Semaglutide

Grade A applies only to the FDA-approved brand products (Ozempic, Wegovy, Rybelsus), which are backed by multiple outcome trials with thousands of participants; it does not extend to research material.

Strengths: 5, 10, 20, 30, 50 mg
Also known as: Ozempic (brand), Wegovy (brand; pen and pill), Rybelsus (brand), GLP-1 receptor agonist
Molecule: 31-amino-acid lipidated peptide (GLP-1 analog)
Formula: C187H291N45O59
Mol. weight: 4113.58 g/mol
CAS: 910463-68-2

Origin

A long-acting analog of human GLP-1, a gut hormone. An Aib substitution at position 2 resists enzyme breakdown, and a fatty-acid side chain binds albumin to extend its half-life to about a week.

How it works

Activates GLP-1 receptors. In studies it raises insulin and lowers glucagon only when glucose is high, slows stomach emptying and reduces appetite signaling in the brain.

What the research shows

One of the most studied molecules in metabolic research. Large phase 3 trials studied it in obesity (STEP program), type 2 diabetes (SUSTAIN), cardiovascular outcomes (SELECT), kidney outcomes (FLOW) and fatty liver disease with fibrosis (ESSENCE). Trials reported average weight reductions of about 14–15% at the standard top dose and about 21% at a higher dose over roughly 68–72 weeks. Open questions include how much lean mass is lost and whether it matters, weight regain after stopping, and very long-term safety.

Key studies

Wilding et al., NEJM 2021 (STEP 1) 1,961 adults with obesity; mean weight change 14.9% vs 2.4% on placebo over 68 weeks.
Lincoff et al., NEJM 2023 (SELECT) 17,604 adults with heart disease and overweight; major cardiovascular events 6.5% vs 8.0%.
FLOW trial, 2024 3,533 adults with type 2 diabetes and kidney disease; 24% lower risk of major kidney events.
ESSENCE Part 1, 2025 MASH resolution 63% vs 34%; fibrosis improvement 37% vs 22%.

Safety findings

Gastrointestinal effects were the most common findings in trials (nausea, diarrhea, vomiting, constipation). Brand labels carry a boxed warning for thyroid C-cell tumors seen in rodents, plus warnings for pancreatitis, gallbladder disease and retinopathy complications. UK regulators classify a rare optic-nerve condition (NAION) as a very rare risk.

Regulatory status

The molecule is FDA-approved for specific uses as Ozempic, Wegovy (a pen and, since its December 2025 approval, the Wegovy pill) and Rybelsus; that approval does not cover research material. FDA declared the shortage over in February 2025, ending mass compounding of copies. Not prohibited by WADA as of the 2026 list (on its monitoring program).

Catalog notes

Available in 5, 10, 20, 30 and 50 mg. Current-lot certificates cover 5 mg (99.75%), 10 mg (99.9%), 20 mg (99.9%) and 30 mg (99.87%); none is published for 50 mg. Follow the storage stated on the label and certificate.