NAD+ (nicotinamide adenine dinucleotide) is an essential coenzyme found in all living cells, playing a crucial role in cellular energy production and the regulation of numerous biological processes. Its potential impact on hair regrowth is an increasingly explored subject, although research is still in its early stages.
A recent study, primarily conducted on animal models, has shown that increasing levels of β-nicotinamide mononucleotide (NMN), a precursor of NAD+, could have a positive effect on hair growth. A study in vivo observed that the administration of NMN in mice post-hair removal helped to reduce signs of ageing in hair follicles. NMN not only helped to restore the size of hair follicles, but also to reduce hair thinning caused by a treatment with dihydrotestosterone (DHT), a factor commonly associated with hair loss. The observed effects were similar to those of minoxidil, a treatment commonly used to stimulate hair regrowth.
The underlying mechanisms of these results include the reduction of inflammation in the dermal cells of the hair papilla treated by DHT, as well as the protection against oxidative stress. Furthermore, hair growth markers, such as Vascular Endothelial Growth Factor (VEGF) and β-catenin, showed increased expression, while androgen receptors and inhibitors like DKK-1 were decreased, thus promoting hair regrowth.
Another study in vivo has also validated the effect of NAD+ on DNA repair, directly through the activation of PARP1 and by acting on hair growth cycles. In summary, it has been demonstrated that the activation of PARP1 under the control of NAD+ could reduce DNA losses from hair follicles and regulate the stages of hair growth.
However, although the studies are promising, large-scale human clinical trials are needed to confirm these effects, which are currently only hypothesised in humans. Ongoing studies indeed show that NAD+ could play a role in the regeneration of hair follicles, but there is still no proof that it is effective in a practical application against hair loss.