Is CBL-514 a Peptide? Small Molecules and Peptides in the Lab
Why a small molecule gets sold as a peptide, and what changes at the bench: solubility, reconstitution, stability and what to look for on a COA.
Short answer: no. CBL-514 is a small molecule. The 2026 Phase 2b paper describes it as "a small-molecule injectable lipolysis agent", and the developer calls it a small-molecule drug. It has no amino-acid sequence. It still appears under searches such as "CBL-514 peptide", because research-chemical sellers group almost everything they stock under that word.
The difference is not just vocabulary. It changes how the powder should be dissolved, how it is stored, and which analytical results confirm what is in the vial.
Peptide or small molecule: the definition
A peptide is a chain of amino acids joined by peptide bonds. By convention, chains of up to roughly fifty residues are called peptides and longer ones proteins. A peptide has a sequence, such as the sixteen residues of AOD-9604, and its identity is defined by that sequence.
A small molecule is a defined, non-polymeric organic compound, typically with a molecular weight well under 1,000 Da. It has a structure rather than a sequence. Most conventional drugs are small molecules, and CBL-514 belongs to that group.
What changes at the bench
Solubility. Peptides usually dissolve in aqueous solvents such as sterile or bacteriostatic water, which is why most peptide protocols follow the same pattern. Many small molecules are less water-soluble, and protocols for them may call for an organic co-solvent, a pH adjustment or a formulation vehicle. Reconstitution habits learned on peptides, such as bacteriostatic water at 1 to 2 mg/mL, should not be assumed to work for CBL-514; use the solvent your protocol specifies.
Stability. Peptides are cleaved by proteases in biological samples and are prone to oxidation of methionine or cysteine residues and deamidation of asparagine or glutamine. A small molecule degrades by different routes, such as hydrolysis, oxidation or light sensitivity, so stability information for one class does not transfer to the other. As a general precaution, keep the lyophilized powder sealed, cool, dry and away from light, refrigerate any solution after reconstitution, and prepare only what a run needs.
What a certificate of analysis should show
The two analytical results that matter for both classes are purity by HPLC and identity by LC-MS, where the measured mass is compared with the theoretical mass. HPLC purity is a percentage of the total peak area, so the method and detection wavelength matter. For a small molecule, structure confirmation is often supported by NMR as well, whereas peptides are usually confirmed by mass and sequence data.
Our listing for CBL-514 shows a stated purity of 99.0% or higher but does not print a molecular weight or CAS number. If you need either for a calculation, ask for the batch documentation before ordering rather than taking a figure from a third-party listing.
Calculations
Mass-based arithmetic is the same for every compound: concentration in mg/mL is the milligrams in the vial divided by the millilitres of solvent, so a 10 mg vial in 2 mL gives 5 mg/mL, and the reconstitution calculator on our tools page does this. Converting to moles needs the molecular weight, and that must come from the documentation for your lot.
A useful comparison inside one category
In our lipolytic category, AOD-9604 and CBL-514 sit side by side but are different kinds of molecule. AOD-9604 is a sixteen-residue peptide with a CAS number of 221231-10-3 and a mass of about 1815.1 Da, handled like other lyophilized peptides. CBL-514 is a small molecule with no sequence, and its handling follows the notes above. Treat them as two separate protocols.
QSC supplies CBL-514 as lyophilized powder strictly for laboratory research. It is not approved for human or veterinary use, and nothing here is medical advice. For the published clinical work on the compound, see our overview of the CBL-514 literature.
Source
Lorenc ZP et al. Randomized Phase 2b Trial of CBL-514 Injection for Abdominal Subcutaneous Fat Reduction With Clinician- and Patient-reported Outcomes and MRI Assessment. Aesthetic Surgery Journal, 2026 (online ahead of print, 20 May 2026). doi:10.1093/asj/sjag092. PMID 42159040.
