SubQ or IM: The Difference Between Subcutaneous and Intramuscular Injections

Subcutaneous injections and intramuscular injections in hormone replacement therapy achieve the same result but slightly vary in method & equipment

Different subcutaneous and intramuscular injection sites

For many, hormone replacement therapy (HRT) involves needles: this can be daunting or it might leave someone totally unfazed. All of these feelings are valid! Some people feel they notice faster changes using injectable hormones than other methods such as patches, pills, or gels (more on those routes for estrogen here and testosterone here).

There are two methods for delivering testosterone or estrogen with needles: subcutaneously or intramuscularly. This can be done by the person taking the hormones, or with the help of a friend or family member. Whatever the feeling about needles or hormones being taken, there are ways to make the process simple and safe!

FOLX clinicians can offer training for how to do this and be there to answer any questions!

Subcutaneous injections (or SubQ or SC, if you like)

SubQ.jpg

A subcutaneous injection sends a sterile liquid form of testosterone or estrogen (suspended in oil) into the fatty tissue under the skin. After drawing the correct volume of hormones into a syringe and sterilizing the injection site, the needle is inserted at a 45° angle into an area of the body where there is some fatty tissue (belly, inner thigh).

For most folx, this is a more comfortable and less painful method than Intramuscular. Needles are relatively thin and short (typically a 25G needle, and ⅝ inches in length) since they go right underneath the skin. Because this is a smaller needle than the one used for IM, it might take a little bit longer to fully inject the medication. 

Some common side effects, however, can include some bruising in the area especially in the beginning when getting used to the injection technique. Some people also have a local site reaction with itching and redness of the area that tends to fade over time. 

If you're a visual person, this is what that might look like:

Intramuscular injections (or the shorthand, IM)

IM.jpgAn intramuscular injection sends a sterile liquid form of testosterone or estrogen (suspended in oil) straight into the muscle. After drawing the correct volume of hormones into a syringe and sterilizing the injection site, the needle is inserted at a 90° angle into an area of the body that has a good sized muscle (thigh, buttocks).

‍Because the injection is directly into the muscle, and the needle is longer (22G or 23G and 1 to 1.5 inches in length) IM can be a more painful method for folx. Common side effects include muscle soreness, bruising, or a bit of bleeding that can squirt out after the injection. There are no big or scary blood vessels in the area to worry about, it might just mean the needle hit a small capillary or vein. If this happens, just use a tissue, cotton, or gauze to hold some pressure.

If you're a visual person, this is what that might look like:


Disclaimer: FOLX prescribes estrogen and testosterone injectable form. The medication used in this video is progesterone, and not currently prescribed by FOLX in injectable form, and is used for demonstration purposes only.

The method can sometimes impact the frequency of injection

With intramuscular injection, there is the possibility to inject every other week as the large muscle in which the hormones are injected can hold more supply. However for subcutaneous injections, the fatty tissue does not hold onto the injected supply of hormones for the same length of time, meaning the possible need for the weekly injection.

Most people do weekly subcutaneous or intramuscular injections, but there can be variation on frequency dependent on dose and personal preference. Be sure to talk with a FOLX clinician to help determine which frequency, dosage, and method is right for you.

With the different routes and dosages of hormones, there are a lot of ways to find the one that fits best for each individual body. For existing FOLX members with questions about self-injecting, don't hesitate to schedule time with a clinician. And for those who’ve just got some more questions, read up on self-injecting here, and feel free to reach out to us at support@folxhealth.com.