How many units of semaglutide do I draw for my dose?

Units to draw equal ( dose in mg ÷ concentration in mg/mL ) × 100. For a 5 mg/mL vial and a 0.25 mg dose, that's ( 0.25 ÷ 5 ) × 100 = 5 units on a U-100 insulin syringe. Every concentration and every dose is one arithmetic step from that formula.

The calculator above does this live for the four most common compounded concentrations (1, 2.5, 5, 10 mg/mL) plus a custom input, and shows where to draw on a visual syringe. The static reference tables below match those numbers exactly so the answer is available even before you scroll.

What is semaglutide?

Semaglutide is a GLP-1 receptor agonist injected once weekly (Wegovy, Ozempic) or taken as a daily tablet (Rybelsus). It mimics the gut hormone GLP-1: it slows gastric emptying, increases mealtime insulin release, and acts on brain appetite centres, together producing meaningful weight loss and improved glycemic control.

The same molecule is sold under three brand names for different indications. Wegovy is FDA-approved for chronic weight management. Ozempic is approved for type 2 diabetes. Rybelsus is oral semaglutide for type 2 diabetes. Compounded semaglutide vials are dispensed by some pharmacies but are not FDA-approved.

What is the standard semaglutide dose schedule?

Wegovy titrates 0.25 → 0.5 → 1.0 → 1.7 → 2.4 mg once weekly, four weeks at each dose. Ozempic titrates 0.25 → 0.5, then escalates to 1.0 or 2.0 mg only if additional glycemic control is needed. Both use once-weekly injections on the same day each week, with or without food.

How often does the semaglutide dose increase?

Semaglutide doses increase every 4 weeks. Each level is held for at least 4 weeks before escalating because semaglutide reaches steady state in 4–5 weeks and gradual increases sharply reduce nausea. Prescribers commonly delay an increase, or step back down, if side effects are difficult.

That is a normal, FDA-anticipated adjustment, not a setback. Judging effectiveness in the first four weeks is premature by design: the starter 0.25 mg dose is for tolerability, not for glycemic control or weight loss.

Why does semaglutide have to be titrated?

Titration protects tolerability. Skipping steps produces severe nausea and vomiting in a large fraction of users, and both the STEP obesity trials and SUSTAIN diabetes trials specifically used the stepped schedule because adherence tracked tolerability directly. People who titrate gradually stay on treatment longer and lose more weight.

The starting 0.25 mg dose is not intended to deliver clinical effect, so judging the medication in the first four weeks under-rates it. The full response is what a maintenance dose delivers after 4–5 weeks at that level, not what a starter dose delivers in month one.

What is the difference between Wegovy and Ozempic dosing?

Wegovy and Ozempic are the same molecule (semaglutide) with different dose ceilings and different indications. Wegovy tops out at 2.4 mg once weekly and is FDA-approved for chronic weight management. Ozempic tops out at 2.0 mg once weekly and is FDA-approved for type 2 diabetes.

What is the maximum semaglutide dose for weight loss?

The maximum semaglutide dose for weight loss is 2.4 mg once weekly (Wegovy). For blood sugar control, the maximum FDA-approved dose is 2.0 mg once weekly (Ozempic). Participants on 2.4 mg in the STEP 1 trial lost ~15% of body weight over 68 weeks.

Exceeding these ceilings does not accelerate weight loss. It raises the risk of pancreatitis, acute kidney injury and severe nausea. If you're losing steadily and feeling well at a lower dose, staying there is a common and appropriate clinical decision.

What should I do if I miss a semaglutide dose?

If it's less than 5 days late, take the missed dose as soon as you remember and then continue your normal weekly schedule. If it's more than 5 days late, skip the missed dose and take your next injection on the usual day — do not double up.

If you've been off semaglutide for more than 2 weeks, your prescriber may restart you at a lower dose and re-titrate, because tolerance to nausea fades. Every one of these branches ends the same way: confirm the plan with your prescriber before your next injection.

• Less than 5 days late — take now, resume normal schedule
• More than 5 days late — skip, take next dose on the usual day
• More than 2 weeks off treatment — contact your prescriber before restarting
• Never take two doses within 48 hours to catch up

How do I switch between Ozempic, Wegovy and compounded semaglutide?

All three contain the same active molecule, so the mg number generally carries over: 1.0 mg on Ozempic is 1.0 mg on Wegovy or a compounded vial. What changes is the delivery device, the maximum dose, and (for compounded) the concentration you draw from. Every switch is a prescriber decision.

Wegovy → Ozempic: Ozempic's ceiling is 2.0 mg, so anyone maintaining on Wegovy 2.4 mg drops down. Ozempic → Wegovy: your prescriber may keep you at the same mg or continue titrating to 2.4 mg. Brand → compounded (or the reverse): the mg stays the same but you switch from a fixed-dose pen to drawing units from a vial, so the units-calculator above becomes essential.

What is the semaglutide dose for teenagers?

Wegovy is FDA-approved for adolescents aged 12 and older with obesity (BMI at or above the 95th percentile for age and sex). The titration schedule is the same as for adults — 0.25 → 0.5 → 1.0 → 1.7 → 2.4 mg once weekly, four weeks at each step — with a target maintenance dose of 2.4 mg.

In the STEP TEENS trial (Kelly et al., NEJM 2022), adolescents on Wegovy 2.4 mg lost about 16% of body weight over 68 weeks versus 1% on placebo. Every dose decision in this population belongs to a pediatric or adolescent-experienced prescriber; do not extrapolate an adult protocol to a teen without one.

Does semaglutide dosing change with kidney or liver problems?

