Women's Health

GLP-1s and the pill: which ones affect oral contraceptives, and what the labels say

By the US Health Digest editorial team · Published August 26, 2026 · Every claim linked to its primary source

This is not a class effect, and the honest answer depends entirely on which product is prescribed. Three carry an explicit switch-or-add-a-barrier instruction: Zepbound and Mounjaro (both tirzepatide) ask prescribers to advise patients on 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 (the two sentences differ only in where the brand name falls; both are quoted uncut below), and Foundayo (orforglipron) gives the same instruction with a 30-day window instead of 4 weeks. The semaglutide labels — Wegovy injection and tablets, Ozempic injection, and Rybelsus and Ozempic tablets — carry no such instruction. The Wegovy and oral-semaglutide labels state in section 12.3 that no clinically significant differences were seen in the pharmacokinetics of ethinyl estradiol and levonorgestrel; the Ozempic injection label carries the same oral-contraceptive data as a figure, and all three still direct prescribers to monitor or use caution with oral medications generally. All wording below is quoted from the current DailyMed labels as of August 26, 2026. Which product you are on is the question that decides the answer, and that conversation belongs with your prescriber.

The table that is the whole story

Seven labels, four different answers. Widen the check and the picture does not simplify: the liraglutide labels for Saxenda and Victoza report contraceptive pharmacokinetics in section 12.3 — peak concentrations of ethinyl estradiol and levonorgestrel lowered by 12% and 13% — without issuing any instruction, and the dulaglutide label for Trulicity does not mention contraceptives at all. That is why a sentence beginning "GLP-1s reduce the effectiveness of the pill" is wrong however it ends.

The mechanism: delayed gastric emptying, largest at the start

None of these drugs changes how an oral contraceptive works in the body. They change how fast the stomach delivers it. The Zepbound label states the pharmacology plainly: "Tirzepatide delays gastric emptying. The delay is largest after the first dose and this effect diminishes over time." That single sentence explains the shape of the instruction: a defined window after the first dose and after each step up, not the whole course of treatment.

The size of the effect was measured. In a drug-interaction study reported in the tirzepatide labels, a combined oral contraceptive (0.035 mg ethinyl estradiol and 0.25 mg norgestimate) was given alongside a single 5 mg dose of tirzepatide: peak concentrations of ethinyl estradiol, norgestimate and norelgestromin fell by 59%, 66% and 55%, total exposure (AUC) fell by 20%, 21% and 23%, and time to peak was delayed by 2.5 to 4.5 hours. Peak concentration moved far more than total exposure — which is what a slower stomach, rather than faster metabolism, looks like.

Semaglutide was tested the same way and behaved differently. In a published crossover study in 43 postmenopausal women with type 2 diabetes, ethinyl estradiol exposure at semaglutide steady state met the prespecified bioequivalence criterion (AUC ratio 1.11, 90% CI 1.06–1.15) and levonorgestrel exposure was 20% higher, not lower. Two caveats belong with that result: it was run at semaglutide 1 mg, not the 2.4 mg weight-management dose, and the participants were postmenopausal. The Ozempic label adds that "In a separate study, no apparent effect on the rate of gastric emptying was observed with semaglutide 2.4 mg."

Foundayo is a third case again, and the label is candid about it: "The effect of FOUNDAYO on the absorption of oral contraceptives has not been evaluated in a clinical trial. Because delayed gastric emptying may affect the absorption of oral medications, 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." Tirzepatide's instruction rests on a measured interaction; orforglipron's rests on a mechanism and a precaution. Both instructions are on the label; they are not built on the same evidence.

A 2024 review in the Journal of the American Pharmacists Association reached the same reading of the literature: of six trials examined, only the tirzepatide study showed a statistically significant reduction in oral-contraceptive exposure, while the five GLP-1 receptor agonist studies did not — and the authors attribute the difference to tirzepatide's rapid dose escalation and greater delay in gastric emptying. That review was published in January 2024, before orforglipron existed as an approved product, so its five GLP-1 receptor agonist studies say nothing about Foundayo either way.

