Best Practices for Subcutaneous Injections

If you've been prescribed a medication that requires subcutaneous injections, you might feel unsure about where to start. With a little guidance, giving these injections at home can be safe and manageable. This guide walks you through what subcutaneous injections are, where to give them, how to do it properly, and how to avoid common mistakes so you can feel more confident and in control of your care.

What is a Subcutaneous Injection?

Subcutaneous means “under the skin.” A subcutaneous (SC) injection, one of the approaches to administer medications, is given into the fatty tissue just below the surface of the skin.

Subcutaneous injections are also called SC injection, sub-Q injection, and subcut injection.

This innermost part of the skin is above the muscle layer and has comparatively less blood flow, allowing the medicine to be absorbed more slowly compared to intravenous (IV, or into a vein) injections and intramuscular (IM, or into a muscle) injections.

The subcutaneous tissue, also called the hypodermis, varies in thickness in different body regions and the body fat percentage. It is thinnest over the eyelids and external genitalia, which is less than 1 millimeter (mm) thick, and thickest over the abdomen and buttocks, which could be over 3 centimeters (cm) thick.

What Drugs Are Given Subcutaneously?

Common injections that are given by the subcutaneous route include:

Insulin, except for regular insulin, which can be given both SQ and IV
Injectable diabetes medications such as Ozempic and Mounjaro
Weight loss drugs such as Wegovy and Zepbound
Fertility drugs
Blood thinners such as Lovenox and heparin

It can take up to 24 hours for a medication given by subcutaneous injection to absorb fully.

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Preparing for a Subcutaneous Injection

Necessary Supplies and Equipment

You will need the following equipment and supplies for a subcutaneous injection:

A syringe with a short, thin subcutaneous needle attached.
An alcohol pad.
Clean gauze pads.
A sharps container.

Step-by-Step Preparation Process

Wash your hands with soap and water for at least 1 minute. Dry your hands with a clean paper towel.
Clean the subcutaneous injection site with an alcohol pad. Start at the intended needle insertion point and wipe outwards with a circular motion.
Allow your skin to air dry or use a clean gauze pad to dry it.

Preventing Infection

Never use the same needle and syringe more than once.
If the needle is damaged or the cap is broken, discard it in your sharps container and use a new syringe and needle.
Needle and syringe administration sets should never be used multiple times by the same patient or by multiple patients. Each needle and syringe is for one-time use by a single patient.
Check the medicine label to make sure you are taking the correct dose.
Check the expiration date on the medicine label and make sure it has not passed.

Choosing the Right Injection Site

A subcutaneous injection should not be given in any area of skin that is hardened, red, inflamed, burned, swollen, or damaged.

The best subcutaneous injection sites are:

The outer part of the upper arm, at least 3 inches (~7.5 cm) below the tip of the shoulder and 3 inches (~7.5 cm) above the elbow.
The outer part of the upper thigh.
The belly area below the ribcage and above the hips, at least 2 inches (5 cm) away from the belly button.

If you need to regularly take subcutaneous injections, it is very important to rotate between injection sites to keep your skin healthy and damage-free.

If injections are repeated in the same spot, it can lead to hardening and scarring of the skin.

Injecting a medicine into hardened areas can be painful and interfere with how the medicine is absorbed by the body.

Make sure each subcutaneous injection is at least 1 inch away from the last injection site. You can mark a previous injection site with a small Band Aid.

It’s best to start the injections at the highest point of a chosen area and progressively move towards the lowest point, for example, from the shoulder towards the elbow for upper arm injections.

Use all the available sites on one body part (arm or leg) before moving on to another.

However, children may be more accepting of injections if they are rotated between different body parts.

How to Administer a Subcutaneous Injection

Step-by-Step Guide to Self-Administration

Hold the syringe like a pen in your hand with the needle pointing up.
Remove the cover from the needle.
Tap the syringe with your fingers to move any air bubbles up.
Slowly push the plunger up until the dark rubber septum lines up with the correct dose of your medicine. You may get a pre-filled syringe that has the correct dose of your medicine. Or you may need to draw up the medicine from a vial. If you are filling the medicine from a vial, your healthcare provider or pharmacy tech will teach you the correct technique.
With your non-dominant hand, pinch 1 inch (2.5 cm) of fatty tissue between your fingers. Be sure not to pinch a muscle.
Insert the needle into the pinched skin at a 90-degree angle (you can inject at a 45-degree angle if you don’t have enough fatty tissue).
Once the needle has gone all the way in, release the skin.
Push the plunger to inject the medicine.
Once all the medicine is injected, quickly pull the needle out.
Discard the needle in your sharps container.
Place a clean gauze pad on the injection site and apply firm pressure for a few seconds to stop bleeding.
Wash your hands again.

