Mirena vs. Kyleena
Updated August 2026
Quick answer: Mirena and Kyleena are two versions of the same idea — a hormonal IUD that releases progestin right inside the uterus — and the difference between them is dose. Mirena carries 52 mg of hormone, lasts up to 8 years, and is the one approved to treat heavy menstrual bleeding; it often stops periods entirely. Kyleena carries 19.5 mg in a slightly smaller frame and lasts up to 5 years; periods usually get lighter but are less likely to stop. Both prevent pregnancy over 99% of the time.
Key facts
- Mirena contains 52 mg of hormone and lasts up to 8 years; Kyleena contains 19.5 mg and lasts up to 5.
- Mirena is FDA-approved to treat heavy menstrual bleeding; Kyleena is approved for contraception only.
- About 1 in 5 Mirena users stop having periods by the first year, rising to around half after several years.
- Kyleena usually makes periods lighter, but they're less likely to stop completely than with Mirena.
- Kyleena's frame is slightly smaller, which some people find more comfortable.
- Both are progestin-only and estrogen-free, so both are safe for people who can't take estrogen.
Mirena vs. Kyleena: full comparison table
| COMPARE | Mirena | Kyleena |
|---|---|---|
| What it is | The higher-dose hormonal IUD, lasting up to 8 years | A lower-dose, slightly smaller hormonal IUD, lasting up to 5 years |
| Hormones | Progestin only | Progestin only |
| How you use it | Small device inserted by a clinician | Small device inserted by a clinician |
| How often you think about it | Up to 8 yrs | Up to 5 yrs |
| Pregnancy prevention (typical use) | 99.8% | 99.8% |
| Pregnancy prevention (perfect use) | 99.8% | 99.8% |
| What happens to periods | Periods often stop | Periods lighten, may not stop |
| Hormone dose | 52 mg — the highest-dose hormonal IUD. | 19.5 mg — a lower dose in a slightly smaller frame. |
| Heavy periods | The go-to: it's FDA-approved specifically to treat heavy menstrual bleeding. | Usually lightens periods, but it isn't approved as a heavy-bleeding treatment. |
| First few months | Irregular spotting and cramping are common for 3–6 months, then usually settle. | Same — irregular spotting and cramping at first, which usually settle. |
| Stopping | A clinician removes it in minutes; fertility returns right away. | Same quick removal, same fast return of fertility. |
The real difference: hormone dose
Mirena and Kyleena work the same way: a small T-shaped device sits in the uterus and releases a progestin (a lab-made hormone similar to the progesterone your body makes naturally) right where periods start. The difference is how much. Mirena carries 52 mg and releases the most hormone of any IUD; Kyleena carries 19.5 mg and releases far less. That reservoir also sets the lifespan: up to 8 years for Mirena, up to 5 for Kyleena.
The dose drives almost everything else. More hormone at the uterine lining means heavier period suppression — Mirena thins the lining so much that periods often stop. It also means slightly more hormone reaching the rest of your body, so hormonal side effects like breast tenderness or mood changes are a bit more likely with Mirena. With both devices, though, most of the hormone stays local, which is why IUD side effects tend to be milder than pill side effects.
Mirena vs. Kyleena for heavy periods
If heavy bleeding is the problem you're solving, this comparison has a clear answer. Mirena is FDA-approved specifically to treat heavy menstrual bleeding — not just to prevent pregnancy — and it's the strongest period-lightening option in contraception. About 1 in 5 users stop having periods by the first year, rising to around half after several years.
One detail worth knowing: Mirena's heavy-bleeding approval runs for 5 years, even though its contraception approval runs 8. If heavy periods are the reason you have it, your clinician may suggest replacing it sooner than the contraception timeline alone would. Kyleena usually makes periods lighter too, but it isn't approved as a heavy-bleeding treatment, and periods are less likely to stop on it.
Size, insertion, and who each suits
Kyleena's frame is slightly smaller than Mirena's, and it's often suggested for people who haven't given birth. It's worth being clear-eyed about what that buys: the difference is millimeters, and the evidence that a smaller frame makes insertion meaningfully easier or less painful is weak. Insertion is the same short procedure either way — strong cramps for a minute or two — and pain relief options are worth asking about with either device.
So the choice usually comes down to what you want from your periods. Want the best odds they stop, or need heavy bleeding treated? Mirena. Want years of IUD-grade protection with less hormone, and don't mind keeping a light period? Kyleena. Either way you get the same safety profile and the same over-99% protection.
Which should you choose?
Choose Mirena if:
- Heavy or painful periods are part of why you're getting an IUD — Mirena is the one approved to treat heavy bleeding.
- You'd love your periods to stop entirely, and you want the best odds of that.
- You want the longest run of protection: up to 8 years from one insertion.
- You've tried a lower-dose option and your periods are still too heavy.
Choose Kyleena if:
- You want an IUD's reliability with less hormone in the mix.
- You'd rather keep a light monthly period than lose it completely.
- You haven't given birth and like the idea of the slightly smaller frame.
- You're sensitive to hormonal side effects and want to keep the odds as low as possible.
Frequently asked questions
Which is better for heavy periods — Mirena or Kyleena?
Mirena. It releases the most hormone of any IUD, and it's the one FDA-approved specifically to treat heavy menstrual bleeding. About 1 in 5 Mirena users stop having periods by the first year, rising to around half after several years. Kyleena usually lightens periods, but it isn't approved as a heavy-bleeding treatment.
Does Kyleena stop your period like Mirena does?
It's less likely to. Kyleena's lower dose usually makes periods lighter, and for some people they do stop — but complete stopping is less common than with Mirena. If a period-free life is the goal, Mirena gives you better odds. If you'd rather keep a light period, Kyleena's pattern may actually suit you better.
Is Kyleena easier to insert because it's smaller?
Maybe marginally, but don't count on it. The size difference is millimeters, and the evidence that it makes insertion meaningfully easier or less painful is weak. Both are placed the same way in the same short appointment, with strong cramps for a minute or two. Whichever you pick, ask your clinician about pain relief options beforehand.
How long does each one last?
Mirena prevents pregnancy for up to 8 years; Kyleena for up to 5. One nuance: Mirena's approval for treating heavy bleeding runs 5 years, so if that's why you have it, your clinician may suggest an earlier replacement than the 8-year contraception limit.
Do Mirena and Kyleena have the same side effects?
The same kinds, yes: irregular spotting and cramping in the first 3–6 months are the big ones, and they usually settle. Because Mirena releases more hormone, side effects like breast tenderness or mood changes are slightly more likely with it — but with both devices, most of the hormone stays in the uterus, so these effects are less common than with pills.
What about Skyla and Liletta?
Skyla is the smallest hormonal IUD, releasing the least hormone, and lasts 3 years — a common choice for people who haven't given birth. Liletta is clinically the same as Mirena — same hormone, same dose, same 8-year lifespan — and is usually the most affordable hormonal IUD, so it's worth asking about if price is the deciding factor.
Can I get either one if I've never had a baby?
Yes. Never having been pregnant doesn't rule out any hormonal IUD. Smaller, lower-dose devices like Kyleena and Skyla were designed with people who haven't given birth in mind, but Mirena is an option too — especially if heavy periods are the reason you want one.
Is one safer than the other?
No — they share the same safety profile. Both are estrogen-free, so both are safe for people who can't take estrogen (estrogen is the ingredient that raises clot risk, and neither IUD has any). Serious problems are rare with both, and choosing between them is about periods, dose, and duration — not safety.
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