“Birth control pills make you gain weight.”
Birth control pills have not been shown to cause weight gain: trials comparing pills with a placebo found no sign that they do.
If you are choosing a pill, fear of weight gain is not a good reason to avoid it, because trials do not show that pills cause it. If your weight does change after starting, other parts of life may be the cause, and a different pill or method is always an option.
If weight is a worry, weigh yourself before starting and again after three months, and talk with your prescriber if there is a change you do not like.
Safety note: Pills that contain estrogen raise the risk of blood clots and stroke and are not advised for people who have migraine with aura, a past blood clot, or who smoke and are 35 or older. If you switch or stop pills, have another method ready if you do not want to get pregnant.
Talk to a healthcare professional if: you notice a weight change that worries you after starting a pill, or you want to compare pill types or other methods.
Dozens of randomized trials of combined pills show no large effect on weight, and the few that compared pills with a placebo or no pill found no sign that pills cause weight gain; progestin-only pills have little data, and one study's small rise in body fat with a progestin-only pill is not the same as weight gain. Confidence is moderate because only four trials had a placebo or no-pill group.
Birth control pills have not been shown to cause weight gain: trials comparing pills with a placebo found no sign that they do. Average weight changes in pill studies were small, and people did not stop their pills because of weight any more often on one pill than another.
Many people gain a little weight over time whether or not they take a pill, which is why trials need a placebo or no-pill group to tell the difference. A review of 49 trials found most comparisons between different combined pills showed no real weight difference. For progestin-only methods, average gains in most studies were under 4.4 pounds at 6 to 12 months; one study of a progestin-only pill found a small rise in body fat compared with women not using hormones. The birth control shot stood out: in one study, shot users gained about 5 pounds more than copper IUD users in the first year and about 7 pounds more by year three.
- Gallo MF, Lopez LM, Grimes DA, Carayon F, Schulz KF, Helmerhorst FM. Combination contraceptives: effects on weight. Cochrane Database of Systematic Reviews. 2014;(1):CD003987. DOI: 10.1002/14651858.CD003987.pub5. PMID: 24477630. PMCID: PMC10640873
- Lopez LM, Ramesh S, Chen M, Edelman A, Otterness C, Trussell J, Helmerhorst FM. Progestin-only contraceptives: effects on weight. Cochrane Database of Systematic Reviews. 2016;(8):CD008815. DOI: 10.1002/14651858.CD008815.pub4. PMID: 27567593. PMCID: PMC5034734
- US Centers for Disease Control and Prevention. U.S. Medical Eligibility Criteria for Contraceptive Use, 2024. Appendix D: Classifications for Combined Hormonal Contraceptives