Hair loss is an emotionally traumatic experience for patients, and the standard therapeutic armamentarium is frustrating at best. Fortunately, there are several promising supplements and topical botanical agents on the horizon for alopecia.
Balding? Hurray! (Said no one, ever.)
In fact, a quick Google search of “hair loss” generates 71,600,000 results in less than half a second (as compared to 41 million for Botox, 22 million for eczema, and 20 million for melanoma). Many of us have taken histories of hair shedding by the handful, sorted through plastic baggies containing a daily or weekly collection, or offered tissues to ever-younger patients who tearfully bemoan their receding hairlines.
Hair loss, or alopecia, is a common presenting complaint, and one for which the standard therapeutic armamentarium is frustrating at best. Focusing specifically on androgenetic alopecia, rooted in genetics, hormones, and a degree of je ne sais quoi, currently available FDA-approved therapies are limited to two medications and one medical device: topical minoxidil (sold under the trade name Rogaine, for men and women), oral finasteride (trade name Propecia, approved for men only), and the HairMax laser comb, a home hand-held device which emits a low level 655nm beam. As such, there is ample opportunity for research and new product development, and this article will review some botanical compounds under study specifically for hair growth.1
It is now well-accepted that the local conversion of testosterone to dihydrotestosterone (DHT) is an important mechanism in the pathogenesis of male, and possibly female, pattern hair loss. This reaction is catalyzed by the enzyme 5-alpha reductase, inhibition of which is the mechanism of finasteride. Aiming to mimic this benefit while simultaneously avoid finasteride’s undesirable side effects (loss of libido, breast tenderness, erectile dysfunction), scientists continue to investigate a number of botanical sources of 5-AR inhibitors.
Saw palmetto (beta-sitosterol), green tea (epigallocatechin gallate conjugated with palmitic acid), and sophora flavescens are three plant sources with demonstrable benefits in prostate health, and some studies to also support hair growth, although more research is required before formats and required quantities may be standardized and more commercially available. So don’t go downing those gallons of green tea just yet.2,3,4
Antioxidants, such as polyphenols and flavonoids, have long been used in anti-aging skincare regimens.5 One group of Japanese researchers studied the in vitro / vivo effects of procyanidin flavonoids (compressed tannins) on hair growth in mice.6 The oligomeric form of grape seed-derived procyanidins increased the proliferation of mouse hair follicles in vitro by almost one and a half times that of minoxidil (230% vs 160%), and the in vivo effect was comparable between the two groups, via conversion of telogen hairs back into the anagen growth phase.
Further studies in humans demonstrated both increased hair density and shaft diameter in areas treated with apple-derived procyanidin tonics, twice daily for 6-12 months.7,8
One purported mechanism of action is the inhibition of TGF-beta, a negative regulator of hair growth, by plant-derived procyanidins, while another is the similar inhibition of protein kinase C.9 Several commercially available products containing proanthocyanidins include Poly-GRO Procyanidin B-2, manufactured by Apple Poly LLC (Morrill NE), and Revita / Spectral RS (DS Laboratories).
What do chili peppers, raspberries, and soy share in common? They all have the ability to stimulate the release of calcitonin gene-related peptide (CGRP) and thereby increase dermal levels of insulin-like growth factor 1 (IGF-1) and hair growth, via their respective active components including capsaicin, raspberry ketones, and isoflavones.10In vivo experiments in both rodents and human subjects have demonstrated hair growth compared to controls, with dietary inclusion of capsaicin and isoflavones.11,12 A further mechanism of action for soy derivatives includes activation of prostaglandin-E2 (PGE2) and downstream upregulation of NF-kB, which overall suppresses the apoptosis of hair follicles.13
Another oral supplement is red ginseng, the heated or steamed form of Asian Panax ginseng, which has been extensively investigated for its role in treating hair loss. Active ingredients are saponins, which are subdivided into Rb, Rg, and G-Ro. In studies, Rb displays the greatest ability to stimulate cultured hair follicles (Matsuda 2003) as well as prevent cellular apoptosis, and one human trial included daily oral intake of 3000mg of Korean red ginseng extract with overall increased hair density over 24 weeks.15
Korean researchers have also studied essential oil therapy for hair loss-specifically, the oil of zizyphus jujube, medicinally used as an analgesic, contraceptive, and for diabetes management.1 In mouse models, the topical application of 1% and 10% solution increased the anagen growth phase, as measured by longer hairs.16 Some forms of essential oil and aromatherapy may induce a state of relaxation (lavender oil, for example), helping to break the vicious cycle of systemic stress-related inflammation and hair shedding.
