Humulene: Occurrence, Measurement, Research and Limits
Humulene (alpha-humulene) is a woody-scented terpene found in cannabis and other plants. See how it is measured and why human evidence is still missing.
Content last updated . This page has not been medically reviewed.
What humulene is
Humulene, usually meaning alpha-humulene, is a sesquiterpene, a terpene built from fifteen carbon atoms, found in the essential oils of various plant species. [1] PubChem lists its formula as C15H24 and its systematic name as (1E,4E,8E)-2,6,6,9-tetramethylcycloundeca-1,4,8-triene. [2] Beta-caryophyllene has the same formula, C15H24, but a different structure. [3] See Beta-Caryophyllene. This page is information only.Evidence labels used here: preclinical (cells/animals only), insufficient evidence, and marketing claim. "Proper evidence not found" is used where searches turned up nothing usable.
Where it occurs in cannabis
In a study of one hemp variety, α-humulene was among the major compounds made by the plant's terpene enzymes. [4] It was found in high amounts in two strains measured by gas chromatography, [5] and was among the main terpenoids in 33 cannabis samples. [6] One study reported it higher in THC-dominant than in CBD-dominant varieties. [7]Across plants, the share of humulene in extracts ranged from negligible to about 60.9 percent depending on species. [1] In cannabis, no typical percentage is given here. Reviewers note concern about inconsistent terpene composition between cannabis "strains", [8] and ten plants of one strain grown together varied by about 20 percent in the main terpenes. [5] Only batch-specific laboratory data can show what a product holds.
How it is measured
Humulene is measured with the same gas chromatography methods as other terpenes. One method quantified 20 terpenes, [5] another 42, [9] and a headspace method reported a 5 ppm detection limit. [6] A scoping review also lists yield variability and the challenge of terpene bioavailability as barriers to translating humulene research. [1] See Terpene Testing: How Profiles Are Measured and Reported.What research shows
A 2024 scoping review screened 340 articles on humulene. [1] Its main findings are in the table.| Question | What was found | Evidence label |
|---|---|---|
| Cancer cells | Humulene was cytotoxic to several adenocarcinoma cell types in the lab, through mitochondrial dysfunction and oxidative stress, with varied responses in other cells. [1] | Preclinical (cells/animals only) |
| Inflammation in rodents | Oral humulene reduced inflammation markers in paw swelling and allergic airway models in rodents. [1] | Preclinical (cells/animals only) |
| Cannabinoid-like action | In rodents, injected humulene showed cannabimimetic properties through CB1 and adenosine A2a receptors. [1] | Preclinical (cells/animals only) |
| Eye cells | In cultured eye (pterygium) cells, humulene alone did not significantly change the inflammation markers measured, while beta-caryophyllene lowered one (IL-6). [10] | Preclinical (cells/animals only) |
| Effects in people | The scoping review found a paucity of studies translating this research to clinical populations. [1] Proper evidence not found for human benefit. | Insufficient evidence |
Animal and cell findings are not shown to apply to people, and no source read tested humulene from cannabis in humans. In cells, humulene also did not alter the way THC acted on TRPA1 or TRPV1 channels. [11] Statements that humulene "suppresses appetite" or "fights inflammation" in cannabis products are a marketing claim unless backed by human trials. A 140-flower study found terpene profiles unrelated to estimated effects. [12] The "entourage effect" is discussed in The Entourage Effect: Evidence and Uncertainty.
Safety and limits
- No human safety profile. The scoping review points to the need for rigorous pharmacokinetic studies, [1] and the sources read give no established human safety data for concentrated or inhaled humulene.
- Cell toxicity. The review notes humulene reduced intracellular glutathione and induced oxidative stress in cancer cell experiments. [1] That was in laboratory cells and is not a finding about people.
- Heated inhalation. In a laboratory test, adding terpenes to THC raised gas-phase breakdown products from vaping and dabbing. [13] The test did not isolate humulene. See Smoking and Vaping Cannabis: Respiratory and Other Risks.
- Special groups. Pregnancy, children, older adults and people with chronic illness: Proper evidence not found.
If a child or pet swallows a cannabis product, call US Poison Help at 1-800-222-1222, or 911 in an emergency.
Quality and labeling
A humulene figure on a lab report is a batch measurement. It does not establish effects. See How to Read a Cannabis Certificate of Analysis and Terpenes in Cannabis.Frequently asked questions
Does humulene suppress appetite?
No human evidence was found in the sources read. The scoping review found few clinical studies, [1] so an appetite claim is a marketing claim.
Is humulene the same as caryophyllene?
No. They share the formula C15H24 but have different structures. [2] [3]
Is humulene found outside cannabis?
Yes. It is found in the essential oils of various plant species. [1]
Is humulene safe?
Not established for concentrated or inhaled use in people. Cell studies showed toxicity to cancer cells and oxidative stress, [1] which are laboratory findings only.