AndroGel Hair and Skin Changes: What Testosterone Gel Actually Does to Your Body

Where these numbers come from

The skin and hair figures below come from the prescribing information for testosterone gel 1% — the 50 mg, 75 mg and 100 mg strengths — including its 180-day phase 3 trial, which assigned men to one of those three doses, and a 3-year flexible-dose extension study of 162 men [1]. The same label notes that different topical testosterone products carry different doses, strengths and application instructions that may produce different systemic exposure, and it refers readers to a separate label for the 1.62% gel [1].

The label records events that investigators judged at least possibly related to treatment.

Does testosterone gel cause acne?

Yes, and acne is the skin effect the label follows most closely. It is listed among the most common adverse reactions, at an incidence of 5% or more, and the dose table shows a climb with dose: 1% of 77 men on 50 mg, 3% of 40 men on 75 mg, and 8% of 78 men on 100 mg [1]. Those groups are small, so the ordering is a pattern rather than a precise dose curve. Over three years of flexible-dose treatment, acne was reported in 3.1% of 162 men [1].

Sebaceous glands are androgen-sensitive tissue, and skin cells carry the enzymes needed to make dihydrotestosterone (DHT) locally from testosterone [2]. A dermatology review groups seborrhea, acne, hirsutism and androgenetic alopecia together as the skin conditions associated with androgen excess [2].

Will the gel make scalp hair fall out?

Alopecia was reported in 1% of men on 50 mg, 0% on 75 mg and 1% on 100 mg [1] — roughly 1% overall, with no dose pattern. The label does not say what type of hair loss these cases were [1].

Androgenetic alopecia is the hereditary form, and a dermatology review groups it with seborrhea, acne and hirsutism as androgen-associated skin conditions, with androgens affecting hair growth as one of their core skin functions [2].

What about body and facial hair?

Hirsutism appears in the label's under-1% list of less common reactions from the 180-day trial, alongside dry skin, discolored hair and sweating [1].

In skin, androgen activation and deactivation differ from cell type to cell type and between cells at different locations [2].

Skin reactions at the application site

Application-site reactions were reported in 5% of men on 50 mg, 3% on 75 mg and 4% on 100 mg, and in 5.6% of the 162 men followed for three years [1]. In the 180-day trial, skin reactions at the application site occurred, but none was severe enough to require treatment or discontinuation, and no man stopped the gel because of a skin reaction [1]. Dry skin and itching were each reported in 1.9% of the extension-study group; in the 180-day trial, dry skin, discolored hair, hirsutism and sweating each fell below 1% [1].

The label's placement rules are specific: clean, dry, intact skin of the shoulders and upper arms and/or the abdomen, spread evenly between the left and right sides, and not the genitals, chest, armpits, knees or back [1]. The gel is flammable until it dries [1].

The skin warning that matters most: transfer to a woman or a child

The gel carries a boxed warning about secondary exposure. Virilization has been reported in children who were secondarily exposed to testosterone gel [1]. The signs recorded in postmarketing reports include enlargement of the penis or clitoris, development of pubic hair, increased erections and libido, aggressive behavior, and advanced bone age [1]. In most cases these signs regressed once the exposure was removed; in a few, enlarged genitalia did not fully return to age-appropriate size and bone age stayed modestly greater than chronological age [1].

For adult women, the label lists a change in body-hair distribution, a significant increase in acne, or other signs of virilization as reasons to bring the possibility of secondary exposure to a physician's attention [1]. The label says to discontinue the gel until the cause of virilization has been identified [1].

Can a lower dose reduce skin effects?

The label adjusts dose by serum testosterone, not by skin. Treatment starts at 50 mg once daily and moves to 75 mg or 100 mg based on total serum testosterone, with a decrease if the concentration exceeds the normal range and discontinuation if it stays above normal at 50 mg [1]. Acne was most frequent at 100 mg in the 180-day trial [1].