In this article
The short answer: For most healthy adults, the strongest trials of popular longevity supplements have been neutral. In VITAL, a randomized trial of 25,871 adults, neither vitamin D nor marine omega-3s lowered the risk of major cardiovascular events or cancer over a median of 5.3 years (Manson et al., 2019a; 2019b). The US Preventive Services Task Force found the evidence insufficient for multivitamins and recommends against beta-carotene and vitamin E for preventing heart disease or cancer (Mangione et al., 2022). NAD+ precursors raise blood NAD+ levels, but that is not the same as a longer or healthier life. This is general information, not medical advice; talk with a clinician about anything you take.
Jump to key takeawaysWhat Counts as Evidence That a Supplement Helps You Live Longer?
A change in a biomarker is the weakest rung, a randomized trial of real health outcomes is the strongest. Many longevity supplements sit on the bottom rung: they move a number in a blood test or a mouse, but nobody has shown in people that this translates into fewer heart attacks, fewer cancers, or more years in good health.
Evidence ladder, weakest to strongest
1. Cell and animal studies
Shows a mechanism is possible. Often does not carry over to people.
2. Biomarker changes in small human trials
Shows the supplement does something measurable, such as raising a blood level.
3. Observational studies
Supplement users often differ in many other ways, so cause is hard to separate from lifestyle.
4. Large randomized trials of health outcomes
The best test of whether people actually do better, as in VITAL.
This is the same reasoning behind how much of aging is reversible: a favorable marker is a reason to keep studying, not proof of benefit.
What Did the Large Trials of Vitamin D and Omega-3s Find?
In healthy adults, they found no clear benefit on the main outcomes. VITAL randomized 25,871 men aged 50 and older and women aged 55 and older, in a two-by-two design, to vitamin D3 (2,000 IU a day) or placebo and to marine omega-3 fatty acids (1 g a day) or placebo. Vitamin D did not lower cancer incidence or major cardiovascular events over a median follow-up of 5.3 years (Manson et al., 2019a). Omega-3s did not significantly lower major cardiovascular events or cancer either (Manson et al., 2019b).
Vitamin D3
No significant reduction in cancer or major cardiovascular events in the primary analysis (Manson et al., 2019a).
Marine omega-3s
No significant reduction in the primary outcomes; some secondary signals were exploratory and may reflect chance (Manson et al., 2019b).
Caveat: these were healthy adults
VITAL tested prevention in people without existing heart disease or cancer. It does not tell you what happens if you have a documented deficiency or a diagnosed condition. If a blood test shows low vitamin D, or a clinician has advised a supplement, that is a different situation.
Your own intake and blood levels are worth understanding first. See what your omega-3 index tells you before assuming a capsule is the answer.
Do Multivitamins and Antioxidant Pills Help?
The honest answer is that the evidence does not show clear benefit for preventing heart disease or cancer, and for two ingredients it points the other way. The US Preventive Services Task Force concluded the evidence is insufficient to judge the balance of benefit and harm for multivitamins and for most single or paired nutrients, and it recommends against beta-carotene and vitamin E supplements for preventing cardiovascular disease or cancer (Mangione et al., 2022). The statement applies to community-dwelling, nonpregnant adults.
Multivitamins
Insufficient evidence either way for preventing heart disease or cancer (Mangione et al., 2022).
Beta-carotene
The Task Force recommends against it for prevention, citing harms that outweigh benefits (Mangione et al., 2022).
Vitamin E
The Task Force recommends against it for prevention, finding no net benefit (Mangione et al., 2022).
What About NAD+ Precursors Like Nicotinamide Riboside?
They reliably raise NAD+ in the blood, but whether that helps healthspan is unproven. In a randomized, double-blind, placebo-controlled crossover trial in healthy middle-aged and older adults, six weeks of nicotinamide riboside (500 mg twice a day) was well tolerated and raised NAD+ levels (Martens et al., 2018). The authors described blood pressure and arterial stiffness findings as preliminary. A short trial with a biomarker as its main result sits on the second rung of the ladder, not the fourth.
Common misconception
"It raises NAD+, so it slows aging" is an inference, not a finding. NAD+ falls with age in some tissues, but restoring a level does not by itself show people live longer or stay healthier. Read more on how NAD+ declines with age.
What Should You Do Before Buying a Longevity Supplement?
Spend effort on the habits with the strongest evidence first, and treat supplements as an add-on for a specific reason. Use this order as a heuristic, not a rule.
Fix the foundations
Sleep, strength training, aerobic fitness, and protein intake have far stronger outcome evidence than any supplement.
Test before you supplement
A blood test can show whether you are actually low in something, which is a different question from whether a pill helps healthy people.
Ask what outcome it was tested on
Look for randomized trials of health outcomes in people like you, not only biomarker or animal results.
Bring it to a clinician
Supplements can interact with medicines and conditions. Whether to start, stop, or change anything is a decision for you and your clinician.
Frequently Asked Questions
Is there any supplement proven to extend lifespan in humans?
Not in the sense of a large randomized trial showing longer life in healthy people. The major trials discussed here were neutral on their main outcomes (Manson et al., 2019a; 2019b; Mangione et al., 2022).
Should I take vitamin D for longevity?
In VITAL, vitamin D did not lower cancer or major cardiovascular events in generally healthy adults (Manson et al., 2019a). If you may be deficient, a blood test and a clinician can answer that separately.
Do omega-3 capsules protect the heart?
In healthy adults in VITAL, marine omega-3s did not significantly lower major cardiovascular events (Manson et al., 2019b). This does not address people with existing conditions or prescribed treatments.
Does raising NAD+ mean I am aging more slowly?
No evidence shows that yet. Nicotinamide riboside raised NAD+ in a short human trial (Martens et al., 2018), but that is a biomarker result, not a health or lifespan outcome.
Are multivitamins worth taking?
The USPSTF found insufficient evidence for multivitamins to prevent cardiovascular disease or cancer, and recommends against beta-carotene and vitamin E for that purpose (Mangione et al., 2022).
What to remember
The short version.
- 1Judge a supplement by trials of health outcomes, not by whether it moves a biomarker.
- 2In VITAL, neither vitamin D nor marine omega-3s lowered the primary cardiovascular or cancer outcomes in healthy adults (Manson et al., 2019a; 2019b).
- 3The USPSTF found insufficient evidence for multivitamins and recommends against beta-carotene and vitamin E for prevention (Mangione et al., 2022).
- 4NAD+ precursors raise NAD+ in humans, but benefit for healthspan is unproven (Martens et al., 2018).
- 5These findings are about healthy adults; a diagnosed deficiency or condition is a different question for a clinician.
- 6Sleep, strength, fitness, and protein come before any supplement.
Keep reading
Related on Protocol
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LearnNutrition
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Measure your omega-3 status instead of guessing.
Protocol
Put your habits ahead of your supplements.
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Get started freeReferencesSources
Key Studies
- Manson et al. (2019a) New England Journal of Medicine, volume 380, pages 33 to 44. Vitamin D supplements and prevention of cancer and cardiovascular disease (VITAL).
- Manson et al. (2019b) New England Journal of Medicine, volume 380, pages 23 to 32. Marine n-3 fatty acids and prevention of cardiovascular disease and cancer (VITAL).
- Martens et al. (2018) Nature Communications, volume 9, article 1286. Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults.
Guidelines
- Mangione et al. (2022) JAMA, volume 327, issue 23, pages 2326 to 2333. US Preventive Services Task Force recommendation statement on vitamin, mineral, and multivitamin supplementation to prevent cardiovascular disease and cancer.