Gel vs. injections for haematocrit: what the data actually shows

What's this video probably claiming?

Based on the caption, @ali_on_t is almost certainly walking through why testosterone delivery method matters for haematocrit elevation, likely arguing that injections raise red blood cell mass more aggressively than transdermal gels. This is a legitimate and frequently discussed clinical topic in TRT communities, and the creator is probably responding to a question about whether switching delivery routes could reduce polycythaemia risk. There may also be a secondary claim about peak serum levels being the mechanistic driver, with gels producing steadier, lower peaks that spare the haematocrit. These are not fringe ideas. They appear in endocrinology literature and are debated in clinical practice. The question is whether the framing is accurate, nuanced, and appropriately caveated, or whether it oversimplifies a genuinely complicated pharmacokinetic picture into a clean binary that social media audiences love but that real patients should treat with some skepticism.

What does the science actually show?

The core claim has reasonable support. Injectable testosterone esters, particularly cypionate and enanthate administered weekly or biweekly, produce supraphysiological peak levels followed by troughs, and this rollercoaster pattern appears to drive greater erythropoietic stimulation. Coviello et al. (2008, Journal of Clinical Endocrinology and Metabolism) demonstrated that haematocrit increases were significantly associated with testosterone dose and resulting serum levels. A pooled analysis by Grech et al. (2014, European Journal of Endocrinology) found polycythaemia rates around 40 percent in men on intramuscular testosterone versus substantially lower rates in gel users. The Testosterone Trials (Snyder et al., 2016, NEJM) using transdermal gel showed modest haematocrit increases averaging around 3 percentage points over 12 months. That said, gel users absolutely can develop elevated haematocrit, particularly at higher doses or with poor absorption variability. The mechanism is real, but the magnitude difference is not a guarantee of safety.

Where does the social media noise diverge from clinical reality?

The problem with this topic on TikTok is that it gets flattened into a simple rule: gels are safe for haematocrit, injections are risky. That is not what the literature supports. First, individual variability is enormous. Some men on weekly cypionate injections at 100mg maintain haematocrit well within normal range for years. Others on low-dose gel push above 54 percent within six months. Second, frequency of injection matters as much as route. Men using daily subcutaneous injections of small doses, common in optimisation protocols, show far less haematocrit elevation than those on biweekly intramuscular doses, because peak serum levels stay lower. Pastuszak et al. (2017, Urology) noted that administration frequency significantly influenced erythrocytosis rates. Third, lifestyle factors including sleep apnoea, altitude, smoking, and baseline haematocrit are rarely mentioned in these videos but are clinically meaningful. Cherry-picking route of delivery as the single variable is a tidy narrative that does not survive contact with an actual patient chart.

What should you actually know?

If your haematocrit is climbing on TRT, delivery route is one lever among several worth discussing with a clinician. Switching from biweekly intramuscular to more frequent subcutaneous injections often reduces peak levels and can attenuate haematocrit rise without abandoning injectable testosterone entirely. Gels are a legitimate option for patients where haematocrit is the primary concern, but they introduce their own variables including inconsistent absorption and transfer risk. Therapeutic phlebotomy remains the most direct intervention when haematocrit exceeds clinical thresholds, typically above 52 to 54 percent depending on guidelines consulted. The Endocrine Society's 2018 clinical practice guidelines recommend monitoring haematocrit at 3 and 6 months after starting or adjusting TRT, then annually. A TikTok video, however accurate its general premise, cannot replace that monitoring relationship. If you are managing TRT through a regulated telehealth platform, haematocrit should be on your regular lab panel regardless of which delivery method you use.