Searching "where to buy retatrutide" returns dozens of vendors with wildly different pricing, COA practices, and shelf storage. Retatrutide is complex to synthesize, the per-mg price spread is enormous, and the gap between a verified vial and a degraded one matters more than for almost any other research peptide.
This guide is for buyers who already know what retatrutide is and now want the practical buying side: which vendor to trust, what to demand on the COA, fair pricing in 2026, and what to skip. Short answer first: Ascension Peptides remains the cleanest option through the R-10 and R-30 vials, with the R-30 (30mg, $200) being the better value at $6.67/mg.
🔑 Key Takeaways
- Retatrutide is only available as a research peptide, no FDA-approved version exists yet (still in Phase 3 trials)
- Ascension Peptides carries it as R-10 (10mg, $120) and R-30 (30mg, $200)
- R-30 is better value: $6.67/mg vs $12/mg for R-10
- Always verify third-party COA before buying, retatrutide is complex to synthesize and counterfeits exist
- Standard starting dose: 2mg/week subcutaneous, R-30 lasts 15 weeks at this dose
- No prescription needed for research peptide form
What Is Retatrutide?
Retatrutide (LY3437943) is a triple GLP-1/GIP/glucagon agonist developed by Eli Lilly. It's still in Phase 3 clinical trials, making it the most potent weight loss peptide available that has no FDA-approved prescription version yet. Phase 2 trials showed average weight loss of ~24% at 48 weeks, higher than semaglutide (~15%) or tirzepatide (~22%). The only way to access it currently is via research peptide vendors.
Where to Buy Retatrutide, Our Top Pick
Ascension Peptides is our primary recommendation:
- Carries R-10 (10mg, $120) and R-30 (30mg, $200)
- US-based manufacturing
- Third-party COA on every batch, HPLC purity ≥98%
- Mass spectrometry verification (critical for a complex triple agonist)
- Discreet US domestic shipping
→ Buy R-30 at Ascension Peptides
R-10 vs R-30, Which Should You Buy?
Verdict: R-10 is good for a first purchase to verify quality. R-30 is significantly better value for ongoing use. At 2mg/week, R-30 lasts ~15 weeks, over 3 months per vial.
What to Look for When Buying Retatrutide
Non-negotiable criteria:
- Third-party COA, not just "testing available on request." Must be batch-specific, from an independent lab.
- HPLC purity ≥98%, retatrutide is a large, complex peptide. Synthesis errors are common. Substandard purity means weaker or unpredictable effects.
- Mass spectrometry data, confirms the amino acid sequence is correct. Critical for a triple agonist where the sequence determines which receptors it binds.
- US-based or US-warehoused, avoids customs seizure, heat degradation in transit, longer delays.
- Transparent pricing, vendors who hide pricing until checkout or add surprise fees are a red flag.
Red Flags to Avoid
- ❌ No COA or COA only "available on request"
- ❌ Purity not listed, or listed as "≥95%" without HPLC documentation
- ❌ Dramatically underpriced (R-30 for $60 = almost certainly underdosed)
- ❌ Ships from overseas with no US warehouse
- ❌ No mass spectrometry data (especially important for retatrutide)
- ❌ Generic product photos with no lot number information
Retatrutide Pricing Reference (2026)
Reconstituting Retatrutide After Purchase
- Add BAC water to the vial slowly (down the inside wall, never directly onto powder)
- Recommended: 2mL per 10mg vial = 5mg/mL. 3mL per 30mg vial = 10mg/mL.
- Full guide at: /blog/retatrutide-reconstitution-guide
- Calculator: Reconstitution Calculator
- Store refrigerated, use within 28 days
Retatrutide Dosage After Purchase
- Starting dose: 0.5-2mg per week (once weekly subcutaneous injection)
- Titrate up gradually to manage GI side effects
- Most effective protocols reach 4-8mg/week over time
- Full dosage chart: /blog/retatrutide-dosage-chart
The information in this article is for educational purposes only and does not constitute medical advice. Always consult a healthcare professional before starting any new supplement or compound. Results vary by individual.