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

Mirena is one of the most widely used and well-studied intrauterine devices (IUDs) in the United States. Whether you're considering it for the first time or just want to better understand what's inside you, this guide covers everything you need to know about Mirena in 2026 — from what it is to how it works, who it's for, and what to expect.

What Is Mirena?

Mirena is a brand-name intrauterine device (IUD) made by Bayer. It contains 52 mg of levonorgestrel — a synthetic progestin hormone — and slowly releases that hormone into the uterine cavity over time. Mirena was first FDA-approved in December 2000 and has been continuously available ever since, making it the oldest and most studied hormonal IUD on the U.S. market.

Mirena is a small, T-shaped plastic device, about the size of a paper clip. It is inserted into the uterus during a brief in-office procedure by a trained healthcare provider. Once in place, it works continuously — no daily pills, no monthly prescriptions.

What Is Mirena Used For? (FDA-Approved Indications)

Mirena has two FDA-approved uses:

1. Contraception (birth control) — Mirena is approved to prevent pregnancy for up to 8 years. It is over 99% effective, making it one of the most reliable forms of contraception available. Effectiveness is comparable to permanent sterilization but is fully reversible.
2. Treatment of heavy menstrual bleeding (HMB) — Mirena is the only IUD FDA-approved to treat heavy periods (menorrhagia) for up to 5 years in women who also choose to use it for contraception. Many patients see significant reduction in menstrual blood loss, and many eventually stop having periods altogether.

Off-Label Uses of Mirena

Healthcare providers sometimes prescribe Mirena for off-label uses supported by clinical evidence, including:

• Endometriosis-related pain management
• Adenomyosis symptom relief
• Endometrial protection during estrogen therapy in perimenopausal women
• Prevention of endometrial hyperplasia in women at risk

Mirena Dosage and Release Rate

The Mirena IUD contains 52 mg of levonorgestrel and releases it gradually into the uterus:

• At 24 days post-insertion: approximately 21 mcg/day
• After 5 years: approximately 11 mcg/day
• After 8 years: approximately 7 mcg/day

This gradual decline in release rate is why Mirena's contraceptive label extends to 8 years for contraception, but its heavy bleeding treatment label covers only 5 years — the higher hormone levels in the early years are particularly effective at reducing menstrual blood loss.

Who Is Mirena Appropriate For?

Mirena is appropriate for females of reproductive age who:

• Want long-term, highly effective contraception for up to 8 years
• Have heavy menstrual bleeding and want treatment plus contraception
• Prefer a method that doesn't require daily attention or regular prescription refills
• Want a reversible method — fertility returns quickly after removal
• Have previously given birth or haven't — both are appropriate candidates
• Are breastfeeding (with caution — perforation risk is higher shortly postpartum)

Who Should NOT Use Mirena?

Mirena is contraindicated for women with:

• Known or suspected pregnancy
• Breast cancer or progestin-sensitive cancer (current or past)
• Uterine fibroids that distort the uterine cavity
• Active pelvic inflammatory disease (PID) or history of PID without subsequent pregnancy
• Liver disease or liver tumor
• Unexplained uterine bleeding
• Another IUD currently in place

How Long Does Mirena Last?

For contraception: up to 8 years. For heavy period treatment: up to 5 years. Mirena can be removed earlier by your provider at any time if you decide to become pregnant, want to switch methods, or are experiencing bothersome side effects. After removal, fertility returns quickly — 8 out of 10 women who have Mirena removed can get pregnant within one year.

For more detail on how Mirena works, see our guide How Does Mirena Work? Mechanism of Action Explained. If you're ready to get Mirena, medfinder can help you find a provider with it in stock near you.