NMN vs NR: I Changed My Mind About Which NAD+ Booster Works Better

I'll admit something right up front: I used to tell every patient over 40 to take NR (nicotinamide riboside) for anti-aging. The early data looked promising, and it seemed like the clear winner over NMN (nicotinamide mononucleotide). But then—well, let me back up. A patient of mine, a 58-year-old marathon runner named Tom, came in last year complaining that his NR supplement "just wasn't doing anything" for his recovery times. He'd been taking 300mg daily for six months, spending about $80 a month, and felt zero difference. That got me digging into the newer research, and honestly? I've changed my mind about which one I recommend.

What the Research Actually Shows (Not What Supplement Companies Claim)

Look, I get frustrated with how this gets marketed. Every brand claims their form is "the most bioavailable" or "clinically proven"—but when you actually read the studies, the picture gets more complicated.

Let's start with NR. The early hype came from Dr. Charles Brenner's work showing NR could boost NAD+ levels in mice. Human studies followed, like a 2020 trial published in Nature Communications (doi: 10.1038/s41467-020-15638-6) where 250mg NR daily increased NAD+ by about 40% in older adults (n=24) over 8 weeks. That's decent! But—and this is a big but—the increases plateaued quickly. By week 12, levels weren't significantly higher than at week 8.

Now here's where NMN started changing my mind. A 2023 randomized controlled trial (PMID: 37656734) directly compared them. Researchers gave 120 participants (ages 50-75) either 300mg NMN, 300mg NR, or placebo daily for 12 weeks. The NMN group showed a 52% increase in NAD+ levels compared to baseline, while NR showed 38%. The difference was statistically significant (p=0.02). More importantly—and this is what matters in my clinic—the NMN group reported better improvements in fatigue scores and cognitive function tests.

But wait, there's more. A Japanese team led by Dr. Shin-ichiro Imai published work in 2024 (Cell Metabolism, 2024;36(2):234-247) showing something fascinating: NMN gets converted to NAD+ through a more direct pathway than NR. For the biochemistry nerds: NMN uses the NMNAT enzyme directly, while NR has to convert to NMN first via NRK. That extra step matters, especially as we age and enzyme efficiency declines.

Here's what the textbooks miss, though: absorption. NR proponents claim it's smaller so it absorbs better. But a 2024 meta-analysis (doi: 10.1016/j.arr.2024.102345) pooling data from 18 studies (n=2,847 total participants) found NMN actually had better bioavailability when taken sublingually or in enteric-coated capsules. The plain powder? Not so much. That's why I always tell patients: form matters as much as the compound itself.

Dosing & Recommendations: What I Actually Tell Patients

So here's my current protocol, based on what I've seen work across about three dozen patients now taking these supplements:

For NMN: Start with 250mg daily, preferably in the morning. After 4-6 weeks, you can increase to 500mg if you're not noticing benefits. I usually recommend splitting the dose—250mg morning, 250mg early afternoon—because NAD+ levels naturally decline throughout the day. The research supports this: a 2023 study in Aging Cell (n=96) found divided dosing maintained more stable NAD+ levels over 24 hours.

For NR: If you choose NR (and there are still good reasons to, which I'll get to), 300mg daily is the sweet spot. More isn't better—a 2022 trial (PMID: 35876543) found 600mg daily didn't increase NAD+ more than 300mg, but did increase side effects (mainly mild nausea).

Forms that actually work: For NMN, I prefer sublingual tablets or enteric-coated capsules. The powder tastes awful (trust me, I've tried it) and gets destroyed by stomach acid. For NR, capsules are fine—it's more stable.

Brands I recommend: I usually suggest Thorne Research's ResveraCel (which contains NR) or ProHealth Longevity's NMN Pro (sublingual). Both have third-party testing. I'd skip the generic Amazon brands—ConsumerLab's 2024 testing found 30% of NMN supplements didn't contain what they claimed.

This reminds me of a case: Sarah, a 45-year-old software developer, came to me with terrible brain fog. She'd been taking an NR supplement from a popular MLM brand for months. We switched her to NMN (500mg daily, sublingual), and within three weeks she said, "It's like someone turned the lights back on in my brain." Now, that's anecdotal—but when I see that pattern repeatedly, I pay attention.

Who Should Avoid These (Or Be Very Careful)

Here's where I get really cautious—because these aren't harmless vitamins. NAD+ boosters affect fundamental cellular processes.

Don't take either if: You're pregnant or breastfeeding (zero safety data), under 30 (your NAD+ levels are probably fine), or have active cancer (theoretical risk of fueling tumor growth—though the evidence is mixed).

Be extra careful if: You have diabetes or prediabetes. A 2023 study in Diabetes Care (n=214) found NMN improved insulin sensitivity in prediabetic adults, but if you're on glucose-lowering medications, you need monitoring. NAD+ affects sirtuin pathways that regulate glucose metabolism.

Medication interactions: Both might interact with chemotherapy drugs (particularly DNA-damaging agents) and immunosuppressants. Always check with your oncologist or transplant team first. This isn't optional—I've had patients hide supplements from their doctors, and it's dangerous.

Honestly, the research on long-term safety isn't as solid as I'd like. Most studies are 12 weeks or less. We don't know what happens after 5 years of daily use. That's why I recommend cycling: 3 months on, 1 month off, or 5 days on, 2 days off.

FAQs: What Patients Actually Ask Me

Can I get enough NAD+ from food instead? Not really. You'd need to eat impractical amounts—like 100 pounds of broccoli daily for the precursor tryptophan. Supplements are the only realistic way to significantly boost levels.

What about NMN injections? I don't recommend them. The bioavailability isn't significantly better than sublingual, and you're introducing infection risk. A 2024 review in the Journal of Anti-Aging Medicine found no advantage over proper oral forms.

Will these make me live longer? We don't know yet. They improve biomarkers associated with aging (NAD+ levels, inflammation markers, mitochondrial function), but no human study has shown lifespan extension. The mouse data is promising, but mice aren't people.

Can I take both together? I wouldn't. They compete for the same pathways, and you're just wasting money. Pick one based on your needs and response.

Bottom Line: What Actually Matters

• Based on current evidence (2023-2024), NMN appears slightly more effective for boosting NAD+ levels in most adults over 40.
• Form matters enormously—sublingual or enteric-coated NMN works better than plain powder.
• Start low (250-300mg daily), give it 2-3 months to assess effects, and don't expect miracles.
• These are expensive supplements—if money's tight, prioritize sleep, exercise, and a Mediterranean-style diet first.

One-line disclaimer: These supplements aren't FDA-approved to treat any disease, and long-term safety data is still emerging.

Anyway, back to Tom, my marathon runner patient. We switched him to NMN (500mg daily, sublingual), and after two months, he cut 8 minutes off his half-marathon time and said his recovery felt "like I'm 40 again." Now, that's one person—but it's why I've changed my recommendation.