Peptide injection basics

What subcutaneous means

Subcutaneous, often shortened to subQ, means into the layer of fat between the skin and the muscle beneath it. It is distinct from intramuscular, which is into the muscle, and intravenous, which is into a vein. These are different routes with different consequences, and they are not interchangeable.

The terms on a syringe

• Units: an insulin syringe is marked in units rather than millilitres. A U-100 syringe carries 100 units per millilitre, so 10 units is 0.1 mL.
• Gauge: the thickness of the needle. A higher gauge number means a thinner needle.
• Barrel size: how much the syringe holds in total, which is a separate thing from the needle on the end of it.

General information, not instructions for you

The walkthrough in the guides describes how subcutaneous injection is commonly done, in general terms. It is written the same way for everyone who reads it, and it is not an instruction aimed at your situation.

Injecting is a clinical procedure: aseptic technique, the right site for the specific product, disposing of a sharp afterwards, and knowing what to do when something goes wrong. If you have been prescribed an injectable medicine, the prescriber or pharmacist will show you, and the approved patient labelling covers it for that product.

Two things that are not in dispute

• A needle and syringe are single use. CDC puts it as one needle, one syringe, only one time; its injection-safety guidance is written for clinicians, but the principle is not situational.
• Used needles go straight into a sharps disposal container, not into household rubbish. FDA publishes consumer guidance on handling and disposing of sharps at home, at work, and while travelling.