What the labels say about non-oral methods

All three products that carry the instruction attach the same sentence to it: "Hormonal contraceptives that are not administered orally should not be affected." A mechanism that works through the stomach has no route to a method that never passes through it. The CDC's list of reversible methods puts the non-oral options in one place, with typical-use failure rates: the hormonal (levonorgestrel) IUD at 0.1–0.4%, the copper IUD at 0.8%, the arm implant at 0.1%, the progestin injection at 4%, and the patch and vaginal ring at 7% each — the same 7% CDC gives for combined and progestin-only pills.

That is what the labels point to, not a recommendation from us. Method choice turns on medical history, bleeding patterns, cost, coverage and preference, none of which a table can weigh. Each of those three labels offers adding a barrier method as an alternative to switching, so covering the window — 4 weeks on the tirzepatide labels, 30 days on Foundayo's — does not on its own require changing a long-term method. If a telehealth service is prescribing, the contraception question should surface during the medical review; if it did not, it is a fair thing to raise.

The separate problem nobody's label solves: vomiting

There is a second route to a failed pill that has nothing to do with which GLP-1 you take. Vomiting is named among the adverse reactions reported in at least 5% of patients on both the Zepbound and Wegovy labels (see side effects in women), and a pill that comes back up may never have been absorbed. The CDC's US Selected Practice Recommendations for Contraceptive Use, 2024 addresses this directly, and is explicit that the guidance is inferred: "Because of the lack of evidence that addresses vomiting or severe diarrhea while using COCs, these recommendations are based on the recommendations for missed COCs." Its two thresholds:

• Vomiting or diarrhea within 24 hours of a hormonal pill, or continuing for 24 to under 48 hours: "Taking another hormonal pill (redose) is unnecessary. Continue taking pills daily at the usual time (if possible, despite discomfort). No additional contraceptive protection is needed. Emergency contraception is not usually needed but may be considered (with the exception of UPA) as appropriate."
• Vomiting or diarrhea continuing for 48 hours or more after any hormonal pill: "Continue taking pills daily at the usual time (if possible, despite discomfort). Abstain from sexual intercourse or use barrier methods (e.g., condoms) until hormonal pills have been taken for 7 consecutive days after vomiting or diarrhea has resolved." CDC attaches two further steps at that threshold. If it happened during the last week of hormonal pills (for example days 15–21 of a 28-day pack): "Omit the hormone-free interval by finishing the hormonal pills in the current pack and starting a new pack the next day." And: "Emergency contraception should be considered (with the exception of UPA) if vomiting or diarrhea occurred within the first week of a new pill pack and unprotected sexual intercourse occurred during the previous 5 days."

This applies whatever the prescription is, and it applies during the weeks when GI effects are most likely — the start of treatment and each dose increase, the same weeks the tirzepatide and orforglipron labels flag for a different reason.

Questions for your prescriber

• Which molecule am I actually being prescribed — tirzepatide, semaglutide, orforglipron or something else? The answer changes what the label says.
• Does my product's current label carry an oral-contraceptive instruction, and if so, what is the window?
• My dose is due to increase. Does the window restart, and on what date?
• If I am on a compounded product, whose label applies to it, and has anyone checked?
• Given my history, is a non-oral method something we should discuss, or is adding a barrier method for the window the simpler fit?
• If I vomit after a dose, what do you want me to do about that day's pill?
• How does this interact with my plans for a pregnancy, given the separate advice on stopping before conception?

Common questions

Does Wegovy make birth control pills less effective?

The current Wegovy label, which covers both the injection and the tablets, carries no oral-contraceptive instruction. It states that in clinical pharmacology trials with semaglutide 1 mg once weekly injection, semaglutide did not affect the absorption of orally administered medications, and its pharmacokinetics section reports no clinically significant differences in the exposure of ethinyl estradiol or levonorgestrel. The same section 7.2 does still tell prescribers to monitor the effects of oral medications given with Wegovy, and to consider increased clinical or laboratory monitoring for medications with a narrow therapeutic index. That is the label position on August 26, 2026 and it is not medical advice for any individual; a prescriber who knows your history is the person to ask.

How long do the tirzepatide labels say the window lasts?

The Zepbound and Mounjaro labels both specify four weeks after starting the medication and four weeks after each dose escalation, during which they advise switching to a non-oral contraceptive method or adding a barrier method. The Foundayo label uses a 30-day window on the same pattern. Because the window restarts at every dose increase, it can recur several times during titration.

Are IUDs, implants, the shot, the patch and the ring affected?

