Retatrutide Reconstitution Calculator

Not indexed in PubChem: formula, MW, and CAS are from manufacturer/supplier technical data. Treat the MW as approximate and verify against your lot’s certificate of analysis (COA).

Each cell = concentration for that vial mass and diluent volume, with mcg per U-100 unit and nmol/mL (from MW 4731.33). Concentration = vial mg ÷ water mL.

Supplied as a lyophilized powder. Retatrutide is a fatty-acyl-modified peptide, and like other long-acting acylated peptides in this class it can take a short time — often a couple of minutes of gentle rolling — to dissolve fully rather than clearing on contact. A dense, compact freeze-dried cake hydrates slowly and may look clumped or gel-like at first; that is the cake dissolving, not a failed reconstitution.

Technique. Direct the diluent down the inside wall of the vial rather than forcing it in fast: a hard stream plus shaking creates foam, and foam stresses the peptide. Roll or swirl the vial gently between the fingers and give it the time it needs. Bacteriostatic water is generally preferred over plain sterile water here because its 0.9% benzyl alcohol allows repeated draws from one vial across the refrigerated storage window.

What a failed solution looks like. Persistent cloudiness, a color change, or visible floating bits point to a real problem — clumping, breakdown, a temperature or pH issue, or contamination — and the solution should be discarded rather than filtered or re-warmed.

Light sensitivity. Retatrutide is light-sensitive in both powder and solution form, so keep the vial in its carton or otherwise shielded rather than sitting on an open shelf. Lyophilized: -20 C, sealed and desiccated, out of light. Reconstituted: 2-8 C, protected from light, typical working window about four weeks.

On the PubChem row. Retatrutide has no PubChem CID at the time of writing, which is why that field reads "not indexed" rather than carrying a number. The molecular formula and 4,731.33 g/mol molecular weight above are what the molar column on this page is computed from.

A 10 mg vial reconstituted with 2 mL of bacteriostatic water:

• Concentration: 10 mg ÷ 2 mL = 5.00 mg/mL
• Per U-100 unit (1 unit = 0.01 mL): 5.00 mg/mL × 0.01 mL = 0.05 mg = 50 mcg per unit
• Molarity: (5.00 ÷ 4,731.33) × 1,000,000 = 1,057 nmol/mL
• Total yield: 2.00 mL of solution = 200 U-100 units in the vial

A 15 mg vial in 3 mL lands on the same 5.00 mg/mL and the same 50 mcg per unit, with 300 units in the vial instead of 200 — the ratio of milligrams to millilitres is what sets concentration, not either number alone.

Why does retatrutide take longer to dissolve than smaller peptides?
It is a roughly 39-residue, fatty-acyl-modified peptide, and the acyl chain plus a dense freeze-dried cake slow hydration. A couple of minutes of gentle rolling is normal, and an initially clumped or gel-like appearance usually resolves as the cake dissolves.

Why is the PubChem CID field empty on this page?
Retatrutide is not currently indexed in PubChem, so there is no CID to cite. The molecular formula C221H342N46O68 and molecular weight 4,731.33 g/mol are what every molar figure on this page is derived from.

Does retatrutide need to be protected from light?
Yes. It is light-sensitive in both lyophilized and reconstituted form, so the vial should be kept in its carton or another opaque enclosure rather than left exposed on a bench or shelf.

Bacteriostatic water or sterile water?
Bacteriostatic water is generally preferred because the 0.9% benzyl alcohol it contains permits repeated entry into the same vial across the refrigerated window. Plain sterile water carries no preservative and is single-entry. The concentration arithmetic is identical either way.

What does cloudiness after reconstitution indicate?
Cloudiness that does not clear, a color change, or visible floating material indicates a problem such as clumping, degradation, a temperature or pH issue, or contamination. Such a solution should be discarded.