How Compounded Semaglutide Dosing Works
Semaglutide dosing follows a titration schedule, which means your dose starts low and increases gradually so your body can adjust. This step-up approach helps reduce gastrointestinal side effects like nausea, which tend to be strongest when you first start or move to a higher dose.
Unlike the FDA-approved branded version of semaglutide, which comes in a pre-filled injection pen with preset doses, compounded semaglutide comes in multi-dose vials. This format allows prescribers to customize doses, including smaller increments between standard levels, but it also means you need to draw the correct amount into a syringe yourself. Semaglutide is a GLP-1 receptor agonist, a class of medications that works by slowing stomach emptying, supporting insulin release, and reducing appetite.
Compounded semaglutide is not FDA-approved as a finished drug product. It has not been reviewed by the FDA for safety, effectiveness, or quality. A prescriber may prescribe it when they determine that your needs cannot be met by an available FDA-approved product. The FDA has also outlined broader safety concerns about unapproved GLP-1 drugs used for weight loss.
Research on the FDA-approved branded version of semaglutide supports the titration model. In the STEP-1 trial, participants taking the FDA-approved branded version of semaglutide at the 2.4 mg maintenance dose lost an average of about 15% of their body weight over 68 weeks. These results reflect the branded product studied in controlled conditions and may not directly apply to compounded formulations.
Your prescriber determines the right schedule for you. Do not change your dose without talking to your prescriber first.
Compounded Semaglutide Dosage Chart
The table below shows a common titration schedule for compounded semaglutide. Your prescriber may adjust these timeframes or doses based on how you respond.
| Phase | Weeks | Weekly Dose | Purpose |
|---|---|---|---|
| Initiation | 1 to 4 | 0.25 mg | Let your body adjust to the medication |
| First increase | 5 to 8 | 0.5 mg | Gradual step-up to reduce side effects |
| Second increase | 9 to 12 | 1.0 mg | Therapeutic dose for many people |
| Maintenance | 13+ | Up to 2.0 to 2.4 mg | Final dose set by your prescriber based on your goals and tolerance |
A few things to keep in mind:
- Your prescriber controls the schedule. Some people stay at a lower dose longer if side effects are significant. Others may reach the maintenance dose sooner.
- Microdosing is an option. Some prescribers start with very low doses (0.05 to 0.1 mg) for people who are sensitive to medications or who have had strong reactions to GLP-1 receptor agonists in the past.
- Do not self-adjust your dose. Changing your dose without guidance can increase the risk of serious side effects or reduce the medication’s effectiveness.
- Doses above 2.4 mg per week are not supported by published clinical trial data for the FDA-approved branded version of semaglutide used for weight management.
How To Convert Mg to Units for Compounded Semaglutide Vials
Because compounded semaglutide comes in vials rather than pre-filled pens, you need to calculate how many units to draw into your syringe. The number of units depends entirely on your vial’s concentration, which varies by compounder.
The conversion formula
If you are using a U-100 insulin syringe (the most common type for these injections):
Units = (Dose in mg / Concentration in mg/mL) x 100
For example, if your prescriber tells you to inject 0.25 mg and your vial concentration is 5 mg/mL:
Units = (0.25 / 5) x 100 = 5 units
Concentration comparison table
The same dose in milligrams requires very different syringe markings depending on your vial’s concentration:
| Dose (mg) | 1 mg/mL vial | 2.5 mg/mL vial | 5 mg/mL vial |
|---|---|---|---|
| 0.25 mg | 25 units | 10 units | 5 units |
| 0.5 mg | 50 units | 20 units | 10 units |
| 1.0 mg | 100 units | 40 units | 20 units |
| 2.0 mg | Not possible in one draw | 80 units | 40 units |
| 2.4 mg | Not possible in one draw | 96 units | 48 units |
FDA dosing-error alert
In July 2024, the FDA issued an alert about adverse events, some requiring hospitalization, linked to dosing errors with compounded semaglutide. The FDA documented cases where people drew 50 units instead of 5 units, receiving 10 times the intended dose. In some cases, prescribers also miscalculated conversions. The errors stemmed from confusion between milligrams, milliliters, and “units,” compounded by the fact that vial concentrations vary between compounders.
Before your first injection, confirm three things with your prescriber or pharmacist:
- The exact concentration printed on your vial (in mg/mL)
- The correct number of units to draw for your prescribed dose
- That you are using the right type of syringe for your vial
If you switch to a vial from a different compounder, check the concentration again. It may be different, which means your unit calculation will change even though your milligram dose stays the same.
Side Effects and What To Expect at Each Dose
Side effects are most likely when you first start compounded semaglutide and each time your dose increases. For most people, these symptoms improve within two to four weeks at each dose level.
