If you've been taking NR for years and still waiting to feel the difference, here's what the clinical data actually says. And what to do instead.

I'll be honest with you.

I spent years taking nicotinamide riboside.

I bought the good stuff. Not the cheap Amazon brands. I read the studies. I tracked my bloodwork. I did everything right.

And I felt... fine. Not worse. Not dramatically better. Fine.

That bothered me. Because the science on NAD+ is real. Declining NAD+ levels are directly linked to the kind of fatigue, brain fog, and physical slowdown that most people just chalk up to "getting older." David Sinclair's research at HMS. Charles Brenner's foundational work, now at City of Hope National Medical Center. This isn't fringe stuff. It's in peer-reviewed journals.

So if the science was solid, why wasn't I feeling it?

That question sent me down a rabbit hole that took about six months to get out of.

The problem isn't NAD+. It's which precursor actually produces results in people.

Here's what the human trial data actually shows, and most people taking NR haven't seen this.

Raising NAD+ levels in the blood is relatively easy. Both NR and NMN do that comparably, a 2026 head-to-head clinical trial in Nature Metabolism confirmed both roughly doubled circulating NAD+ in 14 days.

But blood NAD+ is a proxy. It's not the goal. The goal is what happens downstream in your tissues, your muscles, your metabolism, your cells' ability to actually use that NAD+.

And that's where the two precursors have so far diverged in the human data.

What the muscle data looks like

In obese, insulin-resistant men, 2,000 mg per day of NR, a very high dose, did not improve insulin sensitivity, mitochondrial function, or muscle NAD+ levels in a 12-week randomized controlled trial published in the American Journal of Clinical Nutrition. A follow-up review noted that across multiple clinical trials, oral NR supplementation has not yet demonstrated improvements in muscle NAD+, mitochondrial respiratory capacity, or insulin sensitivity.

NMN tells a different story so far.

A 10-week randomized, placebo-controlled, double-blind trial from Washington University School of Medicine in St. Louis, published in Science in 2021, found that 250 mg per day of NMN improved muscle insulin sensitivity in postmenopausal women with prediabetes. Muscle remodeling genes were upregulated. The improvement in insulin sensitivity was comparable to effects seen with significant weight loss. The researchers noted this was the first evidence of positive metabolic effects from any NAD+ precursor in humans.

The NR trials and the NMN trials tested similar populations, used rigorous methodology, and arrived at different conclusions for muscle metabolism. That doesn't mean NR can't work, but the evidence for functional downstream effects in humans is currently much stronger for NMN.

What the healthy adults data looks like

A 2022 randomized, multicenter, double-blind, placebo-controlled trial published in GeroScience tested NMN in 80 healthy middle-aged adults, not a sick population, not a special case, at doses of 300, 600, and 900 mg per day for 60 days. Blood NAD+ levels increased significantly at all doses compared to placebo. Physical endurance, measured by a six-minute walking test, also improved significantly, with larger gains at higher doses.

A separate randomized, double-blind trial published in the Journal of the International Society of Sports Nutrition found that 600 to 1,200 mg of NMN per day for six weeks improved aerobic capacity in middle-aged runners by enhancing skeletal muscle oxygen utilization. No adverse effects were reported at any dose.

The question was never just "does NAD+ go up?" The question is whether anything actually changes in how your body performs. The NMN data, at least as it stands today, says yes. The NR data has yet to show the same for tissue-level outcomes.

Then there's the biochemistry

NMN sits at a specific point in your body's main NAD+ production pathway. The step just before it, converting nicotinamide to NMN via an enzyme called NAMPT, is the rate-limiting bottleneck. When you take NMN, you're supplying the compound that sits on the other side of that bottleneck, giving your cells a more direct route to production.

NR requires conversion to NMN as an intermediate step before it can become NAD+. It crosses that same bottleneck, just from the other side. Whether that additional conversion step fully explains the clinical differences in muscle outcomes isn't settled, but the outcomes data points in a consistent direction.

Then there's the dose problem nobody talks about

Even within NMN, most supplements on the market are under-dosed.

The Washington University trial saw results at 250 mg per day. The GeroScience trial saw dose-dependent benefits up to 900 mg. Age matters too, NAD+ levels decline substantially between your 20s and your 50s. Which means adults over 40 need a meaningful dose to restore useful levels, not a symbolic amount.

A lot of NMN products give you 125 mg per capsule. The math doesn't work.

And then there's purity. NMN degrades. It's sensitive to heat and moisture. Independent lab tests of popular NMN brands have found actual NMN content significantly below the label claim by the time it reaches the consumer. Third-party certificates of analysis matter here, not internal testing documents, but independent accredited laboratory results on production batches.

What I actually switched to

After six months of research, I switched to Omre NMN + Resveratrol.

A few reasons.

The dose is 500 mg per serving. That's in line with the clinical data for adults over 40 looking for meaningful NAD+ restoration, not a symbolic amount.

Every batch is third-party tested by an independent ISO-accredited lab. The certificate of analysis is available, an actual test result with compound purity, contaminant screening, and identity verification.

The NMN is stabilized, manufactured and stored in conditions that protect the compound from degradation before it reaches you. That detail is almost never discussed but it's the difference between taking what the label says and taking something that's already partially broken down.

No fillers. No magnesium stearate flow agents. No synthetic coatings. Just the compound.

What changed for me

I want to be careful here, because I'm one person and individual results vary.

But within about three weeks, the afternoon wall I'd been hitting every day started to soften. Not in a stimulant way. No spike, no crash. Just a steadier baseline through the afternoon. I was sleeping the same hours but waking up feeling like the sleep had actually done something.

My focus at work, which had been getting choppier over the past couple of years, felt more consistent. Not perfect. But better.

My Garmin started showing higher heart rate variability scores. Again, one data point. But it was moving in the right direction for the first time in a while.

The joint stiffness I'd been writing off as "just how it is now" has reduced. I'm not going to claim causation. But I notice it.

I've been on it for seven months now. I'm not stopping.

The honest summary for people who've already done the research

If you already know what NAD+ is. If you've already read Sinclair or listened to Huberman. If you've already tried NR and felt underwhelmed. Then you're not starting from zero here.

You're just missing one piece.

NR and NMN raise circulating NAD+ comparably. That part is settled. The question is whether anything changes in your tissues, your muscles, your metabolism, your energy production where it actually matters. The human trials on muscle outcomes and physical performance have, to date, consistently favored NMN. The NR equivalent trials haven't produced the same results yet, and they've had ample opportunity to do so.

The precursor matters. The dose matters. The purity matters.

Most NMN products get one or two of those right. Omre gets all three.

If you've been waiting for something that actually moves the needle, this is worth trying.

You have one body. You only get one shot at this particular decade of your life.

Make the cells count.

References:

• NR failed to improve insulin sensitivity, muscle NAD+ or mitochondrial function in humans: Dollerup et al., Am J Clin Nutr 2018 and iScience 2022 review
• NMN improved muscle insulin sensitivity: Yoshino et al., Science 2021
• NMN raised NAD+ and improved physical performance in healthy adults: Yi et al., GeroScience 2022
• NMN improved aerobic capacity in runners: Liao et al., J Int Soc Sports Nutr 2021
• NMN and NR comparably double circulating NAD+: Christen et al., Nat Metab 2026