The Zepbound, Mounjaro and Foundayo labels each state that hormonal contraceptives that are not administered orally should not be affected. The mechanism behind the instruction is delayed emptying of the stomach, which has no bearing on a method that is not swallowed. Copper IUDs contain no hormone at all and are outside this mechanism entirely.

What this page does not claim

It does not tell anyone to start, stop, switch or change a medication or a contraceptive method. It does not say the semaglutide products are risk-free with the pill; it says their current labels carry no oral-contraceptive instruction and report no clinically significant pharmacokinetic difference, which is a statement about documents and studies, not a guarantee about a person. And it does not extend to compounded copies, whose contents are not covered by any of these labels — a distinction that also runs through Wegovy versus Zepbound and our GLP-1 FAQ for women.

Sources

1. DailyMed. ZEPBOUND (tirzepatide) injection — current prescribing information. National Library of Medicine; SPL version 38, published May 6, 2026. Sections 7.2 (Oral Medications), 8.3 (Females and Males of Reproductive Potential), 12.2, 12.3 and the Medication Guide.
2. DailyMed. MOUNJARO (tirzepatide) injection — current prescribing information. National Library of Medicine; SPL version 38, published May 6, 2026. Sections 7.2, 8.3, 12.3.
3. DailyMed. FOUNDAYO (orforglipron) tablets — current prescribing information. National Library of Medicine; SPL version 10, published August 13, 2026. Sections 7.3, 8.3, 12.2, 12.3, 17.
4. DailyMed. WEGOVY (semaglutide) injection and tablets — current prescribing information. National Library of Medicine; SPL version 19, published June 30, 2026. Sections 7.2, 8.3, 12.3.
5. DailyMed. OZEMPIC (semaglutide) injection — current prescribing information. National Library of Medicine; SPL version 20, published June 10, 2026. Sections 7.2, 8.3, 12.3 including Figure 4.
6. DailyMed. RYBELSUS and OZEMPIC tablets (semaglutide) — current prescribing information. National Library of Medicine; SPL version 14, published August 19, 2026. Sections 7.2, 8.3, 12.3.
7. DailyMed. BYETTA (exenatide) injection — current prescribing information. National Library of Medicine; SPL version 26, published September 8, 2025. Drug Interactions and section 12.3 (Oral Contraceptives).
8. DailyMed. SAXENDA (liraglutide) injection (SPL version 22, published June 15, 2026) and VICTOZA (liraglutide) injection (SPL version 31, published November 17, 2025) — section 12.3, "Oral Contraceptives". National Library of Medicine.
9. DailyMed. TRULICITY (dulaglutide) injection — current prescribing information. National Library of Medicine; SPL version 62, published August 10, 2026.
10. Kapitza C, Nosek L, Jensen L, Hartvig H, Jensen CB, Flint A. Semaglutide, a once-weekly human GLP-1 analog, does not reduce the bioavailability of the combined oral contraceptive, ethinylestradiol/levonorgestrel. Journal of Clinical Pharmacology. 2015;55(5):497-504. PubMed 25475122.
11. Skelley JW, Swearengin K, York AL, Glover LH. The impact of tirzepatide and glucagon-like peptide 1 receptor agonists on oral hormonal contraception. Journal of the American Pharmacists Association. 2024;64(1):204-211.e4. PubMed 37940101.
12. Dilbaz B, Ateş C. The effects of glucagon-like peptide-1 receptor agonists on fertility, contraception, and pregnancy: clinical perspectives. European Journal of Contraception & Reproductive Health Care. 2026;31(4):237-244. PubMed 41860479.
13. Centers for Disease Control and Prevention. U.S. Selected Practice Recommendations for Contraceptive Use, 2024: Combined Hormonal Contraceptives — "Vomiting or severe diarrhea while using COCs" and Figure 4. Page reviewed November 18, 2024.
14. Nguyen AT, Curtis KM, Tepper NK, et al. U.S. Selected Practice Recommendations for Contraceptive Use, 2024. MMWR Recommendations and Reports. 2024;73(3):1-77.
15. Centers for Disease Control and Prevention. Contraception and Birth Control Methods — reversible methods and typical-use failure rates. Page dated August 6, 2024.
16. Eli Lilly and Company. FDA approves Lilly's Foundayo (orforglipron), April 1, 2026.