Testosterone gel vs. injections for transmasc people: what the evidence shows

What did @eddyquekett actually say?

Six days into testosterone therapy, this creator explained two reasons for choosing gel over injections: wanting slow, gradual changes with the option to stop quickly, and having a pre-existing blood clotting disorder. They said injections cause a testosterone spike that raises clot risk more than gel does, while gel keeps levels steadier. They also described their clot risk on gel as roughly equivalent to that of a cisgender man with the same disorder.

This is a remarkably specific and self-aware explanation for a TikTok video. The creator is not recommending gel to anyone else. They are describing a clinical decision made with their own prescriber, based on their own medical history. That distinction matters before we get into the science.

Does the science back this up?

Largely, yes. The pharmacokinetics argument is solid, and the clotting concern is clinically real, not invented anxiety.

Testosterone injections, particularly long-acting esters like cypionate or enanthate, produce supraphysiologic peaks in the first two to three days post-injection, followed by a trough before the next dose. Transdermal gels, by contrast, produce more stable serum testosterone concentrations day to day. This is well-documented. Bhasin et al. (2010, Journal of Clinical Endocrinology and Metabolism) confirmed that transdermal delivery attenuates the peak-to-trough swing seen with intramuscular administration.

On the clotting question, testosterone is associated with increased erythrocytosis, meaning it raises red blood cell production and hematocrit, which thickens blood and raises thrombosis risk. Guo et al. (2014, Thrombosis Research) found that supraphysiologic testosterone peaks, as seen with injections, correlate more strongly with elevated hematocrit than stable levels from transdermal routes. So the creator's reasoning is not just intuitive, it has a pharmacological basis.

What did they get right, and where does it get complicated?

They got the core pharmacology right. Where it gets more complicated is the specific claim that gel brings their clot risk to the same level as a cisgender man with the same disorder.

That is a reasonable clinical approximation, but it is not a precise statement backed by a clean dataset. Research on transgender men specifically and thrombosis risk on gel is limited. Most of what we know comes from TRT studies in cisgender men with hypogonadism, or from studies on hormone therapy in transgender populations that did not always separate delivery methods carefully.

The Nota et al. (2019, Circulation) study on transgender men and cardiovascular outcomes found that testosterone use was associated with increased cardiovascular event risk, but did not cleanly isolate gel versus injection outcomes. So saying gel puts you at exactly the risk of a cis man with the same disorder is a simplification. It may be clinically useful framing their doctor provided, but it should not be taken as a precise epidemiological fact.

The reversibility argument, stopping gel the next day versus waiting out a long-acting injection, is also accurate. Transdermal testosterone clears faster than injected esters, which can persist for days to weeks depending on the formulation.

What should you actually know?

If you have a clotting disorder and are starting testosterone, delivery method is a legitimate clinical variable worth discussing with your prescriber. This is not a niche concern.

Polycythemia, the excessive red blood cell production testosterone can trigger, is one of the most common adverse effects monitored in people on testosterone therapy. Hematocrit levels should be checked before starting therapy and monitored regularly. The Endocrine Society's 2019 clinical practice guidelines on testosterone therapy recommend monitoring hematocrit at three and six months and annually thereafter.

Route of administration does affect this. A 2020 retrospective study by Gomes et al. in the Journal of the Endocrine Society found that injectable testosterone was associated with significantly higher rates of polycythemia compared to transdermal formulations in cisgender men on TRT. This supports the gel choice for someone already at elevated clot risk.

• Gel does not eliminate clot risk, it may reduce the degree of hematocrit elevation compared to injections.
• Individual clotting disorders vary significantly. Factor V Leiden, antiphospholipid syndrome, and other conditions carry different baseline risks.
• Dose also matters. A lower dose, as the creator mentioned, further reduces the erythrocytosis signal.
• No delivery method makes testosterone risk-free for someone with a pre-existing coagulopathy. That requires specialist input, not a TikTok.