Suppression of human spermatogenesis by testosterone implants.

Area of Science:

• Endocrinology
• Reproductive Medicine
• Pharmacology

Background:

• Hormonally induced azoospermia is a reversible male contraceptive method.
• Weekly testosterone enanthate injections can lead to inconsistent azoospermia due to fluctuating hormone levels.

Purpose of the Study:

• To test if stable, physiological testosterone levels from implants consistently induce azoospermia.
• To compare the efficacy and side effects of depot testosterone implants versus weekly testosterone enanthate injections.

Main Methods:

• Nine men received six 200 mg testosterone implants, with sperm output and hormone levels monitored.
• Results were compared to 38 men previously treated with weekly 200 mg testosterone enanthate injections.

Main Results:

• Testosterone implants suppressed sperm output to near-azoospermia by months 2-4, returning to normal by month 6.
• Implant group showed a greater initial sperm reduction (58% vs. 17%) and fewer side effects like acne (0/9 vs. 25/38).
• Both methods suppressed LH and FSH, but implants maintained testosterone within the eugonadal range, unlike injections.

Conclusions:

• Depot testosterone implants provide effective hormonal male contraception with similar azoospermia induction rates as weekly injections.
• Testosterone implants demonstrate higher dose efficiency and potentially fewer androgenic side effects compared to weekly testosterone enanthate injections.