Why I Stopped Taking NMN

Why I Stopped Taking NMN: A Personal Look at Longevity Supplements

For a while, NMN (nicotinamide mononucleotide) was my daily ritual. Touted as a promising anti-ageing compound and praised by scientists and biohackers alike, it sounded like a simple way to boost energy, improve focus and potentially slow down the biological clock. Like many others curious about longevity, I gave it a go.

But somewhere along the way, I stopped. Not because of some dramatic reaction or a big health scare, but because of a gradual shift in how I felt, what I learned, and what I began to question. Here’s an honest account of why I stopped taking NMN, and why for now at least I’ve decided to stick with more traditional paths to health.

What NMN Promises and Why I Was Drawn to It

NMN is a precursor to NAD+, a molecule involved in energy production, cellular repair and metabolic function. As we age, NAD+ levels decline, and researchers suggest that restoring those levels could improve health span and possibly even delay age-related decline. The early science was exciting, particularly the work popularised by Dr David Sinclair and others in the field of longevity.

I was intrigued by the idea that something so simple a daily capsule might help with energy, focus, and cellular repair. At first, it felt like an easy addition to a reasonably healthy lifestyle. I wasn’t expecting a miracle, but I was hopeful for subtle, long-term improvements.

Initial Effects: Subtle, Then Questionable

During the first few weeks, I did notice a bit of a lift mildly better energy, slightly improved concentration, and what felt like a more consistent mood. But over time, that boost seemed to plateau. I found myself wondering if the benefits were real, or if I was experiencing a kind of placebo optimism. When you're taking something that promises to slow ageing, it's hard not to look for signs it’s working even if nothing has truly changed.

After a few months, I couldn’t say with certainty that NMN was improving anything in a way I could feel or measure. I wasn’t sleeping better, I didn’t recover faster from exercise, and there wasn’t a noticeable difference in skin, stamina or sharpness. It had become another supplement in a growing collection expensive, and possibly doing nothing.

The Cost vs Certainty Dilemma

One of the main reasons I stopped was the ongoing cost. NMN isn’t cheap. High-quality formulations can cost upwards of £40–£80 per month, depending on the dose and brand. That’s a significant investment for something that isn’t backed by long-term human clinical data yet.

Most of the exciting results still come from animal studies. While there are emerging human trials, the results are still early and mixed. I reached a point where I asked myself: Would I rather spend this money on real food, fitness, or stress management? For me, the answer became clear.

Side Effects and Unexpected Reactions

Although I didn’t experience anything extreme, I did start to notice low-level anxiety and occasional jitteriness—not dissimilar to taking too much caffeine. It wasn’t enough to make me feel ill, but enough to raise questions. Some people report improved sleep with NMN; for me, it was slightly disrupted. I also felt mentally "on" all the time, which might sound helpful, but became exhausting.

I later discovered that some people metabolise NMN differently, particularly if they’re already taking other supplements that affect methylation or the nervous system. There’s no one-size-fits-all here—and with so little research on long-term use, it started to feel like I was experimenting on myself more than I was supporting my health.

Trusting the Basics Again

After stopping NMN, I focused more on consistent exercise, quality sleep, whole foods and managing screen time. While that sounds less cutting-edge, it turned out to be far more effective and sustainable. I no longer wake up wondering if a capsule is working. I just feel better for doing things that have always made sense movement, rest, nutrition, and purpose.

That’s not to say NMN doesn’t have potential. It’s a fascinating area of science, and I’m not ruling it out forever. But for now, I’ve stepped back, with more curiosity than conviction. I’m waiting for better research, clearer dosing guidelines, and more affordable options none of which currently exist in a fully reassuring form.

Final Thoughts: Curiosity Isn’t the Same as Certainty

There’s a lot of excitement around longevity science right now, and NMN is one of many compounds being studied for its role in healthy ageing. For some, it may offer real benefits. But for me, the cost, uncertainty, and lack of tangible results led to one conclusion: just because it might help someday doesn’t mean I need it today.

In a world full of quick fixes and supplement stacks, sometimes the best move is to take a breath, simplify, and return to what we know works. At least for now, that’s what I’ve chosen.