Capsaicin (C18H27NO3): structure, properties and hazards

Names and identifiers

IUPAC name: (E)-N-[(4-hydroxy-3-methoxyphenyl)methyl]-8-methylnon-6-enamide
Synonyms: chilli, Capzasin, vanilloid
+ 38 more
Zostrix, CAPSAICINE, trans-Capsaicin, Qutenza, Styptysat, Axsain, Ausanil, Isodecenoic acid vanillylamide, trans-8-Methyl-N-vanillyl-6-nonenamide, Mioton, NGX-4010, Dolenon, Ovocap, (E)-8-Methyl-N-vanillyl-6-nonenamide, FEMA No. 3404, Capzasin-hp, 8-Methyl-N-Vanillyl-6-Nonenamide, Togarashi orenji, ALGRX 4975, DTXSID9020241, Ratden pe 40, NCI-C56564, NGX 4010, Capsaicina, (E)-N-[(4-HYDROXY-3-METHOXYPHENYL)METHYL]-8-METHYL-6-NONENAMIDE, Zostrix HP, Cntx-4975, NGX-1998, (6E)-N-[(4-hydroxy-3-methoxyphenyl)methyl]-8-methylnon-6-enamide, (E)-N-[(4-hydroxy-3-methoxyphenyl)methyl]-8-methylnon-6-enamide, 6-Nonenamide, 8-methyl-N-vanillyl-, (E)-, NSC-56353, N-(4-Hydroxy-3-methoxybenzyl)-8-methylnon-trans-6-enamide, ALGRX-4975, CHEBI:3374, S07O44R1ZM, NSC56353, 6-Nonenamide, N-[(4-hydroxy-3-methoxyphenyl)methyl]-8-methyl-, (6E)-
Molecular formula: C₁₈H₂₇NO₃
Empirical formula: C₁₈H₂₇NO₃
Molecular weight: 305.4 g/mol
Exact mass: 305.19909
CAS number: 404-86-4
PubChem CID: 1548943
Canonical SMILES: CC(C)C=CCCCCC(=O)NCC1=CC(=C(C=C1)O)OC
Isomeric SMILES: CC(C)/C=C/CCCCC(=O)NCC1=CC(=C(C=C1)O)OC
InChI: InChI=1S/C18H27NO3/c1-14(2)8-6-4-5-7-9-18(21)19-13-15-10-11-16(20)17(12-15)22-3/h6,8,10-12,14,20H,4-5,7,9,13H2,1-3H3,(H,19,21)/b8-6+
InChIKey: YKPUWZUDDOIDPM-SOFGYWHQSA-N
Molfile

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

Physical properties

TemperaturePressureDensity

Appearance: Pure dark red solid[2]
3 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– White crystalline powder. [1] Occupational Safety and Health Administration (OSHA)
–shown Pure dark red solid [2] Hazardous Substances Data Bank (HSDB)cites Crop Protection Handbook Volume 100, Meister Media Worldwide, Willoughby, OH 2014, p. 156
– Monoclinic, rectangular plates, crystals and scales [2] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 12th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2012., p. 349
Odor: Highly volatile with a pungent odor[2]
Melting point: 65 °C (149 °F)[1]
Boiling point: 210-220 °C (410-428 °F)[1]
log P: log Kow = 3.04[2]
Flash point: 113 °C (235 °F) - closed cup[2]

Value	As written	Source
–	White crystalline powder.	[1] Occupational Safety and Health Administration (OSHA)
–shown	Pure dark red solid	[2] Hazardous Substances Data Bank (HSDB)cites Crop Protection Handbook Volume 100, Meister Media Worldwide, Willoughby, OH 2014, p. 156
–	Monoclinic, rectangular plates, crystals and scales	[2] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 12th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2012., p. 349

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: 22
Rings: 1
Aromatic rings: 1
Fraction sp³ carbons (Fsp3): 0.5
H-bond donors: 2
H-bond acceptors: 3
Rotatable bonds: 9
TPSA (Å²): 58.6
Formal charge: 0
XLogP3: 3.6 PubChem
Complexity: 341 PubChem
Stereocenters: None
Double-bond geometry: C14=C15: E
Point group: C1 of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

C70.79%
H8.91%
N4.59%
O15.72%

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: 3.79 Crippen (Wildman and Crippen 1999)
log S (water solubility): -3.73 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 2.19 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 305.42
log P ≤ 5 (Crippen): 3.79
H-bond donors ≤ 5: 2
H-bond acceptors ≤ 10: 3

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

Danger

Most widely reported: 1,697 company reports to ECHA. Source [3].

Corrosive
Acute toxicity
Harmful or irritant

H301Toxic if swallowed (21.9% of reports)
H302Harmful if swallowed (78% of reports)
H315Causes skin irritation (99.7% of reports)
H318Causes serious eye damage (97.2% of reports)

Precautionary statements: P264, P264+P265, P270, P280, P301+P316, P301+P317, P302+P352, P305+P354+P338, P317, P321, P330, P332+P317, P362+P364, P405, P501

View all classifications (2)

[3] European Chemicals Agency (ECHA) · 1,697 reports · DangerH301, H302, H315, H318
[2] Hazardous Substances Data Bank (HSDB) · DangerH301, H315, H317, H319, H334, H335

Storage

Keep container tightly closed in a dry and well-ventilated place. Recommended storage temperature: 2 - 8 °C.[2]
Store at 15 to 30 °C (59 to 86 °F) (over the counter capsaicin)[2]
Safe Storage of Pesticides. Always store pesticides in their original containers, complete with labels that list ingredients, directions for use, and first aid steps in case of accidental poisoning. Never store pesticides in cabinets with or near food, animal feed, or medical supplies. Do not store pesticides in places where flooding is possible or in places where they might spill or leak into wells, drains, ground water, or surface water.[2]
Store carton between 20 and 25 °C (68 and 77 °F). Excursions between 15 and 30 °C (59 and 86 °F) are allowed. Keep the patch in the sealed pouch until immediately before use. (prescription capsaicin patch)[2]

Incompatibilities

Incompatible materials: Strong oxidizing agents.[2]

Safety data sheets on the supplier’s page: Aladdin Scientific, INTERBIOSCREEN, Sinfoo Biotech.

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]Occupational Safety and Health Administration (OSHA) · Public domain (US DOL) · 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]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
[6]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
[7]MassBank Europe · Linked only · via PubChem · retrieved 2026-10-14
[8]MassBank of North America (MoNA) · CC BY 4.0 · 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.