Peptide comparison
Semaglutide vs Tirzepatide
Semaglutide and Tirzepatide are both research peptides. This side-by-side compares their mechanism, typical research dosing, half-life, routes and safety so you can see how they differ. For research use only.
| Semaglutide | Tirzepatide | |
|---|---|---|
| Category | Metabolic | Metabolic |
| Overview | GLP-1 receptor agonist with strong human-trial evidence for weight loss, glycemic control, and cardiovascular risk reduction. | Dual GIP/GLP-1 receptor agonist with strong human trial evidence for type 2 diabetes glycemic control and weight reduction. |
| How it works | Semaglutide selectively activates the GLP-1 receptor, mimicking the incretin hormone GLP-1. It enhances glucose-dependent insulin secretion and suppresses glucagon release (lowering blood glucose with low intrinsic hypoglycemia risk), slows gastric emptying, and acts on appetite-regulating centers in the hindbrain and hypothalamus to increase satiety and reduce food intake. The glucose-dependent nature of its insulinotropic effect means insulin is stimulated mainly when blood glucose is elevated. Its long duration of action is driven by albumin binding and resistance to enzymatic degradation rather than by a different receptor target. | Tirzepatide is an acylated single-molecule peptide that simultaneously agonizes the GIP and GLP-1 receptors. GLP-1 receptor activation enhances glucose-dependent insulin secretion, suppresses glucagon, slows gastric emptying, and reduces appetite via central pathways. Adding GIP agonism is thought to further augment glucose-dependent insulin response and may improve lipid handling and the tolerability/efficacy balance, producing effects on appetite and energy intake that, in trials, exceeded GLP-1 monotherapy. The net clinical result is improved glycemic control and substantial caloric-intake-driven weight loss. The relative contribution of GIP versus GLP-1 signaling in humans is still an active research question. |
| Half-life | ~1 week (~160 hours) | ~5 days |
| Dosing reference | For type 2 diabetes (Ozempic), subcutaneous dosing typically starts at 0.25 mg once weekly for 4 weeks (a non-therapeutic initiation dose), increasing to 0.5 mg/week, then up to 1 mg or 2 mg/week as needed and tolerated. For chronic weight management (Wegovy), a stepwise 16-week escalation is used: 0.25 mg, 0.5 mg, 1 mg, 1.7 mg, then a 2.4 mg/week maintenance dose. Slow titration is emphasized to limit gastrointestinal side effects; rapid escalation has been linked to severe GI complications including gastroparesis. | Approved once-weekly subcutaneous dosing per prescribing labels: initiate at 2.5 mg once weekly for 4 weeks (a non-therapeutic initiation dose for tolerability), then increase to 5 mg; titrate in 2.5 mg increments no sooner than every 4 weeks as needed/tolerated. Approved maintenance/maximum doses are 5, 10, or 15 mg once weekly. The ~5-day half-life supports once-weekly administration with steady state reached around 4 weeks. Dosing should be individualized and supervised by a qualified clinician. |
| Routes | subcutaneous, oral | subcutaneous |
| Safety & side effects | Most common side effects are gastrointestinal: nausea, vomiting, diarrhea, constipation, and abdominal pain, usually mild-to-moderate and most pronounced during dose escalation. More serious but less common risks include acute pancreatitis, gallbladder disease (cholelithiasis/cholecystitis), and, with rapid dose escalation, gastroparesis. Hypoglycemia risk rises when combined with insulin or sulfonylureas. In rodents semaglutide caused dose-dependent thyroid C-cell tumors; human relevance is considered low, but it is contraindicated in those with personal/family history of medullary thyroid carcinoma or MEN 2, and in pregnancy. Worsening diabetic retinopathy was noted in SUSTAIN-6. Rapid weight loss may contribute to lean-mass loss. Use only under medical supervision; gray-market product carries purity and dosing-accuracy risks. | Most common adverse effects are gastrointestinal: nausea (~24-33% by dose in SURMOUNT-1), diarrhea, constipation, vomiting, and decreased appetite, generally mild-to-moderate, dose-escalation-related, and often transient; discontinuation for GI effects was relatively uncommon. Gallbladder/biliary events were slightly more frequent than placebo (e.g., ~1.1% vs ~0.4% in SURMOUNT-1), partly attributable to rapid weight loss. Meta-analysis did not show a statistically significant increase in pancreatitis versus controls, though acute pancreatitis remains a labeled caution. Rare but serious risks include severe hypersensitivity/anaphylaxis; a boxed warning addresses thyroid C-cell tumors seen in rodents (human relevance unknown) and it is contraindicated with personal/family history of medullary thyroid carcinoma or MEN 2. Hypoglycemia risk rises when combined with insulin or sulfonylureas. Not recommended in pregnancy; may reduce efficacy of oral contraceptives around dose changes due to delayed gastric emptying. Use only under medical supervision. |
For research use only. Not for human consumption. Always verify against current literature.