Per the FDA prescribing information for Ozempic, Wegovy and Rybelsus, no dose adjustment is required in patients with renal impairment (including end-stage renal disease) or in patients with hepatic impairment. The titration schedule and maintenance dose are the same.

That said, dehydration from GI side effects (vomiting, diarrhoea) can transiently worsen kidney function, so hydration matters more in this group. Any patient with significant renal or hepatic disease should still have dosing supervised by the clinician managing that condition.

How is oral semaglutide (Rybelsus) dosed?

Rybelsus (oral semaglutide) is taken once daily, on an empty stomach, with no more than 4 oz (120 mL) of plain water, and at least 30 minutes before the first food, drink, or other medication of the day. Titration is 3 mg daily for 30 days, then 7 mg daily for 30 days, then 14 mg daily as the target maintenance dose.

• Rybelsus mg values are NOT interchangeable with injectable semaglutide mg values
• Oral bioavailability is ~1% versus ~89% for subcutaneous injection
• The same-numbered mg dose delivered orally would produce a very different blood level than injected
• Always follow the exact route and dose your prescriber wrote

What is semaglutide's bioavailability?

Semaglutide's bioavailability is approximately 89% by subcutaneous injection and approximately 1% orally. That ~90-fold difference is why the mg values on Rybelsus (oral) are much larger than the mg values on Ozempic or Wegovy (injected) for a comparable exposure.

The FDA-approved Rybelsus target of 14 mg once daily is designed around that low oral bioavailability. Never treat an oral mg number and an injected mg number as equivalent, and never crush, split or dissolve a Rybelsus tablet — the SNAC absorption enhancer only works when the tablet reaches the stomach intact.

How long does semaglutide stay in your system?

Semaglutide's elimination half-life is approximately 7 days, so a single dose is roughly 50% cleared in one week and effectively cleared in 5 half-lives (about 5 weeks). This is what allows once-weekly dosing and why blood levels build for 4–5 weeks after starting or raising a dose before hitting steady state.

Two practical consequences: (1) each weekly dose stacks on what remains of previous doses, so the full effect of any dose isn't felt for 4–5 weeks; (2) after stopping, meaningful drug activity persists for several weeks — which is exactly why a single missed dose within 5 days can be taken late but a longer gap may require re-titration.

How should semaglutide be stored?

Unopened Wegovy and Ozempic pens are stored refrigerated at 36–46°F (2–8°C), away from the cooling element. A frozen pen must be discarded. Once in use, Ozempic keeps for exactly 56 days at room temperature (up to 86°F / 30°C) or in the fridge. A single-dose Wegovy pen sits at room temperature for up to 28 days unused, but once uncapped must be injected immediately.

• Unopened (both) — refrigerate at 36–46°F (2–8°C), never freeze
• Ozempic in-use — 56 days, room temperature or fridge
• Wegovy single-dose pen — up to 28 days unused at room temperature; once uncapped, inject immediately
• Compounded vials — follow the pharmacy's specific label; typically 28–60 days refrigerated once reconstituted

What are the side effects of semaglutide at each dose?

Most semaglutide side effects are gastrointestinal, cluster in the first weeks at any new dose (including titration steps), and fade as the body adapts. Nausea is the single most common — reported by roughly 44% of Wegovy users in STEP 1 versus 18% on placebo — and is usually mild.

• Nausea — most common, usually worst 24–48 hours after the 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 dehydration — these can indicate rare but serious effects like pancreatitis

What is the FDA boxed warning for semaglutide?

Semaglutide carries an FDA boxed warning for a potential risk of thyroid C-cell tumors, based on rodent studies. It is contraindicated in anyone with a personal or family history of medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia syndrome type 2 (MEN 2).

Contact your prescriber promptly for severe abdominal pain radiating to the back (possible pancreatitis), vision changes, or an unusual neck lump. Dose decisions belong to your prescriber — the calculator on this page does not adjust for individual risk.

What about Ozempic click-counting and dose splitting?

Some forums discuss counting the audible clicks on an Ozempic dial pen to extract non-standard fractions of a dose (roughly 18 clicks for 0.25 mg, 37 for 0.5 mg, 74 for 1.0 mg on the 1 mg pen). This is not endorsed by the manufacturer and getting it wrong under-doses or over-doses.

The 56-day sterility limit still applies, so stretching one pen across many weeks raises infection risk in addition to dosing risk. Do not attempt click-counting without explicit medical supervision — and this calculator will not compute click counts for you, deliberately.

How much protein should I eat on semaglutide?

Aim for roughly 1.2–1.6 g of protein per kg of body weight per day during active weight loss, spread across every meal. Under-eating protein is the single biggest driver of muscle loss during rapid GLP-1 weight loss, and appetite suppression makes protein especially easy to skip.

Combined with resistance training two to three times per week, this range is the most reliable way to keep the loss coming from fat rather than muscle. Higher targets (up to 2.2 g/kg) are appropriate for people prioritising strength during weight loss.

How much water should I drink on semaglutide?

Aim for roughly 30–35 mL per kg of body weight daily — about 2 to 3 litres for most adults — and more during hot weather or nausea. Semaglutide suppresses thirst signals along with hunger, and GI side effects increase fluid loss, so dehydration is a common preventable cause of headache and constipation during titration.

How should I exercise on semaglutide?

Resistance training is the single most valuable form of 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. If nausea is worst 24–48 hours after injection, schedule harder sessions on the days furthest from your shot.

Related GLP-1 calculators

Every link here shares macro context with a semaglutide dosing page. Non-GLP-1 calculators live in the main directory.