Which Longevity Supplements Are Actually Worth Taking?

The supplement aisle of the longevity world has grown enormously in the last few years, and so has the gap between what is marketed and what has actually been tested in people. Gerovia applies the same standard to supplements that it applies to every other treatment covered on this site: what does the human trial evidence actually show, not what does the product page claim, and not what a mouse study or a cell culture experiment suggests might eventually be true in a person.

This matters because a supplement that changes a blood marker in a small short trial is a genuinely different thing from a supplement that has actually been shown to help you live longer or better. The gap between those two claims is where most of the marketing in this space lives. This article looks honestly at three of the most talked-about longevity supplements, creatine, NMN and resveratrol, using recent human trial evidence for each.

Food supplements sold in Ireland are regulated by the Food Safety Authority of Ireland, not the Health Products Regulatory Authority, which instead handles medicines and certain medicinal ingredients. Anyone manufacturing or importing a food supplement for the Irish market must notify the FSAI before marketing it, and only permitted vitamins and minerals may be included under the relevant EU directive.

Critically, food supplement labels in Ireland cannot legally claim to prevent, treat or cure a disease, and any nutrition or health claim made on packaging or in marketing must appear on the EU's approved list of permitted claims under Regulation (EC) No. 1924/2006. This is a genuinely useful thing to know as a consumer: if a supplement's marketing implies it treats a medical condition, that claim itself is a regulatory red flag, regardless of what the underlying research shows. This is a separate regulatory world from the unauthorised injectable peptides covered elsewhere on this site, which have no marketing authorisation in Ireland, fall under HPRA medicines law rather than food supplement rules, and carry a different, stricter set of legal restrictions.

A 2026 randomised controlled trial published in the Journal of the International Society of Sports Nutrition tested creatine monohydrate in 64 healthy adults aged 45 to 65, randomised in a double-blind design to either creatine or a placebo, with some participants also following an exercise and diet programme. Over 12 weeks, creatine supplementation increased lean tissue mass, strength and muscular endurance, and was associated with favourable changes in selected blood lipids, blood sugar control and some markers of cognitive function and memory, whether or not participants also exercised. The supplement was well tolerated throughout.

It is worth noting plainly that the trial's senior author has disclosed industry ties to creatine manufacturers, including a role on a creatine producer's scientific advisory board, a conflict the authors themselves reported openly in the published paper. That does not invalidate the finding, creatine's benefits for muscle mass and strength in older adults are supported by a large independent body of research going back decades, but it is the kind of disclosure worth knowing about when reading any single study.

Creatine is inexpensive, widely available, and has one of the longer safety records of any supplement discussed in the longevity space, which is part of why it is often the one clinicians are most comfortable recommending.

Oral nicotinamide mononucleotide, or NMN, is marketed as a way to raise NAD+ levels in the body, a molecule involved in cellular energy production that declines with age. A 2026 systematic review and meta-analysis in Nutrients pooled 15 randomised controlled trials of oral NMN, with doses ranging from 250 to 2,000 milligrams a day and durations from 14 days to 24 weeks.

The review's central finding on safety was reassuring: NMN did not increase overall or serious adverse events, and did not raise liver enzymes compared with placebo. On effectiveness, the picture was much less impressive than the marketing around NMN would suggest. The review found no significant effects on body weight, BMI, fasting glucose, HbA1c or cholesterol levels. Diastolic blood pressure decreased slightly and insulin resistance showed a non-significant downward trend, described by the authors as a preliminary signal worth exploring further, particularly in older adults or people with early metabolic risk, rather than a confirmed benefit.

The honest summary is that oral NMN looks safe over periods up to six months, but there is no human evidence that it delivers the broad metabolic transformation often implied in marketing, and no trial anywhere has shown, or could easily show, that it extends human lifespan, since a trial capable of answering that question would need to run for decades.

