# Coils: copper IUD vs hormonal IUS

> Two tiny T-shapes, very different personalities.

Category: Contraception · 5 min read · Written by the Splash team · Sources checked October 2026
URL: https://splash.care/learn/contraception/iud-vs-ius

## Quick answer

- Both coils are over 99% effective and reversible straight away.
- Copper IUD: hormone-free, 5–10 years, may make periods heavier.
- Hormonal IUS: 3–8 years, often makes periods lighter.
- Know the warning signs after fitting and check your threads.

Both coils are small T-shaped devices a [doctor](https://splash.care/learn/conditions/talk-to-your-doctor) or nurse places in your womb. Both are over 99% effective, and fertility returns straight away when they’re taken out. The big difference is [hormones](https://splash.care/learn/cycle-basics/hormones-explained).

## Copper coil (IUD)

- Hormone-free – works by releasing copper
- Lasts 5 or 10 years depending on type
- Works as soon as it’s fitted
- Can also be used as [emergency contraception](https://splash.care/learn/glossary/emergency-contraception)
- Periods may become heavier, longer or more painful – this can improve after a few months

## Hormonal coil (IUS)

- Releases [Progestogen](https://splash.care/learn/glossary/progestogen) into the womb
- Lasts 3 to 8 years depending on type (e.g. Mirena, Kyleena, Jaydess)
- Often makes periods lighter, shorter and less painful
- Can be used to treat [heavy periods](https://splash.care/learn/period-care/heavy-periods) and as part of [HRT](https://splash.care/learn/glossary/hrt) later in life

**>99%** Effectiveness of both coils (NHS)

## Fitting

Fitting takes a few minutes and can be uncomfortable or painful for some people. It’s okay to ask about pain relief options before your appointment. Period-like [cramps](https://splash.care/learn/period-care/cramp-relief) for a few days afterwards are common.

> **Splash says:** ask your nurse to show you how to feel for your coil threads. A quick check after each period helps you know it’s still in place.

**Myth:** You can’t have a coil if you haven’t had a baby.

**Fact:** Coils are suitable for many people who have never been pregnant. A clinician will check if it’s right for you.

### When to see a doctor

Get an urgent GP appointment or call 111 if after a coil fitting you have: tummy pain painkillers don’t help, worsening sudden pain, a high temperature, smelly or unusual discharge, very heavy bleeding, you think you’re pregnant, or you can’t feel your threads (use condoms until it’s checked).

> Only condoms (external and internal) help protect against STIs. Every other method on this page prevents pregnancy only.

## Sources

1. [NHS – What is an IUD (copper coil)?](https://www.nhs.uk/contraception/methods-of-contraception/iud-coil/what-is-it/)
2. [NHS – Side effects of an IUD](https://www.nhs.uk/contraception/methods-of-contraception/iud-coil/side-effects/)
3. [NHS – What is an IUS (hormonal coil)?](https://www.nhs.uk/contraception/methods-of-contraception/ius-hormonal-coil/what-is-it/)
4. [NHS – Contraception: effects on periods](https://www.nhs.uk/contraception/choosing-contraception/effects-on-periods/)

This is general information, not medical advice. Splash can’t diagnose. If you’re worried, talk to a GP, pharmacist or sexual health clinic. In an emergency call 999 (UK) or 911 (US).