 guidelines on physical activity and sedentary behaviour. Br J Sports Med. 2020;54:1451–1462. | 33239350 | The WHO 2020 guidelines on physical activity grade the link between regular moderate-intensity aerobic activity and lower all-cause mortality, cardiovascular disease, type 2 diabetes and depression at the highest confidence level, drawing… |
| Whole-body electrical stimulation (EMS) | Teschler M, et al. Four weeks of electromyostimulation improves muscle function and strength in sarcopenic patients: a three-arm parallel randomized trial. J Cachexia Sarcopenia Muscle. 2021;12(4):843–854. | 34105256 | A three-arm randomised trial found four weeks of electromyostimulation improved muscle function and strength in sarcopenic patients, supporting its use where conventional training is hard to access. |
| Sodium (salt) reduction | Neal B, et al. Effect of Salt Substitution on Cardiovascular Events and Death. N Engl J Med 2021. | 34459569 | The hardest evidence is a randomised trial of about 21,000 older adults in rural China in which replacing ordinary salt with a potassium-enriched substitute cut strokes by 14 percent and premature deaths by 12 percent (Neal et al., NEJM… |
| Berberine | Guo J et al., Oxid Med Cell Longev, 2021 (SR/MA, berberine in type 2 diabetes) | 34956436 | Meta-analyses covering dozens of small trials find real drops in HbA1c (a three-month average of blood sugar control), LDL cholesterol and triglycerides, mostly in people with type 2 diabetes or metabolic syndrome. |
| Walking after meals | Buffey et al., Sports Medicine 2022; meta-analysis, light-intensity walking breaks attenuate postprandial glucose and insulin (PMID 35147898) | 35147898 | The cleanest trial here is small. |
| Resistance training | Momma H, et al. Muscle-strengthening activities are associated with lower risk and mortality in major non-communicable diseases: a systematic review and meta-analysis of cohort studies. Br J Sports Med. 2022;56:755–763. | 35228201 | A 2022 systematic review of prospective cohorts found 30–60 minutes a week of muscle-strengthening activity was associated with a 10–20% lower risk of all-cause mortality, cardiovascular disease, cancer and diabetes, with the curve… |
| Daily step count | Paluch AE, et al. Daily steps and all-cause mortality: a meta-analysis of 15 international cohorts. Lancet Public Health. 2022;7:e219–e228. | 35247352 | A 2022 meta-analysis pooling 15 international cohorts (about 47,000 adults) found progressively lower all-cause mortality with more steps, with the benefit levelling off between 6,000 and 8,000 steps a day for adults 60+ and between 8,000… |
| Time-restricted eating | Liu D, et al. Calorie Restriction with or without Time-Restricted Eating in Weight Loss. N Engl J Med. 2022;386:1495–1504. | 35443107 | A one-year randomised trial in 139 adults with obesity compared time-restricted eating with everyday calorie counting and found no significant difference in weight loss, waist circumference or metabolic markers. |
| Cold-water immersion | Azevedo KP, et al. Different Cryotherapy Modalities Demonstrate Similar Effects on Muscle Performance, Soreness, and Damage in Healthy Individuals and Athletes: A Systematic Review and Meta-analysis. J Clin Med. 2022;11(15):4441. | 35956058 | A 2022 systematic review comparing cold-water immersion, ice massage and other cryotherapy modalities found similar small effects on soreness and perceived recovery across methods, with low-quality trials and short follow-up throughout. |
| Daily multivitamin | Baker LD, et al. Effects of cocoa extract and a multivitamin on cognitive function: A randomized clinical trial (COSMOS-Mind). Alzheimers Dement. 2023;19:1308–1319. | 36102337 | The COSMOS-Mind trial reported multivitamin use slowed cognitive decline modestly over three years in older adults, a finding needing replication before it changes practice. |
| Balance training | Montero-Odasso et al., Age and Ageing 2022; World guidelines for falls prevention and management for older adults (PMID 36178003) | 36178003 | A Cochrane review pooled 108 randomised trials covering 23,407 community-dwelling adults. |
| Vibration plate training (whole-body vibration) | de Oliveira RDJ et al., Osteoporos Int, 2023 (SR/MA, WBV and bone density in postmenopausal women) | 36282343 | A 2023 meta-analysis of randomised trials in postmenopausal women found small improvements in bone density under whole-body vibration. |
| N-acetylcysteine (NAC) | Huang C et al., Ther Adv Respir Dis, 2023 (meta-analysis, NAC in COPD) | 36927162 | The strongest human evidence lives in lung medicine. |
