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Can taking weight loss injections affect your period?
Weight loss jabs are effective treatments that you inject weekly (like Wegovy and Zepbound) or daily (like Saxenda). In clinical trials, they’ve been shown to help people lose up to 20.9% on average after 72 weeks (after treatment with the 15mg dose of Zepbound).
Weight loss injections can affect your hormones and how your brain controls your cycle, but the biggest impact on your period comes from the weight loss itself.
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Craig Marsh, Clinical Reviewer
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Last updated on May 05, 2025.
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- Weight loss injections can cause hormonal shifts, which can influence your periods.
- Losing weight can cause your periods to become lighter, shorter, heavier, irregular, or to stop altogether.
- Weight loss jabs can improve insulin sensitivity, restore regular periods, and improve fertility, especially if you have PCOS.
- Eating a healthy diet, getting enough sleep, and staying active can help manage changes in your period.
How does weight affect your menstrual cycle?
Your menstrual cycle is controlled by complex interactions between your brain and your ovaries (called the hypothalamic-pituitary-ovarian axis). Having overweight or obesity can affect your hormone levels, which can cause missed periods or, in other cases, heavy menstrual bleeding.
When you’re dealing with obesity or overweight, having increased body fat (especially around your waist) can cause your body to produce too much estrogen. This can hinder ovulation and cause irregular or missed periods.
On the other hand, if you’re experiencing heavy bleeding, it could be linked to abdominal fat (particularly a type called visceral fat). This can cause your body to make more hormones involved in inflammation, like cytokines and adipokines. Inflammation can slow down how fast your uterus heals after each period and increase the amount of blood you lose during menstruation.
In many cases, losing extra weight can help make your menstrual cycle more regular.
But losing too much weight to the point where you’re underweight isn’t good either, and can cause your period to stop altogether. This is common in athletes or women with eating disorders. For regular periods, your body typically requires a minimum of 22% body fat.
How can taking a GLP-1 agonist affect your period?
GLP-1 agonists like Wegovy and Zepbound can lead to significant weight loss. One study found that when women with overweight or obesity lost weight, their estrogen and testosterone levels dropped significantly. This drop can not only lower your risk of breast cancer, but help restore your normal menstrual cycle.
GLP-1 agonists can improve insulin sensitivity and lower androgen levels, which may help regulate your periods. This is especially true if you have polycystic ovary syndrome (PCOS), where periods are often irregular, missing, heavier, or last for longer than normal.
GLP-1 agonists can also affect the complex system that controls your menstrual cycle and fertility called the hypothalamic-pituitary-ovarian (HPO) axis. So they might also directly impact some of the hormones that regulate your reproductive system, as well as how your ovaries work and, potentially, the lining of your uterus (which sheds when you have your period). This means that your periods might become irregular, more frequent, lighter, or heavier than usual.
And lastly, losing at least 10% of your body weight can reduce inflammation. This drop in inflammation, shown by lower levels of certain molecules like TNF-alpha, IL-6, and leptin, can help reduce heavy periods.
So the effects of GLP-1 agonists on periods are generally positive. But losing over 10–15% of your body weight after taking GLP-1 agonists can also cause a significant amount of stress on your body. Over time, this can lead to irregular periods, missed ovulation, or your period stopping altogether (called weight loss-related amenorrhea). This happens when your body doesn’t get enough energy, which can throw off hormone signals from the brain that control your menstrual cycle.
In what ways can weight loss injections change your period?
There are many ways in which both losing weight and using weight loss jabs can lead to changes in your menstrual cycle. These depend on how your body reacts to weight loss, and will differ from person to person. You can find a list below:
- Lighter periods: Weight loss puts stress on the body, and both the weight loss itself and the injections can cause complex hormonal changes that lead to lighter bleeding.
- Shorter periods: Hormonal fluctuations can also make your period shorter than usual, but this will vary from person to person.
- Heavier periods: Losing a lot of weight can cause your estrogen levels to fluctuate. This can increase blood flow to your uterine lining, thickening it and leading to heavier periods.
- Irregular periods: This is because your body may take rapid weight loss, especially when paired with low nutrition, as a sign of stress. This can throw off your hormonal balance and ovulation, leading to missed or irregular periods.
- Longer periods: This, again, is because of hormonal imbalances, in particular estrogen, which can cause your uterine lining to become thicker, making your periods longer and heavier.
- Spotting between periods: This can be an unwanted side effect of weight loss jabs. But it doesn’t happen to everyone, and if it does it’s usually temporary.
- PMS symptoms: Losing weight and eating healthily can ease PMS symptoms like cramping or bloating.
More research is needed to understand why these happen and identify the factors that can help predict what will happen specifically.
What benefits can losing weight have on menstrual health?
Weight loss injections have been shown to support fertility, improve insulin regulation, and help manage PCOS symptoms.
There’s currently no cure for PCOS, but losing weight can help with its symptoms. For many women with PCOS and obesity, taking GLP-1 agonists consistently for at least 24 weeks, and losing weight as a result, has been shown to help restore regular periods.
