Do Supplements Actually Work for Healthy Ageing and Longevity?

The short answer

For generally healthy individuals consuming a balanced diet, the vast majority of dietary supplements marketed for healthy ageing or longevity lack robust, Tier I evidence of benefit. While some show promise in specific populations or conditions, widespread supplementation for anti-ageing remains largely unproven and potentially wasteful.

What the evidence actually shows

Extensive research, including large-scale randomised controlled trials (RCTs) and meta-analyses, has largely failed to demonstrate significant benefits of multivitamin or single-nutrient supplements for healthy ageing outcomes in well-nourished adults. A landmark systematic review by Fortmann et al. (Annals of Internal Medicine, 2013) concluded that there is no consistent evidence to support the use of most vitamin and mineral supplements for the prevention of cardiovascular disease or cancer in the general healthy population. Similarly, the Physicians' Health Study II, a large RCT involving nearly 15,000 male physicians, found no effect of multivitamin supplementation on major cardiovascular events, cancer, or all-cause mortality over an average of 11 years (Sesso et al., JAMA, 2012). While some studies suggest potential benefits for specific nutrients in preventing deficiencies in at-risk groups (e.g., Vitamin D in the elderly with low sun exposure), these are not directly related to 'anti-ageing' effects in healthy individuals. The evidence for so-called 'longevity' supplements like NMN, resveratrol, or spermidine is predominantly from animal or in vitro studies (Tier III) and small, short-term human trials (Tier II), with a distinct lack of large, long-term RCTs demonstrating improved human healthspan or lifespan.

“We found no clear evidence of benefit of multivitamin and mineral supplements for the prevention of cancer or cardiovascular disease.”

— Fortmann et al., Annals of Internal Medicine, 2013

Where Harvard Health gets it right

Harvard Health often correctly emphasizes that a healthy diet, rich in fruits, vegetables, and whole grains, remains the cornerstone of healthy ageing, and that supplements cannot replace these fundamental nutritional inputs. They frequently advise against widespread use of multivitamins or other supplements for disease prevention in healthy individuals, echoing the consensus from major medical organisations. Harvard also rightly points out that certain populations, such as pregnant women (folic acid), individuals with diagnosed deficiencies, or those with specific dietary restrictions (e.g., vegans for B12), may indeed benefit from targeted supplementation under medical guidance. This nuanced view acknowledges the role of supplements in addressing specific nutritional gaps rather than as a panacea for ageing.

Where the evidence is more nuanced

While Harvard generally takes a cautious approach, some of their articles, or those frequently cited in similar publications, sometimes lean into the 'potential' benefits of certain compounds without adequately highlighting the significant gap between mechanistic theory or animal data and robust human evidence. For instance, the discussion around antioxidants often implies a direct anti-ageing effect, despite large human trials showing no such benefit and, in some cases, harm (e.g., beta-carotene in smokers). The concept of 'micronutrient insurance' from multivitamins is also often presented as a default, despite the lack of evidence for benefit in well-nourished populations. The nuanced reality is that while ageing is associated with oxidative stress and inflammation, simply supplementing with purported 'anti-ageing' compounds has not translated into improved health outcomes in humans at a population level.

Practical implications

For most healthy adults, prioritising a nutrient-dense diet, regular physical activity, adequate sleep, and stress management will yield far greater returns for healthy ageing than any supplement regimen. If you are concerned about specific nutrient deficiencies, consult your GP for testing and personalised advice. Avoid the temptation of 'longevity' supplements based on preliminary animal or in vitro data, as their efficacy and long-term safety in humans remain largely unknown. Investing in high-quality food and a healthy lifestyle is a more evidence-based approach to extending your healthspan than relying on a pill to counteract the natural ageing process.

Where reasonable people still disagree

• The role of specific 'geroprotective' compounds (e.g., NMN, resveratrol) in delaying age-related diseases in humans, given promising animal data but limited human trials.
• Whether marginal, subclinical nutrient deficiencies, not detectable by standard tests, might still contribute to accelerated ageing and could be ameliorated by broad supplementation.
• The potential benefits of certain supplements (e.g., creatine for muscle mass, omega-3 for cardiovascular health) in older adults who may struggle to meet dietary requirements, even if not strictly 'anti-ageing' in a broader sense.