NAD+ vs NMN vs NR: what is the difference?
NAD+ is the finished coenzyme your cells actually use. NR and NMN are precursors, building blocks your body converts into it: NR becomes NMN, and NMN becomes NAD+. In a head-to-head human trial, oral NR and NMN each roughly doubled circulating NAD+ within 14 days while plain nicotinamide did not. Raising the number is the easy part. Proving it changes how you feel is not.
The pathway in one paragraph
All three molecules sit on the same production line, the salvage pathway your cells use to keep NAD+ topped up. Nicotinamide riboside (NR) is a form of vitamin B3. An enzyme adds a phosphate group to it, which turns it into nicotinamide mononucleotide (NMN). A second enzyme joins NMN to an adenine nucleotide, which produces NAD+, the coenzyme that mitochondria use to move electrons through energy metabolism and that enzymes such as sirtuins and PARPs consume during repair signalling.
So the argument between NR and NMN is an argument about where you enter the pathway. Both enter upstream of NAD+. Injectable NAD+ skips the queue and supplies the finished molecule, which is why it needs a prescription and a pharmacy rather than a supplement label.
Plain nicotinamide (NAM), the cheapest B3 form on the shelf, also feeds the same pathway, but in the head-to-head trial below it did not produce the sustained rise in circulating NAD+ that NR and NMN did.
NAD+, NMN and NR compared
| NR | NMN | Injectable NAD+ | |
|---|---|---|---|
| What it is | Nicotinamide riboside, a vitamin B3 form | Nicotinamide mononucleotide, NR with a phosphate added | The finished coenzyme itself |
| Steps to NAD+ | Two, NR to NMN to NAD+ | One, NMN to NAD+ | None, it is NAD+ |
| How it is taken | Oral capsule | Oral capsule or powder | Subcutaneous injection or IV, compounded on prescription |
| Human data on raising NAD+ | Repeatedly demonstrated in randomized trials | Demonstrated in randomized trials | Enters circulation directly, but published human pharmacokinetic data are sparse |
| Human data on clinical benefit | Mixed to negative in rigorous trials | Mixed, performance changes not statistically significant in a systematic review | Very little controlled data |
| Typical cost | Roughly $30 to $90 per month | Roughly $30 to $90 per month | $249/mo at Expert Health, or $675 for about a 10-week supply |
| Prescription needed | No | No | Yes |
Compounded NAD+ is not FDA-approved and is prescribed off-label. Supplement products are not reviewed by the FDA for effectiveness before sale.
What the head-to-head human trial found
For years the NR versus NMN argument was fought with animal data and marketing. A randomized human trial finally compared them directly, giving healthy adults oral NR, NMN, plain nicotinamide or placebo for 14 days and measuring circulating NAD+.
- NR and NMN performed comparably. Both roughly doubled circulating NAD+ over the two weeks.
- Plain nicotinamide did not. It raised levels acutely but did not produce the same sustained rise.
- The gut was part of the story. The trial found evidence that gut bacteria participate in converting these precursors, which is not how the supplement marketing usually explains it.
- What it did not test. Whether any of that made participants feel or function differently. It was a biomarker trial, over two weeks, in healthy adults.
That last point is the one to hold on to. Almost every strong claim in this category rests on biomarker trials like this one and then quietly extrapolates to energy, focus and aging.
So which should you take?
What the evidence supports
- NAD+ is essential to cellular energy metabolism, and levels decline with age
- Oral NR raises blood NAD+ in middle-aged and older adults
- Oral NMN raises blood NAD+, including in older men
- NR and NMN are comparable at raising the biomarker, and both beat plain nicotinamide
- All three are generally well tolerated in the trials run so far
What it does not support
- That any of them extends human lifespan, which is animal data only
- That raising blood NAD+ reliably reduces fatigue or sharpens cognition
- That one precursor is proven superior for outcomes rather than for the biomarker
- That injectable NAD+ outperforms oral precursors in humans, which has not been tested properly
- That any of them replaces sleep, training, protein or treating an actual diagnosis
If you want the cheapest evidence-backed way to raise blood NAD+, that is an oral precursor. If you want the coenzyme itself, prescribed and dosed by a US-licensed provider and compounded by a licensed US pharmacy, that is what Expert Health offers at $249 per month. Either way, go in knowing the outcome data are thin. See injections vs IV vs oral for the route decision.
Why a clinic offers injectable NAD+ at all
The honest reasons are delivery and control, not proof. Injecting NAD+ removes the conversion steps and the digestive variables, delivers a dose someone actually chose for you, and comes from a compounding pharmacy rather than an unregulated supplement supply chain where label accuracy is a known problem. It also puts a provider between you and the decision, including the option of being told no.
The dishonest reason, the one to walk away from, is a clinic claiming injection delivers benefits that oral precursors cannot. That comparison has not been run in humans.
A note on the shifting legal status of NMN
If you have read conflicting things about whether NMN is even legal to sell as a supplement in the US, both versions were true at different times. The FDA took the position in 2022 that NMN was excluded from the dietary supplement definition because it had been authorized for investigation as a drug, then reversed that position in 2025 and confirmed NMN can be marketed as a supplement ingredient.
Injectable NAD+ was never a supplement question. It is a compounded prescription preparation, which means the FDA does not review it for safety, effectiveness or quality before it is dispensed, and a licensed provider carries the decision.
Frequently asked questions
What is the difference between NAD+, NMN and NR?
Is NMN better than NR?
Is it better to take NAD+ directly instead of a precursor?
Does taking NMN or NR actually raise NAD+ levels?
Is plain nicotinamide as good as NR or NMN?
Do NAD+ precursors extend lifespan?
Which one should I take for energy?
Is NMN legal to buy in the US?
Sources
- The differential impact of three different NAD+ boosters on circulatory NAD and microbial metabolism in humans · Nature Metabolism, via PubMed, 2025
- Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults · Nature Communications, via NIH PMC, 2018
- Chronic nicotinamide mononucleotide supplementation elevates blood NAD+ levels and alters muscle function in healthy older men · npj Aging, via NIH PMC, 2022
- Physical performance parameters in patients taking nicotinamide mononucleotide: a systematic review of randomized controlled trials · Cureus, via NIH PMC, 2024
- Effects of nicotinamide riboside on NAD+ levels, cognition, and symptom recovery in long-COVID: a randomized controlled trial · eClinicalMedicine, via PubMed, 2025
- Compounding and the FDA: questions and answers · U.S. Food and Drug Administration
This article is for general educational purposes and is not medical or legal advice. Statements have not been evaluated by the FDA, and treatments referenced are not intended to diagnose, treat, cure, or prevent any disease. Compounded medications are not FDA-approved. Individual results vary. Always consult a licensed provider before starting any treatment.
Explore longevity treatments
Start with NAD+.
As low as $249/mo. Prescribed by a US-licensed provider, compounded by a licensed US pharmacy, and shipped free to your door.
See NAD+ and pricingNot sure it is the right fit? Speak with a health specialist, free, or browse all treatments.