Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Head-to-head comparison of Semaglutide and Tirzepatide — mechanism, side effects, legal status, and pricing.
Semaglutide is an FDA-approved GLP-1 receptor agonist marketed as Ozempic (SubQ, type 2 diabetes), Wegovy (SubQ, chronic weight management and cardiovascular risk reduction in obesity), and Rybelsus (oral, type 2 diabetes). It is a synthetic analog of native GLP-1 with a fatty-acid (C18 diacid) side chain that enables albumin binding, giving it a ~165-hour half-life suitable for once-weekly injection.
Tirzepatide is a unimolecular dual GIP and GLP-1 receptor agonist FDA-approved as Mounjaro for type 2 diabetes (2022), Zepbound for chronic weight management in adults with obesity or overweight with a weight-related comorbidity (2023), and Zepbound for moderate-to-severe obstructive sleep apnea in adults with obesity (2024). It has a half-life of approximately 5 days, allowing once-weekly subcutaneous dosing.
Semaglutide
Tirzepatide
Category
Legal Status
Mechanism
Half-life
Side Effects
COA-verified vendors · trust score ≥70 required · single-vial price — bulk/bundle deals may be lower
Semaglutide
Tirzepatide
COA corpus from Disclosed Labs — independently tested batches only.
Semaglutide
142
COAs
99.6%
Avg purity
14
Labs
Tirzepatide
375
COAs
99.6%
Avg purity
16
Labs
The STEP program (STEP 1–8) showed average weight loss of roughly 15% of body weight over 68 weeks with weekly 2.4 mg semaglutide (STEP 1: Wilding et al., NEJM 2021, PMID 33567185). The SUSTAIN program established A1c and cardiovascular benefit in type 2 diabetes. The PIONEER program established efficacy of oral semaglutide (Rybelsus) versus placebo, sitagliptin, empagliflozin, and liraglutide (PIONEER 4, PMID 31186120). The SELECT trial (Lincoff et al., NEJM 2023, PMID 37952131) showed a 20% relative reduction in major adverse cardiovascular events in adults with overweight/obesity and established cardiovascular disease but without diabetes, leading to an expanded Wegovy indication.
The SURPASS program established efficacy in type 2 diabetes, including SURPASS-2 (Frias et al., NEJM 2021), in which tirzepatide was superior to semaglutide 1 mg for A1C reduction and body weight. The SURMOUNT-1 obesity trial (Jastreboff et al., NEJM 2022) demonstrated up to approximately 20.9% mean body-weight reduction at 15 mg over 72 weeks. SURMOUNT-OSA (Malhotra et al., NEJM 2024) showed large reductions in apnea-hypopnea index in obstructive sleep apnea with obesity, supporting the 2024 FDA indication (Zepbound for moderate-to-severe OSA in adults with obesity). The SUMMIT trial (Packer et al., NEJM 2025) demonstrated a lower risk of cardiovascular death or worsening heart failure in HFpEF with obesity.
Semaglutide and Tirzepatide are both in the Metabolic category and may have overlapping mechanisms. Researchers should review both profiles carefully, understand the mechanisms of action, and monitor the relevant biomarkers when combining compounds in the same class. As always, consult a licensed healthcare provider before making any decisions about combining research compounds.
This platform provides informational tools only, not medical advice. This comparison is for educational purposes only. Consult a licensed provider.
Contraindications
Lab Testing
Disclosed Labs