Why does CAS 520-52-5 appear in more than one EU cosmetic annex?

A substance identified by CAS 520-52-5 may appear in multiple EU cosmetic regulation annexes when it is subject to different conditions in different contexts — for example, restricted under Annex III with specific conditions, while also appearing in Annex IV as an approved colorant under separate entry conditions. Each entry must be reviewed individually.

How do I check if my formula contains a substance with CAS 520-52-5?

Use the INCI Checker on CosIng Checker with INCI names, CAS numbers or EC numbers. Paste CAS 520-52-5 to screen it directly, then review every linked annex record and supplier document.

CAS 1 record

CAS 520-52-5

Q: How do I use CAS 520-52-5 for compliance screening?

Cross-reference CAS 520-52-5 against your raw material specification sheets and CoA documents. When it appears in Annex II, verify absence. When it appears in Annex III, verify that concentration limits and product type conditions are met. All annex entries sharing this CAS number are listed on this page.

CAS 520-52-5 matches 1 EU annex record across Annex II–VI of Regulation 1223/2009.

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Chemical identity and properties

PubChem 2D chemical structure for CAS 520-52-5

CAS 520-52-5PubChem CID 10624

Psilocybin

Psilocybin is a tryptamine alkaloid that is N,N-dimethyltryptamine carrying an additional phosphoryloxy substituent at position 4. The major hallucinogenic alkaloid isolated from Psilocybe mushrooms (also known as Teonancatl or "magic mushrooms"). It has a role as a hallucinogen, a serotonergic agonist, a prodrug and a fungal metabolite. It is an organic phosphate, a tryptamine alkaloid and a tertiary amino compound. It is functionally related to a psilocin. It is a conjugate acid of a psilocybin(1-). — ChEBI

IUPAC name: [3-[2-(dimethylamino)ethyl]-1H-indol-4-yl] dihydrogen phosphate

Molecular formula: C12H17N2O4P
Molecular weight: 284.25 g/mol
Exact mass: 284.09259403 Da
XLogP3: -1.6
Topological polar surface area: 85.8 Å²
Hydrogen-bond donors: 3
Hydrogen-bond acceptors: 5
Covalent units: 1
Defined stereocentres: 0

Also known as

PsilocybineIndocybinPsilocibinTeonanacatlPsilocin phosphate esterPsilocibinaPsilotsibinPsilocybinum

16 more reported names

CY-39O-Phosphoryl-4-hydroxy-N,N-dimethyltryptamine4-Phosphoryloxy-N,N-dimethyltryptamine3-2'-Dimethylaminoethylindol-4-phosphate3-(2-(Dimethylamino)ethyl)-1H-indol-4-ol dihydrogen phosphate ester3-(2-Dimethylaminoethyl)indol-4-yl dihydrogen phosphateCOMP360COMP-360CY392RV7212BP04-Phosphoryloxy-omega-N,N-dimethyltryptamine3-[2-(Dimethylamino)ethyl]-1H-indol-4-yl dihydrogen phosphate1H-Indol-4-ol, 3-(2-(dimethylamino)ethyl)-, dihydrogen phosphate (ester)CHEBI:8614({3-[2-(dimethylamino)ethyl]-1H-indol-4-yl}oxy)phosphonic acid3-(2-(dimethylamino)ethyl)-1H-indol-4-yl dihydrogen phosphate

Open full PubChem record PubChem annotations 3D structure image

External database identifiers

ChEBI:CHEBI:8614
ChEMBL:CHEMBL194378
EPA DTXSID:DTXSID0048898
PubMed:39741434
PubMed:38876450
PubMed:25877327
PubMed:22640760
PubMed:22497939
PubMed:22363492
PubMed:22282432
PubMed:22033605
PubMed:21960543
PubMed:21956447
PubMed:21956378
PubMed:21884255

Retrieved from NIH PubChem on 2026-09-02 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

Records for CAS 520-52-5

1 total

Annex

Entry

278

Psilocybine (INN)

208-294-4

How CAS 520-52-5 is used on this site

CAS 520-52-5 is the Chemical Abstracts Service identifier used to pin this page to a specific substance. In the current dataset, 1 EU annex record shares this identifier, which helps you cross-check whether the same substance appears under one regulatory context or several.

Use this page when a supplier specification, SDS or raw-material dossier gives you CAS 520-52-5 and you need to see every linked Annex II–VI record in one place. The entry cards above are the quickest route to concentration limits, warnings, annex placement and product-type conditions.

Frequently asked questions

A substance identified by CAS 520-52-5 may appear in multiple EU cosmetic regulation annexes when it is subject to different conditions in different contexts. For example, a substance might be restricted under Annex III with specific conditions, and the same CAS might also appear in Annex IV as an approved colorant under separate entry conditions. Each entry must be reviewed individually.

Cross-reference the CAS number against your raw material specification sheets and CoA documents. When a CAS appears in Annex II, verify absence. When it appears in Annex III, verify that concentration limits and product type conditions are met in your formulation. All annex entries sharing this CAS number are listed above.

A CAS number is assigned by the Chemical Abstracts Service (USA) and is globally recognised. An EC number is a European Commission identifier from inventories such as EINECS, ELINCS or the NLP list. Both identifiers may appear in EU cosmetic annex entries. Some substances have both, some have only one, and some older entries may have neither.

The INCI Checker accepts ingredient names, CAS numbers and EC numbers. Check this CAS number directly, then verify the result against supplier specification sheets and every linked annex condition.

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