Yes, the contraceptive implant is a hormonal method of birth control. It releases a single synthetic hormone called etonogestrel, which is a type of progestin. There are no non-hormonal versions of the arm implant available anywhere in the world. Every subdermal contraceptive implant on the market works by slowly releasing a progestin hormone from a small rod placed under the skin of your upper arm.
What Type of Hormone It Uses
The implant sold in the United States (Nexplanon) contains 68 mg of etonogestrel sealed inside a single flexible rod about the size of a matchstick. Etonogestrel is a progestin only. It does not contain estrogen, which makes it different from combination birth control pills and some other hormonal methods that use both estrogen and progestin together.
Other implant brands used in different countries rely on a different progestin called levonorgestrel (Jadelle, for example), but the principle is the same. A slow, steady release of progestin from the rod provides continuous contraception without you needing to remember a daily pill or monthly appointment.
How the Hormone Prevents Pregnancy
Etonogestrel works primarily by stopping ovulation. Without the release of an egg each cycle, pregnancy can’t happen. It also thickens cervical mucus, creating a barrier that makes it much harder for sperm to reach an egg in the unlikely event one is released.
This two-layered mechanism makes the implant one of the most effective contraceptives available. In a large real-world study of Nexplanon users, only 3 pregnancies occurred during use, producing a Pearl Index of 0.02. That translates to roughly 99.9% effectiveness, a rate that holds up in everyday use because there’s no room for user error once the implant is in place.
How It Compares to Non-Hormonal Options
If you’re specifically looking for a long-acting method that doesn’t use hormones, the copper IUD is the main alternative. It sits in the uterus rather than the arm and prevents pregnancy through the copper itself, with no hormonal component. The implant has no equivalent non-hormonal version.
Because the implant is progestin-only, it avoids some of the estrogen-related concerns that lead people to seek non-hormonal options, such as increased risk of blood clots. But it still introduces a synthetic hormone into your system, so it’s not the right fit for someone who wants to avoid hormones entirely.
What the Hormone Does to Your Period
Changes to bleeding patterns are the most noticeable effect of the implant’s hormone, and the experience varies widely. In a study of 350 implant users, about 38% continued to have roughly monthly periods. Around 15% stopped bleeding altogether. The remaining users fell somewhere in between, with irregular spotting or bleeding that didn’t follow a predictable cycle.
Among those who didn’t have regular monthly periods, the majority (about 72%) experienced fewer than 16 days of bleeding or spotting over any 90-day stretch. Only about 10% reported bleeding on more than 45 out of 90 days. Unpredictable bleeding is the most common reason people ask to have the implant removed early, but for many users it settles into a lighter, more manageable pattern over time.
Other Hormonal Side Effects
Because etonogestrel circulates through your bloodstream, it can cause systemic effects beyond your reproductive system. In a cross-sectional study of implant users, the most frequently reported side effects were weight gain (about 25% of users), headache (about 24%), and decreased sex drive (about 20%). These side effects tend to be more common in older users.
Some people also report mood changes or acne, though experiences vary considerably from person to person. The progestin-only formula means you won’t encounter estrogen-specific side effects like nausea or breast tenderness that sometimes come with combination methods, but the implant is not side-effect-free.
How Long the Hormone Stays Active
Nexplanon is approved for up to three years of use. The rod releases the highest amount of hormone in the first year, then gradually tapers. Even at the lower release rate toward the end of the three-year window, hormone levels remain high enough to prevent ovulation reliably.
Once the implant is removed, the hormone clears your system quickly. Ovulation can return within days, and pregnancy is possible almost immediately. Your period will typically go back to whatever pattern was normal for you before the implant. There’s no waiting period or “detox” needed for your fertility to come back.