Keep Factually independent
Whether you agree or disagree with our analysis, these conversations matter for democracy. We don't take money from political groups - even a $5 donation helps us keep it that way.
Can testosterone replacement therapy increase penis size in men?
Executive Summary
Testosterone replacement therapy (TRT) can increase penile size when given during developmental windows—notably in infants or children with conditions like hypospadias or micropenis—but the evidence shows no reliable increase in adult penile length or girth from standard TRT. Recent pediatric studies from 2025 report modest, measurable gains in penile dimensions after preoperative parenteral testosterone in boys with hypospadias, while reviews and clinical summaries from 2013–2024 conclude that once puberty ends, penile growth is largely complete and TRT’s primary benefits for adults are improved sexual function and mitigation of shrinkage related to hypogonadism rather than true enlargement [1] [2] [3] [4] [5].
1. Why the pediatric data show measurable growth — and why that matters now
A 2025 clinical series of 40 boys with hypospadias treated with intramuscular testosterone propionate reports statistically significant increases in base diameter, glans diameter, and stretched length, with average gains around 1.0 cm across measures after three doses of 2 mg/kg (published April–May 2025). Those results are clinically relevant to reconstructive surgeons seeking to optimize penile tissue before repair and demonstrate that androgen exposure during early development or prepubertal windows can drive additional penile growth [1] [2]. The study group was pediatric and had a congenital condition, which both amplify responsiveness to androgens; hence these findings cannot be extrapolated to typical adult TRT candidates. The 2025 papers report only minor side effects like acne and transient behavioural changes, underscoring a controlled perioperative use rather than a general endorsement of TRT for cosmetic enlargement [1] [2].
2. The adult picture: growth plates are closed and expectations should be recalibrated
Clinical reviews and patient-facing medical sources from 2022–2024 consistently explain that penile size is mainly determined during puberty, and TRT after growth completion does not produce meaningful increases in length or girth. In adults, TRT addresses symptoms of low testosterone—fatigue, decreased libido, erectile dysfunction—and can improve erectile function by supporting vascular and tissue health, which may make the penis appear fuller during erections, but this is not the same as anatomical enlargement [3] [4] [6]. Multiple sources emphasize that only in cases of true micropenis identified in infancy or early childhood, or during adolescence before closure of developmental windows, will androgen therapy change baseline penile dimensions [4].
3. Laboratory and historical data reinforce the developmental limit on growth
Earlier experimental studies and cross‑sectional analyses dating back to 1997 and 2013 found that supraphysiological and varying androgen exposures do not reliably increase penile length beyond developmental endpoints. A 1997 fetal-tissue graft experiment showed no significant length gains with supraphysiological testosterone compared with normal exposure, indicating mechanisms other than simple androgen excess govern the cessation of penile growth. A 2013 clinical study failed to find conclusive evidence that TRT increases penile size in adults, noting only weak correlations between circulating testosterone and penile measurements [7] [5]. These older data align with contemporary clinical guidance that adult penile anatomy is resistant to change from hormone therapy alone.
4. Where TRT can help adults: preventing shrinkage and improving function
Although TRT does not enlarge an adult penis, it can prevent or partially reverse penile tissue loss associated with prolonged hypogonadism by preserving vascular health, libido, and erectile function; this may lead to subjective or functional improvements in penile appearance during erections. Contemporary analyses from 2024–2025 emphasize that TRT’s measurable benefits in adults are primarily functional and symptomatic rather than structural increases in girth or length. Patients seeking cosmetic enlargement should be counseled that TRT is not a reliable method for that purpose and that perceived changes often reflect improved tumescence rather than anatomical growth [8] [3] [6].
5. Practical takeaways and unresolved questions clinicians still face
For clinicians and patients, the evidence supports targeted pediatric androgen therapy in specific congenital conditions but cautions against expecting enlargement from adult TRT. The strongest, most recent controlled data supporting size increases come from small, condition-specific pediatric cohorts in 2025; broader, high-quality trials in adults are lacking, and historical experimental work argues against a hormonal route to post‑pubertal growth [1] [2] [7]. Remaining questions include long‑term safety of preoperative androgen protocols in children, the exact threshold where TRT might mitigate—but not reverse—age or disease‑related penile tissue loss in adults, and standardized metrics to separate functional versus anatomical change; these gaps guide practical, evidence-based counseling today [1] [2] [8] [5].