What does NAD+ research show so far?
Pill studies show a blood rise. Shots and drips have much weaker proof.
Which NAD+ findings are firm today?
The firm blood finding is that NMN and NR pills raise NAD+ over several weeks. No study has shown longer life or broad health gains. Mouse work shows what may happen inside tissue. A mouse result can’t tell what will happen to you. Shots and IV drips have the weakest human proof. Clinics sell both forms, yet few strong studies tested the promised gains. That gap matters when you weigh a clinic claim.
How do NMN and NR become NAD+?
Two starting pieces carry the short names NMN and NR. The body can turn either piece into NAD+. Swallowed NAD+ does not cross the gut wall well [8]. In mice, NMN reached body tissue within minutes [8]. NR broke apart more often while still in mouse blood. Both pieces raised more NAD+ in old mice than young mice [8]. Niacin starts a different route to the same cell helper [5].
Which cell jobs use up NAD+?
Three groups of helper proteins spend NAD+ during cell work [5]. One group guides cell care and DNA repair. In yeast, worms, and mice, more of that work went with longer life [6]. Another group spends NAD+ while mending damaged DNA. Too much repair can drain and kill even 1 cell [13]. A third group breaks NAD+ apart. The amount of that protein rises with age and sore, swollen tissue [2].
All three groups draw from one small supply. Heavy DNA repair leaves less NAD+ for other cell jobs.
What did the main NR study find about NAD+?
NR has more human safety study work than NMN. One careful study followed adults with extra weight who were in good health. Each group received 100, 300, or 1000 mg/day for 8 weeks. Blood NAD+ rose 22%, 51%, and 142%, in that order [4]. NR did not raise bad cholesterol or cause flushing. Other problems matched placebo, a look-alike pill with no NR [4]. A Parkinson's safety study tested up to 3000 mg/day. That study did not find a health gain. A 2025 review found no clear broad benefit [14].
What did NMN change in people’s NAD+?
One study followed women past menopause with prediabetes, meaning blood sugar was high but not yet diabetes. They received 250 mg/day for 10 weeks. Insulin then helped their muscles handle sugar better. Weight and body fat did not change [1]. Another study followed middle-aged adults for 60 days. It tested 300-900 mg/day. Blood NAD+ rose at each amount. The adults also walked farther. The study chose 600 mg/day as its best result, with no safety problem [3].
The FDA says NMN doesn’t qualify as a supplement. NMN had first been cleared for study as a drug. Some sellers still dispute that decision. The FDA decision affects how NMN may be sold. It isn’t proof that NMN is safe or dangerous.
What do studies show about NAD+ drips and shots?
Human studies give shots and IV drips the least support. Clinics send NAD+ through a vein or into muscle. Some shots go beneath the skin. A pharmacy mixes these treatments for each order. The FDA has not approved them as treatments. One small study found almost no NAD+ in blood after 2 hours [9]. Clinic visits have given about 250-1000 mg at once. One study gave 3 micromoles per minute, a count of tiny chemical pieces rather than weight in milligrams, through a vein for 6 hours.
One pharmacy-mixed shot had a Class I recall, the FDA’s most serious type. Tests found harmful waste from bacteria inside the shot. Weak proof and that recall both matter when judging risk.
Why is the proof for IV NAD+ still weak?
IV NAD+ therapy is marketed aggressively by wellness clinics, but the controlled evidence base is thin — mostly pilot and retrospective data rather than randomized trials. Combined with rapid plasma clearance [9], that means claims of durable benefit rest on weak data relative to the oral-precursor RCTs. Infusions run too quickly can cause flushing, nausea and chest or abdominal discomfort. This digest describes the published pharmacokinetics and the safety record; it gives no dosing instructions and makes no value judgment about undergoing infusion.
NAD+ care at Promise Peptides (mypromise.com) requires a prescription from a clinician licensed in the United States. A provider reviews each request and makes the prescribing decision; not everyone qualifies. Access is for U.S. patients and depends on the state and treatment. Compounded medications are not FDA-approved; prescription access does not change the weak IV evidence above.
What changed in mice given NMN or NR?
Weight and blood sugar changed most clearly in mice. NMN at 500 milligrams for each kilogram of body weight each day helped insulin control blood sugar in mice eating a high-fat diet. NR at 400 milligrams for each kilogram of body weight each day cut weight gain and liver fat [9]. In 1 kind of mouse immune cell, low NAD+ caused more signs of swelling. NMN stopped that change [11]. Other mouse cells reused old parts to make NAD+ after DNA damage [12]. In 2024, researchers found that NAD+ helped those cells make a protein that drives swelling [15].
Every result here came from mice or cells in a dish. None tells what amount works in people.