GLP-1 Medications FAQ: Common Questions & Glossary
GLP-1 medications have been covered extensively in the news and on social media. The coverage is a mix of accurate information, misunderstood claims, and content that is more about generating clicks than helping someone make an informed decision about a medical treatment.
If you are at the stage where you have done the research and still have specific questions that no one seems to answer directly, this page is for you. Below you will find answers to the questions that come up most often before starting treatment, followed by a glossary of the clinical terms you will encounter in your research. The supporting pages in this section go deeper on each topic.
Common pre-treatment questions
Do I need to have diabetes to qualify?
No. The majority of people currently using GLP-1 medications for weight management do not have type 2 diabetes. The FDA-approved semaglutide and tirzepatide products for chronic weight management are labeled for adults with obesity, or with overweight and at least one weight-related condition such as high blood pressure, type 2 diabetes, or high cholesterol. In the trials behind those labels, that meant a BMI of 30 or higher, or 27 or higher with a weight-related condition.[1][2] A licensed provider decides whether treatment is appropriate based on an evaluation.
The “GLP-1 is only for diabetics” assumption comes from the history of these medications. Semaglutide and related drugs were first developed and approved for type 2 diabetes. The weight management applications came later, once the magnitude of the appetite effects became clear. The prescribing landscape has shifted significantly.
For a detailed answer with eligibility specifics, see Can I Get GLP-1 If I Am Not Diabetic?.
How long does it take for GLP-1 to work?
This depends on what “working” means to you. At the starting dose, most people do not experience dramatic appetite suppression. The starting dose is designed for tolerability, not maximum effect. Appetite effects typically become more noticeable after the first dose increase, usually around weeks five through eight.
Full appetite suppression at the therapeutic dose takes several weeks to establish. In the STEP 1 clinical trial of FDA-approved semaglutide 2.4 mg, average weight loss built gradually over the 68-week study rather than arriving in the first month.[3] Results vary. Trial results describe study participants and are not a prediction for any individual.
For a week-by-week breakdown of what to expect, see How Long Does It Take for GLP-1 to Work?.
Can I take GLP-1 with birth control?
This is one of the more important questions to ask the provider you choose before starting. GLP-1 medications slow gastric emptying, which can affect how quickly oral medications (including oral contraceptives) are absorbed.
The answer differs by medication. The FDA-approved tirzepatide label for weight management says it may reduce the effectiveness of oral hormonal contraceptives, and advises switching to a non-oral method or adding a barrier method for four weeks after starting and for four weeks after each dose increase.[2] The FDA-approved semaglutide label for weight management reports a drug interaction study with an oral contraceptive (ethinylestradiol/levonorgestrel) and does not carry the same recommendation.[1] Ask your prescriber what applies to the specific product you are prescribed.
For a complete answer including specific guidance by contraceptive type, see Can You Take GLP-1 With Birth Control?.
Does GLP-1 medication expire?
Yes. Compounded GLP-1 vials have a use-by date determined by the compounding pharmacy. Under USP 797, a multiple-dose vial is typically usable for up to 28 days after it is first punctured, or until the date on the label if that comes first.[5] An unopened vial can be stored refrigerated until the labeled expiration date.
Medication that has expired should not be used. Potency can degrade, and using expired compounded medication may mean you are getting less than the prescribed dose without knowing it.
For storage requirements and how to handle medication that may have been stored incorrectly, see Does GLP-1 Medication Expire?.
Who is not a good candidate for GLP-1?
GLP-1 medications are not appropriate for everyone. A licensed provider reviews your health history for conditions that may make treatment inappropriate or require additional caution. The labeled contraindications for FDA-approved semaglutide and tirzepatide are a personal or family history of medullary thyroid carcinoma, multiple endocrine neoplasia syndrome type 2 (MEN 2), and a known allergy (hypersensitivity) to the medication or its ingredients.[1][2] A history of pancreatitis is not a listed contraindication, but the labels warn about acute pancreatitis.
