Semaglutide calculator
A GLP-1 receptor agonist prescribed for type 2 diabetes and chronic weight management, dosed once weekly.
Also known as: Ozempic, Wegovy, Rybelsus
FDA status FDA-approved as a prescription drug (Ozempic, Wegovy, Rybelsus). Compounded semaglutide is not FDA-approved and is not reviewed by FDA for safety, effectiveness, or quality.
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What Semaglutide is
Semaglutide is a synthetic analog of GLP-1, a hormone your gut releases after eating. It is one of the most extensively studied peptides in medicine, with large randomized trials behind its approvals for type 2 diabetes and chronic weight management.
Research depth: 5/5 Very large body of research: multiple phase 3 human trial programs (STEP, SUSTAIN, SELECT) plus extensive preclinical work. Human trials: Large randomized trials. This measures how much has been studied — counting animal and laboratory work — not whether it works for you.
How Semaglutide works
It binds GLP-1 receptors in the pancreas, gut, and brain. That increases insulin release when glucose is high, suppresses glucagon, slows gastric emptying, and reduces appetite signaling in the hypothalamus. The slowed stomach emptying is why most of its side effects are gastrointestinal.
Semaglutide side effects
Commonly reported
- Nausea, especially in the days after a dose increase
- Vomiting, diarrhea, or constipation
- Reduced appetite and early fullness
- Fatigue and headache
- Injection-site reactions
Serious — seek medical care
- Pancreatitis — severe, persistent abdominal pain, often radiating to the back
- Gallbladder disease, particularly with rapid weight loss
- Severe dehydration from prolonged vomiting or diarrhea
- Vision changes in people with existing diabetic retinopathy
- Thyroid C-cell tumors in rodents — contraindicated with personal or family history of medullary thyroid carcinoma or MEN2
This list is not exhaustive. Report anything unexpected to the clinician who prescribed it. If you have severe abdominal pain, trouble breathing, or signs of an allergic reaction, seek care the same day. See also our guide to peptide side effects by class.
A worked example
A 5 mg vial reconstituted with 2 mL of bacteriostatic water gives 2.5 mg/mL. A 250 mcg dose is then 0.1 mL — about 10 units on a 100-unit insulin syringe, giving roughly 20 doses per vial before accounting for residual volume left in the vial and syringe.
Prefer paper? Download the printable Semaglutide dosing chart (PDF) — every vial size and water volume in syringe units, with the same review byline as this page. All charts →
Commonly cited dose range
Figures circulating for Semaglutide run from 250 mcg to 2400 mcg. Commonly discussed protocols start low and titrate over several weeks. Weekly dosing.
Read this as reference information, not instruction. These numbers describe what is commonly discussed, not what is right for any individual. Dose, frequency, and whether to use Semaglutide at all are decisions for a licensed clinician who knows your history.
Common questions
How much bacteriostatic water should I add to a 5 mg semaglutide vial?
There is no single correct volume — the water only sets the concentration, not the dose. 2 mL in a 5 mg vial gives 2.5 mg/mL, so a 250 mcg dose is 10 units on a standard 100-unit insulin syringe. Adding more water makes each dose a larger, easier-to-measure draw.
Does adding more water make the dose weaker?
No. More water lowers the concentration, so you draw a larger volume for the same amount of peptide. The milligrams delivered are unchanged as long as you recalculate the draw.
How long does reconstituted semaglutide last?
Storage and beyond-use dating depend on the specific product and preparation. Follow the instructions supplied with your prescription and ask the prescribing clinician or pharmacist — do not rely on general internet guidance.