What is Citronellal?
Citronellal is a volatile organic aldehyde compound (3,7-dimethyl-6-octen-1-al) that occurs naturally in the essential oils of various plants, particularly citronella grass (Cymbopogon nardus) and lemongrass. It is characterized by a fresh, lemony, slightly floral odor and is used primarily in the flavor and fragrance industries. The compound is a colorless to pale yellow liquid at room temperature and is soluble in alcohol and oils.
Common Uses
In food manufacturing, citronellal serves as a flavoring agent to impart citrus and herbal notes to beverages, confectionery, baked goods, and dairy products. It is also used in non-food applications such as cosmetics, perfumery, and insect repellent products. The compound is typically used in very small quantities, measured in parts per million (ppm), as its potent flavor profile requires minimal amounts to achieve the desired sensory effect. Food manufacturers select citronellal when a natural-origin citrus flavoring is desired.
Safety Assessment
Citronellal has been studied for safety in food applications, though it is not currently on the FDA's Generally Recognized As Safe (GRAS) list. However, the FDA has received zero adverse event reports associated with citronellal use in food. Additionally, there have been no FDA-initiated recalls linked to this additive. The compound has been evaluated by the European Food Safety Authority (EFSA) as part of flavoring substance assessments, and it appears in lists of flavoring agents used in the EU.
Toxicological data indicate that citronellal has relatively low acute toxicity when ingested. The lethal dose (LD50) in rats via oral administration is documented in the range of 2,000-3,000 mg/kg body weight, classifying it as having low acute toxicity. Dermal and inhalation exposure studies have also shown relatively low hazard profiles, though skin irritation may occur with undiluted compound contact.
No significant genotoxicity or reproductive toxicity concerns have been identified in available literature. The primary metabolic pathway involves oxidation and conjugation reactions similar to those processing other volatile aldehydes. Long-term dietary exposure studies specific to citronellal are limited, which is typical for flavoring compounds used in minimal quantities.
Regulatory Status
Citronellal is not approved as a GRAS substance by the FDA, meaning it has not undergone the standard GRAS notification process or received formal FDA approval for use in food. However, its absence from the GRAS list does not indicate unsafe status; rather, it reflects that manufacturers have not submitted formal GRAS determinations or that such determinations have not been published. The compound is listed in flavor databases and is used in food products in some jurisdictions. In the EU, citronellal is included in the register of flavoring substances and can be used under Regulation (EC) No. 1334/2008, subject to maximum usage levels established for specific food categories. Usage levels in food typically range from 0.1 to 10 ppm depending on the food category.
Key Studies
Flavor and fragrance industry organizations, including the International Fragrance Association (IFRA), have compiled safety data on citronellal. Studies on citronellal metabolism in humans and animals indicate rapid clearance via oxidative pathways. Olfactory safety assessments have established threshold concentrations for sensory irritation. Research on structurally related compounds (other citrus aldehydes and terpenoid compounds) suggests that citronellal follows expected metabolic patterns for volatile flavor compounds. No published clinical studies report adverse health outcomes from food-level exposure to citronellal in humans.