@spencer_sunboy's testosterone advice, fact-checked

What did @spencer_sunboy actually say?

Spencer laid out a detailed personal timeline: five years on gel testosterone, most physical changes wrapped up within the first two years, and a switch to an auto-injector after feeling like masculinization had stalled. They said voice change happened by ten months, bottom growth by eight months, and body fat redistribution took about two years. After three or four years, they were mostly seeing downsides: acne, a receding hairline, and elevated hemoglobin. Their doctor suggested they may have developed "a resistance to topical medications." They're now one month into weekly auto-injections and hoping to see renewed progress.

One thing worth noting: Spencer is describing their own experience on feminizing-to-masculinizing hormone therapy, not a medically supervised TRT protocol for hypogonadism. The two populations overlap in mechanism but differ in baseline physiology and clinical goals.

Does the science back up the masculinization timeline?

Mostly, yes. The timeline Spencer describes is consistent with published data, though individual variation is wide. The Endocrine Society's guidelines and clinical reviews generally align with the sequence Spencer described, though the exact months vary considerably person to person.

The UCSF Transgender Care guidelines note that clitoral enlargement (what Spencer calls "bottom growth") typically begins within 3-6 months and maxes out within 1-2 years. Voice changes follow a similar early trajectory. Body fat redistribution is slower, often continuing for 2-5 years. A 2017 review by Unger in the Translational Andrology and Urology journal confirmed that most virilizing changes peak within two to five years of testosterone initiation, with diminishing returns after that. Spencer's observation that changes slowed at three to four years is not just plausible, it is what the literature predicts.

The facial masculinization taking years and being hard to track is also supported. These are slow, cumulative changes driven by bone remodeling and soft tissue shifts, not something you can pinpoint on a calendar.

What did they get right, and what needs pushback?

The "resistance to topical testosterone" explanation deserves scrutiny. Spencer's doctor framed it as building resistance to the medication itself. That framing is not quite right, and it matters.

What actually happens with transdermal testosterone is more mundane: absorption through skin is highly variable and can decrease with prolonged use due to skin thickening or changes in subcutaneous fat distribution. A 2014 study by Nieschlag and Behre in Testosterone: Action, Deficiency, Substitution documented significant inter-individual variability in gel absorption. The issue is pharmacokinetic, not immunological. Calling it "resistance" implies the body is actively fighting the drug, which is not the mechanism.

Spencer also correctly identifies that elevated hemoglobin (erythrocytosis) is a real side effect of testosterone therapy. This is well-documented and is actually more common with injectable testosterone due to higher peak serum levels. Switching to injections without monitoring hematocrit is something anyone in this situation should discuss explicitly with their prescriber. That point deserved more emphasis in the video.

What should you actually know if you're in this situation?

A few things Spencer did not cover that are clinically relevant. First, auto-injectors deliver subcutaneous testosterone, which produces steadier serum levels with lower peaks compared to intramuscular injection. Lower peaks may actually reduce erythrocytosis risk, which is ironic given Spencer's existing elevated hemoglobin concern. A 2010 study by Ohlsson et al. in Journal of Clinical Endocrinology and Metabolism found subcutaneous delivery produced stable testosterone levels comparable to IM with potentially fewer androgenic side effects.

Second, the cost Spencer cites, around $100 per month with insurance for an auto-injector versus $10 for gel, reflects a real access gap. Generic testosterone cypionate for injection is dramatically cheaper, and many people achieve stable levels with a standard syringe. The auto-injector is a convenience device, not a medical necessity for most patients.

Third, if you are experiencing erythrocytosis on testosterone, switching delivery methods does not automatically fix the problem. Bloodwork monitoring is non-negotiable here. That is a conversation with a licensed prescriber, not a TikTok comment section.