Semaglutide Reconstitution Calculator
Semaglutide is a GLP-1 analogue with 94% sequence homology to human GLP-1. It binds and activates the GLP-1 receptor, which regulates appetite and caloric intake through receptors in brain regions governing appetite, increases glucose-dependent insulin secretion, and slows gastric emptying. Its half-life is about one week, which is why the injectable products are dosed once weekly. Unlike most peptides in this library it is an approved medicine, sold as a ready-to-use solution in a prefilled pen: that product contains no powder and never needs mixing. The calculator above is for the compounded and grey-market vials sold as a lyophilised powder, which are not the approved product and carry none of its labelling. The published schedules below are quoted from FDA labeling, not recommendations.
Curated by Dosavy from published literature and regulator labels. Published 1 September 2026, last reviewed 19 September 2026. No clinician reviews this page.
Enter a target dose above to see the draw.
What the evidence says
| Experience | Route | Range | Frequency |
|---|---|---|---|
| Beginner | Subcutaneous | 0.25 mg[1]Label starting dosage: 'Start at 0.25 mg once weekly. After 4 weeks, increase the dosage to 0.5 mg once weekly.' The 0.25 mg dose is an initiation dose intended for tolerability and is not effective for glycaemic control on its own. | Once weekly |
| Intermediate | Subcutaneous | 0.5–1 mg[1]Label maintenance range for type 2 diabetes. Increase to 1 mg only after at least 4 weeks on 0.5 mg. The label also directs escalation to 1 mg to reduce risk of sustained eGFR decline, end-stage kidney disease and cardiovascular death. | Once weekly |
| Advanced | Subcutaneous | 2–2.4 mg[1][2]Maximum labelled dosages. 2 mg once weekly is the maximum for type 2 diabetes (Ozempic); 2.4 mg once weekly is the recommended maintenance dosage for chronic weight management (Wegovy), reached by titrating every 4 weeks. These are separate approved products and indications, not a single continuous scale. | Once weekly |
| Beginner | Oral | 3 mg[3]Label: 'Day 1 to 30: Recommended starting dosage is 3 mg orally once daily for 30 days.' This initiation dose is for tolerability and is not effective for glycaemic control. Oral and subcutaneous semaglutide are explicitly not substitutable on a mg-to-mg basis. | Once daily |
| Intermediate | Oral | 7 mg[3]Maintenance dosage after the initial 30 days at 3 mg. Taken on an empty stomach in the morning with no more than 4 ounces of water, waiting at least 30 minutes before food, drink or other oral medication. | Once daily |
| Advanced | Oral | 14 mg[3]Maximum labelled oral dosage, reached after at least 30 days at 7 mg. Two 7 mg tablets must not be substituted for one 14 mg tablet. | Once daily |
- BeginnerSubcutaneous
0.25 mg[1]
Once weekly
Label starting dosage: 'Start at 0.25 mg once weekly. After 4 weeks, increase the dosage to 0.5 mg once weekly.' The 0.25 mg dose is an initiation dose intended for tolerability and is not effective for glycaemic control on its own.
- IntermediateSubcutaneous
0.5–1 mg[1]
Once weekly
Label maintenance range for type 2 diabetes. Increase to 1 mg only after at least 4 weeks on 0.5 mg. The label also directs escalation to 1 mg to reduce risk of sustained eGFR decline, end-stage kidney disease and cardiovascular death.
- AdvancedSubcutaneous
Once weekly
Maximum labelled dosages. 2 mg once weekly is the maximum for type 2 diabetes (Ozempic); 2.4 mg once weekly is the recommended maintenance dosage for chronic weight management (Wegovy), reached by titrating every 4 weeks. These are separate approved products and indications, not a single continuous scale.
- BeginnerOral
3 mg[3]
Once daily
Label: 'Day 1 to 30: Recommended starting dosage is 3 mg orally once daily for 30 days.' This initiation dose is for tolerability and is not effective for glycaemic control. Oral and subcutaneous semaglutide are explicitly not substitutable on a mg-to-mg basis.
- IntermediateOral
7 mg[3]
Once daily
Maintenance dosage after the initial 30 days at 3 mg. Taken on an empty stomach in the morning with no more than 4 ounces of water, waiting at least 30 minutes before food, drink or other oral medication.
- AdvancedOral
14 mg[3]
Once daily
Maximum labelled oral dosage, reached after at least 30 days at 7 mg. Two 7 mg tablets must not be substituted for one 14 mg tablet.
Published ranges, reported as the literature states them and numbered to the sources at the foot of this page. Not a recommendation.
