What hormones regulate penis growth during puberty?
Executive summary
Penile growth during puberty is driven primarily by androgens — especially testosterone and its more potent metabolite dihydrotestosterone (DHT) — under control of the hypothalamic‑pituitary‑gonadal (HPG) axis; androgen‑dependent growth accounts for an estimated ~70–75% of adult penile length [1] [2]. Other hormones and signals — including luteinizing hormone (LH), follicle‑stimulating hormone (FSH), human chorionic gonadotropin (hCG, used therapeutically), growth hormone (hGH) and even estrogen signaling in development — also play roles or modify outcomes, and some research points to additional androgenic metabolites such as androsterone contributing to masculinization [3] [4] [2] [5] [6].
1. The engine of puberty: testosterone, DHT and the HPG axis
Puberty is initiated by the hypothalamus releasing gonadotropin‑releasing hormone (GnRH), which prompts the pituitary to secrete LH and FSH; LH then stimulates testicular testosterone production, which drives penile growth and other male secondary sexual characteristics [3] [2]. The activation of the HPG axis in puberty increases androgen receptor expression and secretion of testosterone and DHT, leading to the characteristic penile growth spurt typically peaking around ages 12–16 [1] [2].
2. Testosterone vs. DHT: complementary and sometimes distinct actions
Clinical and experimental sources emphasize testosterone as indispensable for penile development, while conversion to DHT (via 5α‑reductase) is crucial for masculinization of external genitalia; the literature links both hormones to the pubertal penile growth spurt and notes that androgen‑dependent growth explains a large majority (~70–75%) of adult penile length [1] [2].
3. Upstream regulators and therapeutic mimics: LH, FSH and hCG
LH and FSH are the pituitary hormones that regulate testicular function; when endogenous gonadotropin secretion is deficient (as in idiopathic hypogonadotropic hypogonadism, IHH), clinicians may use hCG to stimulate testicular steroidogenesis and induce penile growth and puberty. Multiple clinical reports document penile length increases after hCG or testosterone therapy in boys with hypogonadism or micropenis [4] [7] [8].
4. Growth hormone, other contributors, and non‑androgen signals
Some popular and clinical discussions include human growth hormone (hGH) as a systemic growth regulator during adolescence — and while hGH contributes to overall pubertal growth, the specific, primary drivers of penile enlargement are androgens; available reporting notes that people often conflate hGH with “penis growth hormone,” but clinical trials do not support routine use of hGH or testosterone to increase adult penile size once puberty is complete [9] [10]. A 2019 study and other work also highlight additional androgenic metabolites (e.g., androsterone) and the presence of estrogen receptors in penile tissue, suggesting more complexity in masculinization pathways [5] [6].
5. Timing matters: why hormone action in development is decisive
Most penile growth occurs during fetal development and again during infancy (“mini‑puberty”) and puberty; androgen exposure during these windows is critical. Deficits in androgen action early in gestation or a failure of postnatal gonadotropin surges can cause micropenis, while androgen replacement before or during puberty can stimulate catch‑up growth in affected children — but the same treatments do not reliably enlarge penises in fully mature adults [2] [11] [12].
6. Evidence on interventions: what works for micropenis and what doesn’t for adults
Clinical studies report that exogenous testosterone in prepubertal boys and hCG in pubertal/postpubertal boys can increase stretched penile length in cases of micropenis or hypogonadism; long‑term data do not show these pediatric hormone treatments reduce final adult penile length, and androgen therapy is a recommended option in specific endocrine disorders [7] [4] [11]. Conversely, multiple sources warn there is little or no evidence that testosterone, hGH, or other hormonal “penis growth” products produce meaningful size increases in adults once puberty is complete [10] [12].
7. Uncertainties, alternative perspectives and possible agendas
Research agrees that androgens are central, but studies also point to estrogens and endocrine disruptors affecting penile development — a perspective that raises environmental and public‑health questions [6]. Consumer‑oriented outlets and commercial clinics sometimes promote hormone or peptide therapies for adult enhancement; available clinical reporting and reviews caution those claims lack robust trial evidence and may reflect marketing agendas rather than proven efficacy [9] [10].
Limitations: reporting here is limited to the provided sources; other peer‑reviewed studies or guidelines may add nuance not covered above — available sources do not mention every molecular pathway, genetic factor, or long‑term safety study relevant to all hormone therapies.