Hemp & Cannabinoid Science / Terpene Monographs / Alpha-Humulene
Alpha-Humulene
The monocyclic eleven-membered-ring sesquiterpene isomeric with beta-caryophyllene, with genuine rodent anti-inflammatory data in oedema and in allergic airway inflammation — and no cannabinoid receptor activity.
At a glance
| Structure class | monocyclic sesquiterpene — an eleven-membered carbocycle (humulane skeleton) |
|---|---|
| Molecular formula | C15H24 |
| Molar mass | about 204.36 g/mol |
| Relationship to beta-caryophyllene | a ring-opened isomer; identical formula and mass, different skeleton, different pharmacology |
| Boiling point at 1 atm | not reliably tabulated; expect the sesquiterpene region of roughly 250 to 280 degrees Celsius. The figure of about 106 degrees Celsius that circulates in cannabis terpene charts is a REDUCED-PRESSURE value and is not an atmospheric boiling point |
| Vaporization band | about 180 to 205 degrees Celsius (356 to 401 degrees Fahrenheit) |
| Documented activity | anti-inflammatory in rodent oedema models and in an experimental allergic airway inflammation model, including by oral and aerosol routes |
| Cannabinoid receptor activity | none documented; unlike its isomer beta-caryophyllene, alpha-humulene is not a CB2 agonist |
| Aroma | hoppy, woody, faintly earthy |
On this page
Structure: the isomer that is not a cannabinoid
Alpha-humulene, historically alpha-caryophyllene, is C15H24 at about 204.36 g/mol — the same formula and the same molar mass as beta-caryophyllene. The difference is the skeleton: alpha-humulene is a single eleven-membered ring with three double bonds, where beta-caryophyllene is the bicyclic form with the strained cyclobutane. The two interconvert in the laboratory and co-occur in nature, and they are the clearest demonstration on this shelf that terpene pharmacology is about shape rather than composition. Beta-caryophyllene's rigid bicyclic geometry lets it occupy CB2 at nanomolar affinity. Alpha-humulene, with the same atoms in a floppy macrocycle, has no documented cannabinoid receptor activity at all. Anyone tempted to reason from formula to activity in this space should keep this pair in mind.
Sources: Gertsch J 2008 · Fernandes ES 2007 · Compiled from public compound databases (PubChem 2026*
A boiling-point warning specific to this compound contested
Cannabis terpene charts very commonly list alpha-humulene with a boiling point of about 106 degrees Celsius. That number is a reduced-pressure distillation figure — a temperature measured under vacuum — and it is not an atmospheric boiling point. Reproducing it in a chart headed "boiling point" next to atmospheric values for the monoterpenes creates a nonsensical ordering in which a sesquiterpene appears to be the most volatile compound in cannabis, which it is not. This shelf does not assert a precise atmospheric figure for alpha-humulene because we do not have one we can verify; by analogy with beta-caryophyllene, the same formula and a similar polarity, expect the 250 to 280 degrees Celsius region. The practical vaporization band, which is what a device user actually needs, is around 180 to 205 degrees Celsius and is given above.
Contested — caveat. We do not assert an atmospheric boiling point for alpha-humulene. The commonly circulated figure near 106 degrees Celsius is a reduced-pressure value, and the 250 to 280 degrees Celsius estimate given here is an analogy to beta-caryophyllene, not a measurement.
Sources: Compiled from public compound databases (PubChem 2026* · Lanz C 2016
Anti-inflammatory pharmacology contested animal
Alpha-humulene has better-characterised anti-inflammatory data than most terpenes. Fernandes and colleagues isolated alpha-humulene and (-)-trans-caryophyllene from Cordia verbenacea essential oil and reported that both inhibited oedema and inflammatory mediator release in rodent models, by oral and topical routes. Rogerio and colleagues then tested alpha-humulene specifically in an experimental model of allergic airway inflammation and reported both preventive and therapeutic anti-inflammatory effects, with reductions in eosinophil recruitment and in inflammatory mediators, including when administered by aerosol. The aerosol result is worth flagging for this industry because it is direct evidence of activity by an inhaled route for a sesquiterpene that a vaporizer delivers. Mechanistically the reports implicate reduced pro-inflammatory cytokine and mediator production rather than a specific receptor; no cannabinoid receptor involvement is described, and the operator's own material correctly lists alpha-humulene as anti-inflammatory rather than as a cannabinoid.
Contested — caveat. Rodent models with systemic, topical and aerosol dosing at defined doses. No human trial on isolated alpha-humulene is cited here, and no specific molecular target has been established.