| Vibration plate training (whole-body vibration) | Tan X et al., Arch Phys Med Rehabil, 2023 (SR/MA, WBV strength and performance in older adults) | 37169245 | A 2023 meta-analysis of randomised trials in postmenopausal women found small improvements in bone density under whole-body vibration. |
| Taurine | Singh P et al., Science, 2023 (taurine deficiency as a driver of aging) | 37289866 | The 2023 Science paper tracked taurine decline across species, then found supplementation lengthened life in middle-aged mice and improved monkey health markers. |
| Sleep consistency | Windred DP, et al. Sleep regularity is a stronger Predictor of mortality risk than sleep duration: A prospective cohort study. Sleep. 2024;47(1):zsad253. | 37738616 | In a prospective UK Biobank analysis of about 88,000 adults wearing accelerometers, sleep regularity predicted mortality more strongly than duration did, with the most irregular quintile at substantially raised risk across cardiovascular… |
| Cutting ultra-processed food | Lane MM, et al. Ultra-processed food exposure and adverse health outcomes: umbrella review of epidemiological meta-analyses. BMJ. 2024;384:e077310. | 38418082 | A 2024 BMJ umbrella review pooled the epidemiological meta-analyses: ultra-processed exposure was associated with higher risks of all-cause mortality, cardiovascular disease, type 2 diabetes, obesity and depression, with no outcome… |
| NMN / NR (NAD+ boosters) | Chen F, et al. Effects of Nicotinamide Mononucleotide on Glucose and Lipid Metabolism in Adults: A Systematic Review and Meta-analysis of Randomised Controlled Trials. Curr Diab Rep. 2025;25(1):4. | 39531138 | A 2024 systematic review of randomised trials found NMN produced modest improvements in insulin sensitivity and lipid measures in some small studies, with heterogeneous designs, short durations and no hard endpoints anywhere. |
| Hyperbaric oxygen therapy | Fisher SM, et al. Hyperbaric Oxygen Therapy in Aesthetic Medicine and Anti-Aging: A Systematic Review. Aesthetic Plast Surg. 2025;49(9):2534–2544. | 39733047 | A 2025 systematic review of HBOT in aesthetic medicine and anti-aging concluded that while the therapy may prove useful, the evidence to support its use and justify its cost is limited, calling for large standardised randomised trials. |
| Massage therapy | Rizzo RR et al., Cochrane Database Syst Rev, 2025 (overview: non-drug treatments for low back pain) | 40139265 | A 2025 overview of Cochrane reviews counts massage among the hands-on options with small short-term gains in low back pain, with benefits shrinking over following months. |
| Hydrogen-rich water | Jin J et al., MedComm, 2025 (review: molecular hydrogen therapy) | 40297245 | Bench science shows molecular hydrogen can neutralise certain harmful radicals, and a 2025 review maps dozens of small human trials across metabolic, liver and exercise settings. |
| Yoga | Geiger et al., PLOS ONE 2025; updated systematic review and meta-analysis of yoga for arterial hypertension (PMID 40367243) | 40367243 | Start with blood pressure, the best-studied endpoint here. |
| Berberine | Liu D et al., Front Pharmacol, 2025 (SR/MA, berberine in metabolic syndrome) | 40740996 | Meta-analyses covering dozens of small trials find real drops in HbA1c (a three-month average of blood sugar control), LDL cholesterol and triglycerides, mostly in people with type 2 diabetes or metabolic syndrome. |
| Compression therapy (pneumatic boots) | Canez MS et al., J Bodyw Mov Ther, 2025 (systematic review w/ MA, pneumatic compression for muscle recovery) | 40954632 | A 2025 systematic review with meta-analysis finds intermittent pneumatic compression gives small, inconsistent relief of post-exercise soreness versus resting, with little clear carry-over to next-day performance. |
| Magnesium supplements | Argeros Z, et al. Magnesium Supplementation and Blood Pressure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Hypertension. 2025;82(11):1844–1856. | 41000008 | A 2025 meta-analysis of randomised controlled trials in Hypertension mapped magnesium supplementation to small systolic and diastolic blood-pressure reductions, examined across doses and durations. |
| Curcumin | Bahari H et al., Inflammopharmacology, 2025 (SR/MA, curcumin and inflammatory markers) | 41240262 | A landmark pharmacology review documents how poorly standard curcumin dissolves and gets absorbed, which is why enhanced formulations now fill the market. |
