Some IUDs are hormonal, and some are not. There are two distinct types of intrauterine devices available: hormonal IUDs that release a small amount of progestin, and one copper IUD that contains no hormones at all. The answer depends entirely on which IUD you’re talking about.
Two Types of IUDs
The FDA has approved five IUD brands. Four of them are hormonal: Mirena, Liletta, Kyleena, and Skyla. Each releases a synthetic form of progesterone called levonorgestrel directly into the uterus. The fifth, Paragard, is wrapped in copper wire and works without any hormones.
This is an important distinction because many people seek out an IUD specifically to avoid hormonal birth control. If that’s your goal, the copper IUD is the only hormone-free option in the IUD category. But if you’re open to hormones, the hormonal IUDs deliver a much lower dose than most other methods.
How Hormonal IUDs Work
Hormonal IUDs release levonorgestrel locally into the uterus, where it thickens cervical mucus to block sperm, thins the uterine lining, and in some cases suppresses ovulation. Because the hormone goes directly to the uterus rather than traveling through your entire body first (the way a pill does), the amount that reaches your bloodstream is significantly lower than with oral contraceptives or other systemic methods.
The four hormonal brands differ mainly in how much levonorgestrel they contain and how long they last. Mirena and Liletta each hold 52 mg and release roughly 19 to 20 micrograms per day when first placed. That rate gradually decreases over time. Kyleena holds 19.5 mg and starts at about 17.5 micrograms per day. Skyla, the smallest, holds 13.5 mg and begins at around 14 micrograms per day. For context, a typical birth control pill delivers a much larger hormonal dose systemically each day.
How the Copper IUD Works
Paragard takes a completely different approach. The copper wire continuously releases copper ions into the uterus, which are toxic to sperm. This interferes with sperm transport and fertilization without affecting your hormones or ovulation cycle at all. Your body continues to ovulate normally each month.
The trade-off is that Paragard tends to make periods heavier and longer, especially in the first few months. Menstrual changes are the most common reason people have it removed. For most users, the heavier bleeding diminishes after two to three months, but it doesn’t lighten periods the way hormonal IUDs do.
How They Affect Your Period
This is one of the biggest practical differences between the two types. Hormonal IUDs typically make periods lighter over time, and many users eventually stop getting a period altogether. A systematic review found that about 18% of hormonal IUD users experienced at least one stretch of 90 or more days without any bleeding during their first year. The shift happens gradually: almost no one loses their period in the first three months, but by the end of the first year, roughly 20% of users have reached that point.
The copper IUD does the opposite. Periods often get heavier and come with more cramping, particularly in the early months. Your cycle stays hormonally unchanged, which some people prefer, but the heavier flow is a real consideration.
Effectiveness Comparison
Both types of IUD are among the most effective forms of birth control available. Hormonal IUDs (based on Mirena data) have a typical-use failure rate of 0.2% in the first year, meaning only about 2 in 1,000 users get pregnant. The copper Paragard has a typical-use failure rate of 0.8%, still extremely low compared to methods like the pill, patch, or condoms. The only method slightly more effective is the hormonal arm implant, at 0.05%.
A key advantage of IUDs is that typical use and perfect use are nearly identical. Unlike pills, which require daily attention, an IUD works on its own once placed.
How Long Each Type Lasts
Paragard is approved for up to 10 years, making it the longest-lasting IUD. Among hormonal options, Mirena and Liletta now have FDA approval for up to 8 years, after multiple extensions between 2020 and 2023 pushed their approved duration from the original 5 years. Kyleena is approved for 5 years, and Skyla for 3 years. All IUDs can be removed earlier if you want to become pregnant or switch methods, and fertility returns quickly after removal.
Choosing Between Hormonal and Non-Hormonal
The decision often comes down to a few practical questions. If you want to avoid hormones entirely, whether for medical reasons, side effect concerns, or personal preference, Paragard is your option. If lighter periods or no periods sound appealing, a hormonal IUD is more likely to deliver that. If you’ve had heavy or painful periods, a hormonal IUD may actually improve them, while Paragard could make them worse.
Some people worry that a hormonal IUD will cause the same side effects as the pill, like mood changes, weight gain, or acne. While those effects are possible, they’re generally less common with hormonal IUDs because the hormone dose reaching the rest of your body is so much lower. That said, some users do report systemic effects, so “lower dose” doesn’t mean “no hormonal effects” for everyone.
Both types are placed during a short office visit, and both are reversible. The choice is really about whether you want a hormone-free method you pair with heavier periods, or a low-dose hormonal method that tends to make periods lighter or disappear.