WALKING, BLOOD, AND MUSCLE FINDINGS
What NAD+ pills changed in walking, blood, and muscle
Start with walking, which a person can notice. Metabolism means how the body uses food for power. You'll see when a finding came only from animals.
What people could notice before a blood test
You can notice farther walking more easily than a change in a blood reading. Some NMN pill studies found better walking. Studies of both NMN and NR also measured higher blood NAD+. The raised reading alone does not tell you that health improved.
One study found that women's muscles took sugar from the blood more easily. Insulin is the hormone that helps move that sugar. All the women were past menopause, and their blood sugar ran high. The amounts below describe research; they do not choose a plan for your care.
What NMN changed in muscle but not body weight
The study enrolled women whose sugar readings were high after menopause. They took NMN pills at 250 mg/day for 10 weeks [1]. Insulin helped their muscles remove more sugar from the blood afterward, which was the main finding.
Doctors gave insulin and added sugar to keep each woman's blood level steady. More added sugar meant that her muscles had removed more from the blood. Muscle samples also showed a different response to insulin, but the trial could not tell whether the women felt better.
NMN did not change body weight or the blood test that shows sugar over past months [1]. This was one pill study in one kind of patient. The result needs support from other studies before it can apply more widely [14]. You can read it as a useful lead, not a promise.
What the clinic offers, and what NMN pill studies found
Licensed clinicians working through Promise Peptides (mypromise.com) may prescribe NAD+ after evaluating a request through the telehealth service; that access fact does not establish an effect on any metabolic or performance endpoint summarized here.
NMN sits one enzymatic step from NAD+ and is the precursor most associated with the metabolic-muscle data. Beyond the clamp result, a multicenter, double-blind RCT tested 300, 600, and 900 mg/day for 60 days in healthy middle-aged adults: blood NAD+ rose significantly at days 30 and 60 across all NMN groups versus placebo (p≤0.001), walking distance improved, a biological-age measure did not rise, and 600 mg/day was identified as the optimal dose with no safety issues at any level [3]. A 2024 systematic review pooled ten randomized trials (437 participants, mean age 58, doses 150–1200 mg/day, mean follow-up 9.6 weeks) and reported statistically significant gains in gait speed (p=0.002), five-times sit-to-stand (p=0.04), six-minute walking distance, and SF-36 quality-of-life scores, with no serious adverse events [15]. In rodents, NMN at 500 mg/kg/day improved insulin sensitivity and glucose tolerance in high-fat-diet mice — a preclinical signal, not a human dose [8].
What exercise changed in cells that restore NAD+
Researchers measured 1 protein that restores NAD+ after use, and athletes had about double the amount [7]. The protein does this by reusing a form of niacin. Exercise rose along with the protein, yet this does not mean a pill works like exercise.
In mice, extra amounts of the protein helped muscle grow more mitochondria. These are the small cell structures that release usable power from food. The mice could exercise about three times longer [7]. That mouse research did not test people taking NAD+.
Another mouse study found that newly made NAD+ rose and fell with the time of day. Blocking the same protein stopped most day-and-night changes in fat cells [9]. Leg muscle kept its daily changes even when its NAD+ fell. These findings in mice don't set a best time for a pill.
What NR changed in the muscles and blood of older men
One small study gave NR to 12 older men. When sorted by age, the man in the middle was 75. They took 1 g/day, split into 500 mg twice daily, for 21 days. Their muscle held about twice as much NAD+ and related substances [6].
Four blood proteins that can rise with harmful swelling also fell. The study named three as interleukin 6, interleukin 5, and interleukin 2. These are protein names, and the figures aren't amounts. The blood change did not show that the men felt better.
No side effects appeared, and larger studies also found higher blood NAD+ after NR [4]. This small study can't show that the men gained health or lived longer. A 2025 review found those larger benefits still unproved [14]. Blood and muscle can change without a change a person notices.
What NAD+ pills did about weight gain
The human studies here found no weight gain tied to either pill. In mice and rats, NR reduced gain from a rich diet and cut liver fat [8]. In one human study, NMN helped muscle use insulin, yet weight stayed the same [1]. Researchers have not found that these pills add body weight in people.
What NAD+ pills failed to show about weight loss
In mice and rats, starting materials for NAD+ helped insulin work. The animals also had less liver fat [8], and one human NMN study found better insulin use in muscle [1]. Human studies did not show weight loss, so the proof does not support that promise.
What happened after people swallowed NMN or NR
Whole NAD+ barely passes through the gut into the body. Human trials instead used NMN or NR pills, since the body later changes those materials to NAD+. Both pills increased blood NAD+ [4][3], but that finding says nothing about a whole NAD+ pill.
In one NMN trial, muscle responded better to insulin [1]. A review found farther walking after NMN [15], yet lasting health help is still unproved [14]. Those results concern NMN or NR pills rather than swallowed NAD+.