Supplements for longevity: what the evidence supports

The short list with human trial evidence behind it, the ones with mechanism but no outcome data, and what the large randomized trials of the popular ones actually found.

Key takeaways

Very few supplements have randomized human outcome data. Omega-3 and vitamin D have the largest trials, and their results were more modest than the marketing that preceded them.
VITAL randomized 25,871 adults to omega-3 and vitamin D and found no reduction in the primary cancer or cardiovascular endpoints, with a signal for lower myocardial infarction in the omega-3 arm.
Creatine has the strongest evidence of any supplement in this category for muscle mass and strength alongside resistance training, and it is inexpensive.
NAD+ precursors, resveratrol, urolithin A and most senotherapeutics have mechanism and surrogate markers, not outcome data.
Protein intake, fiber and omega-3 status are dietary questions first. A supplement is the answer only when the diet is not covering it.

Longevity supplements divide into three groups: things with randomized human outcome data, things with mechanism and surrogate markers, and things with neither.

Most of the category sits in the second group. Knowing which group a bottle belongs to is most of the decision.

Three tiers, and why the tier matters more than the ingredient

It is useful to sort anything in this category into one of three tiers before considering price. Tier one has randomized human trials measuring outcomes people care about. Tier two has plausible mechanism and movement in a surrogate marker such as a blood level or a biomarker. Tier three has cell or animal work and a good story.

Almost every product marketed for longevity is tier two or tier three. That does not make them worthless. It does mean the honest expectation is different, and the price should reflect that.

What the large trials found

VITAL randomized 25,871 adults to marine omega-3, vitamin D3, both or neither for a median of 5.3 years. Neither reduced the primary endpoints of invasive cancer or major cardiovascular events. A secondary analysis found fewer myocardial infarctions in the omega-3 group, and later analyses reported a reduction in autoimmune disease incidence in the vitamin D group.

DO-HEALTH randomized 2,157 adults aged 70 and over to omega-3, vitamin D and a home exercise program in combination. None of the three interventions improved the co-primary endpoints of blood pressure, physical function, cognition or infection rate over three years, and later fracture analyses were also null.

D2d randomized 2,423 adults with prediabetes to 4,000 IU of vitamin D3 daily and found no significant reduction in progression to diabetes overall, in a population that was largely vitamin D sufficient at entry.

The pattern across all three is worth sitting with: correcting a deficiency is valuable, and supplementing an already sufficient person mostly is not.

The short list that holds up

Vitamin D, when a measured 25-hydroxyvitamin D level is low. Dose to the level, not to a fixed number on a bottle.
Omega-3, when dietary intake of oily fish is low or an omega-3 index is low. EPA and DHA content is what matters, not the size of the capsule.
Creatine monohydrate, roughly 3 to 5 g daily, alongside resistance training. Decades of trials support the effect on lean mass and strength, and it is one of the most studied supplements in existence.
Magnesium, when intake is low. Glycinate and citrate are better tolerated than oxide, which is poorly absorbed.
Protein sufficient to support training, from food where possible. Powder is a convenience, not a category of its own.
Fiber, where the diet is short. This has more downstream effect on lipids and glycemic control than most of the exotic options.

The tier two group, described accurately

NAD+ precursors such as nicotinamide riboside and nicotinamide mononucleotide reliably raise blood NAD+ in randomized trials. What has not been demonstrated is that raising blood NAD+ produces a measurable clinical benefit in healthy adults. Trials so far have been small and short, with mixed results on surrogate endpoints.

Resveratrol has repeatedly failed to reproduce the effects seen in early model organism work once studied in humans. Urolithin A and spermidine have interesting mechanistic data and small early trials. Taurine drew attention from a 2023 Science paper in mice and monkeys with supporting human association data, and no human outcome trial behind it.

None of this is a reason to dismiss the tier. Early evidence is how good things start. It is a reason to treat these as optional rather than foundational, and to keep expectations matched to the stage of the research.

How we approach it in a program

We recommend lab work first, because supplement choices are much better informed by a panel, and where you choose to have one the review happens after results come back. A low omega-3 index or a low vitamin D level answers its own question. A normal result means the money is better spent elsewhere.

We also review what to remove. Long stacks accumulate by addition and rarely get pruned, and the items that never earned their place are usually the expensive ones.

What this means for you

Cover the measured gaps first, add creatine if you train, and treat the rest of the category as optional and still being studied. The useful question about any product is which tier its evidence sits in.

Therapies discussed here

References

Manson JE, et al., vitamin D supplements and prevention of cancer and cardiovascular disease (VITAL), New England Journal of Medicine, 2019
Manson JE, et al., marine n-3 fatty acids and prevention of cardiovascular disease and cancer (VITAL), New England Journal of Medicine, 2019
Bischoff-Ferrari HA, et al., effect of vitamin D, omega-3 and exercise on functional outcomes in older adults (DO-HEALTH), JAMA, 2020
Pittas AG, et al., vitamin D supplementation and prevention of type 2 diabetes (D2d), New England Journal of Medicine, 2019
Kreider RB, et al., International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation, Journal of the International Society of Sports Nutrition, 2017
Martens CR, et al., chronic nicotinamide riboside supplementation is well tolerated and elevates NAD+ in healthy middle-aged and older adults, Nature Communications, 2018