GLP-1 medications for weight management are not recommended during pregnancy, and there is little data on their use while breastfeeding. If you become pregnant during treatment, contact your prescriber right away.
For a complete reference of known contraindications and conditions that require provider-level caution, see Who Is Not a Candidate for GLP-1?.
Can I take GLP-1 with metformin?
Yes, in most cases. Metformin is commonly prescribed alongside GLP-1 medications for people with type 2 diabetes, and the combination is well-studied in that context. For people without diabetes who are taking metformin off-label for insulin resistance or PCOS, the combination is also generally considered compatible.
That said, the provider you choose needs to know about all medications you are taking, including metformin. The interaction profile, any needed dose adjustments, and monitoring requirements should be discussed before starting.
For a detailed answer on combining GLP-1 with metformin, see Can You Take GLP-1 With Metformin?.
Glossary of key terms
If you have been reading about GLP-1 medications for any length of time, you have encountered terms that are either not explained or explained incorrectly. Below is a plain-English reference for the terms that matter most.
GLP-1 (glucagon-like peptide-1): A hormone produced in the small intestine and colon after eating. It signals the brain to reduce appetite, slows digestion, and triggers insulin release in proportion to blood sugar levels. GLP-1 receptor agonist medications mimic and extend the action of this naturally occurring hormone.
GIP (glucose-dependent insulinotropic polypeptide): A second incretin hormone produced in the small intestine after eating. It works alongside GLP-1 to regulate insulin secretion and, in some contexts, appetite and fat metabolism. Tirzepatide activates both GLP-1 and GIP receptors. Semaglutide activates GLP-1 receptors only.
Incretin: A category of gut hormones released in response to food that stimulate insulin secretion. GLP-1 and GIP are the two primary incretins. In people with type 2 diabetes and certain metabolic conditions, the incretin response is often blunted. GLP-1 receptor agonist medications bypass this blunted response by directly activating the receptors.
Receptor agonist: A drug that binds to a receptor and activates it, producing the same type of response as the natural molecule that normally binds there. A GLP-1 receptor agonist binds to GLP-1 receptors and activates them, producing the effects that natural GLP-1 would produce, but for a longer duration. The extended duration is what makes weekly dosing possible.
Compounded: Prepared by a licensed compounding pharmacy specifically for a patient based on a provider prescription. Compounded medications are not FDA-approved. They are not generics. They differ from commercially available branded medications in how they are formulated, prepared, and regulated. The FDA has not independently evaluated compounded semaglutide or tirzepatide for safety, efficacy, or quality.
503A pharmacy: A traditional compounding pharmacy regulated by state pharmacy boards. Compounds medications in response to individual patient-specific prescriptions from licensed providers. Cannot mass-produce or commercially market compounded drugs. Most compounded GLP-1 programs available through telehealth platforms work with 503A or 503B pharmacies.
503B outsourcing facility: An FDA-registered compounding facility that can produce larger batches of compounded medications without patient-specific prescriptions. Subject to current good manufacturing practice (cGMP) standards, which are more stringent than 503A requirements. Compounded drugs from 503B facilities are still not FDA-approved, but they operate under higher federal oversight.
Tirzepatide: A dual GLP-1/GIP receptor agonist. FDA-approved brand-name tirzepatide is used for both type 2 diabetes and chronic weight management. Compounded tirzepatide is prepared from tirzepatide by licensed compounding pharmacies. It is not FDA-approved and is not the same as the brand-name product.
Semaglutide: A GLP-1 receptor agonist. FDA-approved brand-name semaglutide products are used for type 2 diabetes (injection and oral tablet) and for chronic weight management (weekly injection and daily oral tablet). Compounded semaglutide is prepared from semaglutide by licensed compounding pharmacies. It is not FDA-approved and is not the same as brand-name products.
