Polyphenols are organic chemicals usually found in plants that multiple phenol (C6H5OH) units attached to their structural compositions.
Common foods and drinks that contain polyphenols are green tea, assorted fruits, and green, leafy plants in general.
Polyphenols have been extensively researched for their health benefits to humans, including the area of hair growth.
A 3 Fold Increase in the Antibody Involved in Hair Growth
In a study done by Kwon et al. (2007), both the in vitro effects of green tea and the in vivo effects of topical green tea extract application were analyzed to see whether or not the use of the green tea would increase the rate of hair growth in subjects. The active ingredient in green tea, Epigallocatechin gallate, was the particular polyphenol studied. The results of this study were that the direct, topical application of the Epigallocatechin gallate resulted in an almost 3-fold increase in the expression of the P-Erk antibody, which is an antibody involved in hair growth.
Their results indicate it was possible for EGCG to be used topically to increase hair growth. (Kwon et al., 2007)
10% Increase in Hair Growth
Supporting the results of the above study is another study done on a different polyphenol, Proanthocyanidin. This polyphenol is found in Zizyphus jujuba, also known as the jujube fruit.
Yoon, Al-Reza, & Kang (2010) studied the effects of topical jujube oil on mice. This study too showed that the polyphenol proanthocyanidin initiated hair growth in the shaved mice to 10% more than the control group (Yoon, Al-Reza, & Kang, 2010, pp. 1353-1354).
However, it must be noted that more studies need to be done on polyphenols in a topical sense. Kwon et. al (2007) stated in their conclusion that it was “unclear” how the polyphenol in green tea affected hair growth, particularly in different hair follicles. In addition, a study done by Rho et al. (2005), which suggested that the 45 plant extracts they tried on alopecia patients were helpful to hair growth, made clear that the exact mechanisms of polyphenols in relation to hair growth were unknown, and further research must be done to confirm precisely which plant oils work the best for hair growth.
- Kwon, O., Han, J., Yoo, H., Chung, J., Cho, K., Eun, H., & Kim, K. (2007). Human hair growth enhancement in vitro by green tea epigallocatechin-3-gallate (EGCG). Phytomedicine, 14(7-8), 551-555. doi:10.1016/j.phymed.2006.09.009
- Rho, S., Park, S., Hwang, S., Lee, M., Kim, C., Lee, I., . . . Rang, M. (2005). The hair growth promoting effect of Asiasari radix extract and its molecular regulation. Journal of Dermatological Science, 38(2), 89-97. doi:10.1016/j.jdermsci.2004.12.025
- Yoon, J. I., Al-Reza, S. M., & Kang, S. C. (2010). Hair growth promoting effect of Zizyphus jujuba essential oil. Food and Chemical Toxicology, 48(5), 1350-1354. doi:10.1016/j.fct.2010.02.036