Androgenetic Alopecia in Transgender Men

Exogenous testosterone is the cornerstone of hormone replacement therapy for virilization in transgender men. Some desirable dermatologic effects of treatment include terminal hair growth, particularly in the bearded region. However, for many patients an undesirable side effect of treatment is androgenetic or male pattern alopecia.¹ Androgenetic alopecia largely occurs due to the sensitivity of hair follicles to high levels of the hormone dihydrotestosterone (DHT).² Testosterone is converted to DHT via the enzyme 5-α-reductase. Thus, with an increase in testosterone levels there is an inherent increase in DHT, resulting in a higher likelihood of developing androgenetic alopecia.

Finasteride, a 5-α-reductase inhibitor, has been prescribed for years to treat androgenetic alopecia in cisgender men and women. However, its use in transgender men is less well-established. Prescribers are aware that finasteride affects androgens and may be concerned they could inadvertently interfere with the desired effects of a patient’s hormone replacement therapy. Therefore, treating androgenetic alopecia presents a unique challenge to finasteride treatment, as effects on DHT levels could play a part in the patient’s overall gender-affirming care.³

Treatment Options

Because oral finasteride only impacts DHT concentrations without lowering testosterone levels, it is not thought to affect the gender-affirming goals of transgender men and is a viable treatment option for this patient population.⁴ However, lowering DHT levels can cause certain unwanted side effects, including sexual dysfunction and decreased libido.^5,6 Counseling a patient about the risks and benefits of therapy is the same for cisgender and transgender men. A key difference is that a transgender man who can become pregnant should be counseled about the teratogenicity of the treatment. Providers should not make assumptions about the sexual practices and/or family planning goals of a patient based on appearance.

Some patients may find the potential negative side effects of oral finasteride unacceptable; in these instances, topical treatments may be more appealing. Topical finasteride is an effective alternative with similar effects on hair growth, minimal systemic exposure, and decreased impact on serum DHT levels when compared to oral finasteride.⁷ If a patient wants to avoid the potential for hormonally driven side effects all together, topical and oral minoxidil are also suitable treatments. Extensive counseling is required before prescribing oral minoxidil, as this medication carries a black box warning for certain cardiac effects.

Conclusion

Transgender men may have accepted pattern hair loss as an unwanted side effect of their hormone replacement therapy and may not be aware that there are options for treatment. Conversely, there may be patients who embrace the masculine appearance of their androgenetic alopecia. While it is understandable that providers may be apprehensive about prescribing treatments with potential hormonal effects in a patient on hormone replacement therapy, we hope to increase awareness of treatment options for this patient population. With limited data published on this topic, there is a risk of undertreatment. In general, providers may need to make additional efforts to educate themselves on common dermatologic conditions and appropriate treatment options for LGBTQ+ patients.

Jessica Allred and Alison Boone are second-year medical students at the University of Oklahoma College of Medicine in Oklahoma City, OK. Dr Papac is a PGY4 resident and Dr Levin is an associate professor and residency program director in the department of dermatology at the University of Oklahoma Health Science Center in Oklahoma City, OK.

Disclosure: The authors report no relevant financial relationships.

References

1. Thoreson N, Grasso C, Potter J, King DS, Peebles JK, Dommasch ED. Incidence and factors associated with androgenetic alopecia among transgender and gender-diverse patients treated with masculinizing hormone therapy. JAMA Dermatol. 2021;157(3):348-349. doi:10.1001/jamadermatol.2020.5475

2. Ustuner ET. Cause of androgenic alopecia: crux of the matter. Plast Reconstr Surg Glob Open. 2013;1(7):e64. doi:10.1097/GOX.0000000000000005

3. Irwig MS. Is there a role for 5α-reductase inhibitors in transgender individuals? Andrology. 2021;9(6):1729-1731. doi:10.1111/andr.12881

4. Motosko CC, Tosti A. Dermatologic care of hair in transgender patients: a systematic review of literature. Dermatol Ther (Heidelb). 2011;11(5):1457-1468. doi:10.1007/s13555-021-00574-0

5. Irwig MS, Kolukula S. Persistent sexual side effects of finasteride for male pattern hair loss. J Sex Med. 2011;8(6):1747-1753. doi:10.1111/j.1743-6109.2011.02255.x

6. Anitha B, Inamadar AC, Ragunatha S. Finasteride-its impact on sexual function and prostate cancer. J Cutan Aesthet Surg. 2009;2(1):12-16. doi:10.4103/09742077.53093

7. Piraccini BM, Blume-Peytavi U, Scarci F, et al. Efficacy and safety of topical finasteride spray solution for male androgenetic alopecia: a phase III, randomized, controlled clinical trial. J Eur Acad Dermatol Venereol. 2022;36(2):286-294. doi:10.1111/jdv.17738

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