Correct Administration Techniques

Thrust the needle quickly all the way into the skin.
Do not push the needle slowly or use excessive force.
Do not press on the top of the plunger while piercing the skin with the needle.
After the needle is in the skin, release the pinched skin before injecting the medicine.
Press the plunger in a slow, steady motion. If you are using a pre-filled injection pen, press the button completely or until it clicks. Count to 10 before removing the needle.

Subcutaneous vs. Intramuscular Injections

Subcutaneous injections and intramuscular injections are both parenteral methods of administration, meaning that, unlike oral medications, they bypass the intestines. However, they have significant differences between them, such as:

Key Differences

	Subcutaneous Injection	Intramuscular Injection
Target tissue	Fatty tissue under the skin	Muscle tissue
Medicine absorption rate	Slower absorption due to less blood flow in subcutaneous tissues	Faster absorption due to more blood flow in muscle tissues
Advantages	Easier, less painful process	Faster absorption
Needle length	Short as it only needs to penetrate into tissue under the skin	Longer as it needs to penetrate into muscle
Common sites	Upper arm, upper thigh, abdomen	Upper arm, upper thigh, buttocks
Examples of medicines injected	Insulin, fertility drugs, weight loss medicines, injectable diabetes medicines, blood thinners	Vaccines, antibiotics, hormones

Benefits of Injectable Medications

Parenteral medications (subcutaneous, intramuscular, intravenous injections) have several clinical advantages.

The most important is the rapid onset of action, meaning the drug works much faster than a medicine taken by mouth. Subcutaneous injections are preferred for medications that require a slower, sustained release. Intramuscular injections are preferred for medications requiring a faster onset of action and larger volumes of injection solution.

However, healthcare providers and patients need to follow certain protocols, guidelines, and best practices for injectable medications and fluid infusion to ensure an aseptic technique.

This is essential for preventing infections and ensuring the safety of patients and healthcare workers.

Safe medication practices and isolation precautions have been outlined by organizations such as the Centers for Disease Control (CDC), the National Center for Biotechnology Information, and the World Health Organization (WHO).

Is a Subcutaneous Injection the Same As IV?

No, a subcutaneous injection is not the same as an IV (intravenous, or into a vein) injection.

Subcutaneous injections are injected in the fatty tissue under the skin. In intravenous injections, the medication goes directly into the bloodstream through a vein.

Medications given by IV injection have a faster onset of action than those given by the sub-Q route.

Medications given intravenously are also known as an IV infusion or IV drip.

Unlike subcutaneous injections, where a syringe is used, IV medication is infused using a pump or gravity.

Managing Complications and Side Effects

Any injection technique can lead to infection if you don’t perform hand hygiene and take aseptic precautions.

Signs of infection include severe pain, redness, swelling, warmth, or drainage at the infection site.

Call your doctor immediately if you develop signs and symptoms of an infection or any other complications.

Best Practices in Healthcare Settings

Hand Hygiene refers to the process of handwashing and the use of antiseptics to prevent the spread of infectious agents. Healthcare personnel should perform hand hygiene before and after handling and administering an injectable drug product, before and after coming in direct contact with patients, and before and after putting on and removing gloves.
Other personal protective equipment such as eye protection, masks, and personal protective equipment (PPE) are not needed for routine injections.
Gloves are not necessary if both the patient’s and health care worker’s skin is intact.
Skin disinfection and sterile preparations should be done to the injection site with 60-70% isopropyl alcohol or ethanol (methyl alcohol or methanol is unsafe for humans). The patient’s skin should be disinfected with a single-use swab or cotton ball. All injection preparation surfaces should also be cleaned before the injection session.
A new, sterile syringe should be used for each patient to prevent the transmission of infectious diseases.
A single-dose medication vial should be used whenever possible to ensure medication safety and reduce cross-contamination.
Medication preparation: The immediate patient treatment area should be free of clutter to allow for thorough cleaning and ensure medication safety.
Check the prescription and confirm the patient’s name and dosage before administering an injection.
Prevent Sharps injuries by discarding used syringes in a leak-free and puncture-resistant sharps container kept within arm’s reach. Sharps containers should be sealed and discarded when three-fourths full.

Additional Safety Tips

Here are some more safe injection practice recommendations for healthcare workers:

Do not give injections on injection sites compromised by infection, dermatitis, cuts, new tattoo, open sores, or any other type of open skin or skin lesions.
Cotton wool swabs used for disinfecting the injection site should not be pre-soaked as this increases the risk of contamination.
Do not combine leftover medication in pre-filled syringes for later use.
Do not use the same mixing syringe to mix medications from different single-dose vials.
Never leave a needle in a multidose vial.
Do not use the same needle and syringe for several multidose medication containers.