Semaglutide at a glance
- Category
- GLP-1
- Half-life
- 7 d
- Routes
- Subcutaneous, Oral
- Regulatory status
- Approved
- Also sold as
- Ozempic, Wegovy, Rybelsus, GLP-1 analogue
Mechanism
A GLP-1 analogue with 94% sequence homology to human GLP-1. It selectively binds and activates the GLP-1 receptor, the target of native GLP-1, which regulates appetite and caloric intake; GLP-1 receptors are present in brain regions governing appetite. It also increases glucose-dependent insulin secretion and slows gastric emptying.
Reconstitution
Supplied as a ready-to-use solution in a prefilled pen. Not a lyophilised powder: no reconstitution is required or appropriate.
Storage
Refrigerate at 2°C to 8°C before first use; do not freeze. After first use, pens may be stored per the product label at room temperature or refrigerated for a limited period. Oral tablets are stored at room temperature.
Frequency in practice
Once weekly by subcutaneous injection, or once daily orally, depending on the product.
Regulatory
FDA-approved. Ozempic (subcutaneous) and Rybelsus (oral) are approved for type 2 diabetes; Wegovy (subcutaneous) is approved for chronic weight management. Prescription-only in the US, EU and Switzerland.
What to know before anything else
BOXED WARNING: In rodents, semaglutide causes dose-dependent thyroid C-cell tumors at clinically relevant exposures. Human relevance is undetermined.
Contraindicated with a personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).
Contraindicated after a prior serious hypersensitivity reaction to semaglutide, including anaphylaxis and angioedema.
Acute pancreatitis, including fatal and non-fatal hemorrhagic or necrotizing pancreatitis, has been observed with GLP-1 receptor agonists including semaglutide. Discontinue if pancreatitis is suspected, and do not restart if it is confirmed.
Acute gallbladder disease occurs: in Wegovy trials in adults, cholelithiasis was reported by 1.6% of treated patients versus 0.7% on placebo and cholecystitis by 0.6% versus 0.2%. If cholelithiasis or cholecystitis is suspected, gallbladder studies are indicated.
Severe gastrointestinal adverse reactions occur, and semaglutide is not recommended in patients with severe gastroparesis. Postmarketing acute kidney injury, in some cases requiring haemodialysis, has been reported, mostly in patients dehydrated by nausea, vomiting or diarrhoea.
Combining semaglutide with insulin or an insulin secretagogue (e.g. a sulfonylurea) raises the risk of hypoglycaemia, including severe hypoglycaemia; the label directs considering a dose reduction of the insulin or secretagogue when starting semaglutide.
Semaglutide delays gastric emptying and can affect absorption of oral medications. The tablet label directs increased clinical or laboratory monitoring for co-administered oral drugs with a narrow therapeutic index, and reports levothyroxine exposure increased 33% when taken with semaglutide tablets.
Pulmonary aspiration during general anesthesia or deep sedation has been reported in patients receiving GLP-1 receptor agonists for elective surgeries or procedures; tell any anesthetist about current use before a planned procedure.
Diabetic retinopathy complications were more frequent on semaglutide than placebo in a 2-year trial in type 2 diabetes at high cardiovascular risk (3.0% versus 1.8%, and 8.2% versus 5.2% among patients with retinopathy at baseline). Patients with a history of diabetic retinopathy should be monitored.
Monitor for depression or suicidal thoughts and discontinue semaglutide if they develop, and monitor heart rate at regular intervals. Both directives are carried on the Wegovy label; the Ozempic and Rybelsus labels do not state them.
Compounded semaglutide from non-FDA-registered sources is not the same product as the approved label and its dosing cannot be assumed to transfer.
Titration schedules exist to limit gastrointestinal adverse reactions; escalating faster than the label directs increases them.
Reviewed interactions
These are the pairs Dosavy holds reviewed, cited data on. A combination that is not listed here has not been assessed, which is not the same as being safe.
- Dangerouswith Survodutide
Do not combine. Semaglutide's label is explicit that coadministration with any other GLP-1 receptor agonist is not recommended, and survodutide's GLP-1 arm makes it one. Survodutide is unapproved and has no label defining a ceiling dose, so the combined GLP-1 exposure is not something either product's documentation covers.[2]
Both agonise the GLP-1 receptor; survodutide adds glucagon-receptor agonism. The duplicated GLP-1 activity compounds nausea, vomiting, diarrhoea and the risk of dehydration.
- Dangerouswith Tirzepatide
Do not combine. Both labels say so. Semaglutide's states that coadministration with any other GLP-1 receptor agonist is not recommended; tirzepatide's says the same about any GLP-1 receptor agonist. This matters most when switching: stop one and let it clear before starting the other rather than overlapping doses during a transition.[2][4]
Tirzepatide agonises both the GIP and GLP-1 receptors; semaglutide agonises the GLP-1 receptor. The shared GLP-1 agonism is duplicative and compounds the class's dose-limiting gastrointestinal effects.
