This TikTok about painful testosterone shots is missing context

What did @harleymeds.com actually say?

The creator's core claim is that subcutaneous (SubQ) testosterone injections are painful specifically because of low body fat. Their threshold: if you're "below 25% body fat, there's not a lot of fat there to inject the oil into," so the oil sits just under the skin, causing a painful lump. Above 25%, they say SubQ "works perfectly fine." Below it, they recommend switching to intramuscular (IM) injections instead.

That's a tidy, simple rule. It's also the kind of oversimplification that sounds authoritative on TikTok but starts to fall apart the moment you look at the actual variables involved in SubQ injection comfort.

Does the science back this up?

Partially, but the 25% body fat cutoff is not a clinically established threshold. It appears to be a rule of thumb, not a researched benchmark.

The basic physiology is real: subcutaneous tissue depth does vary with body composition, and thinner subcutaneous fat layers can make oil-based depot injections more uncomfortable and slower to absorb. A study by Kamineni et al. (2021, Journal of Clinical Endocrinology and Metabolism) confirmed that SubQ testosterone cypionate produces comparable pharmacokinetics to IM in most patients, but absorption variability was higher in leaner individuals. Separate work by Olsson et al. (2014, Drug Delivery) showed that injection site adipose thickness directly affects absorption rate and local tolerability for oil-based depots.

However, needle length, injection volume, injection speed, oil viscosity, and site selection (abdomen vs. flank vs. thigh) are all variables that affect SubQ comfort regardless of overall body fat percentage. None of these appear in the creator's explanation.

What did they get wrong (or right)?

They got the directional relationship right: leaner individuals can experience more discomfort and slower absorption with SubQ testosterone. Credit where it's due. But the specific 25% body fat figure is presented as a clinical rule when it isn't. There is no peer-reviewed study that identifies 25% as the cutoff below which SubQ testosterone becomes problematic.

What the creator also misses is that many lean individuals inject SubQ successfully by adjusting technique. A 2019 review by Spratt et al. (Endocrine Practice) noted that SubQ testosterone is increasingly preferred for its convenience and reduced injection anxiety, and that proper technique, including smaller volumes (0.5 mL or less), slower injection speed, and appropriate needle gauge, substantially reduces discomfort across body types.

The recommendation to switch to IM if you're lean isn't wrong as a general option, but framing it as the primary solution while ignoring technique variables is incomplete at best. It also skips over the fact that IM injections carry their own risks, including intravascular injection, hematoma, and injection site fibrosis with repeated use.

What should you actually know?

SubQ testosterone is a legitimate and increasingly common route of administration. Whether it works comfortably for you depends on more than a body fat number.

• Injection volume matters more than most people realize. Volumes above 0.5 mL SubQ consistently produce more local reactions regardless of body fat.
• Injection speed is underappreciated. Slow, steady injection over 10 to 15 seconds reduces pressure-related discomfort in the SubQ space.
• Site selection changes the experience. The abdomen and flanks typically have more subcutaneous tissue than the thigh in leaner individuals.
• Oil temperature affects viscosity. Cold testosterone cypionate is thicker and harder to inject. Warming the syringe to body temperature before injection improves flow.
• Needle gauge matters. A 27- or 28-gauge needle for SubQ dramatically reduces injection pain compared to larger gauges sometimes used for IM.

If you are experiencing persistent SubQ injection pain, that is a conversation to have with the clinician managing your testosterone therapy, not a TikTok comment section. Route of administration should be decided based on your individual anatomy, dose, and tolerability, not a single percentage-based rule.