GLP-1s and birth control: which labels warn about the pill
The answer depends on the molecule, and the labels are specific about it. Tirzepatide and orforglipron carry a warning about the pill; semaglutide was tested and does not.
Do GLP-1s make the birth control pill less effective?
Tirzepatide can. The Zepbound and Mounjaro labels say it may reduce the efficacy of oral hormonal contraceptives because it delays stomach emptying, an effect largest after the first dose. They advise switching to a non-oral method, or adding a barrier method, for 4 weeks after starting and for 4 weeks after every dose increase. Foundayo (orforglipron) gives the same advice for 30 days, and says its effect on the pill has not been tested in a clinical trial.
Semaglutide does not carry the warning. Wegovy's label lists ethinyl estradiol and levonorgestrel among the drugs whose levels showed no clinically significant change, and Ozempic's says no dose adjustment is needed. Contraception that is not swallowed — patch, ring, implant, IUD, injection — is not affected, which the tirzepatide labels state in so many words.
Last updated 2026-09-02 — the newest FDA label version quoted below. Read and dated by Alex Seot.
Label by label
From sections 7, 8.3 and 12.3 of each label — drug interactions, reproductive potential and pharmacokinetics.
Switch or add a barrier method for 4 weeks after starting and after each dose increase
“Use of ZEPBOUND may reduce the efficacy of oral hormonal contraceptives due to delayed gastric emptying. This delay is largest after the first dose and diminishes over time. … Advise patients using oral hormonal contraceptives to switch to a non-oral contraceptive method, or add a barrier method of contraception for 4 weeks after initiation with ZEPBOUND and for 4 weeks after each dose escalation. Hormonal contraceptives that are not administered orally should not be affected.”
Switch or add a barrier method for 4 weeks after starting and after each dose increase
“Use of MOUNJARO may reduce the efficacy of oral hormonal contraceptives due to delayed gastric emptying. This delay is largest after the first dose and diminishes over time. Advise patients using oral hormonal contraceptives to switch to a non-oral contraceptive method or add a barrier method of contraception for 4 weeks after initiation and for 4 weeks after each dose escalation with MOUNJARO.”
Switch or add a barrier method for 30 days after starting and after each dose increase; untested in a trial
“Advise patients using oral hormonal contraceptives to switch to a non-oral contraceptive method or add a barrier method of contraception for 30 days after initiation with FOUNDAYO and for 30 days after each dose escalation. … The effect of FOUNDAYO on the absorption of oral contraceptives has not been evaluated in a clinical trial.”
Tested: no clinically significant change
“No clinically significant differences in the pharmacokinetics of the following drugs were observed when used concomitantly with semaglutide: lisinopril, S-warfarin, R-warfarin, metformin, digoxin, ethinyl estradiol, levonorgestrel, furosemide or rosuvastatin.”
Tested with an oral contraceptive: no dose adjustment
“No clinically relevant drug-drug interaction with semaglutide (Figure 4) was observed based on the evaluated medications; therefore, no dose adjustment is required when co-administered with semaglutide.”
Peak levels 12–13% lower, total estrogen exposure unchanged; no advice given
“Liraglutide lowered ethinylestradiol and levonorgestrel C max by 12% and 13%, respectively. There was no effect of liraglutide on the overall exposure (AUC) of ethinylestradiol.”
The same liraglutide study as Saxenda; no advice given
“VICTOZA lowered ethinylestradiol and levonorgestrel C max by 12% and 13%, respectively. There was no effect of VICTOZA on the overall exposure (AUC) of ethinylestradiol.”
Spotting more likely, pregnancy risk not raised — and contraception is required anyway
“Although this interaction is not anticipated to increase the risk of pregnancy, irregular bleeding (spotting) may occur more frequently due to both the increased exposure to the progestin and lower exposure to the estrogen, which tends to stabilize the endometrium.”
Labels that say nothing on it
These labels say nothing about hormonal contraception:
GLP-1s and birth control, answered
- How long should I use backup contraception on Zepbound?
- For 4 weeks after the first dose and for 4 weeks after each dose increase, per the label. Across the standard climb from 2.5 mg to 15 mg that is six separate 4-week windows. The label's alternative is to switch to a non-oral method, which removes the question.
- Does Ozempic or Wegovy affect the pill?
- Their labels say no clinically significant effect was measured: semaglutide was studied alongside ethinyl estradiol and levonorgestrel and their levels did not change enough to matter. Vomiting soon after taking any oral pill is a separate problem, and the labels do not address it.
- Why does tirzepatide affect the pill and semaglutide not?
- Both slow the stomach. The tirzepatide labels attribute the reduced pill effect to that delay, largest after the first dose and fading after, which is why the warning attaches to starts and dose increases rather than the whole course. The semaglutide labels report a study in which the pill hormones' levels did not change meaningfully.
- Are the patch, ring or IUD affected?
- No. The Zepbound and Mounjaro labels state that hormonal contraceptives not taken by mouth should not be affected, because the mechanism is absorption from the gut.
- What about Qsymia?
- Qsymia lowered estrogen exposure from a combined pill by 16% and raised progestin exposure by 22% in its interaction study. The label does not expect more pregnancies from that, but spotting becomes more common — and Qsymia requires effective contraception regardless, because topiramate can harm a fetus.