What it is used for
- Long-term contraception
- Managing heavy or painful periods (when prescribed)
- Endometriosis-related pain (in certain formulations)
How it works
A progestogen hormone given by injection that stops the ovaries releasing an egg, thickens cervical mucus, and thins the womb lining.
How it is taken
Given as an injection at regular intervals by a healthcare professional, or in some places as a self-administered under-the-skin version. The timing of repeat doses matters, so keep to the schedule your clinician sets and follow their instructions exactly.
No doses here on purpose. The right strength and schedule depend on you — only a doctor or pharmacist should set them. Always follow your prescription and the label.
Common side effects
- Irregular bleeding, then often lighter or no periods
- Weight changes
- Headache
- Mood changes
- Reduced libido
- Delay in fertility returning after stopping (can take several months to over a year)
Serious effects — get help
- Signs of a serious allergic reaction
- Severe depression
- Severe abdominal pain
- Symptoms of a blood clot
If a reaction is severe — for example trouble breathing, swelling of the face or throat, or collapse — go to the nearest emergency room now or call your local emergency number. Do not wait for an online consultation.
Interactions to watch
- Generally fewer interactions than pills, but tell your clinician about all medicines
- Some medicines for diabetes or other long-term conditions may need monitoring
Who should take care
- Long-term use may lower bone density, which usually recovers after stopping; discuss this if you are young or have osteoporosis risk
- Not ideal if you want to conceive in the near future, because fertility can take time to return
- Tell your clinician about any history of breast cancer, liver disease, or unexplained vaginal bleeding
- Does not protect against STIs