Understanding Administration: Does Semaglutide Go Into the Muscle?

October 9, 2025 •

3 min read

According to a 2024 poll, about 12% of adults in the U.S. have used a GLP-1 agonist medication like semaglutide. A common question for new users is about proper administration: Does semaglutide go into the muscle? The answer is no; it is designed for subcutaneous injection.

Quick Summary

Semaglutide is administered as a subcutaneous injection into the fat layer, not into the muscle. This method ensures slow, steady absorption for its once-weekly dosing schedule. Intramuscular injection is not recommended.

Key Points

Subcutaneous Only: Semaglutide must be injected into the fatty tissue (subcutaneously), not the muscle.
Slow Absorption: The subcutaneous route is chosen for slow and sustained absorption, which is ideal for a once-weekly dose.
Key Injection Sites: The recommended injection sites are the abdomen, the front of the thighs, and the back of the upper arms.
Site Rotation is Crucial: Users must rotate their injection spot each week to prevent irritation, lumps, and ensure proper absorption.
IM vs. SC: Intramuscular (IM) injections are absorbed much faster due to higher blood flow, which is not suitable for semaglutide's design.
Accidental IM Injection: Injecting into muscle by mistake may increase side effects like nausea but is not typically dangerous.
Correct Technique: A 90-degree angle injection with a short needle ensures delivery into the fat layer, not muscle.

What is Semaglutide?

Semaglutide is a medication belonging to the class of glucagon-like peptide-1 (GLP-1) receptor agonists. It mimics the natural GLP-1 hormone in the body, which plays a key role in regulating blood sugar and appetite. By activating GLP-1 receptors, semaglutide helps the pancreas release insulin when blood sugar is high, slows down the rate at which food leaves the stomach, and acts on brain centers to reduce hunger and increase feelings of fullness.

This medication is approved for several uses, including:

Controlling blood sugar in adults with type 2 diabetes.
Aiding in weight loss for adults and children aged 12 and older who are obese or overweight with weight-related medical problems.
Reducing the risk of major cardiovascular events like heart attack and stroke in adults with type 2 diabetes and heart disease.

It is available under brand names like Ozempic® and Wegovy® for injection and as an oral tablet called Rybelsus®.

The Direct Answer: Subcutaneous, Not Intramuscular

Semaglutide is administered as a subcutaneous injection, which means it goes into the fatty tissue just under the skin. It should not be injected into the muscle (intramuscularly) or into a vein. The recommended injection sites are the abdomen, front of the thighs, or the back of the upper arms, ensuring enough subcutaneous fat is present for proper delivery.

Why is Semaglutide Injected Subcutaneously?

Subcutaneous injection is used because it allows for slow and sustained absorption of semaglutide into the bloodstream. This slow release is necessary for the medication's once-weekly dosing schedule and its half-life of about one week. Muscle tissue has a richer blood supply, which would cause faster absorption, potentially affecting the drug's intended action and duration.

Accidental Intramuscular Injection

While not ideal, accidentally injecting semaglutide into the muscle is generally not dangerous. However, it may lead to faster absorption and potentially increase side effects like nausea or discomfort. It could also reduce the medication's long-term effectiveness. If this occurs, monitor for side effects and ensure future injections are correctly placed in the subcutaneous fat.

Subcutaneous vs. Intramuscular Injections: A Comparison

Understanding the differences between these two common injection types clarifies why semaglutide requires a specific method.


Feature	Subcutaneous (SC) Injection	Intramuscular (IM) Injection
Injection Site	Fatty tissue layer (adipose tissue) just under the skin. Common sites: abdomen, thigh, upper arm.	Directly into a muscle. Common sites: deltoid (upper arm), gluteus (buttocks).
Absorption Rate	Slow and gradual.	Fast and rapid.
Blood Supply	Less vascular (fewer blood vessels).	Highly vascularized.
Needle Size	Shorter needle (e.g., 4 mm to 8 mm).	Longer needle to reach muscle.
Primary Use	Medications requiring slow, sustained release (e.g., insulin, semaglutide).	Medications needing rapid absorption (e.g., some vaccines, emergency medications).

How to Properly Administer a Semaglutide Injection

Correct technique is crucial for safety and effectiveness. Key steps typically include:

Wash hands and gather supplies (pen, new needle, alcohol swab).
Check the pen and medication appearance.
Attach a new needle and select the prescribed dose.
Choose and clean an injection site on the abdomen, thigh, or upper arm. Rotate sites weekly to prevent skin issues.
Insert the needle straight into the skin at a 90-degree angle, press the dose button until it shows '0', and hold for a slow count of six.
Dispose of the used needle in a sharps container immediately; do not reuse needles.

Conclusion

Semaglutide is intended for subcutaneous injection into the fatty tissue of the abdomen, thigh, or upper arm, not the muscle. This method ensures the necessary slow and steady absorption for its once-weekly dosing. Following the correct injection technique and rotating sites are vital for effective treatment and minimizing potential side effects.

For more information, consult resources from the U.S. National Library of Medicine: MedlinePlus

Frequently Asked Questions

Injecting semaglutide into muscle can cause the medication to be absorbed too quickly, which may lead to more intense side effects like nausea and discomfort. While not usually dangerous, you should use the correct subcutaneous technique for your next dose.

Semaglutide is designed for slow, steady release over a week. Muscle tissue has a rich blood supply that would absorb the drug too rapidly, altering its effectiveness and duration of action.

The best places are areas with a layer of fat under the skin, specifically the abdomen (at least two inches from your belly button), the front of your thighs, and the fatty part on the back of your upper arms.

Using the short needle provided with the pen and injecting at a 90-degree angle into a recommended site (abdomen, thigh, upper arm) is designed to deliver the medication into the subcutaneous fat layer. Some people find pinching a fold of skin helps ensure the injection goes into the fatty tissue.

Yes, it is very important to rotate injection sites each week. This helps prevent skin irritation, lumps (lipohypertrophy), and ensures the medication is absorbed consistently.

An intramuscular (IM) injection is absorbed much faster because muscle tissue has a greater blood supply than the subcutaneous (SC) fatty tissue.

The most common side effects are gastrointestinal, including nausea, vomiting, diarrhea, abdominal pain, and constipation. These are often more pronounced when starting the medication or increasing the dose.