Choosing the Correct Needle to Give Yourself a Shot

Different injectable medications require different needles

Woman giving herself a shot
Tuomas Marttila/Getty Images

For most people, one of the most daunting aspects of being prescribed an injectable medication is rarely the potential side effects or learning how to measure the correct dosage: It's the prospect of sticking a needle into their own body. After all, it's one thing when a trained medical professional gives you a shot, but doing it to yourself is another one entirely.

If you've been prescribed an injectable medication—to give yourself fertility drugs, for example—Even if you aren't squeamish about injecting yourself, you'll want to make sure you get everything absolutely right, from which medication you're supposed to take when to the dosage.

Equally important: using a needle that's the right size. Of course, your doctor will thoroughly go over the details of how to give yourself injections, including telling you which needles to use and how, but these tips may help to make the process less mysterious and perhaps even easier to master.

What Syringe and Needle Size Mean

Syringes are labeled based on how much liquid they can hold. Some syringes measure medication in milliliters (ml), others use cubic centimeters (cc). The good news is, 1 cc is equal to 1 ml, so you don't have to worry about confusing conversions when matching a syringe to your dosage. You just need to make sure you select a syringe that will hold the amount of medication you've been prescribed. It sounds intuitive, but if you aren't used to drawing up injectable medications it's worth pointing out. For example, if you're supposed to give yourself 3 cc of a drug, don't use a syringe that holds only 2 cc.

Needles are labeled differently. The packaging will have a number, then a "G," and then another number. The first number (in front of the G) indicates the gauge of the needle. The higher the number, the thinner the needle. The second number indicates the length of the needle. For example, a 22 G 1/2 needle has a gauge of 22 and a length of an inch.

Size Matters

The size syringe and needle you need will be based on the medication you've been prescribed as well as the dose. It also will depend on which of two types of shots you'll be giving yourself:

Subcutaneous injections go into the fatty tissue just below the skin. Since these are relatively shallow shots, the needle required is small and short—typically one-half to five-eighths of an inch long with a gauge of 25 to 30.

Intramuscular Injections are just what they sound like—shots that must go directly into muscle. Because muscle lies below the subcutaneous layer of skin, the needle must be thicker and longer. The size needles that usually are best are 20 or 22 G needles that are an inch or an inch-and-a-half-long. The length of the needle usually is chosen based on the amount of body fat. Someone who's thin can usually use an inch-long needle. A person who's on the heavier side may need to use an inch-and-a-half-long needle.

The most important thing to keep in mind when you need to give yourself an injectable medication is that your doctor or another medical professional who's involved in your care will be happy to help you if you get stuck figuring out which needles or syringes to use, or how to give yourself a shot.

If you find you simply can't do it, a friend or family member will be able to learn how to do it.