Common side effects
The most frequently reported side effects in clinical trials of the FDA-approved branded version of semaglutide include:
- Nausea
- Vomiting
- Diarrhea
- Constipation
- Stomach pain
These gastrointestinal effects are related to how GLP-1 receptor agonists slow stomach emptying, one of the mechanisms that contributes to appetite reduction. Eating smaller meals, avoiding high-fat foods, and staying hydrated may help. Your prescriber may recommend a short course of an anti-nausea medication such as ondansetron if nausea is disrupting your daily routine. Do not take additional medications without your prescriber’s guidance.
For more detail on semaglutide precautions and interactions, the Mayo Clinic and MedlinePlus both offer thorough patient-education pages.
When to contact your prescriber
Persistent vomiting, severe bloating, or inability to pass stool can signal gastroparesis or, rarely, bowel obstruction. These are not typical side effects and need prompt medical attention. Gallstones and gallbladder disease (cholelithiasis) have also been reported with semaglutide, and the risk may be higher if you have a history of gallstones. Tell your prescriber about sudden, severe pain in your upper-right abdomen, which can signal a gallbladder problem.
Boxed warning: thyroid C-cell tumors
In animal studies, semaglutide caused thyroid C-cell tumors. It is not known whether semaglutide causes thyroid C-cell tumors in humans. Semaglutide is contraindicated if you have a personal or family history of medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia syndrome type 2 (MEN 2). Talk to your prescriber about your family history before starting treatment.
Surgery and anesthesia
If you are scheduled for any procedure that involves sedation, inform your anesthesiologist that you are taking a GLP-1 receptor agonist. Semaglutide can delay gastric emptying, which may increase the risk of aspiration (inhaling stomach contents) during anesthesia. Your surgical team may ask you to stop injections or fast for a longer period before the procedure.
Pregnancy and contraception
Semaglutide is not recommended during pregnancy. If you are planning to become pregnant, the current guidance is to stop semaglutide at least two months before your planned conception date. Whether GLP-1 receptor agonists meaningfully reduce the absorption of oral contraceptives is uncertain for semaglutide; unlike tirzepatide, its label does not carry a specific contraception warning. Talk to your prescriber about contraception options while on treatment.
Lab Tests That Can Help You Monitor Your Health on Semaglutide
One of the reasons lab testing matters with GLP-1 receptor agonists is that some serious side effects, like pancreatitis and kidney injury, can be caught early through routine bloodwork. Below are lab tests your prescriber may want to check before you start and periodically while you are on treatment.
Baseline labs to consider before starting
- Lipase: A baseline lipase reading is optional. Routine lipase monitoring is not recommended for people without symptoms; your prescriber may check it only if you develop signs of pancreatitis, such as severe stomach pain that spreads to your back.
- Comprehensive metabolic panel (CMP): Includes creatinine and eGFR, which track kidney function. This is the most important baseline lab, because semaglutide-related nausea and vomiting can cause dehydration that stresses the kidneys and, rarely, leads to acute kidney injury.
- A1c: Measures your average blood sugar over two to three months. Useful for tracking metabolic changes, especially if you have type 2 diabetes or prediabetes.
- Lipid panel: Monitors cholesterol and triglyceride levels. Some research on the FDA-approved branded version of semaglutide suggests it may improve lipid profiles.
Labs to recheck on therapy
- Creatinine: This is the most important lab to recheck on treatment. Periodic monitoring of creatinine and eGFR can detect kidney changes, particularly if you have significant nausea, vomiting, or dehydration.
- A1c and lipid panel: Tracking these over time shows how your metabolic markers are responding to treatment.
Talk to your prescriber about which labs to check before starting and how often to recheck while on treatment. The right testing schedule depends on your health history and any other medications you take. If you have type 2 diabetes, your prescriber may also recommend diabetic retinopathy screening (an eye exam), because rapid improvements in blood sugar have been linked to short-term worsening of retinopathy in some people.
How To Get Started
If you are considering compounded semaglutide, your next step is a conversation with a licensed prescriber who can evaluate whether it is appropriate for you, determine the right starting dose, and walk you through how to measure and inject from a vial.
For more information about compounded semaglutide, including what to expect from a prescriber consultation, visit the compounded semaglutide treatment page. You may also want to explore compounded tirzepatide, another GLP-1 option your prescriber may discuss with you.
Frequently Asked Questions
Sources
- Wilding JPH, Batterham RL, Calanna S, et al. Once-weekly semaglutide in adults with overweight or obesity. N Engl J Med. 2021;384(11):989-1002. doi:10.1056/NEJMoa2032183 (STEP-1 trial)
- U.S. Food and Drug Administration. FDA alerts health care providers, compounders and patients of dosing errors associated with compounded injectable semaglutide products. July 26, 2024.
- U.S. Food and Drug Administration. FDA’s concerns with unapproved GLP-1 drugs used for weight loss. Updated June 15, 2026.
- U.S. Food and Drug Administration. Semaglutide prescribing information (FDA label).
- Mayo Clinic. Semaglutide (subcutaneous route): side effects and dosage.
- MedlinePlus. Semaglutide injection. National Library of Medicine.