TRT dosing videos on TikTok: what the science actually says

What did @kmartfit actually say?

The creator walked through how to calculate a TRT injection dose using their own prescription as an example. Their personal dose is 180 milligrams of testosterone per week, split into two injections. The prescription reads "inject 0.45 milliliters twice a week," drawn from a 200 mg/mL testosterone vial. They demonstrated the math: 200 mg/mL multiplied by 0.45 mL equals 90 mg per injection, times two equals 180 mg weekly. They also pointed out that their syringe is marked from 0.1 mL to 1.0 mL, and they pull back to the 0.45 mL line.

The video is procedural rather than prescriptive. The creator is not telling viewers what dose to take. They are explaining how to read a syringe and verify that the volume drawn matches the prescribed dose. That framing matters when evaluating whether this content is helpful or dangerous.

Does the science back this up?

The underlying math is correct, and the method described is exactly what pharmacists and clinicians teach patients. Testosterone cypionate and enanthate are most commonly compounded or manufactured at 200 mg/mL in the United States, which is what this video assumes. The calculation, concentration times volume equals dose, is basic dimensional analysis and does not require a study to validate.

What the research does support is the importance of dose accuracy in TRT. A 2018 paper by Ramasamy et al. in The Journal of Urology noted that inconsistent dosing is one of the primary drivers of erratic serum testosterone levels in men on self-administered injectable therapy. Pulling to the wrong line on a syringe is a genuinely common patient error. Misreading a 0.45 mL draw as 0.54 mL, for instance, represents a 20 percent overdose. Teaching patients to verify their math against their prescription label is consistent with standard pharmacy counseling practice.

The Endocrine Society's 2018 clinical practice guideline on male hypogonadism also emphasizes patient education on self-injection technique as a component of safe TRT management.

What did they get wrong (or right)?

Mostly right, with one important omission. The math checks out. The syringe reading advice is accurate. Pulling back to 0.45 mL from a 200 mg/mL vial does yield 90 mg of testosterone. The creator deserves credit for framing this as their own prescription rather than a general recommendation.

The gap is context. Testosterone vials are not always 200 mg/mL. Compounded preparations frequently come at 100 mg/mL, 150 mg/mL, or even 250 mg/mL. A viewer watching this video with a 100 mg/mL vial who copies this math will inject half the intended dose. The creator never states that this calculation only works for 200 mg/mL concentrations, which is a meaningful oversight when the content is reaching 42,000 viewers with varying prescriptions.

The video also does not mention that patients should always defer to their prescription label, not a TikTok video, when in doubt. That single disclaimer would have made this content significantly safer without changing anything else about the presentation.

What should you actually know?

The formula itself is worth understanding. Dose in milligrams equals concentration in mg/mL multiplied by volume in mL. But this only works if you know your vial's concentration, which is printed on the label. Do not assume 200 mg/mL. Check the label every time, especially if you switch pharmacies or receive a new vial.

Syringe markings are in milliliters, not milligrams. Your prescription may be written in either unit. If your prescription says 100 mg and your vial is 200 mg/mL, you draw 0.5 mL, not 100 mL, and not 1.0 mL. This confusion is a documented source of dosing errors in home injectable therapy settings, as noted by Pastuszak et al. in a 2017 review in Current Opinion in Urology.

If you are ever unsure whether the volume you are drawing matches your dose, call your prescribing clinician or dispensing pharmacy before injecting. That is not a complicated ask. Most telehealth TRT platforms have messaging systems specifically for this kind of question. Using a TikTok video, including this one, as your primary verification method is not a substitute for that conversation.

Is this video safe to follow?

For someone whose prescription matches the creator's, yes, with caveats. The math is accurate and the demonstration of syringe reading is practical. However, the video implicitly assumes viewers share the same vial concentration, and many will not. The content is most useful as a secondary illustration of a concept your clinician has already explained, not as a standalone tutorial. Anyone starting TRT or changing their protocol should confirm their specific calculation with their prescriber or pharmacist before drawing a single injection.