FlavScents AInsights Entry for Alpha-Humulene (CAS: 6753-98-6)
1. Identity & Chemical Information
Alpha-humulene, also known as α-humulene, is a naturally occurring monocyclic sesquiterpene. Its IUPAC name is (1E,4E,8E)-2,6,6,9-tetramethylcycloundeca-1,4,8-triene. The CAS number for alpha-humulene is 6753-98-6. It is identified by the FEMA number 3546. The molecular formula of alpha-humulene is C15H24, and it has a molecular weight of 204.35 g/mol. Alpha-humulene is characterized by its cycloundecatriene structure, which contributes to its distinct woody, earthy aroma, often associated with hops and cannabis. The presence of multiple double bonds in its structure is significant for its odor profile, influencing its volatility and interaction with other fragrance components.
Citation hooks: FlavScents; PubChem; FEMA
2. Sensory Profile
Alpha-humulene is known for its woody, earthy, and spicy aroma, reminiscent of hops, which is why it is a key component in the flavor profile of beer. It has a moderate intensity and diffusion, making it suitable as both an impact note and a background modifier in fragrance compositions. The odor threshold of alpha-humulene is relatively low, allowing it to impart its characteristic scent even at minimal concentrations. In flavor applications, it contributes a subtle bitterness and a complex, herbal note that enhances the overall sensory experience.
Citation hooks: FlavScents; peer-reviewed sensory literature
3. Natural Occurrence & Formation
Alpha-humulene is naturally found in a variety of plants, most notably in hops (Humulus lupulus), where it plays a crucial role in the aroma profile of beer. It is also present in cannabis, sage, and ginseng. The formation of alpha-humulene in plants is typically through the mevalonate pathway, a key biosynthetic route for terpenes. Its presence in natural sources qualifies it for use in products labeled as "natural flavor" or "natural fragrance," depending on the extraction and processing methods used.
Citation hooks: FlavScents; food chemistry literature; EFSA/JECFA monographs
4. Use in Flavors
In flavor applications, alpha-humulene is primarily used in beer and other alcoholic beverages to impart a characteristic hoppy note. It is also used in savory flavors, such as those for soups and sauces, where it adds depth and complexity. Typical use levels in finished food or beverages range from 0.1 to 5 ppm, with higher concentrations potentially leading to an overpowering bitterness. Alpha-humulene is relatively stable under heat but can be susceptible to oxidation, which may alter its sensory properties.
Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature
5. Use in Fragrances
Alpha-humulene is utilized in fragrance formulations for its woody and earthy notes, fitting well within the chypre and fougère fragrance families. It serves as a modifier and impact note, providing a natural, green character to perfumes and personal care products. Typical concentration ranges in fragrances are from 0.01% to 0.5%, depending on the desired intensity and product type. Due to its moderate volatility, alpha-humulene contributes primarily to the middle notes of a fragrance composition.
Citation hooks: FlavScents; IFRA; fragrance chemistry texts
6. Regulatory Status (Regional Overview)
In the United States, alpha-humulene is recognized as GRAS (Generally Recognized As Safe) by FEMA for use in flavors. In the European Union, it is regulated under Regulation (EC) No 1334/2008 and has an assigned FL number. The United Kingdom follows similar regulations post-Brexit. In Asia, countries like Japan and China have specific guidelines for its use in food and cosmetics, while ASEAN countries generally align with international standards. In Latin America, Brazil and MERCOSUR countries have their own regulatory frameworks, often harmonized with international norms.
Citation hooks: FEMA; EFSA; national authority publications
7. Toxicology, Safety & Exposure Considerations
Alpha-humulene is considered safe for oral exposure in flavor applications, with an acceptable daily intake (ADI) not specifically established but generally recognized as safe at typical use levels. For dermal exposure in fragrances, it is not known to cause irritation or sensitization, aligning with IFRA standards. Inhalation exposure is considered low risk due to its moderate volatility, but occupational exposure should be managed with standard safety practices. The risk profiles for food and fragrance applications are similar, with no significant differences noted.
Citation hooks: EFSA; FEMA; PubChem; toxicology literature
8. Practical Insights for Formulators
Alpha-humulene is valued for its ability to impart a natural, earthy character to both flavors and fragrances. It synergizes well with other terpenes and aromatic compounds, enhancing the complexity of formulations. Common pitfalls include overuse, which can lead to an undesirable bitterness in flavors or an overpowering note in fragrances. It is often under-utilized in non-alcoholic beverages and personal care products, where its unique profile can offer differentiation.
Citation hooks: FlavScents; industry practice
9. Confidence & Data Quality Notes
The data on alpha-humulene is well-established, with comprehensive sensory and regulatory information available. Industry practices are well-documented, though some regional regulatory nuances may require further clarification. Known data gaps include specific ADI values and detailed toxicological studies, which are typically addressed through industry-standard safety assessments.
Citation hooks: FlavScents
QA Check
- All required sections 1–9 are present
- "Citation hooks:" line is present under each section
- Flavor section includes ppm ranges
- Toxicology section covers oral, dermal, inhalation
- Regulatory section mentions US, EU, UK, Asia, Latin America
- If complex natural material: includes section 5a (not applicable here)
About FlavScents AInsights (Disclosure)
FlavScents AInsights integrates information from authoritative government, scientific, academic, and industry sources to provide applied, exposure-aware insight into flavor and fragrance materials. Data are drawn from regulatory bodies, expert safety panels, peer-reviewed literature, public chemical databases, and long-standing professional practice within the flavor and fragrance community. Where explicit published values exist, they are reported directly; where gaps remain, AInsights reflects widely accepted industry-typical practice derived from convergent sensory behavior, historical commercial use, regulatory non-objection, and expert consensus. All such information is clearly labeled to distinguish documented data from professional guidance or informed estimation, with the goal of offering transparent, practical, and scientifically responsible context for researchers, formulators, and regulatory specialists. This section is generated using advanced computational language modeling to synthesize and structure information from established scientific and regulatory knowledge bases, with the intent of supporting—not replacing—expert review and judgment.
Generated 2026-04-30 17:49:51 GMT (p2)