Resveratrol, a compound found in red grape skins and sold as a concentrated supplement, has one of the larger evidence bases of any longevity supplement, if you look at it the right way. A 2026 umbrella review in Nutrition Journal pooled 45 separate systematic reviews covering 129 associations between resveratrol supplementation and human health outcomes. Using the GRADE framework to rate certainty, the researchers identified four associations backed by high-certainty evidence: reduced waist circumference generally, reduced total cholesterol specifically among overweight adults, and reduced diastolic and systolic blood pressure specifically among patients with type 2 diabetes.

Those are real, well-supported findings, but notice how specific they are. The strongest evidence applies to particular populations, people who are overweight or who have type 2 diabetes, measuring particular cardiometabolic markers, not a general anti-ageing effect measurable in a healthy adult without those conditions. Moderate-certainty evidence extended somewhat further, suggesting resveratrol may help with glucose metabolism, kidney function, endothelial health, working memory and liver fat, but with more uncertainty attached.

The lesson here applies to reading longevity supplement research generally: a real, high-certainty finding in one population, such as people with type 2 diabetes, does not automatically carry over to a different population, such as a healthy 40 year old hoping to slow general ageing. Where the evidence is specific, the claims made about it should stay specific too.

Every supplement discussed here has been shown, to varying degrees, to move a measurable number in the right direction, a blood lipid, a blood pressure reading, a strength test, a cognitive score. None of them has been shown to extend how long a person lives, and it is worth understanding why that gap exists rather than treating it as a technicality.

A genuine human lifespan trial would need to randomise thousands of people to a supplement or placebo and then follow them for decades to see who lives longer, an undertaking that is essentially never done for a nutritional supplement, for reasons of cost, practicality and the sheer length of time involved. This is why longevity supplement research relies almost entirely on biomarkers and surrogate outcomes, measurements believed to correlate with future health, rather than on the outcome people actually care about. A biomarker changing in a promising direction is a reasonable, worthwhile signal. It is not proof of the bigger claim that gets attached to it in marketing copy.

It would be a disservice to spend this much time on three supplements without saying plainly that none of them come close to the evidence base behind the fundamentals: regular exercise, adequate sleep, a reasonably balanced diet, not smoking, moderate alcohol intake, and attending to established medical care such as blood pressure and cholesterol management. These levers have decades of large-scale human evidence behind them for reducing disease risk and extending healthy years, evidence that dwarfs anything currently available for NMN or resveratrol.

A biohacking centre, a supplement stack, or a longevity clinic protocol is, at best, a genuine addition on top of those fundamentals, not a substitute for them. Anyone spending significant money on longevity supplements while neglecting sleep, exercise or basic preventive medical care is very likely optimising in the wrong order.

A few practical questions help separate a genuinely evidence-backed supplement from one riding on plausible-sounding marketing. Was the claimed benefit actually tested in humans, in a randomised controlled trial, rather than only in animals or in a laboratory dish. Was the trial population similar to you, since evidence from people with type 2 diabetes or who are overweight does not automatically apply to a healthy adult, and vice versa. Does the claimed benefit match what was actually measured, a change in a biomarker is not the same claim as extended lifespan, improved disease outcomes, or reversed ageing. And has the supplement been through Ireland's FSAI notification process, with permitted ingredients and compliant labelling, rather than being imported informally with unverified contents.

If you are taking any prescription medication, or have an existing health condition, it is worth discussing any new supplement with your GP or a pharmacist first, since interactions between supplements and medications are not always well studied and are rarely covered in the kind of trials discussed in this article.

Of the three supplements covered here, creatine currently has the broadest and most consistent human evidence, including for outcomes relevant to healthy ageing like muscle mass, strength and some cognitive markers in adults in their 40s, 50s and 60s. Resveratrol has genuinely high-certainty evidence, but for specific cardiometabolic markers in specific populations rather than as a general anti-ageing supplement. NMN appears safe over the periods studied so far, up to about six months, but has not yet shown the broad metabolic benefit its marketing often implies.

None of this means these supplements are worthless, the evidence for each is real and worth taking seriously on its own terms. It does mean the marketing language around longevity supplements routinely runs ahead of what has actually been shown in people, and that a supplement worth taking is one whose claims match its evidence, not one whose evidence gets stretched to match its claims.