Semaglutide 20mg Metabolism
The most-studied GLP-1.
- In stock in France
Ordered with its water: shipped in a magnetic box
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The vial alone cannot be used as is. Add what you need to prepare it:
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Research Use Only (RUO) · Prohibited for human or veterinary use.
Key facts
Optimal reconstitution with 2ml bacteriostatic water giving 10 mg/ml: 5U = 0.5 mg, 10U = 1 mg, 24U = 2.4 mg. Caution: this vial is twice as concentrated as the 10mg vial (5 mg/ml), do not reuse its markings. To start at 0.25 mg, use the 5 or 10 mg vial.
Economic advantageThe 20mg vial typically offers a unit price 25-35% lower per mg than the 10mg vial, and 45-55% lower than the 5mg vial. For high-volume research, cost-usage ratio is unbeatable.
Protocol and preparation
| Water added | Concentration | Reading marker |
|---|---|---|
| 2 ml | 10 mg/ml | 10 UI = 1 mg |
| 3 ml | 6,67 mg/ml | 40 UI = 2,67 mg |
The volume of water does not change the product, only its concentration. Add the water slowly along the vial wall, then swirl without shaking.
Asepsis
Disinfect surfaces and stoppers (70% alcohol).
Solvent
Draw the required volume of bacteriostatic water.
Introduction
Add gently against the vial wall (avoid a direct jet on the powder).
Solubilization
Roll the vial gently. Do not shake vigorously (degradation risk).
Solution storage Once reconstituted: 2-8°C (refrigerator).
Warning Theoretical tool for chemical handling. Does not constitute medical advice.
I open the dilution calculator- The amount of powder looks tiny. A lyophilisate takes up a few millimetres at the bottom of the vial, sometimes just a translucent film. The stated weight is there.
- The powder is compact, stuck to the wall or to the stopper. Transport moves the freeze-dried cake around. It changes nothing to reconstitution.
- The vial carries no individual label. That is our standard packaging, not a downgraded vial.
- After reconstitution, deposits or filaments appear. This is common, especially with small molecules. Let it settle and roll the vial between your palms, never shake it.
- The parcel is plain. Nothing on the outside indicates the contents or the brand name.
What is not normal: a cracked vial, an uncrimped cap or a stopper that moves, powder that has liquefied or changed colour. In those specific cases, write to us with a photo and we take the vial back.
Economic-fiscal advantage: the 20mg vial is best quality-price ratio on usage range exceeding 10 cycle weeks. Below that, 10mg remains more relevant to avoid wasting expired peptide-solution residue.
Technical data
- Reconstitution
- 2 ml d'eau → 10 mg/ml. 5 UI = 0,5 mg ; 10 UI = 1 mg ; 24 UI = 2,4 mg. Attention : deux fois plus concentré que le flacon de 10 mg (5 mg/ml), ne pas reprendre ses repères. Pour démarrer à 0,25 mg, prendre le flacon de 5 ou 10 mg.
- Peptide sequence
- HXEGTFTSDVSSYLEGQAAKEFIAWLVRGRG (X = Aib ; lysine acylée)
- Molecular formula
- C187H291N45O59
- Molecular weight
- 4113.58 g/mol
- CAS number
- 910463-68-2
- Physical form
- Poudre lyophilisée blanche
- Recommended solubility
- Eau bactériostatique, NaCl 0.9%, acide acétique 0.1%
- Storage conditions
- Au réfrigérateur (+2 à +8 °C), à l'abri de la lumière. En poudre, possible au congélateur pour une conservation longue. Une fois préparé : réfrigérateur, jamais au congélateur.
- Use
- Research reagent, in vitro only (RUO)
Storage & handling
- N-terminal amide bond: sensitive to acid or enzymatic hydrolysis. - Methionine residue Met14: oxidation to methionine sulphoxide under prolonged dissolved oxygen exposure. - Glutamic linker ester bond: possible hydrolysis in acidic solution (pH < 5). - C18 acylated chain: chemically stable but can undergo progressive beta-oxidation over several weeks. Optimal storage conditions:
- Unopened vial: 15-25°C, original cardboard packaging, protected from light, humidity < 60%. - Opened reconstituted vial: strict 2-8°C, vertical position, vial covered or in cardboard box for light protection, do not freeze. Temperatures > 30°C accelerate peptide degradation in solution. Errors to avoid:
- Freeze-thaw: freeze-thaw cycles form ice crystals denaturing peptide tertiary conformation, 20-40% activity loss per cycle. - Direct solar exposure: Met14 methionine and acylated Lys26 are photodegradable, 1-2 hour direct sun exposure can reduce activity by 5-15%. - Vigorous agitation: semaglutide forms reversible oligomers in solution (dimers and trimers via C18), mechanical agitation can favour irreversible insoluble aggregates. - Mixing with other peptides in same vial: unpredictable interactions with pH / ionic strength / other lipophilic residues. One vial = one peptide. Recommended reconstitution with bacteriostatic water 0.9% benzyl alcohol. Typical reconstitution volume depending on nominal dosage (detailed below in Protocols section). Reconstituted peptide presents a clear solution, possibly slightly opalescent after a few hours (reversible C18 micro-oligomer formation), colourless. Any yellow or brown colouration signals oxidation or contamination -> rejection. Alteration visual indicators: solution that remains turbid, appearance of floating particles, formation of deposit at vial bottom, perceptible odour (normally odourless), swollen vial (possible suspect internal pressure). Faced with any of these signs, discard the vial and use a new one.
Mechanism of action
Semaglutide is a complete and selective GLP-1 receptor agonist (Glucagon-Like Peptide-1 Receptor, GLP-1R), resulting from sophisticated molecular engineering carried out by Novo Nordisk on the native scaffold of endogenous human GLP-1. The base peptide is modified at three critical positions to simultaneously resolve the two major limitations of native GLP-1: plasma half-life of 1-2 minutes (rapid degradation by dipeptidyl peptidase-4, DPP-4) and weak albumin affinity compromising duration of action.
- Ala8 to Aib (alpha-aminoisobutyrate) substitution: totally blocks DPP-4 cleavage at the N-terminal site, primary cause of native GLP-1 inactivation.
- Lys34 to Arg34 substitution: removes a potential glycation site and stabilises conformation.
- Lys26 acylation with C18 diacid fatty chain (octadecanedioic acid) via glutamic linker: creates a highly lipophilic covalent anchor that reversibly binds to serum albumin.
Semaglutide's GLP-1R selectivity distinguishes it from dual agonists (Tirzepatide GLP-1/GIP) or triple agonists (Retatrutide GLP-1/GIP/GCGR). This monospecificity offers a more predictable and better-characterised pharmacological profile (extensive clinical corpus SUSTAIN + STEP + SELECT), but limits metabolic amplitude vs more recent multi-receptor agonists. Semaglutide nevertheless remains the historical reference of the class and the best-documented GLP-1 molecule to date.
Frequently asked questions
How is semaglutide stored?
The complete guideSemaglutide in research: complete guide to the GLP-1R mechanism, pharmacokinetics and experimental protocolsReference dossier on semaglutide for research use: molecular structure, GLP-1R mechanism, extended half-life, preclinical models, QC analytics and reconstitution best practices. Mandatory RUO reminder.Read the guide 