Do Birth Control Pills Cause You to Gain Weight?  

A common question around the contraceptive pill is whether it can lead to weight gain. The short answer is no, it won’t, at least not directly.   

Many studies have shown that there is no conclusive evidence that birth control pills will cause you to put on weight. 

However, in reality it’s a little more complicated than that. Let’s find out more about how birth control can affect your body.  

Three key takeaways  

• There is very little evidence that birth control pills will make you gain weight.  
• Some users report changes in their weight, but this is usually down to other factors, like water retention, increased appetite, and how fat is stored in the body.  
• Some methods of hormone-based birth control, like the contraceptive injection, are more likely to cause weight gain.  

Can birth control pills make you gain weight?  

Multiple studies have shown that neither the mini pill nor the combined pill will cause you to put on weight, despite weight gain being listed as a side effect of mini pill. 

A 2014 round-up of studies looked at years of research and found that birth control pills had no major effect on weight change. A 2013 study, meanwhile, included women with BMIs of 30-39 as well as those of 19-25, and found no significant weight gain.  

However, there are some reasons why it may feel like you have gained weight after starting to take contraceptive pills:  

You may experience bloating  

Birth control pills can cause water retention, particularly in the first few months. Hormone changes can cause your body to bloat, which may feel like weight gain, and your clothes may feel tighter.  

Your body shape may change  

The hormones in pills may also affect where and how you store fat, so your body shape might change a little. In addition, one study suggests that young women on brands of pill that contain a specific lab-made progesterone may find it more difficult to gain muscle. 

Changes in hormone levels can increase your appetite 

Some pills contain synthetic progestogen, which can make you hungrier, and crave sweets in particular. These cravings usually subside after the first few months but speak to your clinician if your appetite levels remain higher, and they can prescribe a lower-dose pill.  

Everyone tends to put on weight as they grow older  

Studies show that the average person gains half a kilo every year. So, it can be easy to associate this gradual weight gain with taking your pill.  

Do birth control pills make your breasts bigger?  

Some people report an increase in breast size while taking birth control, and one study has suggested that this is a possibility.  Your breasts might also swell due to water retention, while hormones can cause your body shape to change.  

Your breasts might feel or look bigger at certain times of the month while taking the pill. However, the result is usually temporary, and your breasts will generally return to their original size within a few months.  

Can the contraceptive implant cause weight gain?  

Studies show that users do not gain weight while using the implant. However, some women have reported weight gain. This is believed to be because they expected weight gain while using the implant.  

Other forms of birth control and weight gain  

Weight gain is also listed as a side effect of other forms of hormone-based birth control. Like with the pill, there are no studies proving this in most cases. However, there is some evidence that the contraceptive injection may cause weight gain.  

Method of birth control	Weight gain listed as a side effect?	Have studies proved weight gain?
Combined pill	Yes	No
Progestogen-only pill	Yes	No
IUS (intrauterine system or hormonal coil)	Yes	No
Contraceptive implant	Yes	No
Contraceptive injection	Yes	Some studies show no weight gain, but others indicate you may put on weight, particularly if you’re under 18 and overweight.
Contraceptive patch	No	No

Can birth control cause you to lose weight?  

Most forms of contraceptive pills are not associated with weight loss. However, Yasmin, a form of combined pill that contains drospirenone, sometimes reduces water retention, which can feel like losing weight. 

So, if temporary weight gain is a concern, Yasmin might be the best contraceptive pill for you. However, Yasmin should not be taken as a weight loss method. 

While increased appetite can be a side effect of the pill, some people find it reduces their appetite. If that’s true for you, you may experience fewer cravings and therefore lose weight.  

Weight loss injections and birth control  

“Weight loss injections like Mounjaro can affect the way your body absorbs pills and may reduce the effectiveness of your birth control. 

“The effect is particularly strong when you first start using injections, or for a month after you increase your dose, so bear it in mind before you begin your weight loss journey.  

“You might consider switching to the injection, patch or a barrier method, either during this period or long-term. Speak to your clinician for more advice. “ 

Hanna Yusuf, Prescribing Pharmacist at Chemist4U 

What else can cause weight gain?  

There are a range of reasons you may gain weight on the pill, completely unrelated to the pill itself. For example, you may start taking the contraceptive pill when you enter a settled relationship, which can cause your eating and exercise patterns to change. 

Many people also start taking the pill as they become an adult, a point when most people start to put on weight every year.  

Additionally, muscle weighs more than fat. So, changes in the way you exercise may lead to more muscle mass and you may become heavier. 

5 tips to manage weight on birth control  

Some ways to manage your weight on birth control include:  

• keeping your exercise levels consistent 
• being aware of your diet and lifestyle 
• riding out any cravings for sweet food caused by progestogen 
• reducing water retention by cutting down on salty foods, alcohol and caffeine while drinking enough water and eating plenty of fibre and potassium-rich snacks 
• being patient, as any water retention will disappear after two or three months 

How our expert clinicians can help  

If you want to find out more about the contraceptive pill, you can speak to one of our prescribers about which one might be right for you. 

Both the consultation and your contraception will be entirely free via our NHS Free Contraception service. 

Frequently asked questions about birth control and weight gain  

Will I lose weight if I go off birth control?  

No, you won’t lose weight if you stop taking your contraceptive tablets. However, you may notice a reduction in water retention.  

Which pill makes you gain more weight?  

Weight gain is more commonly reported by users of the combined pill, and it is listed as an uncommon (rare) side effect. However, studies have shown that users will not put on weight.  

Does the mini pill change your body shape?  

Hormones in pills can affect where and how you store fat so your body shape might, change a little, with hips, breasts and thighs becoming more pronounced.  

Sources  

• Side effects and risks of the combined pill NHS. [Accessed 4 February 2026].  
• Side effects and risks of the progestogen-only pill NHS. [Accessed 4 February 2026]. 
• Effect of birth control pills and patches on weight (2014). Cochrane. [Accessed 4 February 2026]. 
• Weight and Body Composition Changes During Oral Contraceptive Use in Obese and Normal Weight Women (2014). National Library of Medicine. [Accessed 4 February 2026]. 
• Changes in Diet and Lifestyle and Long-Term Weight Gain in Women and Men (2011). New England Journal of Medicine. [Accessed 4 February 2026]. 
• Oral Contraceptive Use Impairs Muscle Gains in Young Women (2009). FASEB Journal . [Accessed 4 February 2026].
• Breast Size in Relation to Endogenous Hormone Levels, Body Constitution, and Oral Contraceptive Use in Healthy Nulligravid Women Aged 19–25 Years (1997). American Journal of Epidemiology. [Accessed 4 February 2026]. 
• Association of Progestin Contraceptive Implant and Weight Gain (2016). Obstetrics & Gynaecology. [Accessed 4 February 2026].