03 / 1 names NMN, 2 names NR; neither is ranked first
NMN vs NR: higher blood NAD+ is clearer than better health.
NAD+ is needed for cell work, including repairs. This comparison explains the two ingredients studied in pills meant to raise your NAD+ supply.
NMN or NR was swallowed; NAD+ was measured in blood
NAD+ helps cells gather usable energy and carry out repairs. This page compares NMN and NR, smaller substances commonly used in NAD+ pills. Cells can assemble NAD+ from either ingredient. A study can give NMN or NR, then measure NAD+ in blood. Giving and measuring are different parts of the test. Whole NAD+ isn't absorbed well when swallowed. The full names are nicotinamide riboside for NR and nicotinamide mononucleotide for NMN; cells must first change NR to NMN before completing NAD+, so starting with NMN skips that change. Human blood NAD+ rose with either ingredient, but skipping a step hasn't shown that NMN brings better health.
Read what happened to people before judging one ingredient better than the other.
Pills labeled NAD+ often contain material for making it
NAD+ is a large, charged dinucleotide (663.43 Da), and it is not freely taken up intact by most cells [5]. That is the practical reason the oral market runs on precursors: smaller molecules the body can absorb and then assemble into NAD+. The two dominant oral precursors are nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR). Both feed the salvage pathway, the dominant route of NAD+ synthesis in mammals, which recycles nicotinamide back into NAD+ via the rate-limiting enzyme NAMPT [5][14].
Unlike over-the-counter precursors, injectable NAD+ needs a prescription. At mypromise.com, Promise Peptides now prescribes this form after an individual assessment by a licensed U.S. clinician. The clinician may decline to prescribe. Patients must be in the United States, with the state and treatment setting limits on what is offered. The compounded NAD+ medicine has no FDA approval.
The routes differ by one enzymatic step. NR is first phosphorylated to NMN by nicotinamide riboside kinases (NRK1/NRK2), then converted onward to NAD+ — a Preiss-Handler-independent entry whose structural basis was worked out from crystal structures of human Nrk1 [13]. NMN sits one step further along, directly adjacent to NAD+ in the salvage sequence. That single-step difference is the heart of the NMN-vs-NR debate.
NMN helped a muscle test without changing long-term blood sugar
These NMN studies were short and modest in size. Women past menopause with blood sugar above normal received 250 milligrams a day for 10 weeks. Insulin helps sugar enter cells; their muscles responded to that hormone more readily. Their fat, muscle amount, and longer-term blood sugar test were unchanged [1]. That muscle result didn't prove better everyday health.
Another study compared NMN with placebo, a similar-looking pill containing no NMN.
People took 300-900 milligrams a day for 60 days. Their NAD+ blood readings rose, and they walked farther in a timed test. They also rated their health more favorably. Authors favored 600 milligrams a day overall after assessing blood and physical results. No safety concerns arose [3]. The findings don't specify which daily tasks became easier.
Your long-term benefit remains uncertain, despite those short-term changes.
Nicotinamide riboside (NR) has the fuller set of human tests
The NR test lasted eight weeks in healthy but overweight adults. That doesn't settle long-term use. Daily amounts were 100, 300, or 1000 milligrams. NAD+ blood readings increased by 22%, 51%, and 142%, respectively, and stayed higher. People were assigned by chance to NR or placebo, a similar-looking pill containing no NR, and the contents were hidden from the people taking the pills as well as the staff. No flushing, meaning red, hot skin, was reported. Side effects didn't differ clearly between NR and placebo [4]. Tests found no rise in “bad” cholesterol. The body uses small chemical parts to build DNA and other cell materials. Tests found no disruption of that work [4]. Lab work explains NR's change into NMN before cells finish making NAD+ [13].
More human tests give NR a fuller record; they don't prove lasting health gains.
NAD+ shots give a different substance from NMN or NR pills
A shot gives NAD+ itself. A pill usually supplies NMN or NR, which cells use to make NAD+. Most cells can't easily take whole NAD+ inside, and your body absorbs whole NAD+ poorly when swallowed [5]. Pills containing the smaller materials account for most of the swallowed products studied [4]. I found that keeping the pill ingredient separate from the blood-test result made the research easier to follow.
Your response to a NAD+ shot can't be predicted from an NR pill study.
Swallowed ingredients increased NAD+; lasting benefits remain unproved
People taking the tested ingredients had higher NAD+ readings. Many pills use the ingredients NMN or NR because those materials are absorbed better than whole NAD+. People taking those pills had higher blood NAD+ in the studies [4][3]. A 2025 review found health benefits much less certain [15].
For you, a blood rise still leaves the health question open.