Does Proviron (mesterolone) improve or reduce sperm count and quality?

Does Proviron Improve or Reduce Sperm Count and Quality?

Proviron (mesterolone) shows modest improvements in sperm parameters for men with moderate oligospermia (5-20 million/ml), but current guidelines do not recommend its use because the benefits are small and superior alternatives exist through assisted reproductive technology.

Current Guideline Position

The 2021 AUA/ASRM guidelines explicitly state that medical treatments for idiopathic male infertility, including androgenic agents, provide limited fertility benefits that are outweighed by the advantages of assisted reproductive technologies like IVF with ICSI 1. The guidelines emphasize that these medical interventions result in only incremental increases in pregnancy rates and are not cost-effective compared to ART 1.

Evidence from Clinical Studies

Moderate Oligospermia (5-20 million/ml)

• In a study of 250 men with idiopathic oligospermia treated with mesterolone 100-150 mg/day for 12 months, 70% with moderate oligospermia showed significant improvement in sperm density, total count, and motility 2
• This same study achieved 46% pregnancy rates overall, with most success in the moderate oligospermia group 2
• An earlier trial of 42 patients showed that 93% had improved or unchanged sperm parameters, with 30% achieving normozoospermia and 6 pregnancies 3

Severe Oligospermia (<5 million/ml)

• Only 12% of men with severe oligospermia showed improvement with mesterolone therapy 2
• The treatment was found to be ineffective for severe oligospermia and is not recommended for this population 2

Hormonal Effects

• Mesterolone had no depressing effect on normal or low FSH and LH levels, but suppressed elevated levels in 25% of cases 2
• The treatment did not significantly affect testosterone levels or liver function 2
• Plasma testosterone and FSH levels remained unchanged in most studies 3

Why Guidelines Don't Recommend It

The fundamental problem is that while mesterolone may improve semen parameters in some men, the clinical benefit is marginal compared to modern ART 1, 4. Key considerations include:

• Time factor: Treatment requires 3-12 months to show effects, delaying more effective interventions 2, 5
• Limited efficacy: Even when sperm parameters improve, pregnancy rates remain modest 1
• ART superiority: IVF with ICSI provides higher pregnancy rates and faster time to conception 1, 4
• Lack of FDA approval: Mesterolone is not FDA-approved for male infertility treatment in the United States 1

Modern Treatment Algorithm

For men with oligospermia seeking fertility:

1. First-line: Refer to reproductive specialist for ART evaluation, particularly IVF with ICSI for severe cases 1, 4
2. Optimize modifiable factors: Weight loss, smoking cessation, exercise (these have better evidence) 4, 6
3. Treat underlying conditions: Varicocele, infections, hormonal abnormalities 4
4. Consider hormonal therapy only for specific indications: Hypogonadotropic hypogonadism with gonadotropins, not idiopathic oligospermia 1

Important Caveats

• Avoid exogenous testosterone: This suppresses spermatogenesis and worsens fertility 1, 7
• Genetic testing: Men with severe oligospermia should undergo karyotype and Y-chromosome microdeletion testing before treatment 4, 7
• Sperm banking: Consider cryopreservation before any treatment that might further impair fertility 4, 6
• Historical context: Studies showing mesterolone benefits are from the 1970s-1980s, before modern ART was available 3, 8, 2, 5

Bottom Line

While older studies demonstrate that mesterolone can improve sperm parameters in select patients with moderate oligospermia, current evidence-based guidelines prioritize ART as the superior approach for achieving pregnancy in couples with male factor infertility 1, 4. The small incremental benefits of mesterolone do not justify delaying more effective treatments that offer higher pregnancy rates and better time efficiency 1.