The hair cycle and hair follicle structure are highly affected by various hormones. Androgens—such as testosterone (T); dihydrotestosterone (DHT); and their prohormones, dehydroepiandrosterone sulfate (DHEAS) and androstendione (A)—are the key factors in terminal hair growth.
Androgen hormones, sometimes referred to as “male” hormones, like DHEA and testosterone, play the largest role in your overall hair growth.
Estrogen and Progesterone
These hormones also help with hair growth. Estrogen and progesterone can help keep your hair in the growing (anagen) phase. Therefore, these hormones can help your hair stay on your head longer and may even help your hair grow faster.
Lifestyle changes, such as a healthier diet, exercise, and stress reduction will also help you get your hormone levels back on track. Once equilibrium is restored to your hormones, hair loss associated with your hormone issue should slow or cease, and in many cases, hair that was loss may be replaced by new growth.
This increase in DHT can potentially come from other things that affect hormonal balance, including menopause, stress, and/or underlying thyroid issues [3]. It's important to understand an important factor is genetic sensitivity to DHT.
DHT is a hormone that contributes to hair loss in both men and women. Green tea, onions, pumpkin seeds, and edamame, among other foods and beverages, contain nutrients that may lower DHT levels and prevent hair loss.
Too much estrogen can cause hair loss and thinning hair. Many times, an increase in estrogen is caused by perimenopause, ingesting or touching endocrine disruptor items and gaining weight. Estrogen affects the hormones, which in turn affect the ability for your hair to grow.
DHT, a derivative of the male hormone testosterone, is the enemy of hair follicles on your head. Simply put, under certain conditions DHT wants those follicles dead. This simple action is at the root of many kinds of hair loss. Testosterone converts to DHT with the aid of the enzyme 5-alpha reductase.
Lower estrogen and progesterone levels: Estrogen and progesterone stimulate hair growth, which is why pregnant women—who are producing extra levels of these hormones—tend to experience thickening hair during their pregnancy.
Estrogen is related to hair growth — and hair loss. During pregnancy, for example, a woman's estrogen levels are higher than normal, which signals more hair follicles to "grow" and fewer to "rest." While estrogen levels are high, women have full, thick hair.
Estrogen and progesterone levels fall, meaning that the effects of the androgens, male hormones, are increased. During and after menopause, hair might become finer (thinner) because hair follicles shrink. Hair grows more slowly and falls out more easily in these cases.
Biotin. Biotin, also known as vitamin B7, is a complex B vitamin that is often touted for having hair growth benefits. And some of that hype may actually be worth it. Biotin has functions in “creating red blood cells, which carry oxygen and nutrients to the scalp and hair follicles,” says Dr. Green.
When the levels of estrogen and progesterone drop, hair grows more slowly and becomes much thinner. A decrease in these hormones also triggers an increase in the production of androgens, or a group of male hormones. Androgens shrink hair follicles, resulting in hair loss on the head.
In addition to keeping your bones strong, estrogen and progesterone keep your hair healthy. A decrease in these hormones causes an increase in androgen production which causes hair follicles to shrink and contribute to hair loss.
Excess thyroid, estrogen, progesterone and DHEA supplements can all cause hair loss. When the hair follicle is exposed to higher-than-normal levels of hormone, it shuts down and stops responding.
A Fred Hutchinson Cancer Research Center study involving postmenopausal, overweight, and obese women who took 2,000 IUs of vitamin D daily for a year found that those whose vitamin D blood levels increased the most had the greatest reductions in blood estrogens, which are a known risk factor for breast cancer.
It depends on your situation. Not all women need, want or are candidates for estrogen therapy. Estrogen can reduce menopausal symptoms like hot flashes, night sweats and vaginal dryness. If you have a uterus, you'll likely need to take progesterone along with the estrogen.
Of the many nutrients and oils touted as natural DHT blockers, rosemary oil is one of the best proven. In a 2015 study, men applied either rosemary oil or minoxidil (an FDA-approved topical treatment for male pattern hair loss) to their scalps twice daily for six months.
Finasteride is an oral, prescription-only medication that works by inhibiting the enzyme responsible for converting testosterone to DHT. Originally developed to treat an enlarged prostate, finasteride works by blocking DHT from shrinking the hair follicles.
Biotin doesn't block DHT, but it can still lend a hand in promoting hair growth.