The longevity supplement market is huge and growing. Most of it is speculation dressed up as science. A small subset is genuinely interesting. The challenge is knowing which is which, because the marketing language is nearly identical regardless of the evidence behind the product.
Here’s an honest assessment of the supplements with the best current evidence, alongside what the research actually says versus what the labels claim. Check with your GP or pharmacist before starting any of them, especially if you take medication.
Tier 1: Reasonable evidence, accessible
Magnesium. Commonly under-consumed and involved in hundreds of enzymatic processes, including energy production and protein synthesis. Low intake is associated with worse cardiovascular and metabolic health. Glycinate and citrate are well-tolerated forms. Keep supplements within the label dose and the upper limit, and avoid them with kidney disease unless your doctor advises.
Vitamin D. Deficiency is common in northern climates and is associated with poorer bone and muscle health. In Ireland and the UK, the general advice is 10µg (400 IU) a day in autumn and winter; adults shouldn’t exceed 100µg (4,000 IU) a day without medical advice. If you think you’re deficient, ask your GP for a test rather than self-prescribing high doses. Some products add vitamin K2; evidence for the pairing is limited, and K2 can interact with warfarin.
Omega-3 fatty acids (EPA/DHA). Among the most studied nutrients. Oily fish two or three times a week is the best-supported approach. Supplement trials are mixed: the large VITAL trial didn’t find a significant reduction in its main cardiovascular or cancer outcomes. High-dose omega-3 supplements have also been linked to a higher risk of atrial fibrillation, so talk to your GP before taking large doses.
Tier 2: Promising, still unproven
NAD+ precursors (NMN and NR). NAD+ is essential for cellular energy production and DNA repair, and levels appear to fall with age. NMN and NR raise NAD+ levels in blood. Human trials so far are small and short, with mixed results on function and metabolic markers. Interesting, but not proven to slow ageing, and quality products are expensive.
Spermidine. A polyamine linked to autophagy, the cellular cleaning process. Found in wheat germ, soybeans, mushrooms and aged cheese. Population studies show associations between dietary intake and lower mortality; human trial evidence is still early.
Berberine. A plant compound that lowers blood glucose in studies of people with type 2 diabetes. It interacts with several medications and can cause stomach upset. It is not a substitute for prescribed medication; if you have blood-sugar concerns, see your GP.
Tier 3: Interesting but overhyped
Resveratrol. Popularised by sirtuin research in the early 2000s. Human trial evidence has been consistently underwhelming despite compelling animal data, and bioavailability is poor.
Most antioxidant supplements. The free radical theory of ageing has been significantly revised. High-dose antioxidants may blunt some exercise adaptations, and high-dose vitamin C and E supplements have shown neutral or negative effects in some trials.
Before supplements — know your baseline.
The free Body Age Challenge takes 3 minutes and shows you where your lifestyle habits sit against the research — so you’re not paying for supplements to fix problems you don’t have.
Frequently Asked Questions
What supplements actually work for longevity?
No supplement is proven to extend human lifespan. The best case is for correcting real gaps: vitamin D in winter, enough magnesium, and omega-3 if you don’t eat oily fish. NAD+ precursors are the most discussed emerging category but remain unproven.
What is NAD+ and why does it matter for ageing?
NAD+ is a coenzyme in every cell, needed for energy production and DNA repair. Levels appear to decline with age. NMN and NR raise NAD+ in blood, but human trials haven’t yet shown clear benefits for ageing.
Should I take magnesium for longevity?
Food first: leafy greens, nuts, seeds, beans and whole grains. If your intake is low, a supplement within the label dose is generally well tolerated. Avoid supplements with kidney disease unless your doctor advises.
Is berberine as good as metformin?
Some studies show similar effects on blood glucose, but they are not interchangeable, berberine interacts with several medications, and neither is proven to slow ageing in humans. Metformin’s role in ageing is still being studied (the TAME trial). Talk to your GP rather than self-treating.
What are the most overhyped anti-ageing supplements?
Resveratrol tops the list. High-dose antioxidants have also underperformed in large trials. Marketing often runs years ahead of the human evidence.
Are longevity supplements worth the money?
Correcting a real deficiency is worthwhile and cheap. Expensive exotic blends offer the worst evidence per euro spent. No supplement substitutes for sleep, exercise and diet.
This article is for general informational purposes only and is not medical advice. Consult a healthcare professional before starting any supplement regimen.
Leave a Reply