FlavScents AInsights Entry for Isovaleric Acid (CAS: 503-74-2)

1. Identity & Chemical Information

• Common Name(s): Isovaleric acid, 3-Methylbutanoic acid
• IUPAC Name: 3-Methylbutanoic acid
• CAS Number: 503-74-2
• FEMA Number: 3102
• Other Identifiers: FL No. 08.005
• Molecular Formula: C5H10O2
• Molecular Weight: 102.13 g/mol

Isovaleric acid is a branched-chain fatty acid with a carboxylic acid functional group. Its structure contributes to its characteristic pungent odor, often described as cheesy or sweaty, which is significant in both flavor and fragrance applications.

Citation hooks: FlavScents; PubChem; FEMA

2. Sensory Profile

Isovaleric acid is known for its strong, penetrating odor reminiscent of cheese, sweat, or fermented products. It is often used as an impact note in flavor compositions to add authenticity and complexity. The odor threshold is relatively low, making it a potent material in formulations. Its sensory role is typically as a background realism enhancer or a character modifier in both flavors and fragrances.

Citation hooks: FlavScents; peer-reviewed sensory literature

3. Natural Occurrence & Formation

Isovaleric acid naturally occurs in various foods and beverages, including cheese, beer, and soy sauce, often as a result of fermentation processes. It can also be formed through the enzymatic degradation of leucine, an amino acid. Its presence in natural products allows it to be designated as a "natural flavor" in certain contexts.

Citation hooks: FlavScents; food chemistry literature; EFSA/JECFA monographs

4. Use in Flavors

Isovaleric acid is utilized in a variety of flavor categories, including dairy, savory, and fermented profiles. It serves as a functional component to enhance authenticity and depth. Typical use levels in finished food products range from 0.1 to 5 ppm, depending on the desired intensity and application. It is stable under typical processing conditions but may degrade under extreme heat or acidic environments.

Citation hooks: FlavScents; FEMA GRAS documentation; formulation literature

5. Use in Fragrances

In fragrance formulations, isovaleric acid is used to impart a natural, earthy note, often in trace amounts to avoid overpowering the composition. It is found in fragrance families such as chypre and fougère. Its volatility contributes to its role as a top to middle note, providing a distinctive character to the fragrance.

Citation hooks: FlavScents; IFRA; fragrance chemistry texts

6. Regulatory Status (Regional Overview)

• United States: Recognized as GRAS by FEMA for flavor use.
• European Union: Approved under Regulation (EC) No 1334/2008 with FL number 08.005.
• United Kingdom: Aligns with EU regulations post-Brexit.
• Asia: Approved for use in Japan and China, with specific restrictions in ASEAN countries.
• Latin America: Generally accepted, with specific regulations in Brazil and MERCOSUR countries.

Explicit approvals and harmonized assumptions are common, though country-specific variability may exist.

Citation hooks: FEMA; EFSA; national authority publications

7. Toxicology, Safety & Exposure Considerations

For oral exposure, isovaleric acid is considered safe within the established ADI and MSDI limits. Dermal exposure in fragrance applications is generally low risk, but it may cause irritation or sensitization in sensitive individuals. Inhalation exposure is minimal due to its low volatility in typical use concentrations. The risk profiles are similar between food and fragrance applications, with no significant differences noted.

Citation hooks: EFSA; FEMA; PubChem; toxicology literature

8. Practical Insights for Formulators

Isovaleric acid is valued for its ability to enhance the authenticity of flavors and fragrances. It synergizes well with other fatty acids and esters. Formulators should be cautious of its potent odor, which can easily dominate a composition if overused. It is often under-utilized in low concentrations where its impact can be most beneficial.

Citation hooks: FlavScents; industry practice

9. Confidence & Data Quality Notes

The data on isovaleric acid is well-established, with comprehensive documentation available from authoritative sources. Industry practices are well-documented, though some variability in sensory perception may exist. Known data gaps are minimal, with regulatory ambiguities primarily related to regional differences.

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 2026-03-04 09:46:09 GMT (p2)