Recent studies show that phytoestrogens work like natural estrogens and can support hair growth.

Research published by Ebling in 1957 showed that estrogens increased the growth rate of cells in the skin and hair and also reduced the size and activity of sebaceous glands.  The two main estrogens that effect hair growth are estradiol (E2) and estrone (E1).  Estradiol is a more potent activator of hair growth than estrone but must be synthesised from testosterone.

The anagen (growth) and telogen (resting) phase of the hair follicle are modulated by a number of hormones including testosterone and DHT.  Estradiol, the most potent estrogen for hair growth can be produced from testosterone or estrone by 17-beta-hydroxysteroid dehydrogenase, a zinc dependant enzyme.  Most often, hair loss is due hormonal alterations that disrupt the hair growth cycle.

Estrogen and hair growth


Hormonal alterations can effect hair growth because they can increase or decrease substances such as growth factors that influence hair follicle survival.  Growth factors directly control how long hair remains in anagen phase (growth phase) and when hair goes into telogen (resting phase) in preparation to be shed.

Induction of anagen phase is dependant on transforming growth factor beta and keratinocyte (keratin cell) growth factor (KGF) or fibroblast growth factor (FGF).  Maintenance of anagen phase is controlled by insulin-like growth factor-1 (IGF-1) and vascular endothelial growth factor (VEGF).

The anagen-to-catagen transition involves cross-talk between keratinocyte growth factor and transforming growth factor-beta.

Estrogens and estrogen receptors play an important role in the signalling pathways that regulate hair growth.

Functional cross-talk between estrogens and receptors regulate the action of growth factors that control the hair growth cycle.

Growth Factor Action Modulation
Insulin -like growth factor-1 (IGF-1) Stimulates hair growth Estrogen receptor cross-talk
Vascular endothelial growth factor (VEGF) Development of blood vessels that surround the hair follicle unit Estrogen increases production
Transforming growth factor beta (TGF-B) Stimulates resting and shedding phase of the hair cycle Estrogen receptor cross-talk
Keratinocyte growth factor (KGF) An important mediator of hair follicle growth and development Estrogen receptor crosstalk


Phytoestrogens are a general term for compounds of various structures, originating in plant sources and mimicking or modulating the action of estrogenic hormones.  The estrogenic potential of certain plants was first reported in the 1940s from an observation of sheep that suffered reproductive disorders as a consequence of a diet mostly based on clover.

Female hop-pickers suffered from disturbances in their menstrual cycles during the hop harvests, and this phenomenon led to the assumption that hops exerted estrogenic activities.  The active substance, 8-PN, which is responsible for the estrogenic effect in hops, was identified in 1999 by Milligan [1].

Phytoestrogens in the body act like weak estrogens and when applied topically will not impact hormonal balance in the body.  Estrogens profoundly alter hair growth by binding to estrogen receptors in the hair follicle.  Besides altering estrogen dependant genes, estrogen modify hair follicle metabolism in the hair follicle and the sebaceous gland.

Phytoestrogens are plant derived, non-steroidal estrogens from hops or soy. The most well known phytoestrogens have been shown to modulate the hair growth cycle and clinical trials have shown that soy isoflavones help reduce the severity of alopecia areata.


Alopecia areata has been shown to respond to phytoestrogens within soy bean oil.  Soy beans and it’s derivatives have been associated with a reduction in susceptibility to several autoimmune diseases.  The beneficial effects have been attributed to the high levels of phytoestrogens present in soy bean oil.  The principal phytoestrogens in soy bean oil are daidzein and genistein.


In a study investigating the effects of isoflavones on hair growth it was found that hair regrowth in mice was greatly accelerated when capsaicin (an active component of chilli peppers) and isoflavones were administered for 4 weeks than in mice who were treated with capsaicin alone.

It is likely that hair growth was greater in the mice that had a combination of capsaicin and phytoestrogens due to the antioxidant effect of daidzein and genistein.  These antioxidants have a high level of potential scavenging activity for the increased reactive oxidative species often associated with alopecia areata relapse.

This study was repeated in humans with an administered dose of 6mg per day of capsaicin and 75mg per day of isoflavones.  It was found that plasma levels of insulin-like growth factor were significantly increased from baseline. When compared to those given a placebo, the percentage of volunteers who showed hair regrowth was significantly higher, 64.5% experienced some level of hair regrowth within 5 months when compared to 11.8% given a placebo.


