Yes, Nexplanon is a hormonal form of birth control. It contains a single synthetic progestin called etonogestrel, which it releases steadily into your bloodstream through a small, flexible rod inserted just under the skin of your upper arm. It does not contain estrogen, making it a progestin-only method.
How the Hormone Works
The implant prevents pregnancy primarily by stopping ovulation. Without an egg being released, fertilization can’t happen. It also thickens cervical mucus, creating a barrier that makes it harder for sperm to reach the uterus. These two mechanisms together make it one of the most effective contraceptives available. Across 11 international clinical trials, no pregnancies occurred while the implant was in place, giving it a Pearl Index of 0.38 over three years, which translates to greater than 99% effectiveness.
How Much Hormone It Releases
Nexplanon doesn’t deliver a constant dose. It starts at its highest output and gradually tapers. In the first several weeks, the implant releases about 60 to 70 micrograms of etonogestrel per day. By the end of year one, that drops to roughly 35 to 45 micrograms. By year two, it’s down to 30 to 40 micrograms, and by year three, about 25 to 30 micrograms per day.
For context, those doses are measured in micrograms, which are one-thousandth of a milligram. This is a very small amount of hormone compared to what many oral contraceptives deliver, and because it goes directly into the bloodstream rather than passing through the digestive system first, the body can use it more efficiently. The implant is now FDA-approved for up to five years of use, extended from the original three-year approval, and must be removed by the end of the fifth year.
How It Affects Your Period
Because Nexplanon is hormonal, it changes bleeding patterns for most users. This is one of the most noticeable effects and often the reason people either love or dislike the implant. Clinical data from the FDA shows how bleeding patterns look over time, measured in 90-day windows:
- Normal frequency (3 to 5 bleeding episodes per 90 days): The most common pattern, seen in about 54% of users initially and rising to nearly 59% over time.
- Infrequent bleeding (fewer than 3 episodes): Around 16 to 17% of users.
- No periods at all: About 6 to 7% of users stop bleeding entirely.
- Frequent bleeding (more than 5 episodes): Roughly 10 to 11%, decreasing slightly over time.
- Prolonged bleeding (more than 14 continuous days): About 12% of users early on, dropping to around 7% with longer use.
There’s no way to predict which pattern you’ll experience before insertion. The good news is that prolonged and frequent bleeding tend to improve the longer the implant is in place.
Common Hormonal Side Effects
Since etonogestrel circulates through your entire body, it can cause side effects beyond changes to your period. The most frequently reported reasons users have the implant removed include mood swings, depressed mood, weight gain, headache, and acne. Nervousness is also commonly reported.
These side effects overlap with what many people experience on other hormonal birth control methods, and they’re driven by the same basic mechanism: introducing a synthetic hormone that interacts with receptors throughout the body, not just in the reproductive system. Not everyone experiences them, and for many users they’re mild enough to be outweighed by the convenience of not thinking about birth control for years at a time.
Why Progestin-Only Matters
The fact that Nexplanon contains no estrogen is a meaningful distinction. Estrogen is the component in combined birth control pills that’s linked to rare but serious risks like blood clots, stroke, and heart attack, particularly in smokers and people over 35. Because Nexplanon skips estrogen entirely, it’s generally considered a safer option for people who can’t use estrogen-containing methods, including those with a history of blood clots or certain cardiovascular risk factors.
This also makes it different from most combination pills, patches, and hormonal rings, which rely on both estrogen and a progestin to prevent pregnancy. Nexplanon achieves its effectiveness with progestin alone.
What Happens When It’s Removed
Once the implant is taken out, the hormone clears from your system quickly. Fertility can return almost immediately. It’s possible to get pregnant right away after removal, so if you’re not planning a pregnancy, you’ll need a new contraceptive method in place before or at the time of removal. If you want to continue using the implant, a new one can be inserted during the same visit.