Promising, not proven.
NAD+ is a reasonable topic to raise with a clinician, as support for your levels rather than a promised result.
What NAD+ does in your body
NAD+, short for nicotinamide adenine dinucleotide, is a coenzyme your cells use to release energy from the food you eat. It also fuels two groups of enzymes that draw most of the attention: sirtuins, and the PARP enzymes that repair DNA. A 2021 review in Nature Reviews Molecular Cell Biology links NAD+ to metabolism, DNA repair and immune function, which puts it at the center of aging research.
Your body builds NAD+ from raw materials in your diet. Niacin (vitamin B3) is the best known, and the amino acid tryptophan can be converted too. According to the NIH Office of Dietary Supplements, once niacin is absorbed, normal amounts are converted to NAD. Nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN) are newer precursors that sit closer to NAD+ in the same pathway.
Women and men share the same cell biology. What differs is which questions researchers have asked, and for women the list of answered ones is short. For the basics, Harbor’s overview of NAD+ therapy covers who considers it and how a program works.
Why NAD+ levels fall with age
In the 2021 review, tissue NAD+ declines gradually with age in rodents and in humans, and in animal studies restoring it slowed or reversed some age-related disease. It is careful about people. How to restore NAD+ in aging adults, whether doing so is safe, and whether it helps are all listed as open questions.
One of the few human tissue studies included women. Researchers measured NAD+ in 49 skin samples from people aged newborn to 77 and found that NAD+ fell with age in both male and female tissue. Some related markers, such as activity of the DNA-repair enzyme PARP, tracked age less closely in women.
That shows the decline happens in women, and little more. It does not show that a woman with lower NAD+ feels worse, or that raising her levels changes how she ages.
NAD+ & energy, what the trials measured
Energy is the benefit most often promised, and it has the least direct evidence. Because NAD+ sits at the core of cellular energy, the idea is reasonable on paper. What trials measured is narrower: whether a precursor raises NAD+ in the blood, and whether that moves a physical marker such as blood pressure or fitness.
In a randomized crossover trial of 30 healthy adults aged 55 to 79, men and postmenopausal women took NR or placebo for six weeks each. NR was well tolerated and raised NAD+ in blood cells, but it did not clearly improve aerobic capacity in people who were already fit (Martens et al., 2018).
Neither trial used tiredness or day-to-day energy as an outcome. If you are exhausted, MedlinePlus lists common causes to rule out first, such as iron deficiency, thyroid problems, sleep disorders and depression. NAD+ does not replace that workup.
The NMN trial in postmenopausal women
The clearest data in women comes from a 10-week randomized, placebo-controlled, double-blind trial at Washington University, published in Science in 2021. It enrolled postmenopausal women with prediabetes and overweight or obesity. Twenty-five completed it: 13 took NMN and 12 took a placebo.
What the researchers found:
- Muscle insulin sensitivity, measured with a hyperinsulinemic clamp, improved after NMN and did not change after placebo.
- NAD+ rose in blood cells, but not inside the muscle itself.
- Genes linked to muscle remodeling became more active.
- No adverse events were reported, and standard blood tests stayed normal in both groups.
It is careful and it is small: 25 women over 10 weeks, from one specific group, with a metabolic outcome rather than energy, mood or menopause symptoms. Two of the authors hold patent interests related to NMN, which the paper discloses.
Several NR trials in middle-aged and older men found no change in insulin sensitivity, the authors note. A result from one precursor, in one group, does not carry over automatically.
The human & animal evidence side by side
Most claims about NAD+ and women trace back to a handful of studies.
| Study | Who was studied | What it found | What it does not show |
|---|---|---|---|
| Massudi, 2012 | 49 human skin samples, both sexes | NAD+ fell with age in male and female tissue | Any effect of raising NAD+ |
| Martens, 2018 | 30 adults 55 to 79, incl. postmenopausal women | Oral NR raised blood NAD+ and was well tolerated | A clear gain in fitness or energy |
| Yoshino, 2021 | 25 postmenopausal women with prediabetes | Oral NMN improved muscle insulin sensitivity | Effects on hormones, symptoms or aging |
| Bertoldo, 2020 | Aged female mice | NMN restored egg quality and fertility | Any result in women |
| Grant, 2019 | 8 men given IV NAD+, 3 controls | Infused NAD+ cleared from plasma fast; no adverse events | Any data in women |
| Reyna, 2026 | Records of IV NAD+ and IV NR clients | IV NAD+ often caused stomach and chest symptoms | Effectiveness beyond 30 days |
Hormones, menopause & fertility
During the menopausal transition, the ovaries make less estrogen and progesterone, which drives symptoms such as hot flashes and trouble sleeping, according to MedlinePlus. NAD+ often gets pulled into that conversation, though the evidence has not caught up.