Semaglutide questions
Does semaglutide need to be reconstituted, and why is it dosed once weekly?
It does not. Semaglutide is supplied as a ready-to-use solution in a prefilled pen, so there is no lyophilised powder to mix and no bacteriostatic water involved: reconstitution is neither required nor appropriate for the approved products. The weekly interval comes from the molecule itself: its elimination half-life is approximately 168 hours, about seven days, which is exceptionally long for a peptide. The same property means plasma concentrations take roughly five weeks to settle after a dose change, so effects and adverse effects both resolve slowly rather than within hours.
What dosing schedules are published for semaglutide?
The FDA prescribing information for Ozempic (section 2.2) directs starting at 0.25 mg once weekly for 4 weeks, increasing to 0.5 mg once weekly, then to 1 mg once weekly after at least a further 4 weeks, with a maximum of 2 mg once weekly for type 2 diabetes. The Wegovy label describes a separate weight-management product titrated every 4 weeks to a recommended maintenance dosage of 2.4 mg once weekly. Those are two approved products with two indications, not one continuous scale.
Is there an established dose for semaglutide?
Yes, unusually for this library: semaglutide has approved labelling and randomised controlled trial evidence behind it. That is exactly why the numbers should come from the label and a prescriber. The label also gives the titration schedule a reason: escalation steps exist to limit gastrointestinal adverse reactions, and moving faster than the label directs increases them. The starting dosages, 0.25 mg weekly by injection and 3 mg daily orally, are initiation doses for tolerability and are stated not to be effective for glycaemic control on their own.
Are the oral and injectable forms interchangeable?
No. The Rybelsus label states explicitly that oral and injectable semaglutide are not substitutable on a milligram-to-milligram basis, which the numbers make obvious: the oral maintenance dosages are 7 mg and 14 mg once daily, against 0.5 mg to 2 mg once weekly by injection. The oral tablet also carries administration conditions the injection does not: taken on an empty stomach in the morning with no more than 4 ounces of water, waiting at least 30 minutes before food, drink or other oral medication. The label further specifies that two 7 mg tablets must not be substituted for one 14 mg tablet.
What are the boxed warning and contraindications?
Semaglutide carries a boxed warning: in rodents it causes dose-dependent thyroid C-cell tumors at clinically relevant exposures, and the human relevance of that finding is undetermined. It is contraindicated in anyone with a personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2, and in anyone who has had a prior serious hypersensitivity reaction to semaglutide, including anaphylaxis and angioedema.
Can semaglutide be combined with tirzepatide or another GLP-1?
No. The Wegovy label's Limitations of Use section states that coadministration with other semaglutide-containing products or with any other GLP-1 receptor agonist is not recommended, and the Zepbound (tirzepatide) label says the same about any GLP-1 receptor agonist. The shared GLP-1 agonism is duplicative and compounds the class's dose-limiting gastrointestinal effects. This matters most when switching products: the labels point to stopping one and letting it clear rather than overlapping doses during a transition.
How is semaglutide stored, and does compounded material follow the same label?
Approved product is refrigerated at 2°C to 8°C before first use and not frozen; after first use, pens may be kept at room temperature or refrigerated for a limited period per the product label, and oral tablets are stored at room temperature. Compounded semaglutide from non-FDA-registered sources is not the same product as the approved label. Its storage conditions, concentration and stability are not covered by that labelling, and its dosing cannot be assumed to transfer.
Every number above, and where it came from
4 sources, numbered where they are used. Each one links to the paper or the label itself, not to a summary of it.
- [1]OZEMPIC (semaglutide) injection, for subcutaneous use: FDA prescribing information
2026 · FDA approved label
- [2]WEGOVY (semaglutide) injection, for subcutaneous use: FDA prescribing information
2024 · FDA approved label
- [3]RYBELSUS / OZEMPIC (semaglutide) tablets, for oral use: FDA prescribing information
2026 · FDA approved label
- [4]ZEPBOUND (tirzepatide) injection, for subcutaneous use: FDA prescribing information
2026 · FDA approved label
The rest of the math
- Reconstitution calculatorVial size and diluent to mg/mL and syringe units, with barrel sizes and IU conversion.
- Vial longevityHow many doses a vial holds and the date it runs out.
- Cost per doseVial price against doses drawn, so two vial sizes can be compared honestly.
- Half-life and decayFirst-order clearance, time to steady state, and what remains at a given hour.
- GLP-1 titration scheduleEscalation steps and week-by-week timing for GLP-1 receptor agonists.
You worked out the draw. Now log this dose.
A calculator answers once and forgets. Dosavy keeps the schedule you set, the doses you actually took, and the reminder for the next one, with the same evidence labels you see on this page.