Can the implant make you feel unwell? A comprehensive guide to side effects

October 2, 2025 •

4 min read

While the birth control implant is over 99% effective at preventing pregnancy, it can cause some users to experience side effects that make them feel unwell, particularly during the initial adjustment period. Understanding these potential hormonal changes is key to managing expectations.

Quick Summary

Yes, the hormonal implant can cause side effects like headaches, nausea, or mood changes in some people, which are typically most noticeable in the first few months as the body adjusts to the etonogestrel hormone. Many find these symptoms improve or resolve completely over time.

Key Points

Temporary Side Effects: Many initial symptoms like headaches, nausea, and breast tenderness are temporary and often resolve within the first few months.
Mood and Mental Health: Hormonal changes from the implant can lead to mood swings and, in some cases, feelings of depression.
Irregular Bleeding: A change in your menstrual pattern is the most common side effect and typically not a sign of a serious health problem.
Rare but Serious Risks: Though uncommon, risks like blood clots or implant migration can occur and require immediate medical attention.
Professional Guidance is Key: Discuss any persistent or severe side effects with your healthcare provider to explore management options or alternative contraception.
It's an Adjustment Period: The body needs time to get used to the new hormonal balance, which is why many side effects lessen over time.

Understanding the Birth Control Implant

The birth control implant, a small flexible rod inserted under the skin of the upper arm, releases a progestin hormone called etonogestrel over several years. This hormone works primarily by preventing ovulation and thickening cervical mucus to block sperm. The introduction of these hormones into the body is the reason many individuals experience side effects, particularly during the initial adjustment phase.

Common Side Effects That Can Make You Feel Unwell

Many of the initial side effects are a result of the body adapting to a new hormonal balance. While some women experience no issues at all, others may notice a range of symptoms. Most of these tend to be temporary and subside after the first few months.

Physical Discomfort and Changes

Headaches and Dizziness: These are commonly reported, especially in the first few months. For some, headaches may be more frequent or severe than usual.
Nausea: A feeling of sickness or an upset stomach can occur, though it often lessens over time.
Breast Tenderness: Swollen or sore breasts are a common symptom due to hormonal fluctuations.
Changes in Bleeding Patterns: This is one of the most reported side effects. Bleeding can become irregular, stop completely (amenorrhea), or be heavier or lighter than usual. While concerning for some, altered bleeding patterns are not a health risk.
Weight Fluctuations: Some people report mild to moderate weight gain, while others experience no change.
Acne: Skin changes, including acne flare-ups or, for some, improvements, are possible.

Psychological and Mood-Related Side Effects

Beyond the physical symptoms, the hormonal changes from the implant can also impact mental health. This is a significant factor for those who feel generally unwell or out of sorts.

Mood Swings: Many users report experiencing mood swings, irritability, or increased nervousness.
Depressed Mood: In some cases, the implant can trigger feelings of depression. Anyone who notices a significant change in their mental health should contact their healthcare provider.
Reduced Libido: A decreased sex drive is a possible effect for some individuals.

Less Common but Significant Concerns

While most side effects are mild, it is important to be aware of the rare, more serious risks that require immediate medical attention.

Blood Clots: Though very rare, the implant can slightly increase the risk of blood clots. Symptoms might include persistent pain, swelling, or warmth in the leg, or chest pain and shortness of breath.
Ectopic Pregnancy: If a user does become pregnant while on the implant (which is extremely unlikely), there is a higher chance it will be an ectopic pregnancy, where the fertilized egg implants outside the uterus.
Implant Migration: In very rare cases, the implant can move from its insertion site. This may require an ultrasound or X-ray to locate for removal.

Comparison: Implant vs. Other Hormonal Contraceptives


Feature	Birth Control Implant (Nexplanon)	Combined Hormonal Pill	Hormonal IUD (Mirena)
Hormone Type	Progestin (Etonogestrel)	Estrogen + Progestin	Progestin (Levonorgestrel)
Typical Side Effects	Irregular bleeding, headaches, nausea, mood changes, breast tenderness	Nausea, breast tenderness, headaches, weight gain, mood changes, blood clots (rare)	Irregular bleeding/spotting (initially), headaches, breast tenderness, mood changes
Bleeding Patterns	Often causes irregular bleeding or cessation of periods.	Regulates periods, often making them lighter and more predictable.	Causes irregular spotting initially, then lighter or absent periods.
Mental Health Impact	Possible mood swings or depression.	Possible mood changes, less common for some.	Less systemic hormonal effect, often fewer mood-related issues.
Longevity	Up to 3-5 years (depending on type).	Daily pill.	5-8 years (depending on type).
Effectiveness	Over 99% effective.	91-99% (depends on perfect use).	Over 99% effective.

Managing Side Effects: What You Can Do

If you are experiencing side effects, here are some steps you can take in consultation with your healthcare provider:

Give it Time: Many side effects are temporary and may resolve on their own as your body adjusts. Giving it a few months may be enough for symptoms to subside.
Track Your Symptoms: Keep a journal of your side effects. This can help you and your doctor identify patterns and triggers.
Consult Your Doctor: Before starting any medication for symptom relief, discuss it with your healthcare provider. For example, over-the-counter pain relievers can often manage headaches, but your doctor's advice is crucial.
Consider Removal: If side effects are persistent, severe, or significantly impact your quality of life, discuss removal of the implant with your doctor.

Conclusion: Informed Decisions for Your Health

For many, the convenience and high effectiveness of the birth control implant outweigh the side effects. However, feeling unwell is a valid and important concern that should not be dismissed. By understanding the potential physical and psychological impacts, individuals can make an informed decision and work closely with their healthcare provider to manage their experience. For more detailed information on contraceptive options, you can consult reliable sources like the Mayo Clinic's guide on the contraceptive implant.

Frequently Asked Questions

For most people, any mild side effects, such as nausea or headaches, are most noticeable during the first few months. The body typically adjusts within 3 to 12 months, and symptoms often improve or disappear entirely during this time.

Yes, some individuals report experiencing mood swings, irritability, or a depressed mood as a side effect of the hormonal changes from the implant. If you notice a significant or persistent change in your mental health, it is important to speak with a healthcare professional.

Yes, it is a known side effect. Like many other hormonal contraceptives, the implant can cause nausea, especially during the initial adjustment period. It often subsides over time.

The most common side effects include changes in menstrual bleeding patterns (irregular, lighter, or absent periods), headaches, breast tenderness, mood swings, weight gain, and acne.

You should contact your doctor immediately if you experience severe chest pain, shortness of breath, sudden severe headaches, or signs of a blood clot (like persistent pain or swelling in your leg). Any signs of infection at the insertion site should also be reported.

Once the implant is removed, etonogestrel levels in the blood decrease rapidly. Most temporary side effects, such as headaches or mood changes, will begin to improve within a few days or weeks after removal.

Some individuals report weight gain while using the implant. While studies show the average weight gain is modest, it is a reported side effect for some people.

Some people experience persistent headaches. While many find they subside over time, if they are severe or do not improve, you should speak with your healthcare provider to rule out other causes and discuss options.