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. According to RAND Health research from 2025, the largest group of GLP-1 users is women without diabetes between the ages of 30 and 55. GLP-1 medications are prescribed for weight management in adults with a BMI of 27 or higher (or 25 or higher with a qualifying health condition such as hypertension or high cholesterol), based on provider 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 patients 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. The STEP 1 clinical trial of the FDA-approved branded semaglutide showed that the most significant body weight changes occurred between weeks eight and sixteen, not in the first month.

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 your provider before starting. GLP-1 medications slow gastric emptying, which can affect how quickly oral medications (including oral contraceptives) are absorbed. Reduced absorption speed may lower the effectiveness of oral birth control during the initial weeks of GLP-1 treatment and after each dose increase.

Clinical guidance from the manufacturers of FDA-approved semaglutide recommends considering a backup contraception method for four weeks after starting treatment and for four weeks after each dose increase if you are taking oral contraceptives.

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. An opened vial stored in the refrigerator is typically usable for 28-30 days after opening. 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. Your provider will review your health history for conditions that may make treatment inappropriate or require additional caution. Key contraindications for most GLP-1 medications include a personal or family history of medullary thyroid carcinoma, a history of multiple endocrine neoplasia syndrome type 2, and a history of pancreatitis.

GLP-1 medications are also not currently recommended during pregnancy or breastfeeding. If you become pregnant during treatment, contact your provider immediately.

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 patients with type 2 diabetes, and the combination is well-studied in that context. For patients without diabetes who are taking metformin off-label for insulin resistance or PCOS, the combination is also generally considered compatible.

That said, your provider 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. Tirzepatide is FDA-approved as a branded medication for both type 2 diabetes and chronic weight management. Compounded tirzepatide is a separate, not-FDA-approved formulation prepared by licensed compounding pharmacies.

Semaglutide: A GLP-1 receptor agonist. Semaglutide is FDA-approved as branded medications for type 2 diabetes (injection and oral tablet) and for chronic weight management (injection). Compounded semaglutide is a separate, not-FDA-approved formulation prepared by licensed compounding pharmacies.

GLP-1/GIP dual agonist: A medication that activates both GLP-1 and GIP receptors. Tirzepatide is currently the only GLP-1/GIP dual agonist available in compounded form. This dual mechanism is associated with stronger appetite suppression in some patients compared to GLP-1-only agonists, based on clinical trials of the FDA-approved branded version.

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. It is not a direct pharmacological side effect of GLP-1 medications, but it has been reported by some patients during the early months of treatment when calorie intake is significantly reduced. 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. It is used by patients who have completed an active treatment phase and want to sustain results at a lower dose and cost. Transformation Health’s microdose program is designed for patients with a BMI of 20 or higher with prior GLP-1 experience.

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 patients 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 clinical guidance recommends for patients 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 a complete overview of GLP-1 programs including eligibility, pricing, and how to get started, see our GLP-1 Weight Loss guide.