These medications also improve insulin sensitivity, a common issue in PCOS. About 50–80% of people with PCOS have insulin resistance, meaning their cells don’t respond well to insulin. This can lead to high blood sugar and even type 2 diabetes. GLP-1 agonists can help with that.
They can also help regulate hormone levels, especially by lowering androgens (male hormones like testosterone), which tend to be high in people with PCOS.
Balancing hormone levels can improve fertility too. Nearly 40% of people with PCOS have trouble getting pregnant naturally, but early research shows that GLP-1 agonists may increase natural pregnancy rates, either on their own or when combined with metformin, more effectively than metformin alone.
What can be done if you experience period changes due to weight loss?
If you notice changes in your period after losing weight, it’s important to keep track of what’s happening to your body. If you’re concerned, reach out to your clinician. Period changes may not always be linked to weight loss or GLP-1 injections, they could be caused by something else. It’s always a good idea to speak with a doctor to rule out any underlying medical conditions.
How can period changes be managed?
If your period changes aren’t too concerning and you don’t feel the need to see a physician, there are still a few things you can do to manage them:
- Eat a healthy, balanced diet, get enough sleep, and exercise regularly, as these can all impact your menstrual cycle.
- If you experience any pain or discomfort, take pain relievers like ibuprofen or naproxen.
- Keep track of your periods. If you’re worried about any changes in your periods like longer, shorter, or heavier cycles, contact your clinician for advice.
Reference Popover #ref1
Treated trusted source
Jastreboff, A.M., Aronne, L.J., Ahmad, N.N., Wharton, S., Connery, L., Alves, B., Kiyosue, A., Zhang, S., Liu, B., Bunck, M.C. and Stefanski, A. (2022).
Tirzepatide Once Weekly for the Treatment of Obesity. New England Journal of Medicine, 387(3).
Reference Popover #ref2
Treated trusted source
Zheng, L., Yang, L., Guo, Z., Yao, N., Zhang, S. and Pu, P. (2024).
Obesity and its impact on female reproductive health: unraveling the connections. Frontiers in Endocrinology, 14(1326546).
Reference Popover #ref3
Treated trusted source
Frisch, R.E. (1987).
Body fat, menarche, fitness and fertility. Human Reproduction, 2(6), pp.521–533.
Reference Popover #ref4
Treated trusted source
Campbell, K.L., Foster-Schubert, K.E., Alfano, C.M., Wang, C.-C., Wang, C.-Y., Duggan, C.R., Mason, C., Imayama, I., Kong, A., Xiao, L., Bain, C.E., Blackburn, G.L., Stanczyk, F.Z. and McTiernan, A. (2012).
Reduced-calorie dietary weight loss, exercise, and sex hormones in postmenopausal women: randomized controlled trial. Journal of Clinical Oncology: Official Journal of the American Society of Clinical Oncology, 30(19), pp.2314–2326.
Reference Popover #ref5
Treated trusted source
Zhou, L., Qu, H., Yang, L. and Shou, L. (2023).
Effects of GLP1RAs on pregnancy rate and menstrual cyclicity in women with polycystic ovary syndrome: a meta-analysis and systematic review. BMC Endocrine Disorders, 23(1).
Reference Popover #ref6
Treated trusted source
Sola‐Leyva, A., Pathare, A.D.S., Apostolov, A., Aleksejeva, E., Kask, K., Tammiste, T., Ruiz‐Durán, S., Risal, S., Acharya, G. and Salumets, A. (2024).
The hidden impact of GLP‐1 receptor agonists on endometrial receptivity and implantation. Acta Obstetricia et Gynecologica Scandinavica, 104(2), pp.258–266.
Reference Popover #ref7
Treated trusted source
Forsythe, L.K., Wallace, J.M.W. and Livingstone, M.B.E. (2008).
Obesity and inflammation: the effects of weight loss. Nutrition research reviews, 21(2), pp.117–33.
Reference Popover #ref8
Treated trusted source
Chen, L., Lu, Y., Zhou, Y.-F., Wang, Y., Zhan, H.-F., Zhao, Y.-T., Wang, Y.-L., Zhang, F.-F., Chen, H. and Li, X. (2023).
The effects of weight loss-related amenorrhea on women’s health and the therapeutic approaches: a narrative review. Annals of Translational Medicine, 11(2), pp.132–132.
Reference Popover #ref9
Treated trusted source
Szczesnowicz, A., Szeliga, A., Niwczyk, O., Bala, G. and Meczekalski, B. (2023).
Do GLP-1 Analogs Have a Place in the Treatment of PCOS? New Insights and Promising Therapies. ProQuest, 12(18), p.5915.
Reference Popover #ref10
Treated trusted source
Austregésilo de Athayde De Hollanda Morais, B., Martins Prizão, V., de Moura de Souza, M., Ximenes Mendes, B., Rodrigues Defante, M. L., Cosendey Martins, O. and Rodrigues, A. M. (2024).
The efficacy and safety of GLP-1 agonists in PCOS women living with obesity in promoting weight loss and hormonal regulation: A meta-analysis of randomized controlled trials. Journal of diabetes and its complications, 38(10), p.108834.
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