High intakes of soy have been associated with breast cancer and endometriosis, though studies have shown they don’t increase C-reactive protein (an inflammatory marker that generally increases in breast cancer) and it does not increase your risk of being diagnosed with endometriosis.

Soy bean oil is high in omega-6 oils which can potentially cause an imbalance in your omega 3/ omega 6 ratio (which should be 1:1-3:1). Soy is a known potential allergen, capable of ramping up an already deranged immune reaction (as is normally seen in alopecia areata).  Soy in foods such as, soy milk, soy-based “meats” and soy-based ice creams are considered to be heavily processed and should be avoided.

Topical application of a phytoestrogen based product can be reliable for the treatment of alopecia when combined with other appropriate supplements or medication.  Addressing systemic immune activation by assessment of zinc levels and other confounding factors is likely to increase the success rate of this remedy.


Two types of estrogen receptor are distinguishable in the human hair follicle.  Estrogen receptor α is involved in keeping the hair follicle in anagen (growth activation of the hair follicle), while estrogen receptor β is responsible for inducing telogen in preparation for the hair to be shed.  In humans estrogen receptor α is the predominant estrogen receptor in hair follicles.

Due to the mixed ability of 8-PN to interact with estrogen receptor α and estrogen receptor β, this compound is able to exert actions that increase hair follicle growth.  Human estrogen (17 β — estradiol) tends to interact with estrogen receptor β (the primary estrogen receptor in the hair follicle).

Phytoestrogens can act as an anti- estrogen by temporarily binding to estrogen receptor β, thus inhibiting the telogen inducing activity of human estrogen by blocking binding sites.  This means 8-PN can prevent activation of estrogen receptor β and reduce premature telogen and extend anagen phase.

Substrates binding to an estrogen receptor usually have a preferential affinity to one receptor type. In this regard, the majority of phytoestrogens show a preference for estrogen receptor β, while 8-PN predominantly binds to estrogen receptor α.

Phytoestrogens for hair growth
Phytoestrogens for hair growth

Phytoestrogens extracted from hops (8-PN) stimulates extends the hair follicle growth period.  Shortening of the anagen phase gives the impression that hair does not grow even though the hair is going through a complete growth cycle.


The interaction of 8-PN with estrogen receptors makes it a powerful compound for the reversal hormone dependent hair loss disorders.  Whilst this compound provides excellent activation of growth factors, the hair follicle will need starter biomaterials such as sulphur (cysteine precursor), haemoglobin, iron and zinc to support the induced and prolonged anagen cycle.


Whilst research supports supplementation of phytoestrogens, topically applied phytoestrogens may be preferable to prevent systemic changes of hormone concentration.

Phytoestrogens are an effective component of any hair loss regime designed to reduce the severity and reverse the effects of telogen effluviumandrogenic alopecia, alopecia areata and to support adequate hair regrowth in women with thin, slow growing hair.


Ebling FJ, The action of testosterone on the sebaceous glands and epidermis in castrated and hypophysectomized male rats.
p.306, 1957

Milligan S., Kalita J., Heyerick A., Rong H., De Cooman L., De Keukeleire D. Identification of a potent phytoestrogen in hops (Humulus lupulus L.) and beer. J. Clin. Endocrinol. Metab. 1999;84:2249. doi: 10.1210/jcem.84.6.588

Harada N, Okajima K, Arai M, Kurihara H, Nakagata N. Administration of capsaicin and isoflavone promotes hair growth by increasing insulin-like growth factor-I production in mice and in humans with alopecia. Growth hormone & IGF research. 2007 Oct 1;17(5):408-15.

Conrad F, Paus R. Estrogens and the hair follicle: Östrogene und der Haarfollikel. JDDG: Journal der Deutschen Dermatologischen Gesellschaft. 2004 Jun;2(6):412-23.

Green, Sarah E. “In Vitro Comparison of Estrogenic Activities of Popular Women’s Health Botanicals.” Master of Science Thesis, University of Illinois. doi 10 (2015).

Alexander NJ, Smythe NL, Jokinen MP. The type of dietary fat affects the severity of autoimmune disease in NZB/NZW mice. The American journal of pathology. 1987 Apr;127(1):106.

Prie BE, Voiculescu VM, Ionescu-Bozdog OB, Petrutescu B, Iosif L, Gaman LE, Clatici VG, Stoian I, Giurcaneanu C. Oxidative stress and alopecia areata. Journal of Medicine and Life. 2015;8(Spec Issue):43.