What Are the Side Effects of the Pill?

Reviewed by Usama Ali, MPharm (GPhC: 2224726). Last reviewed: April 2026.

Side effects of the contraceptive pill are usually mild. Not everyone gets them. For many people, any effects settle within the first 2 to 3 months as the body adjusts to the change in hormones.

The most commonly reported side effects across both the combined pill and the mini pill include irregular bleeding or spotting, nausea, headaches, breast tenderness, mood changes, and acne.

What Side Effects Happen When You Start the Pill?

Starting a new pill means introducing hormones your body is not used to. Some temporary effects are normal in the first few weeks.

Spotting or irregular bleeding is the most common early side effect, particularly with the mini pill. Nausea is more common with the combined pill because of the oestrogen. Taking your pill with food or in the evening can help with this.

"The first three months are the adjustment period," says Usama Ali, MPharm (GPhC: 2224726), pharmacist at Contraception Direct. "We always say give it time if the side effects are manageable. But if they're making you miserable, come back to us sooner and we can look at alternatives."

What Are the Side Effects of the Mini Pill?

The mini pill contains only progestogen, so it avoids oestrogen-related side effects like nausea and bloating. The trade-off is that changes to your bleeding pattern are more common.

You may find your periods become irregular, lighter, more frequent, or stop altogether. Acne, breast tenderness, headaches, and mood changes are also reported. These are listed in the Cerelle SPC and apply to all desogestrel mini pills.

The mini pill does not carry an increased risk of blood clots. This is one of its advantages over the combined pill.

What Are the Side Effects of the Combined Pill?

The combined pill contains both oestrogen and progestogen. The oestrogen component can cause nausea, headaches, breast tenderness, and fluid retention, particularly in the first few weeks.

The combined pill carries a small increased risk of venous thromboembolism (blood clots). For levonorgestrel-containing pills, the risk is approximately 5 to 7 per 10,000 users per year, compared to about 2 per 10,000 in non-users (FSRH, 2023). Pills containing desogestrel, gestodene, or drospirenone carry a slightly higher risk. For context, the risk during pregnancy is around 29 per 10,000.

How Do Side Effects Compare?

Side effectCombined pillMini pill
Irregular bleedingLess common (regular withdrawal bleeds)More common, especially early on
NauseaMore common (oestrogen)Less common
HeadachesCan occur, especially during the 7 day breakCan occur
Breast tendernessCommon initiallyCommon initially
Mood changesReported by someReported by some
BloatingMore common (oestrogen-related)Less common
AcneOften improves (anti-androgenic pills)May worsen in some people
Blood clot riskSmall increased riskNo increased risk

Neither pill type is better or worse overall. The right choice depends on your body, your medical history, and which side effects matter most to you. Your pharmacist can help you find the right pill.

What Happens When You Stop the Pill?

Stopping the pill means your body returns to its natural hormone cycle. Your periods may take a few months to settle back into a regular pattern. If you had heavy or painful periods before starting, those symptoms may return.

Some people notice temporary acne, mood changes, or changes to their skin and hair. These settle as your body readjusts. Stopping the pill does not affect your long-term fertility. Your natural fertility returns quickly, usually within days, regardless of how long you were taking it.

How Long Do Side Effects Last?

Most side effects settle within 2 to 3 months. This adjustment period is normal. If you have only just started a new pill, it is usually worth giving it at least 3 months before deciding whether it suits you.

If side effects are severe or affecting your daily life, do not wait the full 3 months. Speak to your pharmacist sooner.

When Should You Seek Urgent Medical Help?

Serious side effects are rare. But you should seek urgent medical attention if you experience any of the following while taking the combined pill: painful swelling in one leg (especially the calf), sudden chest pain or difficulty breathing, a severe or unusual headache, sudden changes in your vision, or collapse.

These could be signs of a blood clot (venous thromboembolism). Call 999 or go to A&E. Do not wait for a GP appointment. The mini pill does not carry this risk.

What Should You Do About Side Effects?

If side effects are mild and you have recently started or switched pills, give your body time. Three months is reasonable for most people.

If side effects persist, your pharmacist can help you switch. Moving from the combined pill to the mini pill (or the other way around) is common. So is switching between brands within the same type. Many people try more than one pill before finding what works.

Do not stop taking your pill without speaking to a pharmacist or GP first. Stopping without advice could leave you without contraceptive protection.

With Contraception Direct, you can book a free phone consultation to review your current pill or discuss switching.

Frequently Asked Questions

How long do side effects of the pill last?
Most side effects settle within the first 2 to 3 months as your body adjusts to the hormones. If they continue beyond that or are affecting your daily life, speak to your pharmacist about trying a different pill.
Can the pill cause weight gain?
Current UK guidance does not clearly show the contraceptive pill causes significant weight gain. Some people report minor changes, often linked to fluid retention rather than fat gain.
Does the pill affect your mood?
Some people notice mood changes when starting the pill, including low mood or mood swings. Others find their mood improves because premenstrual symptoms reduce. If mood changes feel persistent or severe, speak to your pharmacist.
Are side effects different for the mini pill and the combined pill?
Yes. The combined pill is more commonly linked to nausea, headaches, and breast tenderness because of the oestrogen. The mini pill is more likely to cause irregular bleeding. Both can cause mood changes and acne.
What should I do if side effects do not go away?
Speak to your pharmacist. They can suggest switching to a different pill type or brand. Do not stop taking your pill without advice first, as you could lose contraceptive protection.
Can I switch pills if I get side effects?
Yes. Many people try more than one pill before finding what works. Your pharmacist can help you switch safely, usually without a gap in protection. Switching between types or brands is common.
Are there any serious side effects?
Serious side effects are rare. The combined pill carries a small increased risk of blood clots. Warning signs include painful leg swelling, chest pain, sudden breathlessness, severe headache, or vision changes. Seek urgent medical help if you experience any of these.

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