Cagrilintide is the long-acting amylin analog that Novo Nordisk pairs with semaglutide in CagriSema — the combination that produced up to 22.7% weight loss in the REDEFINE-1 Phase 3 trial. Amylin works through a different satiety pathway than GLP-1, which is why cagrilintide is one of the most interesting adjunct peptides of 2026 for anyone already running semaglutide or tirzepatide and hitting a plateau.
This guide covers what you should actually pay per milligram, which vial size fits a once-weekly titration protocol, how to verify a COA for a 37-amino-acid peptide with a C20 fatty-diacid side chain, and the vendor red flags to avoid. Cagrilintide is chemically complex — same fatty-acid conjugation chemistry as semaglutide — so synthesis shortcuts produce ineffective product, not just lower-potency product.
This is not a ranked vendor list — for that, see our Best Cagrilintide Vendors comparison. This guide teaches you how to evaluate any vendor yourself.
Why Cagrilintide Is Worth Buying Carefully
Cagrilintide is a long-acting analog of amylin, the pancreatic hormone co-secreted with insulin. Native amylin has a half-life of roughly 13 minutes. Cagrilintide's C20 fatty-diacid modification extends half-life to ~7 days, making it viable for once-weekly dosing alongside semaglutide or tirzepatide.
Amylin agonism drives three things: delayed gastric emptying, central satiety signaling through the area postrema, and suppression of postprandial glucagon. The satiety effect is additive with GLP-1 agonism because the pathways don't overlap — which is why CagriSema outperforms semaglutide monotherapy and tirzepatide on some endpoints.
For research purposes, the practical use cases are:
- GLP-1 plateau rescue — adding cagrilintide to a stalled semaglutide or tirzepatide protocol
- GLP-1 dose reduction — using cagrilintide to maintain weight loss while tapering GLP-1
- Standalone titration — cagrilintide at 2.4 mg/week produced ~8-10% weight loss in monotherapy trials
But here's the synthesis problem: cagrilintide has the same lipid-conjugation chemistry as semaglutide. The peptide backbone is easy to make. The C20 fatty-diacid side chain attached via a γ-Glu linker to lysine is not. Cheap manufacturers produce the bare 37-amino-acid peptide, skip the lipidation, and sell it as "cagrilintide." It weighs right on HPLC but has a half-life closer to the native hormone — roughly useless for weekly dosing.
This is why COA verification matters more for cagrilintide than for most peptides.
Understanding Cagrilintide Pricing
Cagrilintide is sold as lyophilized powder in sealed glass vials. Three factors move price: vial size, whether the vendor sources the fully-conjugated product or the cheaper unmodified backbone, and third-party testing investment.
Current Market Pricing (2026)
| Vial Size | Typical Price Range | Price Per mg | Best For |
|---|---|---|---|
| 2 mg | $25-50 | $12.50-25/mg | Trial vial, single-dose testing |
| 5 mg | $40-90 | $8-18/mg | Standard — fits 28-day window at 1-2.5 mg/week |
| 10 mg | $70-150 | $7-15/mg | Extended protocols, best $/mg |
| 20 mg | $130-250 | $6.50-12.50/mg | Long protocols, requires aliquot planning |
The pattern is clear: 5mg is the sweet spot for most users because it fits comfortably inside the 28-day reconstitution window at standard doses. 10mg offers ~15% better per-mg pricing but requires more careful planning.
Cheapest single-vial option: Ascension Peptides's 50% off drops the 10mg vial to $57.50 ($5.75/mg effective) — the lowest effective price we track for buying one vial. Get the code →
Cost Per Week at Common Doses
| Weekly Dose | Vial Duration (5mg) | Vial Duration (10mg) | Monthly Cost (5mg vial) |
|---|---|---|---|
| 0.6 mg/week (start) | 8 weeks | 16 weeks | $5-11/month |
| 1.2 mg/week (mid) | 4 weeks | 8 weeks | $10-22/month |
| 2.4 mg/week (max) | 2 weeks | 4 weeks | $20-45/month |
| 4.5 mg/week (CagriSema dose) | 1 week | 2 weeks | $40-90/month |
For current vendor-specific pricing with exact $/mg breakdowns, see our Best Cagrilintide Vendors comparison.
What to Look For: COA, Purity, Storage
Cagrilintide is a 37-amino-acid peptide (based on the amylin backbone) with a C20 fatty-diacid side chain conjugated to lysine-20 via a γ-Glu spacer. Molecular weight is 3,749.2 Da. The synthesis is non-trivial — SPMS assembly of the backbone, followed by selective lipidation of the protected lysine. Skipping the lipidation step produces a ~3,400 Da unmodified amylin analog, which is why mass spec matters here more than it does for simple peptides.
What a COA (Certificate of Analysis) Should Include
Identity Confirmation
- Mass spectrometry confirming the 3,749.2 Da molecular weight (the full lipidated form, NOT the ~3,400 Da backbone)
- Amino acid sequence verification including the Lys-20 lipidation point
Purity Testing
- HPLC purity — look for 98%+ purity
- Chromatogram showing a single dominant peak with minimal truncated or unlipidated impurity peaks
Contamination Testing
- Endotoxin levels (cagrilintide is injected subcutaneous)
- Residual solvent analysis (acetonitrile, TFA from SPMS cleavage)
- Heavy metals screening
How to Verify a COA Is Legitimate
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Check the testing lab — Janoshik Analytical, MZ Biolabs, and Colmaric Analyticals are the standard. In-house-only testing is a red flag for a peptide this complex.
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Verify the mass is 3,749 Da, not 3,400 Da — this is the single most important check for cagrilintide. A mass below 3,600 Da almost certainly means the fatty-acid conjugation was skipped.
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Verify on the lab's website — Janoshik COAs have a task number lookup at janoshik.com.
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Check the date — COAs should be recent (within 6 months).
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Match the batch — batch/lot number on the COA must match your vial.
