Semaglutide Dosage Calculator

Semaglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist that shares approximately 94% sequence homology with endogenous human GLP-1. It was developed by Novo Nordisk and is marketed under the brand names Ozempic (weekly subcutaneous injection for diabetes), Wegovy (higher-dose weekly injection for weight management), and Rybelsus (daily oral tablet). Its defining structural feature is a C18 fatty acid chain attached via a linker to lysine at position 34, which enables reversible albumin binding and dramatically extends its half-life to approximately seven days — making once-weekly dosing possible.

In clinical research, semaglutide has been studied across multiple large-scale trial programs. The SUSTAIN program (eight Phase 3 trials) established its glycemic efficacy, while the STEP program demonstrated body weight reductions averaging 14.9% over 68 weeks at the 2.4 mg maintenance dose in subjects with obesity. Beyond metabolic outcomes, researchers are actively investigating semaglutide's potential in metabolic dysfunction-associated steatohepatitis (MASH), heart failure with preserved ejection fraction, chronic kidney disease, and even neurodegenerative conditions such as Parkinson's disease. The SELECT trial (2023) demonstrated a 20% reduction in major adverse cardiovascular events in subjects with established cardiovascular disease and overweight or obesity, irrespective of diabetes status.

Semaglutide activates the GLP-1 receptor, a class B G-protein-coupled receptor expressed throughout the body. In the pancreas, receptor activation stimulates glucose-dependent insulin secretion from beta cells and suppresses inappropriate glucagon release from alpha cells — a dual effect that lowers blood glucose without the hypoglycemia risk associated with insulin secretagogues.

In the central nervous system, particularly in the hypothalamus, brainstem nucleus tractus solitarius, and area postrema, GLP-1 receptor signaling reduces appetite, increases satiety signaling, and modulates reward pathways linked to food intake. Delayed gastric emptying contributes to reduced postprandial glucose excursions and prolongs the subjective sensation of fullness. Cardiovascular and renal benefits observed in large outcomes trials appear to be mediated through a combination of reduced inflammation, improved endothelial function, blood pressure reduction, and direct cardioprotective signaling in cardiomyocytes.

Semaglutide lyophilized powder is reconstituted with bacteriostatic water for injection. Draw the desired volume of bacteriostatic water (typically 1–2 mL for a 5 mg vial) into a sterile syringe, insert the needle into the septum of the semaglutide vial, and inject the water slowly against the glass wall of the vial — do not squirt directly onto the powder cake. Allow the vial to rest for 60 seconds without disturbance, then gently swirl in a circular motion until the powder fully dissolves. Do not shake the vial, as this can cause protein aggregation. The reconstituted solution should be clear to very slightly yellow and free of visible particles or cloudiness.

A 5 mg vial reconstituted with 2 mL of bacteriostatic water yields a concentration of 2,500 mcg per mL (2.5 mg/mL). With a 1 mL reconstitution the concentration doubles to 5,000 mcg/mL. Use the calculator above to determine the exact injection volume for your chosen dose.

All semaglutide clinical trials employ a step-up titration schedule to minimize gastrointestinal adverse effects during the early weeks of use. Based on the STEP and SUSTAIN trial protocols, the standard weekly dose escalation is as follows: 0.25 mg per week during weeks 1 through 4 (initiation phase), 0.5 mg per week during weeks 5 through 8, 1.0 mg per week during weeks 9 through 12, 1.7 mg per week during weeks 13 through 16, and 2.4 mg per week from week 17 onward as the maintenance dose in the STEP weight management program.

For glycemic research (the SUSTAIN program), 0.5 mg and 1.0 mg per week represent common maintenance dose levels. Some protocols allow extending each escalation tier by an additional four weeks if gastrointestinal tolerability is a concern. Semaglutide is administered once weekly on the same day each week, subcutaneously into the abdomen, upper thigh, or upper arm.

Using the calculator: a 5 mg vial with 2 mL of bacteriostatic water gives 2,500 mcg/mL. A 0.25 mg (250 mcg) initiation dose therefore requires 0.10 mL (10 IU on a U100 syringe), while the 2.4 mg (2,400 mcg) maintenance dose requires 0.96 mL (96 IU).

Lyophilized (dry powder) semaglutide vials should be stored at 2–8°C (standard refrigerator temperature), away from direct light and heat sources. Do not freeze the powder or the reconstituted solution. Once a vial has been reconstituted with bacteriostatic water, the solution remains stable at refrigerator temperature for approximately 28 days, consistent with standard bacteriostatic water-preserved peptide storage guidelines. Some researchers report extended stability at 56–60 days under consistent cold-chain conditions, but the 28-day window is the conservative standard. Always inspect the solution for clarity, color changes, and particulates before each use; discard the vial if any abnormalities are observed.

The most common adverse effects reported in semaglutide clinical trials are gastrointestinal: nausea, vomiting, diarrhea, and constipation, which are most pronounced during dose escalation and typically attenuate over time. Rare but serious adverse events documented in clinical data include acute pancreatitis, cholelithiasis (gallstones), and severe hypoglycemia when combined with insulin or sulfonylurea agents. Medullary thyroid carcinoma has been observed in rodent studies at suprapharmacological doses; while this has not been confirmed in humans, semaglutide is contraindicated in those with a personal or family history of medullary thyroid carcinoma or MEN2. This compound is a research chemical intended strictly for laboratory investigation.