Testosterone Cypionate Gynecomastia: Diet Protocols That Help

Why gynecomastia happens on testosterone cypionate

Aromatase converts androgens to estrogens [3]. In male breast tissue estrogens stimulate growth while androgens inhibit it, so most gynecomastia reflects deficient androgen action or excessive estrogen action [2].

The Depo-Testosterone label says gynecomastia may develop and occasionally persists in patients treated for hypogonadism [1]. Adipose tissue expresses aromatase, and a 2001 article links greater fat mass with greater conversion of testosterone to estradiol [8].

What the human diet studies measured

A controlled feeding study in 43 healthy men measured urinary and plasma hormones, not breast changes [4]. In that 1996 crossover trial, men aged 19 to 56 ate a low-fat, high-fiber diet (18.8% of energy from fat, 4.6 g fiber per MJ) or a high-fat, low-fiber diet (41.0% of energy from fat, 2.0 g fiber per MJ) for 10 weeks each, with energy adjusted to keep body weight constant [4]. Urinary excretion of estradiol, estrone and their 2-hydroxy metabolites was 12 to 28% lower on the high-fat, low-fiber diet [4]. Plasma total testosterone was 13% higher on that diet, but the difference was statistically significant only for the SHBG-bound fraction [4].

In a study of 34 healthy postmenopausal women, greater Brassica vegetable consumption was associated with a higher urinary 2-hydroxyestrone to 16alpha-hydroxyestrone ratio after adjustment for other dietary factors; each 10 g per day increase was linked to a 0.08 rise (95% CI 0.02 to 0.15), while the crude analysis was not significant [5]. A review notes that indole-3-carbinol and DIM alter urinary estrogen metabolite profiles in women, with unknown effects on breast cancer risk [9].

Zinc studies measured testosterone rather than estradiol: six months of oral zinc gluconate at 459 micromol per day raised serum testosterone in nine marginally zinc-deficient older men from 8.3 to 16.0 nmol/L [6].

What the gynecomastia guideline says

The 2019 European Academy of Andrology guideline recommends a history and examination of the breast and genitalia, including testicular ultrasound; laboratory investigations may be part of the evaluation, and breast imaging is used when the examination is equivocal [7]. It recommends watchful waiting after treatment of an underlying pathology or discontinuation of substances associated with gynecomastia, and says testosterone treatment should be offered to men with proven testosterone deficiency [7]. It states that selective estrogen receptor modulators, aromatase inhibitors and non-aromatizable androgens are not justified in general, and that surgery is the treatment of choice for long-lasting gynecomastia [7].