Last reviewed: October 2026 · Cleared Peptides research team
Research use only. Polysorbate 80: Laboratory Surfactant Note is supplied for laboratory research. It is not a drug, food, cosmetic, or dietary supplement. It is not FDA-approved. It is not for human or veterinary administration. This page does not give a dose or a method of administration. A study cited on this page describes that study’s own test article. It does not make this lot an approved medicine. To check a fact, open the PubMed or DOI link, confirm the authors and year, and match the paper’s compound name, CAS number, or sequence to the specification table. The full method is on the research desk page. Identity and purity for a lot are only what that lot’s certificate of analysis reports. An HPLC percentage is not a sterility result and not an endotoxin result unless the certificate prints those tests.
Polysorbate 80 is polyoxyethylene (20) sorbitan monooleate, a nonionic surfactant mixture. Chemical catalogs assign CAS 9005-65-6. A single molecular formula is not printed here because the material is a polymer mixture, not one discrete molecule. A public compound-name lookup does not return one structure, which matches that description.
| Name | Polysorbate 80 |
|---|---|
| Other names | Polyoxyethylene sorbitan monooleate; Tween 80 in supplier catalogs |
| CAS number | 9005-65-6, the catalog number for the mixture |
| Formula | Not one formula. It is a mixture of related chains. |
| Class | Nonionic surfactant. Not a peptide. |
| Catalog status | Not a current Cleared Peptides lot. |
Laboratory note
Surfactants change how a solid wets and how a peptide adsorbs to surfaces in an assay. This page does not give a percentage or a formulation.
Analytical testing notes for Polysorbate 80
Polysorbate 80 is identified in this guide as CAS 9005-65-6, the catalog number for the mixture, formula Not one formula. It is a mixture of related chains.. An identity test compares a measurement with those values. A mass spectrum is the usual measurement for a peptide. FTIR, when a certificate uses it, is a supporting infrared fingerprint and is less specific for closely related sequences.
Polysorbate 80 is not a peptide. Identity and purity may be chromatographic (HPLC or GC) or spectroscopic, depending on the method named on the certificate. The peptide-specific notes below — sequence mass, 214 nm peptide-bond detection, and net peptide content — should not be assumed. Sterility and endotoxin still apply only when those lines are on the report.
Read the method named on the certificate before treating a purity percentage as an HPLC area-percent result. Small molecules in this library may be assessed by HPLC, gas chromatography, or spectroscopy. The instrument named on the report is the one that applies. A purity result still does not measure sterility, endotoxin, or a labeled fill weight.
A sterility test and an endotoxin test are not included in a chemical purity result. The compendial sterility test is a culture method (USP <71>): membrane filtration or direct inoculation into fluid thioglycollate medium and soybean-casein digest medium, incubated for 14 days. A PCR sterility screen uses a thermal cycler to detect microbial DNA and is a different method. The endotoxin test (USP <85> LAL, or USP <86> recombinant Factor C) reports endotoxin units with an incubating reader or a cartridge reader. Use a result only when that method is printed on the lot certificate. One published example in this catalog states that the report does not cover microbial contamination or endotoxins. The full description of equipment, standards, and how US laboratory accreditation works is in peptide analytical testing. Lot records are on the COA page.
Frequently Asked Questions
Why is there no molecular weight?
Polysorbate 80 is a mixture. One molecular weight would be misleading.
Is Tween 80 a different chemical?
Tween 80 is a supplier name used for polysorbate 80, not a second CAS substance.
Is this for human use?
No. Laboratory reference only.
Selected References
Registry records and peer-reviewed literature listed as scientific background. Citation does not imply endorsement, a benefit, or any use.
- Catalog identity: polyoxyethylene (20) sorbitan monooleate, CAS 9005-65-6. Cited as the mixture name, not as a single-molecule structure.
Research Use Only Notice
This guide is provided for educational and laboratory reference purposes. It summarizes published structural and biochemical literature. It does not describe, recommend, or imply any use in humans or animals. These materials are not drugs, foods, cosmetics, or dietary supplements on this page, are not offered here as a treatment, and no dosing or administration instructions are provided. Cleared Peptides does not currently list a lot for every compound on this page.
