Retinol, also known as Vitamin A and trentinoin, is essential for the growth of and maintenance of skin and hair (Ehrlich, 2011). It is thought that retinol regulates hair follicle growth through biological manipulation of the immune system (Everts, Sundberg, King, & Ong, 2007).
Topical retinol has also been shown to increase blood flow to hair follicles and encourage new blood vessel formation (Rogers & Avram, 2008, p. 552). The anti-inflammation capabilities seen in topical retinol have made it widely accepted by the scientific community as a potential treatment for hair loss (Rahman & Bagchi, 2014).
In a study focusing on the benefits of the topical application of 0.025% retinol, on average, test subjects saw moderate increases in hair growth and some saw extreme increases in hair growth. The combination of minoxidil and topical retinol saw even more statistically significant hair growth (Bazzano, Terezakis, & Galen, 1986).
Minoxidil and Retinol Shown to Increase Hair Growth
Supporting this assertion, Yoo et al. showed in a study that a mixture of minoxidil and retinol increased hair growth significantly in alopecia areata patients (2007). Bazzano, Terezakis, & Galen state in their study that the combination of minoxidil and retinol should be studied more than just topical retinol alone, as the two medications together seem to stimulate the biological effects the other lacks (1986). In addition, larger controlled studies need to be done to confirm these hair growth effects in hair growth patients, according to scientists, as most controlled studies done on both topical retinol and topical retinol combined with minoxidil (Terezakis & Bazzano, 1988). This need for further research is backed by recent studies on aging, where it is stated that topical retinol needs to be studied on hair loss due to aging to conclusively prove the hair growth properties of topical retinol (Rahman & Bagchi, 2014, p. 240).
- Bazzano, G. S., Terezakis, N., & Galen, W. (1986). Topical tretinoin for hair growth promotion. Journal of the American Academy of Dermatology, 15(4), 880-893. doi:10.1016/s0190-9622(86)80024-x
- Ehrlich, S. D. (2011, June 21). Vitamin A (Retinol). Retrieved June 16, 2015, from http://umm.edu/health/medical/altmed/supplement/vitamin-a-retinol
- Everts, H. B., Sundberg, J. P., King, L. E., & Ong, D. E. (2007). Immunolocalization of Enzymes, Binding Proteins, and Receptors Sufficient for Retinoic Acid Synthesis and Signaling During the Hair Cycle. J Investig Dermatol Journal of Investigative Dermatology, 127(7), 1593-1604. doi:10.1038/sj.jid.5700753
- Rahman, I., & Bagchi, D. (2014). Aging and Anti-Aging in Hair and Hair Loss. In Inflammation, advancing age and nutrition: Research and clinical interventions (pp. 231-246). Academic Press. doi:10.1016/B978-0-12-397803-5.00019-8
- Rogers, N. E., & Avram, M. R. (2008). Medical treatments for male and female pattern hair loss. Journal of the American Academy of Dermatology, 59(4), 547-566. doi:10.1016/j.jaad.2008.07.001
- Terezakis, N. K., & Bazzano, G. S. (1988). Retinoids: Compounds important to hair growth. Clinics in Dermatology, 6(4), 129-131. doi:10.1016/0738-081x(88)90077-6
- Yoo, H. G., Chang, I., Pyo, H. K., Kang, Y. J., Lee, S. H., Kwon, O. S., . . . Kim, K. H. (2007). The Additive Effects of Minoxidil and Retinol on Human Hair Growth in Vitro [Abstract]. Biological & Pharmaceutical Bulletin Biol. Pharm. Bull., 30(1), 21-26. doi:10.1248/bpb.30.21