Side-by-side comparison
Implant vs injection
The implant is more effective in real life (over 99% vs about 96%) because there are no repeat appointments to miss. Fertility returns quickly after the implant is removed but can take up to a year after the last injection.
By the AltFTool health editorial teamLast reviewed Checked against WHO, CDC and NHS guidance
Key differences
| Feature | Implant | Injection |
|---|---|---|
| Typical-use effectiveness | Over 99% | 96% |
| Perfect-use effectiveness | Over 99% | Over 99% |
| Hormones | Progestogen | Progestogen |
| How long it lasts | 3 years on the US license; UK guidance now supports up to 5 years | 8 to 13 weeks depending on the type; the most common type is given about every 3 months (every 13 weeks in the UK, every 12 to 13 weeks in the US) |
| Protects against STIs | No | No |
| Needs a clinician to start | Yes | Yes |
| Daily or every-time action | No | No |
| You can stop it yourself | No | Yes |
| Fertility after stopping | Quickly after removal | Can take up to about a year |
| While breastfeeding | Yes | Usually yes (ask a clinician about timing after birth) |
| Effect on periods | Bleeding often becomes irregular or unpredictable; some people stop bleeding altogether. | Bleeding often becomes irregular at first, and periods stop for many people the longer they use it. |
Read each guide
Contraceptive implant
People who want highly effective, long-lasting contraception without daily effort, including those who cannot take estrogen.
Contraceptive injection
People who want effective contraception without a daily pill or a fitted device and who are not planning a pregnancy within the next year.
FAQ
Which is more effective, implant or injection?
The implant is more effective in real life (over 99% vs about 96%) because there are no repeat appointments to miss. Fertility returns quickly after the implant is removed but can take up to a year after the last injection.
Does the implant or injection protect against STIs?
Neither does. Use condoms as well if you need protection from sexually transmitted infections.
Can I switch from the implant to the injection?
Usually yes. A clinician or pharmacist can tell you when to start the new method and whether you need extra protection (such as condoms) for a few days while switching.
More comparisons
Sources
Reviewed 1 November 2026. We link to the guidance itself so you can check it.