Retinol (C20H30O): structure, properties and hazards

Names and identifiers

IUPAC name: (2E,4E,6E,8E)-3,7-dimethyl-9-(2,6,6-trimethylcyclohexen-1-yl)nona-2,4,6,8-tetraen-1-ol
Synonyms: vitamin A, vitamin A1, axerophthol
+ 38 more
all-trans-Retinol, Agoncal, trans-retinol, Veroftal, Bentavit A, Homagenets Aoral, Sehkraft A, Testavol S, all-trans-Vitamin A, All-trans retinol, Super A, Axerophtholum, Wachstumsvitamin, Vitaminum A, Vitamine A, Retinolo, Retinolum, Retinol, all trans-, (2E,4E,6E,8E)-3,7-dimethyl-9-(2,6,6-trimethylcyclohex-1-en-1-yl)nona-2,4,6,8-tetraen-1-ol, Ro-a-vit, (2E,4E,6E,8E)-3,7-dimethyl-9-(2,6,6-trimethylcyclohexen-1-yl)nona-2,4,6,8-tetraen-1-ol, Antixerophthalmisches Vitamin, DTXSID3023556, (all-E)-3,7-Dimethyl-9-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,4,6,8-nonatetraen-1-ol, G2SH0XKK91, NSC-122759, CHEBI:17336, DTXCID203556, 3,7-Dimethyl-9-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,4,6,8-nonatetraen-1-ol, (all-E)-, 3,7-dimethyl-9-(2,6,6-trimethyl-1-cyclohexenyl)-nona-2,4,6,8-tetraen-1-ol, (2E,4E,6E,8E)-3,7-dimethyl-9-(2,6,6-trimethyl-1-cyclohexenyl)nona-2,4,6,8-tetraen-1-ol, All Trans Retinol, CHEBI:50211, Nepalm, RerinolCream, Recovery Cream, Surfree Firming, Firming Cream
Molecular formula: C₂₀H₃₀O
Empirical formula: C₂₀H₃₀O
Molecular weight: 286.5 g/mol
Exact mass: 286.22967
CAS number: 68-26-8
PubChem CID: 445354
Canonical SMILES: CC1=C(C(CCC1)(C)C)C=CC(=CC=CC(=CCO)C)C
Isomeric SMILES: CC1=C(C(CCC1)(C)C)/C=C/C(=C/C=C/C(=C/CO)/C)/C
InChI: InChI=1S/C20H30O/c1-16(8-6-9-17(2)13-15-21)11-12-19-18(3)10-7-14-20(19,4)5/h6,8-9,11-13,21H,7,10,14-15H2,1-5H3/b9-6+,12-11+,16-8+,17-13+
InChIKey: FPIPGXGPPPQFEQ-OVSJKPMPSA-N
Molfile

Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.

Physical properties

TemperaturePressureDensity

Appearance: Vitamin a appears as yellow crystals or orange solid. Practically water insoluble. (NTP, 1992)[1]
Melting point: 62 to 64 °C (144 to 147 °F, NTP 1992)[1]
Boiling point: 137 to 138 °C (279 to 280 °F) at 1 × 10⁻⁶ mmHg (NTP, 1992)[1]
Solubility in water: Practically insoluble (NTP, 1992)[1]
log P: log Kow = 5.68[2]
Vapor pressure: 7.5 × 10⁻⁸ mmHg at 25 °C (estimated)[2]

Each value as its source reports it, with the source's number after it (listed under References). Where several sources report a property, the row shows the value most of them agree on, the rule the app uses; open the values to see every one.

Calculated

Heavy atoms: 21
Rings: 1
Aromatic rings: 0
Fraction sp³ carbons (Fsp3): 0.5
H-bond donors: 1
H-bond acceptors: 1
Rotatable bonds: 5
TPSA (Å²): 20.2
Formal charge: 0
XLogP3: 5.7 PubChem
Complexity: 496 PubChem
Stereocenters: None
Double-bond geometry: C10=C11: E · C12=C14: E · C15=C16: E · C17=C19: E
Point group: C1 of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

C83.86%
H10.56%
O5.59%

Isotope pattern

Each peak is a nominal mass with its abundance-weighted exact mass, as a percentage of the tallest, from IUPAC natural isotope abundances.

Computed from the structure with RDKit 2026.09 when this page was built, beside PubChem's own computed values from its record; where the two differ, both are shown.

Predicted

log P: 5.51 Crippen (Wildman and Crippen 1999)
log S (water solubility): -4.76 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 3.23 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 286.46
log P ≤ 5 (Crippen): 5.51
H-bond donors ≤ 5: 1
H-bond acceptors ≤ 10: 1

Breaks 1 of the four rules.

¹³C NMR shifts, predicted

Predictions, not measurements; each names its method. A measured log P, where a source reports one, is under Physical properties.

Safety

Danger

Most widely reported: 311 company reports to ECHA. Source [3].

Harmful or irritant
Health hazard

H302Harmful if swallowed (15.8% of reports)
H317May cause an allergic skin reaction (74.9% of reports)
H319Causes serious eye irritation (75.6% of reports)
H360May damage fertility or the unborn child (88.1% of reports)
H413May cause long lasting harmful effects to aquatic life (74.9% of reports)

Precautionary statements: P203, P261, P264, P264+P265, P270, P272, P273, P280, P301+P317, P302+P352, P305+P351+P338, P318, P321, P330, P333+P317, P337+P317, P362+P364, P405, P501

View all classifications (4)

[3] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for 0.3% (1 of 311) of reports.
[3] European Chemicals Agency (ECHA) · 311 reports · DangerH302, H317, H319, H360, H413
[3] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for 1% (1 of 105) of reports.
[3] European Chemicals Agency (ECHA) · 105 reports · DangerH317, H319, H360D

First aid

Eyes: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. If symptoms (such as redness or irritation) develop, immediately transport the victim to a hospital. Skin: Immediately flood affected skin with water while removing and isolating all contaminated clothing.[1]

Storage

Vitamin A is unstable in, and should be protected from, air and light. Vitamin A preparations should be stored at a temperature less than 40 °C, preferably between 15-30 °C. Oral vitamin A preparations should be stored in tight, light-resistant containers and the injection should be protected from light and freezing.[2]

Safety data sheets on the supplier’s page: eNovation Chemicals, 001Chemical, Finetech Industry Limited.

Always read the supplier’s safety data sheet before working with it.

Spectra

Experimental spectra held by these sources; each link opens the source's own record.

Literature

Reading PubChem, OpenAlex and GSRS…

Bioactivity

Reading ChEMBL…

References

[1]CAMEO Chemicals · Public domain (NOAA) · via PubChem · retrieved 2026-10-14
[2]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
[3]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[4]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[5]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
[6]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[7]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
·Literature on PubChem

Data last updated 2026-10-14.

Similar structures

Tanimoto similarity on Morgan fingerprints (radius 2) with RDKit 2026.09, at least 45%.