Androgenetic alopecia refers to hair loss due to the effects of androgens, such as testosterone and its derivatives, on the hair follicles. Typically, testosterone is converted to dihydrotestosterone (DHT) by the enzyme 5-alpha reductase. In some people, DHT acts on hair follicles on the scalp, resulting in hair loss.

Incidence

Androgenetic alopecia is a common problem for trans men and transmasculine people who are taking testosterone for their masculinising hormone treatment. A recent study has suggested that the rate of androgenetic alopecia in trans men is roughly 1.3 times greater than the rate in cis men and roughly 2.5 times greater than the rate in cis women (Gao et al., 2023a). The development of androgenetic alopecia tends to peak in the fourth year of masculinising hormone treatment (Thoreson et al., 2021).

Trans women can also suffer from androgenetic alopecia. The rate of androgenetic alopecia in trans women is roughly similar to the rate in cis men, but is roughly 1.9 times greater than the rate in cis women (Gao et al., 2023a).

Treatments

There are a number of treatments that are available for androgenetic alopecia (Gao et al., 2023b).

First-line treatments

• Topical minoxidil 5% is a cream that is applied to the scalp once or twice daily.
• Finasteride 1mg daily is taken as a tablet.
• For trans women and transfeminine people, spironolactone 200mg daily can be used to treat androgenetic alopecia.
• If available, low level laser light therapy can be helpful to treat hair loss.

Second-line treatments

• Oral minoxidil dosed at 1.25mg daily for trans women and 2.5mg daily for trans men can be used as a second-line treatment if first-line treatments have been unsuccessful.
• Dutasteride 0.5mg daily taken as a tablet can be used as a second-line treatment.
• If available, hair restoration procedures could be considered.

Cautions when combining treatments

• Topical minoxidil 5% cream can be taken alongside oral finasteride tablets.
• However, oral minoxidil tablets cannot be taken alongside oral finasteride tablets. Hence, a maximum one form of oral medication can be taken at a time.

Testosterone levels in trans men

Although androgenetic alopecia is related to testosterone treatment, it is important to maintain your testosterone levels within the recommended target ranges. This is because sufficient levels of testosterone are required for the desired masculinising changes to occur. Furthermore, having insufficient levels of testosterone may lead to menopause-like symptoms, such as hot flashes, mood instability, and loss of bone density.

There is currently no evidence that the severity of androgenetic alopecia is related to the dose of testosterone. Therefore, decreasing your testosterone dose may be unlikely to alleviate androgenetic alopecia.

Gao, J. L., Sanz, J., Tan, N., King, D. S., Modest, A. M., and Dommasch, E. D. (2023a). "Androgenetic alopecia incidence in transgender and gender diverse populations: A retrospective comparative cohort study". JAMA Dermatology, 89 (3): 504-510.

Gao, J. L., Streed, C. G. Jr, Thompson, J., Dommasch, E. D., and Peebles, J. K. (2023b). "Androgenetic alopecia in transgender and gender diverse populations: A review of therapeutics". JAMA Dermatology, 89 (4): 774-783.

Thoreson, N., Grasso, C., Potter, J., King, D. S., Peebles, J. K., and Dommasch, E. D. (2021). "Incidence and Factors Associated With Androgenetic Alopecia Among Transgender and Gender-Diverse Patients Treated With Masculinizing Hormone Therapy". JAMA Dermatology, 157 (3): 348–349.