Tirzepatide side effects in women
The parts of the Zepbound and Mounjaro labels that apply to women specifically, and the side effects women reported more often.
Key facts
- Tirzepatide can make birth control pills less reliable: the label advises a non-oral method or a barrier method for 4 weeks after starting and after each dose increase.
- It should be stopped when a pregnancy is recognised; weight loss offers no benefit in pregnancy.
- Hair loss was reported in 7.1% of women against 0.5% of men on Zepbound, and was linked to weight loss.
- The most common side effects, nausea, diarrhoea, vomiting and constipation, are the same for everyone and peak after dose increases.
Tirzepatide and birth control pills
Tirzepatide slows how fast the stomach empties. That can reduce how well an oral contraceptive is absorbed. The effect is largest after the first dose and fades over time, which is why the warning is tied to starting and to each increase1.
Pregnancy
The label says weight loss offers no benefit during pregnancy and may cause harm to the fetus, and advises stopping tirzepatide when a pregnancy is recognised1. Tell your prescriber if you are pregnant or planning to be. Lilly runs a pregnancy exposure registry for anyone who was taking Zepbound when they became pregnant.
Breastfeeding
In a single-dose study, tirzepatide in breast milk was undetectable or low. There are no data on effects on a breastfed baby or on milk production, so the label asks prescribers to weigh the benefits of breastfeeding against the mother’s need for the medicine1.
Hair loss in women
In the two main Zepbound weight trials, hair loss was reported by 7.1% of women on tirzepatide against 0.5% of men, and by 1.3% of women on placebo. The label links it to the weight loss itself rather than to the drug, and no one on tirzepatide stopped treatment because of it1.
Common side effects by dose
Reported by adults in the Zepbound weight trials (about two-thirds were women in the first trial)1:
| Side effect | Placebo | 5 mg | 10 mg | 15 mg |
|---|---|---|---|---|
| Nausea | 8% | 25% | 29% | 28% |
| Diarrhoea | 8% | 19% | 21% | 23% |
| Vomiting | 2% | 8% | 11% | 13% |
| Constipation | 5% | 17% | 14% | 11% |
| Hair loss | 1% | 5% | 4% | 5% |
Serious warnings
Frequently asked questions
Does tirzepatide affect birth control?
It can make birth control pills less reliable. The label advises switching to a non-oral method, or adding a barrier method, for 4 weeks after starting and 4 weeks after each dose increase. Non-oral methods are not affected.
Is tirzepatide safe in pregnancy?
No. The label says it may harm the fetus, that weight loss offers no benefit in pregnancy, and that it should be stopped when a pregnancy is recognised.
Does tirzepatide cause hair loss in women?
Hair loss was reported in 7.1% of women on Zepbound against 0.5% of men. The label links it to weight loss, and no one stopped treatment because of it.
Can I take tirzepatide while breastfeeding?
There are no data on effects on a breastfed baby. Levels in breast milk were undetectable or low in a single-dose study; the decision is one to make with your prescriber.