Why do I feel older than my age?

You're not unwell. Nothing is specifically wrong. But you feel heavier, slower, and less resilient than you did five or ten years ago. Recovery takes longer. Energy is less reliable. Small things that didn't used to cost you much - a late night, a stressful week, a harder training session - leave a mark that takes longer to clear. You feel, in short, older than your age suggests you should.

This is more common than it's acknowledged to be, and it tends to be dismissed as inevitable - just getting older, just how it is. But biological ageing and chronological ageing aren't the same thing, and the gap between how old you are and how old you feel is largely determined by factors that are either within your control or addressable with the right support.

Your chronological age is fixed. Your biological age - how your cells and systems are actually functioning - is considerably more malleable than most people realise.

The cellular energy problem

One of the most fundamental drivers of feeling older than your age is a decline in cellular energy production. Every cell in the body produces energy through a process in the mitochondria, and this process depends on a coenzyme called NAD+ (nicotinamide adenine dinucleotide). NAD+ is central to energy metabolism, DNA repair, and the activation of proteins called sirtuins that regulate cellular health and longevity.

The problem is that NAD+ levels decline significantly with age - roughly halving between your 20s and 40s, and continuing to decline thereafter. This isn't a fringe theory; it's one of the most well-established mechanisms of biological ageing and has been the subject of substantial research over the past decade. As NAD+ falls, cells become less efficient at producing energy, less capable of repairing DNA damage, and more prone to the dysfunction that underlies many age-related declines.

NMN (nicotinamide mononucleotide) is a direct precursor to NAD+ - the body converts it efficiently into NAD+, raising levels in a way that dietary intake alone cannot. Research in both animal models and, increasingly, human trials shows that restoring NAD+ levels produces improvements in energy, metabolic function, and markers of cellular health. It's one of the more scientifically credible interventions in the longevity space.

Inflammation and accelerated ageing

Chronic low-grade inflammation - sometimes called "inflammaging" in the research literature - is increasingly understood as a primary driver of accelerated biological ageing. It underlies most age-related conditions including cardiovascular disease, cognitive decline, joint deterioration, and metabolic dysfunction. It doesn't always produce obvious symptoms; it often just makes everything slightly harder, slightly slower, slightly less resilient.

The main drivers of chronic inflammation are largely lifestyle-related: poor diet (particularly high in refined carbohydrates, processed food, and seed oils), inadequate sleep, chronic stress, physical inactivity, excess body fat, and smoking. Addressing these is the primary intervention - no supplement compensates for a consistently inflammatory lifestyle. But for people whose lifestyle is already reasonable, targeted anti-inflammatory support can make a meaningful difference to how the body functions and feels day to day.

Oxidative stress and cellular damage

Alongside inflammation, oxidative stress is a central mechanism in biological ageing. Free radicals - unstable molecules produced during normal metabolism, and significantly increased by stress, pollution, alcohol, and poor diet - damage DNA, proteins, and cell membranes. The body's primary defence is glutathione, an antioxidant produced internally. Glutathione levels decline with age and under chronic stress, reducing the body's capacity to neutralise oxidative damage.

NAC (N-acetyl-cysteine) is the most effective way to raise glutathione levels through supplementation - it provides cysteine, the rate-limiting precursor to glutathione synthesis. Supporting glutathione production doesn't stop ageing, but it meaningfully reduces the oxidative load that accelerates it.

Sleep, recovery and biological age

Sleep is perhaps the most underrated anti-ageing intervention available. During deep sleep, growth hormone drives cellular repair, the brain's glymphatic system clears metabolic waste, and the immune system performs maintenance that keeps inflammatory load in check. Chronic poor sleep accelerates biological ageing in measurable ways - telomere shortening, increased inflammatory markers, impaired glucose metabolism. The people who tend to feel significantly younger than their chronological age almost universally sleep well.

What actually helps

The lifestyle inputs matter most. Consistent sleep, regular exercise (especially resistance training, which is one of the most powerful signals for cellular renewal and muscle maintenance), a diet built around whole foods, and effective stress management produce genuine biological age improvements that are measurable in blood markers.

On the supplementation side, the most evidence-backed interventions for the "feeling older than your age" picture are: NMN for NAD+ restoration and cellular energy; Coenzyme Q10 for mitochondrial efficiency (levels also decline with age and it works synergistically with NMN); NAC for glutathione support and oxidative stress reduction; and curcumin for the chronic inflammation piece. These address different but complementary mechanisms, and the evidence behind each is substantially better than most of what the anti-ageing supplement industry sells.