What Is Endometrin? Uses, Dosage, and What You Need to Know in 2026

Endometrin Is a Vaginal Progesterone Insert Used to Support Pregnancy During IVF and Other Fertility Treatments

If your fertility doctor has mentioned Endometrin, you probably have questions. What is it? Why do you need it? How do you use it? This guide covers everything you need to know about Endometrin in 2026 — from what it does to how much it costs.

What Is Endometrin?

Endometrin is the brand name for a vaginal insert containing 100 mg of micronized Progesterone. It belongs to the progestogen drug class — medications that mimic or supplement the natural hormone Progesterone.

Key facts about Endometrin:

• Generic name: Progesterone (vaginal insert)
• Manufacturer: Ferring Pharmaceuticals
• Drug class: Progestogen
• FDA-approved: Yes, for progesterone supplementation in ART treatment
• Controlled substance: No — Endometrin is not a controlled substance
• Generic available: Yes — Xiromed launched the first generic Progesterone vaginal insert in September 2025

What Is Endometrin Used For?

Endometrin is FDA-approved for one specific use: progesterone supplementation as part of assisted reproductive technology (ART) treatment for infertile women. In practical terms, that means it's primarily used during IVF cycles.

Here's why it's needed: During a normal menstrual cycle, your ovaries produce Progesterone after ovulation. This hormone prepares the uterine lining (endometrium) for a potential pregnancy. But during IVF, the egg retrieval process can disrupt your body's natural Progesterone production. Endometrin replaces that missing Progesterone to support embryo implantation and early pregnancy.

Doctors also use Endometrin off-label for:

• Frozen embryo transfer (FET) cycles — To build and maintain a supportive uterine lining
• Recurrent pregnancy loss — Some doctors prescribe it to support early pregnancy in women with a history of miscarriage
• Luteal phase defect — When the body doesn't produce enough Progesterone on its own after ovulation

For more on how Endometrin works in your body, read our guide: How Does Endometrin Work?

How Is Endometrin Taken?

Endometrin comes as a small vaginal insert (sometimes called a vaginal suppository) with a disposable applicator. Here's how it's typically used:

• Dose: One 100 mg insert, two to three times daily
• Route: Vaginal insertion using the provided applicator
• When to start: The day after egg retrieval (oocyte retrieval)
• How long: Up to 10 weeks total, or as directed by your doctor

Tips for Using Endometrin

1. Lie on your back with your knees bent.
2. Insert the applicator gently into the vagina and push the plunger to release the insert.
3. Stay lying down for a few minutes after insertion.
4. Do not use other vaginal products (such as antifungal creams or spermicides) at the same time — they can interfere with absorption.
5. A white or off-white discharge after insertion is normal. It's the dissolved insert residue.

Your fertility clinic will give you specific instructions about timing and frequency. Follow their protocol exactly — consistency matters with Endometrin.

Who Should Not Take Endometrin?

Endometrin is not right for everyone. You should not use Endometrin if you have:

• A known allergy to Progesterone or any ingredient in Endometrin
• Undiagnosed abnormal vaginal bleeding
• Known or suspected breast cancer
• Active blood clots (deep vein thrombosis or pulmonary embolism), or a history of these conditions
• Active arterial thromboembolic disease (such as stroke or heart attack)
• Known liver disease or liver dysfunction
• Known or suspected pregnancy-related cancer of the genital organs

Always share your full medical history with your fertility doctor before starting Endometrin. For a complete list of potential side effects, see our guide: Endometrin Side Effects.

How Much Does Endometrin Cost?

Endometrin can be expensive, especially without insurance coverage. Here's what to expect in 2026:

• Brand-name Endometrin: $327–$393 for one box of 21 inserts at retail pharmacy (cash price)
• Generic Progesterone vaginal insert (Xiromed): As low as $91 for 21 inserts with a GoodRx coupon
• With insurance: Coverage varies widely. Many commercial plans cover Endometrin as part of ART treatment with prior authorization. Some require step therapy. Medicare generally does not cover fertility treatments.

Since a typical treatment course lasts up to 10 weeks at two to three doses per day, you may need multiple boxes. That adds up quickly at brand-name prices.

Ways to Save

• Ask for the generic. The Xiromed generic is therapeutically equivalent and significantly cheaper.
• Ferring h.e.a.r.t.+ Savings Card: Savings of up to $30 every two weeks for eligible patients. Available at ferringfertility.com.
• Ferring HeartTomorrow program: Discounted pricing for eligible cash-paying patients undergoing fertility treatment.
• Patient assistance programs: Check NeedyMeds.org and RxAssist.org for additional options.
• Discount coupons: GoodRx and other coupon sites can reduce cash prices significantly.

For a detailed breakdown, read our full guide: How to Save Money on Endometrin.

Final Thoughts

Endometrin is a widely used fertility medication that plays a critical role in supporting pregnancy during IVF and other ART cycles. It's safe, effective, and now available in a more affordable generic form.

If your doctor has prescribed Endometrin, the most important things to know are: use it exactly as directed, don't skip doses, and reach out to your clinic if you have any concerns about side effects.

Need to fill your prescription? Use Medfinder to check which pharmacies have Endometrin in stock near you.