No Anabolic Steroid Increases Adult Penile Size
No anabolic steroid or testosterone preparation will increase penile size in adults with normal development. Penile growth is dependent on androgen exposure during specific developmental windows—fetal development, infancy, and puberty—after which the penis becomes unresponsive to testosterone regardless of dose 1, 2.
Why This Doesn't Work in Adults
The evidence is clear that testosterone's effect on penile growth is developmentally restricted:
In adults with normal development, the penis has completed its growth trajectory and will not respond to exogenous androgens. Studies in men with congenital hypogonadotropic hypogonadism demonstrate that testosterone treatment initiated during puberty can normalize penile size, but this window closes after skeletal maturity 1.
Research using human fetal penile tissue grafts showed that supraphysiological testosterone doses did not enhance growth beyond normal physiological levels, and importantly, the mechanism for growth cessation is NOT down-regulation of androgen receptors 2. This means even massive doses won't overcome the developmental programming that stops penile growth.
The only clinical scenarios where androgens increase penile dimensions are:
What Anabolic Steroids Actually Do to Adult Male Genitalia
Supraphysiological doses of anabolic steroids cause testicular atrophy, not penile growth 5. The abuse of anabolic-androgenic steroids leads to:
- Suppression of the hypothalamic-pituitary-gonadal axis
- Testicular shrinkage
- Oligospermia or azoospermia
- Erectile dysfunction
- Infertility that can persist for up to 3 years after discontinuation 5
The 2025 EAU Guidelines on Male Sexual and Reproductive Health 6 and the 2020 American College of Physicians guideline on testosterone treatment 7 make no mention of penile enlargement as an indication or effect of testosterone therapy in adults, because it simply doesn't occur.
Common Pitfalls
Marketing claims are fraudulent: Any product claiming to increase adult penile size through hormonal manipulation is scientifically unfounded.
Confusing girth enhancement with actual growth: Hyaluronic acid or other fillers can temporarily increase girth 8, but this is mechanical augmentation, not anabolic steroid-induced growth.
Misunderstanding pediatric data: Studies showing penile growth with oxandrolone 3 or testosterone 1, 4 apply only to prepubertal patients with specific medical conditions, not healthy adults.
The Bottom Line
If you are an adult seeking penile enlargement, anabolic steroids will not achieve this goal and will cause significant harm including testicular atrophy, infertility, and potential cardiovascular and psychiatric complications 9, 5. The only evidence-based interventions for adult penile concerns are surgical (for Peyronie's disease or congenital abnormalities) or mechanical fillers for girth 6, 8, neither of which involve anabolic steroids.