| Taurine | Nie Z et al., Nutr Rev, 2025 (meta-analysis of oral taurine RCTs) | 41275513 | The 2023 Science paper tracked taurine decline across species, then found supplementation lengthened life in middle-aged mice and improved monkey health markers. |
| Compression therapy (pneumatic boots) | Phung H et al., EClinicalMedicine, 2026 (network MA, compression systems for venous leg ulcers) | 42518940 | A 2025 systematic review with meta-analysis finds intermittent pneumatic compression gives small, inconsistent relief of post-exercise soreness versus resting, with little clear carry-over to next-day performance. |
| DASH diet | Appel LJ, et al. A clinical trial of the effects of dietary patterns on blood pressure. N Engl J Med 1997. | 9099655 | The original randomised trial in 459 adults found the fruit-and-vegetable-rich, low-fat dairy combination lowered systolic pressure by 5.5 mmHg overall and by 11.4 mmHg in those with hypertension, rivalling a starting blood-pressure tablet… |
| Ketogenic (very low-carb) diet | Yancy WS, et al. Ann Intern Med. 2004;140:769–777. | 15148063 | A low-carbohydrate ketogenic diet produced greater weight loss at 6 months than a low-fat diet in adults with obesity; the difference narrowed by 12 months. |
| Ketogenic (very low-carb) diet | Parry-Strong A, et al. Diabetes Obes Metab. 2022;24:2431–2442. | 36064937 | Meta-analysis of randomised trials: very-low-carbohydrate (ketogenic) diets improved HbA1c and triglycerides in type 2 diabetes at 6–12 months, with greater early weight loss. |
| Ketogenic (very low-carb) diet | Seidelmann SB, et al. Lancet Public Health. 2018;3:e419–e428. | 30122560 | U-shaped association: both very low and very high carbohydrate intake were linked to higher all-cause mortality; lowest-carbohydrate diets with animal-based fat/protein carried the highest risk. |
| Cited in the cost articles | |||
| Vitamin D | USPSTF Recommendation Statement. Ann Intern Med. 2014. | 25419853 | Same "insufficient evidence" verdict as the 2021 update, reached independently 7 years earlier. |
| Multi-cancer early detection | Lennon AM, Buchanan AH, Rego SP Cancer Prev Res (Phila). 2024. | 38705577 | DETECT-A, the first large prospective interventional study of a multi-cancer early detection blood test, reports the outcomes after a positive result in asymptomatic people - the first real data on the follow-up cascade such a test sets off. |
| Overdiagnosis | Jung M Curr Probl Cancer. 2017. | 28104314 | Review of overdiagnosis across breast, prostate and thyroid cancer screening: some abnormalities detected by screening would never have caused harm, which is harm caused by screening itself. |
| Overdiagnosis | Marcondes FO, Armstrong K Ann Intern Med. 2022. | 35226534 | Reducing the burden of overdiagnosis in breast cancer screening and beyond: the scale of overdiagnosis and the paths to reducing it. |
| Screening ethics | Yong SEF, Wong ML, Voo TC BMC Med Ethics. 2022. | 35672820 | Peer-reviewed Singapore analysis arguing that health screening packages are not always beneficial for people without symptoms - the closest published statement of this site's thesis, from Singapore. |
This list covers the study or guideline statement anchoring each test's grade, not every source consulted — several test cards cite the same landmark study (e.g. the CAC and DEXA PMIDs each appear on two pages: their own evidence card and the matching long-tail article). Counted once per unique PMID, 19 distinct studies/statements are cited live across the site as of August 2026.
Limitations of this review
- This is a narrative evidence review conducted by one author with AI assistance, not a formally registered systematic review (no PROSPERO registration, no dual independent screening, no formal risk-of-bias scoring per study). Grades reflect a structured but qualitative synthesis of major trials, cohorts, and guideline positions per test — treat them as a starting point for discussion with a clinician, not as a substitute for a full guideline panel's work.
- Evidence changes. A grade here reflects the literature as reviewed in August 2026; several areas (Lp(a)-lowering therapies, epigenetic clock validation, GLP-1-era metabolic risk markers) are moving quickly and may re-grade within a year or two.
- Grades are population-level judgements. An individual patient's history, symptoms, and family history can make a "Weak" test appropriate for them specifically — that determination requires a clinician, not this website.
Independence
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