Claimed effect · NAD+ and precursors

Does NAD+ and precursors help with insulin sensitivity / metabolic health?

C
Grade C — weak human evidence1 small RCT (n=25), contested · effect size: small
Short answerWeak human evidence. 1 small RCT (n=25), contested: enough to be interesting, not enough to count on. Where an effect is seen it is a small effect. A 10-week NMN trial in prediabetic postmenopausal women improved muscle insulin sensitivity — a single small study whose interpretation was publicly disputed and which has not been replicated.

What the studies show

A 10-week NMN trial in prediabetic postmenopausal women improved muscle insulin sensitivity — a single small study whose interpretation was publicly disputed and which has not been replicated.

“These results demonstrate that NMN increases muscle insulin sensitivity, insulin signaling, and remodeling in women with prediabetes who are overweight or obese.”

Verbatim, from the abstractYoshino M, et al. Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women. Science, 2021;372:1224–1229

A few small or poorly-controlled human studies. Enough to be interesting; not enough to count on. Most of what gets called “clinically proven” online lives here.

  1. 1
    Yoshino M, et al. Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women.Science, 2021;372:1224–122925 women, 10 weeks; single, contested trial.

In context

NAD+ is a coenzyme every cell uses for energy metabolism; it is not a peptide, but its precursors (NMN and NR) and intravenous NAD+ itself are sold across the same anti-ageing market. Randomised trials show the oral precursors reliably raise NAD+ levels and are well tolerated. What they have not yet shown is a clear clinical benefit — trials of metabolism, muscle and ageing are small, mixed and contested. Intravenous NAD+ has essentially no controlled evidence.

NAD+ and precursors is sold as supplement (nr/nmn); iv nad+ unlicensed. Legal status differs by country — see the regulation section or the jurisdiction pages.

Questions

Is NAD+ and precursors proven to help with insulin sensitivity / metabolic health?
No. The human evidence is weak (1 small RCT (n=25), contested); LYO grades it C.
What studies are behind the grade?
A 10-week NMN trial in prediabetic postmenopausal women improved muscle insulin sensitivity — a single small study whose interpretation was publicly disputed and which has not been replicated.
Is NAD+ and precursors approved for this?
No. NAD+ and precursors is sold as supplement (NR/NMN); IV NAD+ unlicensed; it is not an approved medicine for any indication in the jurisdictions LYO covers.

Other outcomes for NAD+ and precursors

Written and maintained by LYO Research — how pages are written and checked. Reviewed 3 September 2026. Grades count human evidence only; see how LYO grades. Not medical advice. Correct this page →