Sleep is one of the three things every NAD⁺ seller promises, alongside energy and focus. It is also the rare claim in this category that somebody actually went and measured.
Three trials looked at it. What they found is more specific, and more qualified, than “NAD⁺ helps you sleep” — and one of them found nothing at all.
The trial where sleep was a secondary endpoint
A randomized, double-blind, placebo-controlled study allocated 60 older adults (n = 60) to placebo or 250 mg a day of NMN for 12 weeks. The primary outcome was a stepping test, and at both 4 and 12 weeks there was no significant difference between the groups on it [1].
The secondary outcomes are where the interesting results are. Blood NAD⁺ and its metabolites were significantly higher in the NMN group, 4-meter walking time was significantly shorter, and — the part that matters here — the NMN group had improved sleep quality at 12 weeks relative to placebo, shown by lower scores for “Daytime dysfunction” and Global PSQI on the Pittsburgh Sleep Quality Index [1].
That is a real, placebo-controlled signal on a validated questionnaire, and it is the strongest thing on this page. It also carries two qualifiers that never make it onto a product page: it was a secondary endpoint, in a trial whose primary endpoint was null, and one of the two scores that moved — daytime dysfunction — is about how you function during the day, not about how you slept.
The larger trial, and the detail everyone drops
A second randomized, double-blind, placebo-controlled study ran 108 older Japanese adults (n = 108) through 12 weeks on 250 mg of NMN or placebo, split four ways by whether the capsule was taken in the morning or the afternoon. Sleep quality was scored on the Pittsburgh Sleep Quality Index and fatigue on a Japanese self-rating questionnaire[2].
The headline finding was that afternoon NMN improved lower limb function and reduced drowsiness, with the largest effect sizes in that group — d = 0.72 for five-times sit-to-stand and d = 0.64 for drowsiness [2].
Two things about that are routinely left out when it gets summarized as a sleep result.
Drowsiness is not sleep. It is a subscale of a daytime fatigue questionnaire — how sleepy you feel during the day. The trial also administered the PSQI, which is the actual sleep-quality instrument, and the abstract does not report a significant PSQI finding. The result that traveled is the one from the fatigue scale.
The placebo group improved too. Drowsiness improved at mid- and post-intervention in the afternoon NMN group and in the afternoon placebo group, both against their own pre-intervention scores [2]. Taking a capsule in the afternoon made people less drowsy whether or not there was anything in it — which is exactly what a placebo arm is for, and exactly the comparison that gets dropped.
The trial that found nothing
A separate study gave single oral doses of 100, 250 and 500 mg of NMN to ten healthy Japanese men and followed them for five hours, assessing sleep quality before and after. The sleep quality score showed no difference [3].
That is a single dose rather than 12 weeks, so it is not a fair test of the same question. It is worth knowing anyway, because it is the only published check on whether you would notice anything quickly — and the answer was no.
Nothing has been measured for the expensive formats
Everything above is an oral capsule, at 250 mg, in older adults, over 12 weeks. That is a narrow slice of the market.
On September 13, 2026 we searched for NAD+ injection sleep quality trial and got zero results. We searched for nicotinamide riboside sleep polysomnography randomized and got zero results — so nobody has run the objective measurement on any NAD⁺ precursor, in any population. Every sleep finding in this field is a person filling in a questionnaire about themselves.
The one sleep number attached to an infusion comes from an uncontrolled series of fifty patients in addiction treatment, where sleep rose from 6.28 hours before infusions to 7.34 after and the authors describe the improvement as non-significant[4]. That series also used a six-ingredient infusion rather than NAD⁺ alone, so even the non-result is not a NAD⁺ result.
So does NAD⁺ help you sleep?
The honest summary, in one paragraph. Two placebo-controlled trials of 250 mg of oral NMN in older adults reported improvements on self-report questionnaires — one on Global PSQI and daytime dysfunction as a secondary endpoint, one on a daytime drowsiness subscale where the placebo group improved as well. A single-dose study found no change. No trial has measured sleep objectively, and none has tested an injection, a drip, a spray or a patch. That is the whole evidence base.
It is not nothing, which puts sleep ahead of most of what this category sells — the broader picture is that precursors reliably raise the blood marker and rarely move an outcome. If you want to try it on the strength of the above, note what the trials used: an oral precursor at 250 mg a day, which is the cheapest thing in the category and a fraction of what an injection costs. Everything sold at a premium for better sleep is being sold on a result that belongs to a capsule.