Today we are talking about peptide injections. We’ll cover the difference between subcutaneous and intramuscular injections, choosing needle length and needle gauge or “thickness”.

Several weeks ago, we talked about WHY we inject most peptides. So now we’ll cover the two common types of peptide injections.

What is the difference between a subcutaneous and intramuscular injection?

Intramuscular peptide injections are given into a muscle that has a blood supply. This allows peptides to be absorbed faster than they would be by the subcutaneous route. Intramuscular injections require a needle around 1 inch long for most adults. The correct needle length is determined by the patient’s size, age, and the amount of fat tissue in the chosen injection site. This length allows the peptides to pass through the different skin and fat layers, but not too long to risk hitting underlying nerves and bone.

The thickness of the needle is measured in millimeters and is referred to as the “gauge .” Needle gauges for intramuscular injections typically range between 22 and 25 gauge. A good way to remember needle thickness is the higher the gauge number, the finer or thinner the needle.

Intramuscular peptide injections should be given so that the needle enters your body at a 90-degree angle. This means it should be a straight injection, not given at an angle. Intramuscular injections are given in the outside of the upper arm, in the hip, in the buttocks, or in the thigh. 

Subcutaneous peptide injections aren’t injected as deep as intramuscular injections. These injections are given in the layer of fat between your skin and muscle. This area is not as richly supplied with blood vessels as your muscles. Peptides given by the subcutaneous route are absorbed more slowly than with intramuscular injections.

Subcutaneous peptide injections require a thinner, shorter needle. Needle gauges for subcutaneous injections typically range between 25 and 31 gauge with needle lengths around ¼ inch to ½ inch long. 

The needle length and needle insertion angle depend on a person’s weight and amount of fatty tissue. Subcutaneous injections can be given so that the needle enters your body at a 45 or 90-degree angle. The needle can be inserted at a 90-degree angle across pinched skin for people with a significant amount of fatty tissue. For those with minimal fatty tissue, the needle should be inserted at a 45-degree angle across pinched skin. 

Subcutaneous injections are given in the back of the upper arm, in your stomach, or in the thigh. Whether you’re giving yourself an intramuscular or subcutaneous injection, remember to try to avoid giving yourself an injection in the same place twice in a row. 

You should always speak to your healthcare provider or pharmacist about which needle length and gauge will work best for your peptide injections. 

As always, you can find more information at pepties.com.  That’s peptides without the D. Where we are tying all the peptide therapy information together. 

Thanks again for listening to The Peptide Podcast. We love having you as part of our community. If you love this podcast, please share it with your friends and family on social media. Leave a comment.. Have a happy, healthy week!

Pro Tips

Giving yourself a peptide injection can be scary or confusing. But we've got you covered. Check out 6 tips to make peptide injections easier. And, make sure you have the supplies you'll need. This may include syringes, needles, alcohol pads, and a sharps container.

We're huge advocates of using daily collagen peptide supplements in your routine to help with skin, nail, bone, and joint health. They also help with anti-aging. Our favorite collagen peptide powder is Thorne® Collagen Plus.