Acne can represent a significant burden for trans people taking testosterone: Wierckx et al. (2014) reported that after 6 months of treatment, 82.4% of trans men developed facial acne and 88.2% experienced acne on their chest or back, and half of the participants in the study began using acne treatments such as topical benzoyl peroxide or oral antibiotics. Notably, Motosko et al. (2019) found that 52% of trans men on testosterone in their study sample experienced acne, compared to only 6.7% of cis men. Higher levels of testosterone also appear to be associated with a greater likelihood of developing acne (Park et al., 2019).
In some cases, acne can be severe and requires continued treatment with medications such as isotretinoin (Accutane) (Turrion-Merino et al., 2015); however, monitoring of liver function is recommended for those taking both testosterone and isotretinoin (Campos‐Muñoz et al., 2018). And while acne can be a risk factor for depression, anxiety, and poor self-esteem, isotretinoin itself has been observed to pose a risk for development of depression – a possible rare side effect of the medication – in adolescent trans boys (Campos‐Muñoz et al., 2020). Treatment of acne with oral antibiotics can pose issues due to the emergence of antibiotic-resistant strains of bacteria associated with use of these medications (Walsh et al., 2016), and systemic hormonal medications such as the antiandrogen spironolactone and synthetic progestins that are commonly used to treat acne in cis women may be undesirable for trans men, as these can counteract the desired effects of masculinizing HRT (Motosko et al., 2018).
So: Acne is a common result of testosterone treatment in trans men and transmasculine, and existing acne treatments are either hampered by various disadvantages or unsuitable for use in the transmasculine population due to their systemic antiandrogenic effects. A recently-developed medication may hold the potential to meet the particular needs of trans men with acne, addressing this condition’s androgenic origin locally without systemic effects.
Clascoterone, a new drug developed by Cassiopea SpA and applied as a topical cream to the affected area, “targets androgen receptors at the site of application and is quickly metabolized to an inactive form, thus limiting systemic activity” (Hebert et al., 2020). In two randomized trials of 1% clascoterone cream applied twice daily for 12 weeks in both AFAB and AMAB patients with moderate to severe acne, some as young as 9 years old, those using clascoterone achieved significantly greater reduction in acne compared to those using a placebo cream. In a safety study with clascoterone cream being used for up to 9 months, the most common adverse effects associated with treatment included swelling, redness, dryness, or itching at the application site, and this study found that systemic effects “including reduced libido and feminization in male participants, were absent” (Eichenfield et al., 2020).
Because clascoterone is a locally active antiandrogen, it is also under investigation for the topical treatment of androgenic (male-pattern) baldness; trans men and transmasculine people can sometimes experience baldness as an effect of testosterone treatment (Marks & Senna, 2019). While the systemic antiandrogen finasteride (Propecia) has been used to treat male-pattern baldness in a small number of trans men, the authors offered their opinion that “it is reasonable to wait until the patient has acquired the desired secondary sex characteristics and testosterone levels are within the recommended range before starting treatment with finasteride” (Moreno-Arrones et al., 2017). A 2019 phase II trial by Cassiopea of twice-daily topical clascoterone applied to the scalps of cis men with androgenic alopecia found that use of clascoterone was associated with regrowth of hair and cessation of hair loss, while the placebo group showed a continued progression of their androgenic baldness.
Cassiopea reports that they have conditional approval from the FDA for the proprietary name Winlevi for topical clascoterone for acne, and intends to market clascoterone for baldness under the name Breezula. This upcoming medication may provide a useful option for trans men and transmasculine people seeking to treat acne or baldness related to testosterone, without compromising their desired masculinization. ■