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CAS Number

A unique registry identifier assigned to a chemical substance by the Chemical Abstracts Service.

A CAS Registry Number is a unique identifier assigned to a chemical substance by the Chemical Abstracts Service, written as digits in three hyphen-separated groups. The final digit is a check digit computed from the others, so a mistyped CAS number is usually detectable as invalid rather than silently wrong.

It is an index entry, not a measurement. A CAS number identifies which substance is under discussion and carries no information about purity, quality or source. Two vials with the same CAS number can be very different material.

Because the identifier is exact, a wrong one does not point at an approximately similar compound — it points at a different molecule entirely. Note also that a free base and its salt are separate registrations with separate numbers. Echo Peptides publishes a CAS number only where it has been verified against a chemical database; where verification was not possible the field is left blank rather than filled.

Topic: Fundamentals

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Guides that cover this

Semax (MEHFPGP): A Research Guide to Its Identity, Binding Site and Preclinical Record

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Melanotan II (MT-2): A Research Guide

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Selank: A Research Guide

Selank is tuftsin plus a Pro-Gly-Pro tail. This guide separates what has been measured — tritiated GABA binding in membrane preparations, IPSCs in rat hippocampal slices, serum peptidase inhibition at 20 μM, plasma degradation fragments — from what the literature never established, including any receptor of its own.

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