GLP-1/GIP dual agonist: A medication that activates both GLP-1 and GIP receptors. Tirzepatide is currently the only FDA-approved GLP-1/GIP dual agonist. In the SURMOUNT-5 trial, adults with obesity but without type 2 diabetes who took FDA-approved tirzepatide lost an average of 20.2% of body weight at 72 weeks, compared with 13.7% for FDA-approved semaglutide.[4] Results vary. Trial results describe study participants and are not a prediction for any individual.
Telogen effluvium: A temporary form of hair shedding triggered by physiological stress, including significant calorie restriction or substantial changes in body weight over a short period. Hair loss was reported more often with the medication than with placebo in the weight-management trials of FDA-approved semaglutide and tirzepatide, and the tirzepatide label notes that it was associated with weight reduction.[1][2] It is typically temporary and resolves as the body adjusts.
Microdosing: In the context of GLP-1 treatment, microdosing refers to using GLP-1 medications at sub-therapeutic doses for weight maintenance rather than active weight loss. Some people who have completed an active treatment phase use it to try to sustain results at a lower dose and cost. Microdosing is not an FDA-approved dosing approach, and there is little clinical trial evidence for it.
What’s in this section
This hub answers the most common pre-treatment questions and provides a glossary of key terms. The supporting pages go deeper on specific questions:
GLP-1 Glossary: Key Terms - An expanded reference glossary of clinical, regulatory, and practical terms used in GLP-1 treatment and telehealth.
Can I Get GLP-1 If I Am Not Diabetic? - A direct answer to one of the most common eligibility questions, including BMI requirements and the shift in GLP-1 prescribing beyond diabetes.
How Long Does It Take for GLP-1 to Work? - A week-by-week timeline of what people typically experience, from the starting dose through full therapeutic effect.
Can You Take GLP-1 With Birth Control? - Guidance on GLP-1 and oral contraceptive interactions, and what the FDA labels say for people on birth control.
Does GLP-1 Medication Expire? - Shelf life, storage requirements, and what to do if medication may have been stored incorrectly.
Who Is Not a Candidate for GLP-1? - A reference guide to contraindications, precautions, and the conditions that require provider review before starting treatment.
Can You Take GLP-1 With Metformin? - Guidance on combining GLP-1 medications with metformin for patients with insulin resistance, PCOS, or type 2 diabetes.
For an overview of how GLP-1 medications work, what the trials found, costs, and what to check in a provider, see the GLP-1 Weight Loss guide.
Citations
- U.S. Food and Drug Administration. Wegovy (semaglutide) injection and tablets prescribing information (NDA 215256). Revised 06/2026. https://www.accessdata.fda.gov/drugsatfda_docs/label/2026/215256s025lbl.pdf
- U.S. Food and Drug Administration. Zepbound (tirzepatide) injection prescribing information (NDA 217806). Revised 08/2026. https://www.accessdata.fda.gov/drugsatfda_docs/label/2026/217806Orig1s041correctedlbl.pdf
- Wilding JPH, et al. “Once-Weekly Semaglutide in Adults with Overweight or Obesity.” New England Journal of Medicine. 2021;384(11):989-1002. https://pubmed.ncbi.nlm.nih.gov/33567185/
- Aronne LJ, et al. “Tirzepatide as Compared with Semaglutide for the Treatment of Obesity.” New England Journal of Medicine. 2025;393(1):26-36. https://pubmed.ncbi.nlm.nih.gov/40353578/
- United States Pharmacopeia (USP). “General Chapter 797: Pharmaceutical Compounding - Sterile Preparations.” Revision published November 1, 2022; official November 1, 2023. https://www.usp.org/compounding/general-chapter-797
Important: This content is for general education and is not medical advice. Talk with a licensed provider about your situation. Transformation Health is an independent publisher. It does not provide medical care, prescribe, or sell medication. Compounded medications are not FDA-approved. The FDA does not review them for safety, effectiveness, or quality, and they are not the same as brand-name products; they may differ in formulation, purity, and potency. Results vary. Trial results describe study participants and are not a prediction for any individual.