GLP-1 drug interactions, as the labels state them

Insulin and insulin secretagogues

All four labels carry this one, and all four give the same instruction: consider reducing the dose of the other drug when starting the GLP-1. Ozempic states the mechanism plainly — it “stimulates insulin release in the presence of elevated blood glucose concentrations”, and patients taking it with an insulin secretagogue such as a sulfonylurea, or with insulin, “may have an increased risk of hypoglycemia, including severe hypoglycemia.”

Wegovy states the same risk in its own terms: “WEGOVY lowers blood glucose and can cause hypoglycemia. The risk of hypoglycemia is increased when WEGOVY is used concomitantly with insulin or insulin secretagogues (e.g., sulfonylureas). The addition of WEGOVY in patients treated with insulin has not been evaluated.”

Oral medications

All four delay gastric emptying, which is part of how these drugs work, and all four say that this can affect how an oral drug is absorbed. What they then advise is not identical, and the differences are worth reading rather than summarizing into one sentence.

Oral contraceptives — on two of these four labels

Both tirzepatide labels carry an explicit contraception precaution. Neither semaglutide label does. This is the single largest difference between the two molecules’ section 7. It is a statement about these four documents, read in September 2026, not a claim about semaglutide in general.

Mounjaro, section 7.2: “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. Hormonal contraceptives that are not administered orally should not be affected”. Zepbound carries the same instruction, worded slightly differently: “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.”

The two are materially identical: a comma, and the drug name sitting in a different clause. Neither label states a different interval or a different route.

The tirzepatide labels also explain why, in section 8.3: use of the drug “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.”

Not an interaction, but on every label: surgery and sedation

All four labels carry a warning about general anaesthesia and deep sedation. It sits in section 5 rather than section 7, so it is not a drug interaction — but it is the thing a reader searching for interactions most often needs, and the labels are unusually candid about the limits of what is known.

Zepbound, section 5.9: there have been “rare postmarketing reports of pulmonary aspiration in patients receiving GLP-1 receptor agonists undergoing elective surgeries or procedures requiring general anesthesia or deep sedation who had residual gastric contents despite reported adherence to preoperative fasting recommendations.” The label then says that available data “are insufficient to inform recommendations to mitigate the risk”, including whether changing fasting instructions or pausing the drug would help, and instructs patients to tell their healthcare providers before any planned surgery or procedure that they are taking it.

That is the label declining to give a stopping interval, not this site failing to find one. Ozempic, Wegovy and Mounjaro carry the same warning under their own numbering.

Sources

Related: the contraindications and the boxed warning, read from the same four documents.

See the providers

An interaction is a fact about the drug and your other medications. The boards list the providers who prescribe it, with what each one publishes about price, pharmacy and cancellation.

• Semaglutide providersprovider board

  Compare semaglutide plans, pharmacy details and cancellation terms.

• Tirzepatide providersprovider board

  Compare tirzepatide plans, pharmacy details and cancellation terms.

More, read from the same labels

• First-year GLP-1 costsresearch guide

  A low monthly headline does not tell you what a year of treatment will cost. Compare the same medication and service package, then separate the total you expect to spend from the amount you must pay before treatment begins.

• Cancellation and refundsresearch guide

  Canceling future membership charges, stopping an upcoming medication order and requesting a refund are three different requests. Get a written answer for each one that applies to you.

• Insurance denial documentsresearch guide

  The next step depends on why coverage was denied. A missing document, a formulary restriction and an excluded benefit are different problems. Start with the written decision before paying someone to submit another request.

• Savings and cash-pay eligibilityresearch guide

  A manufacturer savings card and a self-pay offer can have different eligibility rules, even for the same medicine. Match the offer to your coverage and exact product before using its advertised price in your budget.

• Verify your GLP-1 pharmacyresearch guide

  The website taking your payment, the clinician prescribing and the pharmacy dispensing may be different businesses. Identify each one. A recognizable brand or a reassuring badge does not tell you who will fill the prescription.

• Changing GLP-1 providersresearch guide

  Before ending your current service, establish what the new practice needs, what it will charge and when it can evaluate you. Transferring your records does not guarantee that another clinician will continue the same prescription.

• Weight regain after stoppingresearch guide

  Weight regain occurred after treatment withdrawal in studies of semaglutide and tirzepatide. The findings support planning follow-up and affordability before an interruption, but they do not predict exactly what will happen to one person.

• Semaglutide vs tirzepatideresearch guide

  What the four FDA-approved labels say each molecule is, what each is approved to treat, and where the two differ.

• How they workresearch guide

  The receptor each molecule switches on, what the labels say that does to appetite, blood sugar and the stomach, and why one dose lasts a week.

• Is Ozempic insulin?research guide

  What the Ozempic label calls semaglutide, how that differs from insulin, and where insulin appears on these labels as a separate medicine.

• Zepbound vs Ozempicresearch guide

  Four brand names, two molecules and two kinds of approval: which of these products are the same drug, and what each one is actually approved to do.

• Dose escalation schedulesresearch guide

  The starting dose, the escalation interval and the maximum dose each label sets, and why they are not interchangeable.

• Side effect ratesresearch guide

  What each label reports for nausea, vomiting, diarrhea and constipation — and the sentence every label prints above those numbers.

• Hair lossresearch guide

  Which labels report hair loss, the rate against placebo where a trial measured it, and why two of them put no number on it.

• Fatigue and tirednessresearch guide

  Which labels list fatigue, the rate against placebo where a trial measured it, and what each label counts as fatigue.

• Missed dose rulesresearch guide

  The window each label gives for a late dose, and the minimum gap it requires when the injection day changes.

• Buying one onlineresearch guide

  The agency's own warning signs for a telehealth GLP-1 seller, its 28-day vial rule, and what it says about drugs that arrive warm.

• Zepbound by doseresearch guide

  What each Zepbound dose achieved in the trials printed in its label, what the label says about choosing a maintenance dose, and what the higher doses cost in side effects.

• Zepbound at 3 monthsresearch guide

  What does the Zepbound label report about three-month weight loss and maintenance dosing?

• Injecting tirzepatideresearch guide

  The injection sites, the rotation rule and the steps for the single-dose pen, the KwikPen and the vial and syringe, exactly as the FDA-approved Instructions for Use give them.

• Refrigeration and storageresearch guide

  How cold each pen is kept, how many days it can spend at room temperature, and what the labels say about heat and freezing.

• Who should not take oneresearch guide

  The boxed warning every one of these labels carries, the two contraindications, and which warnings appear on which product.