Dealing with symptoms of low testosterone, like tiredness or decreased libido? Testosterone replacement therapy (TRT) could help.
Some types of TRT are taken as an injection. Here’s what to know if you’re thinking of trying it.
What is a subcutaneous injection?
It’s an injection that goes into the layer of fatty tissue just under your skin, rather than directly into your muscle (aka an intramuscular injection).
There’s pros and cons for either type of injection and both are used for TRT. But subcutaneous testosterone injections are being increasingly used because they’re easy to self-administer, allow for a steadier release of T into the blood, and generally hurt less (they use smaller needles and there’s fewer nerve endings in the fatty tissue under the skin).
Can testosterone be injected subcutaneously?
Yes, definitely. Though for some types of TRT, like Sustanon, intramuscular injection is the preferred route.
The method of delivery is carefully chosen for each product. It depends on how quickly you want the medicine to be released, how much volume you need to inject, and more.
Your provider will also consider your comfort and convenience when deciding which TRT product to prescribe.
Subcutaneous vs intramuscular testosterone injections
Let’s take a closer look at subcutaneous vs intramuscular testosterone injections.
Subcutaneous injections provide a slower and more steady release of the drug than intramuscular ones. However, studies show that overall absorption of T is similar for men using either type of injection.
How to give a subcutaneous testosterone injection: step by step
What you’ll need
First, get your kit ready:
- Your medication
- Alcohol wipe
Choosing subcutaneous injection sites
The two main subcutaneous injection sites you can use are your stomach (avoid your belly button) and your thighs (towards the outer side—ask your provider to show you).
Technique
Okay, you’re ready to go:
- Wash and dry your hands with soap and water
- Clean the injection site with the alcohol wipe
- Hold the syringe in your dominant hand: your thumb should be on the plunger
- Use your other hand to lightly pinch the area you’ll inject into
- Insert the needle in all the way. Subcutaneous injections should be given at a 45 or 90 degree angle to the skin (your provider will confirm. Ninety degrees may be recommended for shorter needles)
- Press the plunger. Take your time: the slower you go, the less likely that you’ll get lumps on the injection site
- Take the needle out at the same angle
Aftercare and disposal
Throw the used needle away in a sharps box or by following your provider’s instructions.
For more information, check out our guide to how and where to inject testosterone.
Common issues and side effects at the injection site
You might experience some discomfort or irritation at the injection site. For example, swelling or minor bruising—though these usually get better within a few days.
The physical impact of the injection, and the inflammation it causes, can sometimes cause small lumps to form around the site. Usually, they’re harmless and go away within weeks.
But if your lumps are warm to the touch, red, painful, or have pus, get in touch with your provider. These could be signs of infection.
Safety, interactions and monitoring
TRT can interact with some other medicines, including:
- Cancer drugs, like methotrexate
- Antibiotics and antifungal medicines
- Medicines for blood clots
Bottom line: tell your provider about the medicines you’re taking before you start TRT. They’ll only prescribe it to you if the benefits outweigh the risks.
Find out if TRT is right for you with our quick, at-home testosterone blood test. Our clinicians will come back to you asap and let you know what treatment they recommend.




