Alternatives to Endometrin If You Can't Fill Your Prescription

When Endometrin Isn't Available, What Are Your Options?

If you're in the middle of an IVF cycle and your pharmacy can't fill your Endometrin prescription, it's understandably nerve-wracking. Progesterone support is a critical part of fertility treatment, and you can't just skip it.

The good news: there are several proven alternatives to Endometrin that your doctor can prescribe. They all deliver Progesterone to support your uterine lining — they just do it in different ways. Let's walk through what Endometrin is, how it works, and what your options are if you can't get it.

What Is Endometrin?

Endometrin is a brand-name vaginal insert containing 100 mg of micronized Progesterone. It's manufactured by Ferring Pharmaceuticals and is FDA-approved for luteal phase support in women undergoing assisted reproductive technology (ART) treatments, including IVF.

During a normal menstrual cycle, the ovaries produce Progesterone after ovulation to prepare the uterine lining for a potential pregnancy. In ART cycles, especially after egg retrieval, your body may not produce enough Progesterone on its own. Endometrin fills that gap.

How Does Endometrin Work?

Endometrin works by delivering Progesterone directly to the uterus through the vaginal route. When inserted vaginally, the micronized Progesterone is absorbed through the vaginal mucosa and achieves high concentrations in the endometrial tissue — even higher than what you'd see with oral Progesterone at the same dose.

This local delivery is part of what makes vaginal Progesterone products effective for fertility treatment. The Progesterone transforms the uterine lining from a proliferative state to a secretory state, creating the right conditions for an embryo to implant and grow.

Endometrin is typically used at a dose of 100 mg two to three times daily, starting the day after egg retrieval and continuing for up to 10 weeks.

Alternatives to Endometrin

If Endometrin isn't available, here are the most common alternatives your fertility specialist may recommend:

1. Generic Progesterone Vaginal Insert (Xiromed)

In September 2025, Xiromed launched the first FDA-approved generic version of Endometrin — a Progesterone vaginal insert, 100 mg. This is the closest alternative because it's essentially the same medication in the same format. It contains the same active ingredient, same dose, and same route of administration.

If your pharmacy doesn't have brand-name Endometrin, ask specifically about the generic Progesterone vaginal insert. It may be available and is often less expensive. Prices with a coupon card can be as low as $91 for 21 inserts compared to $327-$393 for brand-name Endometrin.

2. Crinone (Progesterone Vaginal Gel)

Crinone is a Progesterone vaginal gel (8%) that delivers 90 mg of Progesterone per application. Like Endometrin, it's applied vaginally and achieves high Progesterone concentrations in the uterus.

Pros:

• Once-daily dosing is possible (compared to 2-3 times daily for Endometrin)
• Well-studied in fertility treatment with comparable pregnancy rates
• No applicator insertion of a solid tablet

Cons:

• Gel residue can accumulate in the vagina, which some patients find uncomfortable
• May require periodic removal of residue
• Can be expensive — retail prices are often higher than Endometrin

3. Prometrium (Oral Progesterone Capsules)

Prometrium is an oral micronized Progesterone capsule available in 100 mg and 200 mg strengths. While it's FDA-approved for oral use (to treat absent periods and protect the uterine lining during hormone replacement therapy), many fertility clinics prescribe it for vaginal use off-label.

Pros:

• Widely available as a generic (Progesterone capsules), making it easier to find
• Very affordable — generic Progesterone capsules can cost under $35 for a 90-day supply with a coupon
• Can be used vaginally for local Progesterone delivery

Cons:

• Vaginal use is off-label (not FDA-approved for this route, though widely practiced)
• May cause more vaginal discharge than Endometrin
• Contains peanut oil — not suitable for patients with peanut allergies

4. Progesterone in Oil (PIO) Injections

Progesterone in oil (PIO) is an intramuscular injection typically given in the buttocks area. It's been used for decades and is considered the traditional standard for luteal phase support.

Pros:

• Long track record of effectiveness
• Achieves high and consistent blood Progesterone levels
• Widely available

Cons:

• Painful daily injections with a large needle
• Can cause soreness, bruising, and knots at the injection site
• Requires a partner or self-injection technique
• Some patients develop allergic reactions to the oil carrier (sesame or olive oil)

Many patients prefer vaginal Progesterone options specifically because they want to avoid PIO injections. But if other options aren't available, PIO is a reliable alternative.

How to Choose the Right Alternative

The best alternative for you depends on several factors:

• Your clinic's protocol — some clinics have strong preferences based on their experience and outcomes data
• Availability — what's actually in stock at pharmacies near you
• Cost — generic Prometrium is the most affordable option; brand-name Crinone tends to be the most expensive
• Comfort — some patients prefer avoiding injections; others don't mind them
• Allergies — Prometrium contains peanut oil, which rules it out for some patients

Talk to your reproductive endocrinologist about which alternative makes the most sense for your specific situation and treatment plan.

Final Thoughts

Not being able to find Endometrin is stressful, but it doesn't have to derail your treatment cycle. Effective alternatives exist, and your fertility doctor has prescribed these medications countless times.

If you're still looking for Endometrin or its generic equivalent, try Medfinder to check pharmacy availability in your area. You can also read more about why Endometrin is hard to find and how to save money on Endometrin in our other guides.

Whatever path you and your doctor choose, the goal is the same: giving your pregnancy the best possible start.