Semaglutide Dose Calculator

What is Semaglutide?

Semaglutide is a GLP-1 receptor agonist, a medication that mimics glucagon-like peptide-1, a natural gut hormone released after eating. By activating GLP-1 receptors, semaglutide slows stomach emptying, increases insulin release when blood sugar is high, and acts on appetite centres in the brain to reduce hunger.

It is sold under three brand names: Ozempic (weekly injection for type 2 diabetes), Wegovy (weekly injection for chronic weight management), and Rybelsus (daily tablet for type 2 diabetes). Compounded semaglutide is also dispensed by some pharmacies and telehealth providers, though compounded versions are not FDA-approved.

Because semaglutide affects the digestive system strongly, treatment always starts at a low dose and increases gradually, a process called dose escalation or titration. This calculator maps where you are in that process.

Standard Semaglutide Dose Schedule

Both Wegovy and Ozempic follow a stepped weekly schedule defined in their FDA prescribing information. Every dose is injected once weekly, on the same day each week, with or without food.

How Dose Escalation Works

Dose escalation means staying at each dose level for at least four weeks before moving up. Four weeks matters for two reasons. First, semaglutide has a half-life of about one week, so it takes four to five weeks of consistent dosing for blood levels to reach steady state, and only then do you feel a dose's full effect. Second, gradual increases give your digestive system time to adapt, which dramatically reduces nausea and vomiting.

If side effects are difficult at a new dose, prescribers commonly delay the next escalation or step back down for a few weeks. That is a normal, FDA-anticipated adjustment, not a setback.

Why Titration Matters

Skipping titration steps is the single most common cause of severe GI side effects with semaglutide. Clinical trials of Wegovy (STEP programme) and Ozempic (SUSTAIN programme) used the stepped schedule specifically because tolerability drove adherence: people who escalated gradually stayed on treatment longer and lost more weight.

Titration also protects results. The starting 0.25 mg dose is not intended to produce weight loss or glycemic control; judging the medication's effectiveness in the first four weeks is premature by design.

Common Side Effects by Stage

Most semaglutide side effects are gastrointestinal, appear in the first weeks at any new dose, and fade as your body adapts.

• Nausea: the most common effect, usually mild and worst 24–48 hours after injection
• Constipation or diarrhoea: often improved with fibre, water, and movement
• Early satiety: feeling full quickly; eat smaller, protein-first meals
• Fatigue and mild headache: most common during escalation weeks
• Injection-site reactions: rotate sites (abdomen, thigh, upper arm)
• Seek medical care promptly for severe abdominal pain, persistent vomiting, or signs of dehydration, as these can indicate rare but serious effects like pancreatitis

Protein Recommendations on Semaglutide

When appetite drops, protein is usually the first thing under-eaten, and inadequate protein during rapid weight loss accelerates muscle loss. Most clinicians recommend roughly 1.2–1.6 grams of protein per kilogram of body weight daily during active weight loss, prioritised at every meal. Combined with resistance training two to three times weekly, this is the most reliable way to keep loss coming from fat rather than muscle. Your snapshot above calculates a personalised daily target from your weight.

Water Recommendations

Semaglutide reduces thirst signals along with hunger, and GI side effects increase fluid loss. Aim for roughly 30–35 ml per kilogram of body weight daily (about 2–3 litres for most adults), more in hot weather or during nausea episodes. Consistent hydration also measurably reduces headache and constipation during escalation weeks.

Exercise Recommendations

Resistance training is the highest-value exercise on GLP-1 therapy: two to three full-body sessions weekly preserves muscle mass that dieting alone would sacrifice. Add 150 minutes of moderate cardio per week for cardiovascular health, and schedule harder sessions away from the 24–48 hours after injection if nausea is an issue for you.

Semaglutide Half-Life & Drug Activity

Semaglutide's elimination half-life is approximately one week (about 7 days). This long half-life is what makes once-weekly dosing possible, but it has two practical consequences worth understanding.

First, accumulation: each weekly dose adds to what remains from previous doses, so blood levels climb for four to five weeks after starting or changing a dose before levelling off at steady state. The 'Estimated Drug Activity' figure in your snapshot models this: it estimates how close your current levels are to that dose's steady-state plateau.

Second, slow washout: after a missed or stopped dose, meaningful drug activity persists for weeks. This is why a single missed dose within 5 days can simply be taken late, while a longer gap may require restarting titration. Both decisions belong to your prescriber.