Menthol (C10H20O): structure, properties and hazards

Names and identifiers

IUPAC name: (1R,2S,5R)-5-methyl-2-propan-2-ylcyclohexan-1-ol
Synonyms: peppermint, l-menthol, hexahydrothymol
+ 39 more
l-Menthol, (-)-menthol, Levomenthol, l-(-)-Menthol, (-)-Menthyl alcohol, Levomentholum, U.S.P. Menthol, (1R)-(-)-Menthol, (-)-(1R,3R,4S)-Menthol, D-(-)-Menthol, (-)-trans-p-Menthan-cis-ol, levomentol, (1R,2S,5R)-5-methyl-2-(propan-2-yl)cyclohexan-1-ol, Menthol, (1R,3R,4S)-(-)-, (1R,3R,4S)-(-)-MENTHOL, BZ1R15MTK7, (1R-(1-alpha,2-beta,5-alpha))-5-Methyl-2-(1-methylethyl)cyclohexanol, CHEBI:15409, (1R,2S,5R)-5-methyl-2-(1-methylethyl)cyclohexanol, NSC-62788, NPO-11, NSC62788, (1alpha,2beta,5alpha)-5-methyl-2(1-methylethyl)cyclohexanol, FEMA NO. 2665, (-)-, levomentolo, RefChem:1049117, Auvon 4% Menthol Pain Relief Gel, Freegells Cough Drops Menthol 30ct, Freegells Cough Drops Menthol 80ct, Cough Drops Freegells Strawberry 30ct, Cough Drops Dollar General Cherry 30ct, Freegells Cough Drops Honey Lemon 30ct, Cough Drops Dollar General Menthol 30ct, Cough Drops Dollar General Menthol 80ct, Cough Drops Dollar General Cherry 200ct, Freegells Cough Drops Honey Lemon 200ct, Menthol Drops Dollar General Severe 45ct, Cough Drops Dollar General Menthol 160ct, Freegells Cough Drops Menthol Cherry 30ct
Molecular formula: C₁₀H₂₀O
Empirical formula: C₁₀H₂₀O
Molecular weight: 156.26 g/mol
Exact mass: 156.15142
CAS number: 2216-51-5
PubChem CID: 16666
Canonical SMILES: CC1CCC(C(C1)O)C(C)C
Isomeric SMILES: C[C@@H]1CC[C@H]([C@@H](C1)O)C(C)C
InChI: InChI=1S/C10H20O/c1-7(2)9-5-4-8(3)6-10(9)11/h7-11H,4-6H2,1-3H3/t8-,9+,10-/m1/s1
InChIKey: NOOLISFMXDJSKH-KXUCPTDWSA-N
Molfile

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

Physical properties

TemperaturePressureDensity

Appearance: D,l-menthol is a white crystalline solid with a peppermint odor and taste. (NTP, 1992)[1]
3 values
From CAMEO Chemicals, the most authoritative source here.
Value As written Source
–shown D,l-menthol is a white crystalline solid with a peppermint odor and taste. (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
– Liquid; Other Solid; CBI; Large Crystals [2] EPA Chemical Data Reporting (CDR)
– Other Solid; Liquid [2] EPA Chemical Data Reporting (CDR)
Melting point: 38 °C (100 °F, NTP 1992)[1]
Boiling point: 216 °C (421 °F) at 760 mmHg (NTP, 1992)[1]
Density: 0.904 at 15 °C (59 °F) (NTP, 1992) - Less dense than water[1]
Solubility in water: In water, 456 mg/l @ 25 °C[3]
2 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– less than 1 mg/mL at 70 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
–shown In water, 456 mg/l @ 25 °C [3] Hazardous Substances Data Bank (HSDB)cites Yalkowsky SH, Dannenfelser RM; The AQUASOL dATAbASE of Aqueous Solubility. Fifth ed, Tucson, AZ: Univ Az, College of Pharmacy (1992)
log P: log Kow = 3.3[3]
Vapor pressure: 1 mmHg at 56 °C (133 °F) approximately (NTP, 1992)[1]
Flash point: 91 °C (196 °F, NTP 1992)[1]

Value	As written	Source
–shown	D,l-menthol is a white crystalline solid with a peppermint odor and taste. (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
–	Liquid; Other Solid; CBI; Large Crystals	[2] EPA Chemical Data Reporting (CDR)
–	Other Solid; Liquid	[2] EPA Chemical Data Reporting (CDR)

Value	As written	Source
–	less than 1 mg/mL at 70 °F (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
–shown	In water, 456 mg/l @ 25 °C	[3] Hazardous Substances Data Bank (HSDB)cites Yalkowsky SH, Dannenfelser RM; The AQUASOL dATAbASE of Aqueous Solubility. Fifth ed, Tucson, AZ: Univ Az, College of Pharmacy (1992)

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: 11
Rings: 1
Aromatic rings: 0
Fraction sp³ carbons (Fsp3): 1
H-bond donors: 1
H-bond acceptors: 1
Rotatable bonds: 1
TPSA (Å²): 20.2
Formal charge: 0
XLogP3: 3 PubChem
Complexity: 120 PubChem
Stereocenters: 3 definedCIP: C4: S · C7: R · C10: R
Double-bond geometry: None specified
Point group: C1 of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

C76.86%
H12.90%
O10.24%

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: 2.44 Crippen (Wildman and Crippen 1999)
log S (water solubility): -2.28 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 3.35 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 156.27
log P ≤ 5 (Crippen): 2.44
H-bond donors ≤ 5: 1
H-bond acceptors ≤ 10: 1

Passes all 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

Warning

Most widely reported: 2,060 company reports to ECHA. Source [4].

Harmful or irritant

H315Causes skin irritation (97.6% of reports)
H319Causes serious eye irritation (31.9% of reports)

Precautionary statements: P264, P264+P265, P280, P302+P352, P305+P351+P338, P321, P332+P317, P337+P317, P362+P364

View all classifications (2)

[4] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for 0.3% (7 of 2060) of reports.
[4] European Chemicals Agency (ECHA) · 2,060 reports · WarningH315, H319

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. Immediately transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop. Skin: Immediately flood affected skin with water while removing and isolating all contaminated clothing.[1]

Safety data sheets on the supplier’s page: LGC Standards, Alfa Chemistry, TCI (Tokyo Chemical Industry).

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]EPA Chemical Data Reporting (CDR) · Public domain (US EPA) · via PubChem · retrieved 2026-10-14
[3]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
[4]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[5]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
[6]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
[7]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[8]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[9]MassBank Europe · 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.