Beginner's Guide to Injecting Estradiol

Notice: If you are looking for specific advice on dosing, product usage, or side effects of certain products, refer to our product-specific guides.

IM vs. SubQ Injections: What's the Difference?

Intramuscular (IM) injections go deep into a muscle—typically the thigh or glute.

Subcutaneous (SubQ) injections go just under the skin, often in the belly or thigh fat.

Both methods are valid and commonly used for Estradiol. Some people prefer one over the other based on comfort or how their body absorbs the medication.

How to Know How Much Estradiol to Withdraw

Before you inject, you need to measure out the right dose of Estradiol. The amount is usually given in milligrams (mg), but the liquid in the vial is measured in milliliters (mL)—also known as "cc" (cubic centimeters). Don't worry! The math is super simple once you know your prescription and the concentration of your medication.

Step 1: Identify How Many Milligrams of Estradiol You Would Like To Inject

Example: if the dosing protocol you are following recommends 4mg Estradiol Cypionate every 7 days, you know you will have a once-a-week injection of 4 milligrams of Estradiol Cypionate.

Step 2: Identify the Concentration of the Medication

Most medications will have the concentration specified. Example: "Estradiol Cypionate 10mg/ml, 10ml vial" means that there is 10 milligrams of Estradiol Cypionate per 1 milliliter, and it means that there is 10 milliliters of oil total in the vial. This also means there is is a total 100mg of Estradiol Cypionate in the vial.

Not every medication will come with the concentration labeled. If this is the case, it is often labeled something like "Estradiol Cypionate 100mg". In this case, you will need to find out how many milliliters are in the vial. Once you find that out, you divide the total amount of Estradiol Cypionate specified by the total milliliters of oil in the vial. Let's say the vial contains 10ml of oil. That will be 100mg/10ml in this case. Simplify, you will get 10mg/1ml (aka 10mg/ml). These measurement principles are used across many medications, not just Estradiol Cypionate.

Step 3: Calculating the Amount To Inject

Use this simple formula:

Your dose (mg) ÷ Concentration (mg/ml) = Amount to inject (ml)

For example: If you have 10mg/ml, 10ml vial Estradiol Cypionate and would like to inject a 4mg dose. 4mg (your dose) ÷ 10mg (the concentration) = 0.4ml (the amount to inject).

Another way to interpret this is in a 10mL vial of 100mg Estradiol Cypionate, 0.5ml will contain 5mg Estradiol Cypionate.

Reading the Syringe: What Does That Look Like?

Most syringes are marked in mL (milliliters).

  • If you're using a 1 mL syringe, it's usually marked in 0.01 or 0.1 mL increments, so you can easily draw 0.2 mL, 0.3 mL, etc.
  • If you're using a 3 mL syringe, the markings may be larger (e.g., 0.1, 0.2, 0.3... up to 3).

IM Injection: Step-By-Step

You'll need:

  • A syringe (usually 1–3 mL)
  • A large needle to draw the medication (18–20 gauge)
  • A smaller needle to inject (22–25 gauge, 1"–1.5" length)
  • Alcohol swabs
  • Your Estradiol vial
  • A sharps container (for safe disposal)

Note: syringes, needles, and alcohol prep pads can all be found at West End Medical Supply

Steps:

  1. Wash your hands thoroughly with soap and water.
  2. Clean the vial's rubber top with an alcohol swab.
  3. Draw the medication using the larger needle.
  4. Switch to the smaller needle for injection (never inject with the large draw needle). When a needle penetrates something, it becomes dull. Never use the same needle for multiple insertions.

  5. Identify your injection site:

    In my experience the most comfortable injection site has been the Dorsogluteal site. Here are a few videos showing how to do this. If you choose to go with another injection site, there are plenty of video tutorials online that you should review before injecting. Video 1 | Video 2

  6. Clean the injection site with an alcohol swab and let it dry.
  7. Relax the muscle—tense muscles can make injections feel worse. I recommend to lean against a wall slightly, as this has helped me in the past.
  8. Insert the needle in at about a 90° angle. Avoid "changing course" mid injection. The needle should be inserted straight in. If you feel you injected at a bad angle, simply take the needle out, replace the needle, and try again.
  9. Inject the medication slowly and steadily.
  10. Withdraw the needle. Make sure you withdraw at the same angle you inserted, as well as in a straight line. Apply gentle pressure with gauze or cotton, and use a bandage if needed.
  11. Dispose of needles safely in a sharps container.

Video Tutorial

IM Injection Video Tutorial – Dr. Will Powers — This is a clear and accurate video that shows the proper site, angle, and injection technique.

SubQ Injection: Step-By-Step

You'll need:

  • A syringe (usually 1–3 mL)
  • A large needle to draw the medication (18–20 gauge)
  • A thin needle to inject (25–30 gauge, ½"–⅝" length)
  • Alcohol swabs
  • Your Estradiol vial
  • A sharps container (for safe disposal)

Note: syringes, needles, and alcohol prep pads can all be found at West End Medical Supply

Steps:

  1. Wash your hands thoroughly with soap and water.
  2. Clean the vial's rubber top with an alcohol swab.
  3. Draw the medication using the larger needle.
  4. Switch to the smaller needle for injection (never inject with the large draw needle). When a needle penetrates something, it becomes dull. Never use the same needle for multiple insertions.

  5. Identify your injection site:

    The most common SubQ sites are the abdomen (about 1–2 inches from your belly button) or the fatty area on the front or side of the thigh.

    In my experience the abdomen is the most comfortable.

  6. Clean the injection site with an alcohol swab and let it dry.
  7. Pinch a fold of skin between your fingers to isolate the fatty layer.
  8. Insert the needle at a 45° or 90° angle, depending on your body type (90° if you have more subcutaneous fat). Remember, do not "change course" during insertion. The needle should go in a straight line.
  9. Inject slowly and steadily.
  10. Remove the needle at the same angle as insertion. Apply gentle pressure, and cover with a bandage if needed.
  11. Dispose of everything properly in a sharps container.

Video Tutorial

SubQ Injection Video Tutorial – Sam's Health Corner — This video tutorial accurately shows how to perform a SubQ injection.

Common Questions and Concerns

Does it hurt?

A little, but usually much less than you expect. Most people say it feels like a quick pinch. In my experience, it doesn't usually hurt. If you feel any "seering" deep pain, you might be going too deep or at a wrong angle.

Which method is better, IM or SubQ?

It depends on what you prefer. Both IM and SubQ are medically sound for Estradiol.

Should I be bleeding?

It happens. Most injections either do not have any blood or only a tiny droplet. Every once in a while, an injection may leak a significant amount of blood due to hitting a vein. It is okay, do not be worried.

How do I know I'm doing it right?

Start slow, follow the steps, and refer to the videos. It's actually quite hard to severely mess up as long as you do the proper amount of research.