How to Inject Peptides
Most research peptides are administered via subcutaneous (subQ) injection — meaning the needle goes just under the skin into the fatty tissue layer. This is the same technique used for insulin injections and is straightforward once you understand proper technique. This guide covers everything you need for safe, effective subcutaneous peptide administration.
Last updated: 2026-01-28
What You'll Need
- Reconstituted peptide vial
- Insulin syringes (29-31 gauge, 1/2 inch)
- Alcohol swabs
- Sharps container for needle disposal
Steps
Wash hands and prepare supplies
Wash hands thoroughly with soap and water. Lay out your supplies on a clean surface. Remove the reconstituted peptide from the refrigerator.
Swab the vial top with alcohol
Clean the rubber stopper of the peptide vial with an alcohol swab. Allow to air dry for 10-15 seconds before inserting the needle.
Draw the correct dose
Insert the needle into the vial and invert it. Pull the plunger to your desired dose marking. If air bubbles are present, tap the syringe gently and push the air back into the vial. Verify the dose is correct before withdrawing.
Prepare the injection site
Choose an injection site (abdomen, thigh, or upper arm). Clean the area with an alcohol swab using a circular motion from the center outward. Allow to air dry completely.
Pinch the skin and insert the needle
Pinch a fold of skin between your thumb and forefinger. Insert the needle at a 45-90 degree angle (90 degrees for most people) in a smooth, swift motion. The needle should go into the fatty tissue beneath the skin.
Inject slowly and withdraw
Push the plunger down slowly and steadily. Once fully depressed, wait 5-10 seconds before withdrawing the needle. This ensures the full dose is delivered. Release the skin fold.
Dispose of the needle safely
Place the used syringe directly into a sharps container. Never recap needles. Never dispose of needles in regular trash. Apply light pressure to the injection site with a clean cotton ball or alcohol swab if needed.
Best Injection Sites
The three most common subcutaneous injection sites are:
- Abdomen: The most popular site. Inject at least 2 inches away from the belly button. The abdomen generally has the most consistent subcutaneous fat layer and good absorption rates
- Thigh (outer/front): The middle third of the outer thigh. Good option for self-injection as it's easy to reach and see
- Upper arm (back/outer): The fatty area on the back of the upper arm. May require assistance as it's harder to self-inject here
Site rotation is important. Rotate between different areas within a region and between regions to prevent lipodystrophy (lumps or indentations in the fat tissue from repeated injections in the same spot). Use a different spot each time, spacing injections at least 1 inch apart.
For peptides targeting a specific injury (like BPC-157 for a knee tendon), some protocols suggest injecting near the injury site. However, subcutaneous injection anywhere on the body provides systemic distribution.
Needle and Syringe Selection
For subcutaneous peptide injection, use insulin syringes with the following specifications:
- Gauge: 29-31 gauge (higher number = thinner needle = less pain). 31 gauge is the thinnest commonly available and recommended for comfort
- Needle length: 1/2 inch (12.7mm) for most people. 5/16 inch for very lean individuals
- Syringe volume: 0.5 mL or 1 mL. Use 0.5 mL syringes if your dose is small (under 50 units) for better precision. Use 1 mL syringes for larger volumes
Insulin syringes are marked in "units" — 1 mL = 100 units on a standard insulin syringe. This is important for converting your dose from the peptide calculator to syringe markings.
Timing and Frequency
Injection timing depends on the specific peptide:
- GH secretagogues (sermorelin, ipamorelin): Best taken before bed on an empty stomach, to align with the body's natural nighttime GH surge
- Tesamorelin: Once daily, typically in the evening
- BPC-157: Can be taken 1-2 times daily. Timing is less critical, but some protocols favor morning and evening dosing
- GHK-Cu: Once daily, timing flexible
- AOD-9604: Typically once daily in the morning on an empty stomach
Use our dosage calculator for compound-specific frequency recommendations.
Troubleshooting Common Issues
- Bruising: Small bruises at injection sites are normal and harmless. They indicate a small blood vessel was nicked. Applying light pressure after injection can minimize bruising
- Stinging/burning: Some peptides cause mild stinging during injection. Allowing the peptide to reach room temperature before injection (5-10 minutes out of the fridge) can reduce this. Injecting slowly also helps
- Lumps at injection site: Small welts or bumps are common and usually resolve within 30-60 minutes. Persistent lumps over days may indicate improper injection depth (too shallow) or a reaction to the peptide/preservative
- Bleeding: A drop of blood at the injection site is normal. Apply light pressure with a cotton ball. Heavy bleeding is unusual and may indicate the needle hit a vein rather than subcutaneous tissue
- Air bubbles in syringe: Small air bubbles in a subcutaneous injection are harmless (unlike IV injection). However, they can affect dose accuracy. Tap the syringe to move bubbles to the top and push them out before injecting