Does TRT actually shrink your testicles? Here's the real answer

What did @rethinktestosterone actually say?

Dr. Ashley Winter, introduced as a urologist, answered a viewer question about testicular atrophy on TRT. Her core answer: it depends on the formulation. She said "longer-acting" options like pellets and certain injections "do cause your balls to shrink," while "topical testosterone formulations and nasal testosterone formulations" cause less of this effect. She closed by telling viewers to talk to their doctor if this is a concern.

The transcript has some garbled phrases, likely transcription errors, including "four-sertividrologist" (almost certainly "board-certified urologist") and "testosterone-breakage" (probably "testicular shrinkage"). Setting those aside, the substance of what she said is identifiable and worth examining.

Does the science back this up?

Yes, mostly. The biology here is well-established. Exogenous testosterone suppresses the hypothalamic-pituitary-gonadal (HPG) axis, reducing LH and FSH. Less LH means less intratesticular testosterone production. Less FSH means reduced spermatogenesis. The testicles, no longer receiving those signals, shrink. This is called exogenous androgen-induced hypogonadotropic hypogonadism.

The formulation-dependency claim also holds up. A 2023 review in Fertility and Sterility (Samplaski et al.) confirmed that injectable testosterone significantly suppresses LH and FSH, driving testicular atrophy. Nasal testosterone gel (Natesto) has shown a meaningfully different profile. A study by Ramasamy et al. (2020, European Urology) found that Natesto preserves intratesticular testosterone and maintains FSH levels better than injectable testosterone, largely because its short half-life allows the HPG axis to partially recover between doses. Topical gels also tend to produce less suppression than long-acting injections, though data comparing them directly on atrophy endpoints are thinner.

What did they get wrong (or right)?

She got the core mechanism right. The claim that longer-acting formulations cause more testicular atrophy is accurate and supported by pharmacokinetic logic: sustained high testosterone levels mean sustained HPG suppression. Pellets, which release testosterone over three to six months, and long-acting injectables like testosterone undecanoate are the clearest examples.

What she underplayed: "less shrinkage" is not the same as "no shrinkage." Even Natesto causes some HPG suppression, and the Ramasamy 2020 study used three-times-daily dosing, which most patients do not maintain in practice. Topical gels can also cause significant suppression in consistent users. The framing that certain formulations simply "cause less" atrophy is accurate but risks leaving viewers with an overly optimistic impression of those alternatives.

She also did not mention hCG, which is the most clinically established intervention specifically used to preserve testicular volume and intratesticular testosterone during TRT. That omission is worth flagging for anyone researching their options.

What should you actually know?

Testicular atrophy on TRT is common, not rare, and the degree varies by formulation, dose, and individual response. If preserving testicular size or fertility matters to you, this is a real conversation to have before starting TRT, not after.

Human chorionic gonadotropin (hCG) mimics LH and can maintain intratesticular testosterone production and testicular volume during TRT. A 2013 study by Coviello et al. in The Journal of Clinical Endocrinology and Metabolism demonstrated that low-dose hCG co-administration maintained intratesticular testosterone levels in men on exogenous testosterone. hCG is not mentioned in this video but is a standard option clinicians consider.

Nasal testosterone (Natesto) is a legitimate alternative with a better fertility and atrophy profile in available studies, but those studies involved strict three-times-daily dosing and may not reflect real-world adherence. Anyone considering it should have that conversation with a qualified provider, not a TikTok comment section.

Bottom line: the video is a reasonable 60-second summary of a genuinely complex topic. It gets the key facts right but simplifies the alternatives in ways that could lead viewers to underestimate the tradeoffs.