Sources: Fernandes ES 2007 · Rogerio AP 2009 · Van Kush Family Research Institute (operator) 2026*
Where alpha-humulene actually is, and at what percent contested
Alpha-humulene is named for hops, where it is one of the characteristic oil components, and it is a routine co-traveller of beta-caryophyllene wherever that compound occurs — the biosynthetic routes are related and the two are typically reported together on a terpene panel. The operator's Artemisia capillaris material is one of the inventory sources.
| Botanical | Reported alpha-humulene content | Basis | Source |
|---|---|---|---|
| Hops (Humulus lupulus) | a characteristic constituent of hop oil, variety-dependent | percent of hop oil | operator Temple Pharmacopoeia 2026; reference compilation |
| Yerba Lena Yesca, Artemisia capillaris | present; listed as anti-inflammatory and also found in hops | qualitative | operator Temple Pharmacopoeia 2026 |
| Cordia verbenacea | a constituent of the essential oil, isolated for the anti-inflammatory studies | percent of essential oil | Fernandes 2007; Rogerio 2009 |
| Cannabis sativa | a common sesquiterpene, usually reported alongside beta-caryophyllene | percent of terpene fraction | Booth and Bohlmann 2019; Russo 2011 |
| Sage, ginseng, balsam fir | present as a minor to moderate constituent | percent of essential oil | reference compilation |
Contested — caveat. Mostly qualitative or compiled figures; the operator document does not give a quantitative humulene percentage for Artemisia capillaris or hops.
Sources: Van Kush Family Research Institute (operator) 2026* · Fernandes ES 2007 · Rogerio AP 2009 · Booth JK 2019 · Russo EB 2011 · Compiled from public compound databases (PubChem 2026*
Industry notes
For a lab tech, alpha-humulene and beta-caryophyllene are the pair to check for coelution and misassignment: same formula, same nominal mass, close retention on some columns, and confusion between them is a recurring source of error on terpene panels. Confirm against a reference standard for each, separately. For a formulator, alpha-humulene is the sesquiterpene with the best inhaled-route anti-inflammatory evidence, which makes it interesting in a vaporization context in a way that its lack of receptor pharmacology might otherwise obscure. For a buyer, a terpene panel that reports one of this pair and not the other is reporting an incomplete sesquiterpene picture.
Sources: Rogerio AP 2009 · Gertsch J 2008
See also
- Terpenes and Terpenoids: How to Read This Shelf — Terpene Monographs
- Beta-Caryophyllene — Terpene Monographs
- Vaporization Temperature Bands: An Industry Reference — Terpene Monographs
- Yin Chen Hao — Artemisia capillaris — Botanical Monographs
- The Panels: What Each One Covers, and What It Does Not — Reading a Certificate of Analysis
References
- Gertsch J, Leonti M, Raduner S, Racz I, Chen JZ, Xie XQ, Altmann KH, Karsak M, Zimmer A (2008) Beta-caryophyllene is a dietary cannabinoid Proceedings of the National Academy of Sciences of the USA 105(26):9099-9104. doi:10.1073/pnas.0803601105
- Fernandes ES, Passos GF, Medeiros R, da Cunha FM, Ferreira J, Campos MM, Pianowski LF, Calixto JB (2007) Anti-inflammatory effects of compounds alpha-humulene and (-)-trans-caryophyllene isolated from the essential oil of Cordia verbenacea European Journal of Pharmacology 569(3):228-236. doi:10.1016/j.ejphar.2007.04.059
- Compiled from public compound databases (PubChem, NIST WebBook) and supplier specification sheets (2026) Physical constants for terpenes and terpenoids: formula, molar mass, atmospheric boiling point Reference compilation; individual values vary between sources and are given as ranges here. [identifier unverified]
- Lanz C, Mattsson J, Soydaner U, Brenneisen R (2016) Medicinal cannabis: in vitro validation of vaporizers for the smoke-free inhalation of cannabis PLoS ONE 11(1):e0147286. doi:10.1371/journal.pone.0147286
- Rogerio AP, Andrade EL, Leite DFP, Figueiredo CP, Calixto JB (2009) Preventive and therapeutic anti-inflammatory properties of the sesquiterpene alpha-humulene in experimental airways allergic inflammation British Journal of Pharmacology 158(4):1074-1087. doi:10.1111/j.1476-5381.2009.00177.x
- Van Kush Family Research Institute (operator) (2026) Temple Pharmacopoeia knowledgebase: botanical preparations, extraction science and formulation frameworks Internal operator document, compiled January 2026. [identifier unverified]
- Booth JK, Bohlmann J (2019) Terpenes in Cannabis sativa — from plant genome to humans Plant Science 284:67-72. doi:10.1016/j.plantsci.2019.03.022
- Russo EB (2011) Taming THC: potential cannabis synergy and phytocannabinoid-terpenoid entourage effects British Journal of Pharmacology 163(7):1344-1364. doi:10.1111/j.1476-5381.2011.01238.x
8 references, of which 2 carry no resolved identifier and are marked as such. A DOI is only recorded here when it was resolved against Crossref and the returned title matched the one printed. None was guessed.
Absence is not safety. A substance or a pair that is not in this section was not checked and is not thereby safe. This is a curated mechanism reference built from primary literature and regulatory reference works — not a comprehensive interaction database, and not a substitute for a clinician or a pharmacist.
Posture
Education and harm reduction. Not medical, legal or financial advice. Every factual claim carries a source; contested and single-source claims are marked as such on the page.
The boundary. This section teaches separation, purification, formulation, dosing arithmetic and analytical chemistry with real parameters, because withholding that detail from someone who will proceed anyway is the harm this library exists to prevent. It does not publish preparative routes for converting one cannabinoid into a more intoxicating one; those are described structurally and cited to the literature, without procedures.