TLDR Niacinamide does not promote hair growth.
In a letter to the editor from March 20, 2020, John E. Oblong and colleagues from The Procter & Gamble Company reviewed literature and presented new data to address the belief that topical niacinamide (Nam) promotes hair growth. They concluded that Nam has a neutral effect on hair growth, citing a clinical study that showed increased hair thickness and density with 0.1% Nam treatment but noting the study's limitations, including the absence of a placebo control. Additionally, their in vitro tests revealed that Nam did not stimulate vascular endothelial growth factor (VEGF) synthesis nor showed significant connections to hair growth-related compounds such as adenosine or minoxidil. Based on these findings, they argued that there is no substantial evidence to support the claim that Nam significantly affects hair growth.
11 citations,
April 2015 in “International Journal of Cosmetic Science” Adenosine helps grow thicker hair in Japanese men with hair loss.
27 citations,
December 2005 in “Journal of Cosmetic Dermatology” Niacin derivatives may increase hair fullness in women with hair loss.
269 citations,
August 2002 in “Journal of The American Academy of Dermatology” 5% minoxidil works better for hair growth and density, with minor irritation.
83 citations,
December 2001 in “Journal of Investigative Dermatology” Minoxidil boosts hair growth by targeting adenosine and possibly sulfonylurea receptor 2B.
192 citations,
March 1998 in “British Journal of Dermatology” Minoxidil boosts growth factor in hair cells, potentially promoting hair growth.
1 citations,
October 2021 in “Clinical, Cosmetic and Investigational Dermatology” Vitamin B3 may help prevent hair loss and promote hair growth by protecting scalp cells from stress and reducing hair growth-blocking proteins.
February 2024 in “Molecules/Molecules online/Molecules annual” NMN could potentially treat hair loss by reducing oxidative stress and improving cell health.
10 citations,
June 2019 in “International Journal of Cosmetic Science” Some plant-based chemicals may help with hair growth, but more research is needed to confirm their effectiveness.
88 citations,
January 2013 in “Indian Journal of Dermatology, Venereology and Leprology” Minoxidil and finasteride effectively treat hair loss.
17 citations,
December 2015 in “International Journal of Cosmetic Science” Visible light can improve skin disorders and hair loss, but more research is needed to understand long-term effects.
