Peptides Similar to Semaglutide

Peptides Related to Semaglutide#

Semaglutide belongs to the incretin-based therapeutic class, which leverages the physiological actions of gut-derived hormones to regulate glucose metabolism, appetite, and body weight. As the most clinically established selective GLP-1 receptor agonist with proven cardiovascular benefit, semaglutide serves as the benchmark against which newer multi-agonists are evaluated. The following comparison examines the most clinically relevant agents.

Tirzepatide (Mounjaro / Zepbound)#

Tirzepatide is a first-in-class dual GIP/GLP-1 receptor agonist developed by Eli Lilly, approved as Mounjaro (2022, T2D) and Zepbound (2023, weight management). It is a 39-amino-acid peptide based on the GIP sequence backbone with modifications for dual receptor activity and a C20 fatty diacid for once-weekly dosing.

Mechanism comparison: Semaglutide activates only the GLP-1 receptor, while tirzepatide activates both GIP and GLP-1 receptors. The additional GIPR activation is hypothesized to enhance insulin secretion, improve lipid metabolism, modulate fat distribution, and contribute to appetite regulation through distinct neural pathways.

Clinical efficacy -- head-to-head data: The SURPASS-2 trial directly compared tirzepatide (5, 10, 15 mg) to semaglutide 1 mg in 1,879 adults with T2D over 40 weeks:

• HbA1c reduction: tirzepatide 15 mg -2.46% versus semaglutide 1 mg -1.86% (P<0.001)
• Weight loss: tirzepatide 15 mg -12.4 kg versus semaglutide 1 mg -6.2 kg (P<0.001)
• All three tirzepatide doses were statistically superior to semaglutide

In obesity, cross-trial comparisons show tirzepatide achieving 15.0-22.5% weight loss (SURMOUNT-1) versus semaglutide's 14.9% (STEP 1). SURMOUNT-5 provided head-to-head data in obesity confirming tirzepatide's superiority.

Cardiovascular outcomes: Semaglutide has a significant advantage with two positive CV outcomes trials (SUSTAIN-6 and SELECT), including the landmark 20% MACE reduction in the SELECT trial. Tirzepatide's SURPASS-CVOT is ongoing.

Dosing and formulations: Both are dosed once weekly via subcutaneous injection. Semaglutide offers the additional option of oral tablets (Rybelsus) for T2D, a unique advantage for patients who prefer oral therapy.

Retatrutide (LY3437943)#

Retatrutide is an investigational triple agonist developed by Eli Lilly that activates GIP, GLP-1, and glucagon receptors. It is currently in phase 3 development.

Mechanism comparison: While semaglutide activates only GLP-1R, retatrutide adds both GIPR and glucagon receptor (GCGR) activation. Glucagon receptor agonism promotes hepatic energy expenditure, lipid oxidation, and thermogenesis, potentially contributing to greater fat mass reduction. However, glucagon also stimulates hepatic glucose output, which must be counterbalanced by the incretin agonism.

Clinical efficacy: In the phase 2 trial (NEJM, 2023), retatrutide achieved approximately 24.2% weight loss at the highest dose (12 mg) over 48 weeks, potentially the greatest weight reduction observed with any anti-obesity pharmacotherapy. It also demonstrated remarkable hepatic fat reduction (>80% resolution of steatosis).

Regulatory status: Retatrutide remains investigational and is not FDA-approved. Phase 3 trials (TRIUMPH program) are ongoing. The safety profile is less characterized than semaglutide's, particularly regarding long-term glucagon receptor agonism effects.

Key trade-off: Retatrutide may offer greater weight loss but has substantially less clinical data, no regulatory approval, and unknown long-term safety compared to semaglutide's 7+ years of market experience and proven cardiovascular benefit.

Survodutide (BI 456906)#

Survodutide is an investigational dual glucagon/GLP-1 receptor agonist developed by Boehringer Ingelheim and Zealand Pharma. Unlike tirzepatide's dual GIP/GLP-1 profile, survodutide pairs glucagon with GLP-1 agonism.

Mechanism comparison: Semaglutide provides selective GLP-1R activation, while survodutide adds glucagon receptor agonism. The glucagon component may enhance energy expenditure and hepatic lipid oxidation, potentially offering advantages for MASH/NASH and visceral fat reduction.

Clinical data: Phase 2 results showed survodutide achieving approximately 14.9-18.7% weight loss at 46 weeks in adults with obesity. Phase 3 trials are underway. Survodutide has also shown promising results in MASH, with significant reductions in liver fat and fibrosis markers.

vs. Semaglutide: Survodutide's weight loss magnitude appears competitive with semaglutide but is based on limited phase 2 data. Semaglutide has vastly more clinical evidence, regulatory approval, and proven cardiovascular outcomes.

Liraglutide (Victoza / Saxenda)#

Liraglutide is a selective GLP-1 receptor agonist developed by Novo Nordisk (semaglutide's predecessor). It is a 30-amino-acid GLP-1 analog with a C16 fatty acid at Lys26, providing a half-life of approximately 13 hours requiring once-daily injection.

Clinical efficacy: Liraglutide achieves lower efficacy than semaglutide across both indications:

• T2D: HbA1c reduction of approximately 1.1-1.2% (vs 1.5-2.2% for semaglutide)
• Obesity: Weight loss of 5.4-8.0% at 56 weeks (vs 14.9% for semaglutide)

Practical considerations: Daily injection is the primary disadvantage compared to weekly semaglutide. However, liraglutide has the longest market track record (since 2010), proven cardiovascular benefit (LEADER trial), and pediatric approval for obesity (Saxenda, ages 12+).

Clinical niche: Liraglutide has been largely superseded by semaglutide for most indications due to superior efficacy and weekly dosing convenience. It retains a role in adolescent obesity (approved for ages 12+) and in situations where patients have tried and tolerated liraglutide before semaglutide was available.

Summary Comparison#

Evidence Gaps#

• Head-to-head tirzepatide vs semaglutide in obesity (SURMOUNT-5 recently reported)
• Long-term comparative cardiovascular outcomes across agents
• Comparative body composition effects (lean mass preservation)
• Comparative efficacy in specific comorbidities (MASH, HFpEF, OSA)
• Cost-effectiveness comparisons across agents and indications

Related Reading#

• Semaglutide overview and research guide
• Semaglutide research evidence
• Semaglutide dosing protocols