Testosterone Cypionate and Hair Loss That Doesn't Go Away: What to Do When Male-Pattern Balding Persists

What the testosterone cypionate label says about hair loss

The Depo-Testosterone adverse reactions section lists, under skin and appendages, "hirsutism, male pattern of baldness, seborrhea, and acne" as reactions that have occurred with some androgens [1]. The label presents these as a list of reported reactions rather than as rates from a trial, so it does not give a frequency for hair loss on cypionate [1].

The same label covers dosing. Intramuscular cypionate is given deep in the gluteal muscle at 50 to 400 mg every 2 to 4 weeks, and the half-life after an intramuscular injection is about 8 days [1]. Testosterone esters in oil are absorbed slowly from the depot, so cypionate can be given at intervals of two to four weeks [1].

Why pattern hair loss keeps progressing

Androgenetic alopecia is the common pattern hair loss, and it is progressive: it tends to worsen with time [2]. Hair thinning comes from the effect of dihydrotestosterone (DHT) on androgen-sensitive follicles, with a progressive reduction in hair diameter, length and pigmentation; the male pattern runs from bitemporal recession of the frontal hairline to diffuse thinning at the vertex [2].

Genetic predisposition is the major requirement for the condition. In a genetic study, variability in the androgen receptor gene was the cardinal prerequisite for early-onset androgenetic alopecia, with an etiological fraction of 0.46, and the authors note that the gene's X-chromosome location stresses the importance of the maternal line in inheritance [6].

Scalp dermoscopy is used routinely in androgenetic alopecia. It supports the diagnosis, allows staging of severity, and lets a clinician follow progression and response to treatment over time [2].

What has been tested for male-pattern hair loss

The trials below enrolled men with androgenetic alopecia, not men selected for testosterone therapy.

Finasteride 1 mg daily

Two 1-year trials enrolled 1,553 men aged 18 to 41 with male-pattern hair loss, who took finasteride 1 mg daily or placebo; 1,215 men continued into blinded second-year extensions. Hair count in a 1-inch diameter circular area (5.1 cm²) of balding vertex scalp was 107 hairs higher than placebo at 1 year and 138 higher at 2 years (P<0.001), while placebo-treated men lost hair progressively [3].

Topical finasteride

A 24-week phase III trial randomized 458 men with androgenetic alopecia to topical finasteride or placebo, with an oral finasteride comparator. Target-area hair count rose 20.2 hairs with topical finasteride versus 6.7 with placebo (P<0.001), a change described as numerically similar to oral finasteride, while mean serum DHT fell 34.5% with topical and 55.6% with oral finasteride [7].

Dutasteride

Four hundred sixteen men aged 21 to 45 were randomized to dutasteride 0.05, 0.1, 0.5 or 2.5 mg, finasteride 5 mg, or placebo daily for 24 weeks. Dutasteride increased target-area hair count in a dose-dependent way, and the 2.5 mg dose was superior to finasteride at 12 and 24 weeks [5]. Dutasteride is not approved for hair loss; finasteride and minoxidil are the only drugs approved for androgenetic alopecia [8].

Minoxidil

In a systematic review and meta-analysis of randomized trials, 5% minoxidil in men was superior to placebo (P<0.00001) [4]. Low-dose oral minoxidil has been reviewed as an alternative for people who struggle with topical application: 17 studies involving 634 patients, with androgenetic alopecia the most studied condition, concluded that it was effective and well tolerated in healthy patients, and noted that larger randomized studies with standardized measurements are needed [9].

Where that leaves persistent hair loss on testosterone cypionate

Finasteride and minoxidil are the agents with randomized trial evidence in male-pattern hair loss [3][4]. The Depo-Testosterone label does not link hair loss to a particular dose or injection schedule [1].