In the STEP 1 obesity trial, nausea and diarrhea were the most common adverse events, typically transient and mild to moderate. Gastrointestinal events led to discontinuation in 4.5% of the semaglutide group versus 0.8% on placebo, so for most participants they were tolerable rather than treatment-ending.[1][2]
Reviewed for accuracy · Last reviewed July 7, 2026The product label lists nausea, diarrhea, vomiting, constipation, and abdominal pain as common reactions, and carries a boxed warning for thyroid C-cell tumors. As with any independently sourced vial, the peptide is the same molecule as the branded pen but carries no guarantee of the purity or accuracy testing a regulated product does.
Nausea is often worst early and after a step-up, then eases. Smaller lighter meals and holding a dose steady rather than escalating on schedule are commonly discussed ways to make it more tolerable.
This page is an independent educational reference and is not medical advice. Talk to a doctor before starting or adjusting any compound.