By Judith Wenshuk, peptide research writer
Quick Answer: Semaglutide, Tirzepatide, and Retatrutide activate one, two, and three metabolic receptors respectively, with average trial weight-loss results scaling accordingly — roughly 15%, 20–22%, and up to 28.7%. Semaglutide has the longest track record, Tirzepatide is the current middle ground, and Retatrutide has the strongest results but the least long-term data. All three are available through research peptide suppliers in Canada.
These are the three most-researched compounds in the GLP-1 family, and deciding between them comes down to a genuine tradeoff between trial results and how established the research is. Here’s the full picture side by side.
Mechanism Comparison
- Semaglutide — activates GLP-1 receptors only
- Tirzepatide — activates GLP-1 and GIP receptors
- Retatrutide — activates GLP-1, GIP, and glucagon receptors
Each additional receptor pathway is associated with stronger average trial results, which is the core pattern across all three compounds’ data.
Trial Results Side by Side
- Semaglutide (STEP 1): ~15% average weight loss over 68 weeks
- Tirzepatide (SURMOUNT-1): 20–22% average weight loss over 72 weeks
- Retatrutide (Phase 2 / TRIUMPH): 24.2% at 48 weeks, up to 28.7% in later Phase 3 data
Research Maturity
Semaglutide has by far the longest and largest body of published data. Tirzepatide is well-established with a solid trial history. Retatrutide is the newest, with the strongest early results but the least long-term real-world data of the three.
Typical Escalation Length
Semaglutide’s trial protocol escalates over about 16 weeks to reach maintenance dose; Tirzepatide’s over about 20 weeks; Retatrutide’s over about 12 weeks — the fastest escalation of the three, though individual research protocols vary.
Which One Makes Sense for Your Research
If research history and the largest data set matter most, Semaglutide has the deepest track record. If you want the current best-established balance of results and research maturity, Tirzepatide sits in the middle. If the strongest trial results are the priority and you’re comfortable with a newer, less-established compound, Retatrutide currently leads.
Frequently Asked Questions
Can these be compared directly, or are the trials too different? The trials use different designs and durations, so the numbers are directional rather than a precise apples-to-apples comparison — but the overall pattern (more receptors, generally stronger results) is consistent across all three.
Are all three available in Canada? Yes — Semaglutide, Tirzepatide, and Retatrutide are all available individually through research peptide suppliers in Canada.
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