Do SubQ and IM injections give the same testosterone levels?
In the studies available so far, they give similar average levels. A 2022 review in the Journal of Clinical Endocrinology and Metabolism concluded that subcutaneous testosterone, given at doses similar to the intramuscular route, produces comparable on-treatment testosterone concentrations. The authors also called the evidence limited and asked for larger, longer studies.
Two studies in men with low testosterone help fill in the picture:
| Study | Design | What it found |
|---|---|---|
| Retrospective comparison, 2022 | 234 men on IM cypionate 100 mg weekly or a SubQ enanthate autoinjector 100 mg weekly, 12 weeks | Trough testosterone rose to about 536 and 553 ng/dL; route was not tied to the level reached. SubQ had lower estradiol and hematocrit |
| Autoinjector safety study, 2019 | 133 men self-injecting SubQ enanthate weekly for 26 weeks | Hematocrit of 52% or more in 7.5% of men; clinic blood pressure up 3.4/1.8 mm Hg |
The first study compared different esters and devices, not the same vial given two ways, so its estradiol and hematocrit differences are a signal rather than proof. Still, nothing in this evidence suggests that SubQ testosterone works less well.
How do needle size and pain compare?
SubQ shots use smaller needles and usually hurt less. The 2022 review describes studies using 20- to 25-gauge, 5/8-inch needles for SubQ cypionate and enanthate, and notes that the authors use a 23-gauge needle without difficulty. It reports that pain with SubQ injection is usually lower and that intramuscular shots are associated with discomfort and are harder to give yourself.
Local reactions do happen. Mild redness or soreness was common in the reviewed studies, and a few men noticed small, painless lumps that cleared within two days. Our page on needle size for testosterone injections compares the options in more detail.
When is IM still preferred?
Intramuscular injection still makes sense in a few situations:
| Situation | Why IM may fit better |
|---|---|
| Large-volume doses | In a crossover study of long-acting undecanoate given in a larger volume, 11 of 20 men preferred IM and 6 preferred SubQ |
| Repeated skin reactions or lumps | Moving the oil deeper avoids the fatty layer |
| Preference for clinic-given shots | IM is the traditional in-clinic route |
| Cost | The review notes IM esters are cost-effective compared with the autoinjector |
| Long-standing stable IM routine | No reason to change what works if labs are on target |
MedlinePlus describes both routes for testosterone, an intramuscular shot given in a clinic and a weekly subcutaneous injection that can be self-given, which reflects how both are in routine use.
Can I switch from IM to SubQ?
Yes, with your provider rather than on your own. A switch usually keeps the weekly amount similar, teaches the new technique in person, and adds a follow-up lab to confirm your level and hematocrit where they should be. Our step-by-step guides on subcutaneous injection and intramuscular injection show what each involves.
Before asking, note how much volume you inject per shot, how your last hematocrit and estradiol results looked, and whether you are comfortable giving your own injections. Those three details shape most of the conversation. If you self-inject IM without trouble and your labs are on target, there may be no reason to change; if the shot is the part of TRT you dread, SubQ is worth raising.
How Ultimate Male decides between routes
At Ultimate Male, injectable testosterone can be given in clinic or at home, and the route is chosen around you: how you feel about needles, how much volume your dose requires, your hematocrit history and whether you want to self-inject at all. For men who dread the larger IM needle, SubQ is often the first thing to try; the page for men who dislike needles covers other options too.
Learn more about testosterone injections or explore the full range of testosterone therapy options, then book a free 10-minute call to talk it through.
