Compound note

Semaglutide salt forms and why they matter

Updated October 26, 2026Peptide Federation editorial team3 min read

The semaglutide in Ozempic and Wegovy is the base (free) form of the peptide. Salt forms such as semaglutide sodium or acetate are different active ingredients. The FDA has said that salt forms are not the same as the approved drug substance and has warned against their use in compounding.

What the approved products contain

Novo Nordisk’s injectable products list semaglutide as the active ingredient. Oral Rybelsus also contains semaglutide, combined with the absorption enhancer salcaprozate sodium (SNAC). The sodium in Rybelsus belongs to SNAC, not to the peptide itself.

Where salt forms came from

During the GLP-1 shortages of 2022 to 2024, compounding pharmacies in the US were permitted to prepare semaglutide. Some sourced semaglutide sodium or semaglutide acetate. The FDA stated that these salts are different active ingredients that have not been shown to be safe and effective, and that compounding law requires the same active ingredient as an approved drug. The agency declared the semaglutide shortage resolved in February 2025, which ended that compounding window for most pharmacies.

Why it matters for arithmetic

A salt adds the mass of its counter-ion. If a vial is labelled by the weight of semaglutide sodium, the weight of semaglutide peptide is lower. With semaglutide’s molecular weight of about 4,114 g/mol, the difference from a small number of sodium ions is minor, but acetate salts and residual water can push the gap higher. Net peptide content on the COA is the figure to use.

Identity is the bigger question

For research-supply semaglutide, the larger uncertainty is usually not salt form but whether the product is semaglutide at all, at the stated amount and purity. FDA and state regulators have reported products with incorrect content and contaminants. Mass spectrometry and HPLC on the specific batch are the only ways to know.

Related profiles

GLP-1 receptor agonist Semaglutide Semaglutide is a long-acting GLP-1 receptor agonist approved for type 2 diabetes, chronic weight management and cardiovascular risk reduction. Approved medicine

Questions

Is semaglutide sodium the same as Ozempic?

No. Ozempic contains semaglutide base. The FDA considers semaglutide sodium a different active ingredient.

Can I compare doses between salt and base?

Only by converting to the mass of the peptide itself, using net peptide content. Label mass alone is not enough.

References

U.S. Food and Drug Administration (2024). FDA’s Concerns with Unapproved GLP-1 Drugs Used for Weight Loss. FDA.