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/ comparison

Semaglutide
vs
Retatrutide (GLP-3)

Side-by-side comparison of mechanism, research, dosing, side effects, and pricing.

peptide

Semaglutide

FDA-approved GLP-1 agonist. The most-studied weight management peptide.

Cheapest
$77.60
3mg at Ascension Peptides
See Semaglutide →
peptide

Retatrutide (GLP-3)

Next-generation triple receptor agonist. Phase 3 clinical research underway.

Cheapest
$69.51
5mg at Throne
See Retatrutide (GLP-3) →
/ research scoring

Research base

Semaglutide
Research Maturity★★★★★
Evidence Strength★★★★★

200+ clinical trials. Strongest evidence base for weight research peptides. Works as researched.

Retatrutide (GLP-3)
Research Maturity★★★★☆
Evidence Strength★★★★☆

Phase 2 human trials demonstrate exceptional metabolic effects. 99%+ purity verified across batches in research-grade product.

/ mechanism

How they work

Semaglutide

GLP-1 receptor agonist. Decreases appetite, slows gastric emptying, improves insulin sensitivity.

Retatrutide (GLP-3)

Simultaneously activates GLP-1, GIP, and glucagon receptors. Triple-receptor synergy for metabolic optimization.

/ research dosing

Protocols compared

Semaglutide
Range: 0.25 → 0.5 → 1.0 → 1.7 → 2.4 mg/week (FDA titration)
Frequency: Once weekly subcutaneous
Route: Subcutaneous abdomen, thigh, or upper arm
Standard FDA titration schedule for Wegovy. Each dose held minimum 4 weeks before increase. GI side effects (nausea, constipation) most pronounced in first 2 weeks of each new dose. If missing dose: take within 5 days, otherwise skip to next scheduled week.
Retatrutide (GLP-3)
Range: 2 → 4 → 6 → 8 → 12 mg/week (titration ladder)
Frequency: Once weekly subcutaneous
Route: Subcutaneous abdomen, thigh, or upper arm
Phase 2 trials titrated 2 → 4 → 8 → 12 mg/week over 24 weeks. GI side effects (nausea, occasional vomiting) peak with each dose increase. Heart rate elevation ~3-7 bpm at higher doses. Slow titration is essential — rapid escalation causes significant GI distress.
/ side effects & timeline

What to expect

Semaglutide
Side effects

Common: nausea (30%), GI adjustment. Usually resolve over time.

Timeline

2-4 weeks for appetite suppression, 12+ weeks for significant changes

Retatrutide (GLP-3)
Side effects

Common: GI adjustment, appetite reduction (intended effect). Well-tolerated in clinical trials.

Timeline

Effects observed within 2-4 weeks; full metabolic adaptation 12+ weeks

/ pricing

Price comparison

Semaglutide
Lowest price$77.60 (3mg)
Min $/mg$10.47/mg
Avg $/mg$31.11/mg
Max $/mg$67.79/mg
Retatrutide (GLP-3)
Lowest price$69.51 (5mg)
Min $/mg$5.73/mg
Avg $/mg$17.16/mg
Max $/mg$36.24/mg
/ which to pick

The honest verdict

Pick Semaglutide if: Strong standalone evidence. Most clinical trials test it alone.

Pick Retatrutide (GLP-3) if: Highly effective standalone compound. Triple-receptor agonism is its primary differentiator.

Why not both? Some researchers run them together. Check our Interaction Matrix to see if these compounds synergize or work independently.

FOR RESEARCH USE ONLY. Both compounds are intended for laboratory research and not for human consumption.