The contraceptive implant is one of the most effective birth control methods available, but it comes with a real list of downsides that affect daily life. Irregular bleeding is the most common complaint, followed by weight gain, skin changes, and mood shifts. About one in four users discontinues the implant within the first year, often because of these side effects.
Unpredictable Bleeding Patterns
The single biggest reason people dislike the implant is what it does to their periods. Your bleeding pattern in the first year is essentially a coin toss. Some users bleed more frequently and for longer stretches, some spot randomly for weeks, and others lose their period entirely. In clinical data, about 15% of implant users stop getting a period altogether, while roughly 10% experience bleeding that exceeds 45 days over a reference period. The rest fall somewhere in between, often with irregular spotting that doesn’t follow any predictable schedule.
This isn’t a brief adjustment phase. Bleeding irregularities can persist for the entire time the implant is in place, though they do tend to improve somewhat after the first six to twelve months. For many users, not knowing when bleeding will happen is more frustrating than the bleeding itself. It makes planning around periods nearly impossible and can interfere with sexual activity, exercise, and daily comfort.
Weight Gain
Weight gain is a common concern, and the data shows it’s a real, if modest, effect. The median weight change among implant users is about 3.2 kilograms (roughly 7 pounds). In the largest study comparing implant users to a non-hormonal control group, implant users gained an average of 3 kilograms over 36 months, compared to 1.1 kilograms in the control group. That extra 2 kilograms above what you might gain anyway isn’t dramatic, but it’s measurable.
The range of individual experiences is wide. Some users lose weight, others gain significantly more than the median. Despite being a frequent complaint, weight gain is rarely the primary reason people have the implant removed early. It tends to be the kind of side effect that bothers people in combination with other issues rather than on its own.
Skin Changes and Acne
The implant releases a progestin-only hormone, and progestin can trigger or worsen several skin conditions. Acne is the most commonly reported one, particularly in users who had clear skin before insertion. The hormonal shift can also contribute to increased facial or body hair growth, rosacea flare-ups, and in rarer cases, hair thinning. If you’re someone who previously used a combined pill (which contains estrogen), switching to the implant may feel like a step backward for your skin, since estrogen generally helps keep acne in check.
Mood and Emotional Changes
Mood swings, increased anxiety, and depressive symptoms are reported by a meaningful number of implant users, though pinning down exact rates is difficult because mood is hard to measure objectively in clinical trials. What’s clear is that progestin-only methods, including the implant, affect some users’ emotional wellbeing. You may notice increased irritability, lower mood, or emotional sensitivity that wasn’t there before. These changes can be subtle or significant, and they sometimes take weeks to connect to the implant because they build gradually.
If you have a history of depression or anxiety, this is worth discussing before choosing the implant. Not everyone with a mental health history will have problems, but being aware of the possibility makes it easier to recognize and act on changes early.
Insertion and Removal Risks
Getting the implant placed is a minor in-office procedure, and complications are genuinely rare, occurring in about 0.3% of insertions. The most common issues are bruising, mild pain, and swelling at the site. Infection rates range from 0% to 1.4%, and spontaneous expulsion (the implant working its way out) happens in fewer than 0.6% of cases.
Removal is where things can get more complicated. If the implant is placed too deeply or migrates from its original position, it can be difficult to locate and may require imaging to find. In rare cases, an implant shifts toward the armpit area or settles into deeper tissue, making removal a longer, more involved process. Nerve compression from the implant is uncommon but has been documented, causing temporary tingling or numbness in the arm. After any nerve irritation from insertion or removal, sensation typically returns to normal within about a week.
Drug Interactions That Reduce Effectiveness
The implant works by releasing a hormone that gets processed through a specific liver enzyme pathway. Certain medications speed up that pathway, breaking down the hormone faster and potentially dropping its levels low enough to allow pregnancy. The most well-documented interaction is with efavirenz, an HIV medication. Studies have shown reductions of 49% to 82% in the implant’s hormone levels when used alongside efavirenz, a decrease large enough that the implant may not reliably prevent pregnancy.
Other medications that rev up the same liver pathway can cause similar problems. These include some anti-seizure drugs, certain tuberculosis treatments, and the herbal supplement St. John’s wort. If you take any of these, the implant may not be your best option, and a non-hormonal method like the copper IUD would be unaffected by these interactions.
Who Should Avoid the Implant
The CDC’s medical eligibility criteria flag several conditions where the implant poses elevated risk. A current or recent history of breast cancer is the clearest contraindication, since the hormone released by the implant can stimulate hormone-sensitive tumors. Certain liver conditions also make the implant a poor choice, including hepatocellular adenoma, liver cancer, and decompensated cirrhosis, because the liver plays a central role in processing the implant’s hormone.
The Commitment Factor
Unlike a pill you can simply stop taking, the implant requires a clinic visit for removal. If you develop side effects you can’t tolerate, you’re dependent on scheduling an appointment and finding a provider to take it out. This isn’t always quick or easy, depending on your location and insurance. The implant is approved for three years, though research on over 200 women who used it for five years found zero pregnancies in years four and five, suggesting it remains effective beyond its labeled duration.
About 25% of implant users discontinue within the first year. That’s a slightly higher early dropout rate than the copper IUD, which sees about 20% discontinuation in the same timeframe. The most common reasons are bleeding problems, followed by the accumulation of hormonal side effects like mood changes, headaches, and weight gain. For the roughly 75% who keep it, the implant’s near-perfect effectiveness and low maintenance make the trade-offs worthwhile. But if you’re someone who is sensitive to hormonal changes or values menstrual predictability, the disadvantages are substantial enough to weigh carefully.