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Also native to South Korea, the plant Schisandra nigra was found with topical application to induce anagen progression of the hair shaft in mice, via down-regulation of TGF-beta.17 The teak tree Tectona grandis native to the Indian subcontinent has historical tribal use for hair preservation, and recent research comparing its effects in topical form to 2% minoxidil solution revealed a greater number of follicles entering the anagen phase with the former.18
Finally, certain amino acids may promote hair growth. Taurine, of which dietary intake is critical, demonstrated in vitro prolongation of the anagen phase in human hair follicles,19 while L-carnitine has yielded positive results in upregulating hair shaft proliferation and downregulating apoptosis in both lab studies as well as live human subjects.20,21
So, while Disney princes and princesses continue to give us unrealistic expectations about hair, there are several promising supplements and topical botanical agents on the horizon for alopecia. Keeping in mind potential safety concerns and the need for additional research, botanical therapies may prove useful for the carefully-selected patient.
Rogers, N.E. Integrative therapies for alopecia. In Norman, Shenefelt, & Rupani (Eds.) Integrative Dermatology. Oxford University Press, 242-261. 2014.
Prager N, Bickett K, French N, et al. A randomized, double-blind, placebo-controlled trial to determine the effectiveness of botanically-derived inhibitors of 5-alpha-reductase in the treatment of androgenetic alopecia. Journal of Alternative and Complementary Medicine, 8, 143-152. 2002.
Hiipakka R, Zhang H, Dai W, et al. Structure-activity relationships for inhibition of human 5-alpha-reductases by polyphenols. Biochemical Pharmacology, 63, 1165-1176. 2002.
Roh S, Kim C, Lee M, et al. The hair growth promoting effect of Sophora flavescens extract and its molecular regulation. Journal of Dermatologic Science, 30, 43-49. 2002.
Wayne Z. Pycnogenol and skincare. Drug and Cosmetic Industry, 158, 44-50. 1996.
Takahashi T, Kamiya T, Yokoo Y. Proanthocyanidins from grape seeds promote proliferation of mouse hair follicle cells in vitro and convert hair cycle in vivo. Acta Dermatol-Venerologica, 78, 428-432. 1998.
Takahashi T, Kamimura A, Yokoo Y, et al. The first clinical trial for topical application of procyanidin B-2 to investigate its potential as a hair growing agent. Phytotherapy Research, 15, 331-336. 2001.
Takahashi T, Kamimura A, Kagoura M, et al. Investigation of the topical application of procyanidin oligomers from applies to identify their potential use as a hair-growing agent. Journal of Cosmetic Dermatology, 4, 245-249. 2005.
Kamimura A, Takahashi T. Procyanidin B-2, extracted from apples, promotes hair growth: a laboratory study. British Journal of Dermatology, 146, 41-51. 2002a.
Harada N, Okajima K, Narimatsu N, et al. Effect of topical application of raspberry ketone on dermal production of insulin-like growth factor-1 in mice and on hair growth and skin elasticity in humans. Growth Hormone and IGF Research, 18, 335-344. 2008.
Harada N, Okajima K, Arai M, et al. Administration of capsaicin and isoflavone promotes hair growth by increasing insulin-like growth factor-1 production in mice and in humans with alopecia. Growth Hormone and IGF Research, 17, 408-415. 2007.
Zhao J, harada N, Kurihara K, et al. Dietary isoflavone increases insulin-like growth factor-1 production, thereby promoting hair growth in mice. Journal of Nutritional Biochemistry, 22, 227-233. 2011.
Tsuruki T, Takahata K, Yoshikawa M. Anti-alopecia mechanisms of coymetide-4, an immunostimulating peptide derived from soy beta-conglycinin. Peptides, 26, 707-711. 2005.
Matsuda H, Yamazaki M, Asanuma Y, et al. Promotion of hair growth by Ginseng Radix on cultured mouse vibrissal hair follicles. Phytotherapy Research, 797-800. 2003.
Kim J, Yi S, Choi J, et al. Study of the efficacy of Korean red ginseng in the treatment of androgenetic alopecia. Journal of Ginseng Research, 33 ,223-228. 2009.
Yoon J, Al-Reza S, Kang S. Hair growth promoting effect of Zizyphus jujuba essential oil. Food and Chemical Toxicology, 48, 1350-1354. 2010.
Jabg Hum Kim S, Hyun J, Park D, et al. Promotion effect of Schisandra nigra on the growth of hair. European Journal of Dermatology, 19(2), 119-125. 2009.
Jaybhaye D, Varma S, Gagne N, et al. Effect of Tectona grandis Linn. seeds on hair growth activity of albino mice. International Journal of Ayurveda Research, 1, 211-215. 2010.
Collin C, Gautier B, Gaillard O, et al. Protective effects of taurine on human hair follicle grown in vitro. International Journal of Cosmetic Science, 28, 289-298. 2006.
Foitzik K, Hoting E, Heinrich U, et al. Indications that topical L-carnitine-L-tartrate promotes hair growth in vivo. Journal of Dermatologic Science, 48, 141-144. 2007.
Foitzik K, Hoting E, Pertile P, et al. L-carnitie tartrate promotes human hair growth in vitro. Journal of Investigative Dermatology, 126, s27 (P146). 2006.