None of the human trials above measured estrogen, progesterone or menopause symptoms. There is no human evidence that NAD+ or its precursors change hormone levels, ease hot flashes or stand in for hormone therapy. Anyone who tells you otherwise is ahead of the research.
Fertility is where the headlines come from. In a 2020 study in Cell Reports, NMN restored egg quality and fertility in aged female mice. Striking, and so far only in mice. Several of the authors co-founded a company to develop the approach, as the paper discloses. If you are trying to conceive, NAD+ is a question for your fertility specialist, not something to add on your own.
Pregnancy & breastfeeding
Niacin needs rise a little during pregnancy and breastfeeding, according to the NIH Office of Dietary Supplements. A 2026 trial protocol in BMJ Open notes that human testing of NR has been limited and that no studies in lactating women had been done. If you are pregnant, planning to be or breastfeeding, do not start an NAD+ product without your clinician.
Choosing the best NAD supplement for women
There is no single best NAD supplement for women. Each trial described here tested one form against a placebo, so none says which is better. You can still compare what each form is, and what it has been tested for.
- Niacin. Plain vitamin B3. Women 19 and older need 14 mg a day, and the average woman already gets about 21 mg from food. The upper limit for supplemental niacin is 35 mg a day, set because higher amounts of nicotinic acid cause skin flushing (NIH Office of Dietary Supplements).
- Nicotinamide riboside (NR). In a six-week trial of older men and postmenopausal women, it raised NAD+ in blood cells and was well tolerated.
- Nicotinamide mononucleotide (NMN). Tested in the postmenopausal trial above, with its metabolic findings.
- NAD+ itself, by injection. Prescription-only, compounded rather than FDA-approved, and the least studied route in people.
Supplements are not tested like medications. Under federal law, the FDA does not have the authority to approve dietary supplements before they are marketed, and the serving size on the label is the manufacturer’s decision. A label promising energy or hormone balance has not been checked by any regulator.
Food covers the basics for most women. According to the ODS, only about 1% of adults get less niacin from food than the average requirement. Poultry, beef and fish supply 5 to 10 mg of niacin per serving, and nuts, legumes and grains supply 2 to 5 mg. Harbor’s guide to raising NAD+ with food, exercise and sleep covers those habits.
Where NAD+ injections fit
Injected NAD+ has even less human data than the oral precursors, and almost none in women. When researchers first tracked infused NAD+ in people, they enrolled eight healthy men aged 30 to 55, plus three controls. During a six-hour IV drip, NAD+ vanished from the blood as fast as it went in for the first two hours, and no adverse events were seen (Grant et al., 2019).
A 2026 retrospective review of commercial IV records in Frontiers in Aging is less tidy. People receiving IV NAD+ reported moderate to severe stomach symptoms, a faster heart rate and chest pressure during infusions. The symptoms resolved when each infusion ended, but they slowed infusions to an average of 97 minutes, against 37 for the comparison drip. Its authors call the findings preliminary.
Harbor’s NAD+ program is not an IV drip. It is a small subcutaneous injection you give yourself at home, on a schedule your clinician sets. It is compounded by a licensed U.S. pharmacy, is not FDA-approved, and is dispensed only after a board-certified physician reviews your health history. A program supports your levels under clinician guidance rather than promising a specific result. If it is not the right fit, it is not prescribed. If you are also prescribed glutathione, Harbor’s guide to taking NAD+ and glutathione together covers the routine.
When to stop and get help
Chest pain, trouble breathing, or swelling of the face, lips or throat after an injection means stop and seek emergency care. Mild redness at the injection site, passing nausea or a headache is a message to your Harbor clinician, not an emergency.
What to bring to your clinician
Start with what you hope NAD+ will do. A clinician can then tell you whether the evidence reaches that far, and what else to check first.
- Your goal, in your own words.
- Every supplement you take, including any niacin, NR or NMN, with the amounts.
- Your menstrual and menopause status, and whether you are pregnant, trying to conceive or breastfeeding.
- Your prescriptions and any recent blood work.
- Anything you have tried already and how it went.
After that, the decision is the physician’s. If NAD+ makes sense for you, the online quiz takes about 90 seconds and starts the review.