PinnyPeptide

Retatrutide vs Semaglutide

Side-by-side comparison: effects, dosing ranges, side effects, regulatory status, and reconstitution.

Peptide A

Retatrutide

Weight Management

Lilly's triple-agonist of GLP-1, GIP, and glucagon receptors — the strongest weight-loss data yet reported.

Peptide B

Semaglutide

Weight Management

GLP-1 receptor agonist revolutionizing the treatment of obesity and type 2 diabetes.

Typical vial

10 mg

Typical dose

500-12000 mcg

Half-life

~6 days (~144 hours)

FDA status

Not FDA approved. In Phase 3 clinical trials (TRIUMPH progra…

Typical vial

3 mg

Typical dose

250-2400 mcg

Half-life

~7 days (168 hours)

FDA status

FDA approved. Ozempic (2017) for type 2 diabetes, Rybelsus (…

Retatrutide effects

  • Triple receptor agonism: GLP-1, GIP, and glucagon
  • Mean ~24% weight loss at 12 mg weekly (Phase 2, 48 weeks)
  • Appetite suppression and delayed gastric emptying (GLP-1 / GIP)
  • Increased energy expenditure and hepatic fat oxidation (glucagon arm)
  • Improved glycemic control in type 2 diabetes
  • Reduction in hepatic fat content (MASH-relevant)

Semaglutide effects

  • Significant and sustained weight loss (15-17% body weight in trials)
  • Improved glycemic control and reduced HbA1c
  • Reduced appetite and food cravings through central satiety signaling
  • Cardiovascular risk reduction (20% MACE reduction in SELECT trial)
  • Slowed gastric emptying for prolonged satiety
  • Improved insulin sensitivity and beta-cell function

Retatrutide side effects

  • Gastrointestinal: nausea, vomiting, diarrhea (most common, dose-dependent)
  • Decreased appetite (intended)
  • Constipation
  • Increased heart rate (glucagon-mediated, dose-dependent)
  • Injection-site reactions
  • Risk of pancreatitis (incretin-class concern)
  • Theoretical: thyroid C-cell tumors (incretin-class warning — animal data)
  • Hyperglycemia risk if dose-titration is too rapid (glucagon arm)

Semaglutide side effects

  • Nausea (most common, especially during dose titration)
  • Vomiting and diarrhea
  • Constipation
  • Abdominal pain and dyspepsia
  • Pancreatitis (rare but serious)

Retatrutide dosing ranges

Obesity / weight loss (Phase 2 / 3 protocol)

1-12 mg · Once weekly (SubQ), dose-titrated · Long-term per clinical protocol

Self-experimentation (no clinical guidance)

0.5 mg start, titrate to tolerance · Once weekly · Long-term with careful titration

Semaglutide dosing ranges

Type 2 diabetes (Ozempic)

250-1000 mcg · Once weekly (SubQ) · Ongoing as prescribed

Weight management (Wegovy)

2400 mcg · Once weekly (SubQ, after 16-week titration) · Ongoing as prescribed

Full Retatrutide guide → Full Semaglutide guide →

Retatrutide vs Semaglutide — common questions

What is the difference between Retatrutide and Semaglutide?

Retatrutide: Lilly's triple-agonist of GLP-1, GIP, and glucagon receptors — the strongest weight-loss data yet reported. Typical dose 500-12000 mcg. Semaglutide: GLP-1 receptor agonist revolutionizing the treatment of obesity and type 2 diabetes. Typical dose 250-2400 mcg. Both fall under the Weight Management category.

Can you stack Retatrutide and Semaglutide?

Stacking Retatrutide with Semaglutide is a protocol-design question best raised with a clinician — it depends on your goal, current bloodwork, and whether both peptides target overlapping mechanisms. Both peptides should be tracked independently with separate injection sites and timing. PinnyPeptide supports multi-peptide stacks with automatic injection site rotation.

Which is dosed more frequently, Retatrutide or Semaglutide?

Retatrutide is typically dosed: Once weekly (SubQ), dose-titrated for Obesity / weight loss (Phase 2 / 3 protocol); Once weekly for Self-experimentation (no clinical guidance). Semaglutide is typically dosed: Once weekly (SubQ) for Type 2 diabetes (Ozempic); Once weekly (SubQ, after 16-week titration) for Weight management (Wegovy).

Are Retatrutide and Semaglutide FDA approved?

Retatrutide: Not FDA approved. In Phase 3 clinical trials (TRIUMPH program for obesity, SYNERGY-NASH for MASH). FDA submission anticipated 2026-2027 pending Phase 3 readouts. Semaglutide: FDA approved. Ozempic (2017) for type 2 diabetes, Rybelsus (2019) oral for diabetes, Wegovy (2021) for chronic weight management.

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