NAD+ and Hair Loss: What the Research Shows

Early evidence suggests a link between NAD+ and hair loss, and the mechanism is fairly simple: hair follicles are some of the most metabolically active structures in the body, and they appear to be sensitive to age-related declines in cellular NAD+. A 2025 clinical trial found that women who took an oral NAD+ precursor for 12 weeks saw a measurable increase in the density of actively growing hair. That's a genuinely interesting result, but it doesn't mean NAD+ treats pattern hair loss, or that the same effect applies to injectable NAD+. Here's what the research actually shows, and where the gaps still are.

Why Hair Follicles Are So Sensitive to Cellular Energy

Hair growth is an energy-intensive process. During the active growth phase, known as anagen, cells in the hair follicle's matrix divide faster than almost any other cell type in the body, and that rapid division depends on a steady supply of ATP, the cell's main energy currency. Producing ATP efficiently requires healthy mitochondria, and mitochondria in turn rely on NAD+ as a coenzyme to keep their energy-producing reactions running.

Researchers have long observed that ageing skin and hair show signs of mitochondrial decline. In one widely cited 2018 mouse study published in Cell Death & Disease, scientists used a genetic model to deliberately deplete mitochondrial DNA in adult mice, which led to hair follicle dysfunction and skin thinning that resembled accelerated ageing. When the mice's mitochondrial function was allowed to recover, the hair and skin returned to a normal, healthy state as well. This was an animal study using an engineered model, not evidence that raising NAD+ in humans changes the course of hair loss in people, but it helps explain why mitochondrial and cellular energy status interest hair researchers in the first place.

What NAD+ Actually Does Inside a Growing Follicle

NAD+ (nicotinamide adenine dinucleotide) supports mitochondria in two main ways that could plausibly matter for hair: it's a required coenzyme for the reactions that generate ATP, and it fuels a family of proteins called sirtuins, which help regulate mitochondrial health, DNA repair and cellular stress responses. Because NAD+ levels are known to decline gradually with age, some researchers have theorised that this decline could leave energy-hungry tissues, hair follicles included, less able to sustain the rapid cell division that healthy hair growth requires.

Our guide on how to support NAD+ levels naturally covers the main lifestyle factors involved, including diet, exercise and sleep.

This is still largely a hypothesis supported by cell and animal research rather than a fully proven human mechanism. Hair follicle stem cells appear to be particularly sensitive to shifts in cellular metabolism, and laboratory studies have shown that manipulating energy pathways can change how readily these stem cells activate and divide.

What Does the Actual Research Show?

The most direct human data comes from a small clinical trial published in the journal Cosmetics in 2025. Researchers gave 15 Japanese women aged 40 to 50 an oral NAD+ precursor, nicotinamide mononucleotide (NMN), daily for 12 weeks. By the end of the study, the density of actively growing (anagen) hairs increased significantly, from an average of 55.9 to 87.7 hairs per square centimetre, and average hair shaft diameter increased slightly as well. Participants also reported smoother hair cuticles, more shine and elasticity, and less self-reported fatigue.

That's a real, peer-reviewed result, but it's also a small, short trial in a specific population, using an oral NAD+ precursor rather than injectable NAD+. Separately, laboratory research on human hair follicle cells exposed to DHT, the hormone primarily responsible for pattern hair loss, has found that NMN reduced markers of inflammation in those cells and appeared to counteract some DHT-driven changes, with similar early findings reported in mice. None of this amounts to a treatment claim, but together it's a reasonable case for further study.

Pattern Hair Loss vs Age-Related Thinning: An Important Distinction

Not all hair loss is the same, and this distinction matters for what NAD+ can realistically be expected to do. Androgenetic alopecia, the most common cause of hair thinning in both men and women, is driven primarily by a genetically determined sensitivity to DHT in certain follicles, which causes them to gradually miniaturise over time. This is a hormonal and genetic process, and there's currently no evidence that NAD+ interrupts or blocks that DHT pathway directly.

Age-related thinning that isn't primarily driven by DHT sensitivity, sometimes described more generally as declining hair quality, is the area where the mitochondrial and cellular energy research above is more directly relevant. In other words, current NAD+ research says more about supporting the general metabolic environment hair grows in than about addressing the specific hormonal drivers of pattern baldness. If you're dealing with significant or rapid hair loss, it's worth discussing the underlying cause with a healthcare professional or dermatologist before assuming any single approach will help.

Where NAD+ Might Fit Into a Hair Health Routine

Given the current evidence, NAD+ is probably best thought of as one piece of a broader approach to cellular vitality rather than a targeted hair loss treatment on its own. Established, clinically studied options for pattern hair loss work through different and better-documented mechanisms, and a healthcare professional is the right person to discuss those with.

For people already interested in NAD+ for its wider research around cellular energy and skin appearance, see our related look at NAD+ and skin health. Any visible effect on hair may simply be one expression of a broader shift in cellular energy metabolism. Diet, sleep, exercise and stress management all influence NAD+ levels too, and are worth addressing alongside any supplement or injectable routine.

Frequently Asked Questions

Can NAD+ regrow hair that's already been lost?

There's no clinical evidence that NAD+, in any form, regrows hair in areas where follicles have already stopped producing hair entirely. The research discussed above relates to hair density, shaft thickness and follicle activity in existing, still-active follicles, not to reviving dormant or scarred follicles.

Is oral NMN the same as injectable NAD+ for hair health purposes?

Not exactly. NMN is a precursor that the body converts into NAD+, while an NAD+ injection delivers the molecule more directly. The 2025 clinical trial on hair density used oral NMN, so its results don't automatically transfer to injectable NAD+, even though both are intended to raise the same underlying coenzyme.

How long would it take to notice any change in hair, if any?

The clinical trial referenced above ran for 12 weeks before researchers measured a difference, and hair growth cycles are naturally slow, typically taking several months for changes to become visible. There's no reliable shorter timeline in the current research, so this isn't something to expect quick results from.

Can NAD+ be used alongside minoxidil or other hair loss treatments?

There's no research specifically testing NAD+ alongside minoxidil or prescription hair loss treatments, and no known mechanism suggesting a conflict, but this hasn't been formally studied. Speak with a healthcare professional or dermatologist before combining NAD+ with any prescribed or over-the-counter hair loss treatment.

Does hair thinning mean NAD+ levels are low?

Not necessarily. Hair thinning has many possible causes, including genetics, hormones, nutrition, stress and underlying health conditions, and there's no validated test linking a specific NAD+ level to hair loss. Thinning hair on its own isn't a reliable sign of low NAD+ status.

This article is for general informational purposes only and does not constitute medical advice. Always speak with a qualified healthcare professional before starting any new supplement or injectable therapy.