CS20 (Cagrilintide + Semaglutide) 20 mg

CS20 (Cagrilintide 10 mg + Semaglutide 10 mg) — dual GLP-1 / amylin agonist

CS20 is the high-concentration form of the amylin + incretin combination: 10 mg of Cagrilintide and 10 mg of Semaglutide in one lyophilised vial — 20 mg of peptide in total, ratio 1:1.

Two hormone families, two receptor types, one vial. Semaglutide acts on the GLP-1 receptor, Cagrilintide on the amylin (AMY1, AMY3) and calcitonin receptors. The two pathways are independent — and the combination differs from molecules such as Tirzepatide and Retatrutide, which join incretin receptors in a single chain.

The difference from CS10 is only the quantity; ratio, purity and mechanism are identical. It is intended for longer series, higher concentrations and fewer reconstitution cycles.

It remains an experimental combination. See also peptides for weight loss (GLP-1).

Peptology supplies it as a lyophilised research peptide, purity > 99% (HPLC/MS), with an independent certificate of analysis (CoA) for each batch. Exclusively for research and in vitro use; it is not a medicine.

Composition: 10 mg + 10 mg = 20 mg

Pre-mixed and lyophilised, they go into solution together — no separate dosing or mixing of vials.

The 1:1 ratio is that of the clinical programme. Each batch carries a certificate of purity > 99%.

CS20 or CS10

Same formula, different scale. Choose according to the length of the series and the target concentration.

Both are reconstituted with up to ~3 mL (vial capacity), so CS20 gives a solution twice as concentrated in the same volume.

Mechanism: two independent receptor families

Incretins and amylin act on different receptor families: the GLP-1 receptor and the amylin/calcitonin receptors — CS20 contains agonists for both.

Two molecules or one multi-receptor molecule

The first approach: a single chain that activates several incretin receptors (Tirzepatide, Retatrutide). The second, that of CS20: two ready-made molecules from different hormone families. This way each axis is titrated separately and the combination becomes a model for studying additivity. Data from controlled trials, with no claim made for the research product.

Pharmacokinetic profile

Both are acylated: a fatty-acid residue binds them reversibly to albumin and slows renal clearance. Both have a long half-life (~7 days).

• Semaglutide half-life: ~7 days (~168 hours)
• Cagrilintide half-life: ~7–8 days (~180 hours)
• Mechanism: acylation, reversible albumin binding
• CAS number: 1415456-99-3 (Cagrilintide) + 910463-68-2 (Semaglutide)
• Phase III doses: Cagrilintide 2.4 mg + Semaglutide 2.4 mg / week
• CS20 content: 10 mg + 10 mg — covers a longer cycle with the same regimen

The combination versus each component

The clearest comparison: in REDEFINE 1 the combination, Cagrilintide, Semaglutide and placebo were studied in parallel, with the same population and duration.

Sources: REDEFINE 1 (obesity, n≈3417) and REDEFINE 2 (type 2 diabetes, n≈1206), NEJM 2025. Scientific reference, not a claim for the research product CS20.

What the REDEFINE programme shows

Two phase III trials with over 4600 participants — unusual documentation for a research peptide.

Background

Semaglutide went through STEP and SUSTAIN — tens of thousands of participants. Cagrilintide was studied in phase II in obesity. The combination: two well-characterised molecules in one vial.

REDEFINE 1 — obesity (NEJM 2025)

~3417 adults, 68 weeks. Mean weight reduction 20.4% versus 3.0% on placebo. About 60% lose ≥ 20% and 23% ≥ 30%. Versus 14.9% and 11.5% for the individual components — hence the additivity.

REDEFINE 2 — type 2 diabetes (NEJM 2025)

~1206 adults with type 2 diabetes and overweight or obesity, 68 weeks. Reduction of −15.7% versus −3.1%, with significant improvement in glycaemic control. Threshold ≥ 15%: 51.6%.

CS20 in numbers

• Double the content of CS10 with the same ratio — fewer vials per series
• Two independent receptor families in one vial, with no mixing of products
• 20.4% mean weight reduction at 68 weeks (phase III), above each component separately
• ~60% with ≥ 20% and ~23% with ≥ 30% reduction (REDEFINE 1)
• −15.7% in type 2 diabetes with improved glycaemic control (REDEFINE 2)
• Half-lives of ~7 days for both components

The figures refer to published trials of the combination and are not a promise of results or an instruction for administration.

Regimens from the studies

The logic of all regimens: low starting dose, slow increase, weekly interval.

• Administration: once weekly, subcutaneously, both components together
• Target dose (phase III): Cagrilintide 2.4 mg + Semaglutide 2.4 mg
• Titration: gradual increase over weeks up to the target dose
• Dissolution: a single reconstitution; the ratio stays constant at every dilution
• One vial of CS20 covers a longer period than CS10

With double the concentration the volume calculation is even more critical — use the peptide reconstitution calculator.

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Catalogue: Peptides for weight loss · Peptide solutions · Blog

Parameter	Value
Form	Lyophilised powder
Solvent	Peptide Matrix Water
Reconstitution volume	1–3 mL — 3 mL at most (capacity of the standard vial)
Storage before reconstitution	Room temperature, protected from direct light (refrigeration is not mandatory)
After reconstitution	Up to 60 days at +2 °C to +8 °C with Peptide Matrix Water

✅ Correct	❌ Wrong
Disinfect the stoppers and the work surface with 70% alcohol, work with gloves	Working without disinfection
The solvent is added slowly down the wall of the vial	Direct stream onto the powder — foaming and denaturation
Gentle swirling between the palms	Shaking — foam, in which the peptides denature
10–15 minutes wait at room temperature	Mechanical stirring or heating
Visual inspection: clear, without particles	Working with a cloudy or coloured solution

⚠️ 3 mL of solvent at most. The standard vial does not hold a larger volume — do not exceed it during reconstitution.

• Concentration (mg/mL) = mg in the vial ÷ mL of solvent
• Volume per sample (mL) = amount per sample (mg) ÷ concentration (mg/mL)
• 1 mg/mL = 1 µg/µL · 1 mL = 1000 µL

👉 For any vial and solvent volume — use the calculator. It calculates the concentration (mg/mL, µg/µL) and the volume per sample (mL, µL).

Research status: All Peptology products are intended exclusively for laboratory and research use. They are not pharmaceutical products, are not approved for human or veterinary use and do not replace medical advice. The protocol described is standard laboratory practice for working with lyophilised peptides.