Body & Beauty / Compounds / D-Limonene

D-Limonene on your skin: a safety profile

Moderate risk

Dermal exposure to D-limonene occurs through direct contact with citrus-based cleaning products, personal care products containing citrus fragrance, and occupational handling of concentrated D-limonene or citrus peel oil. The primary dermal concern is sensitization rather than systemic toxicity: D-limonene and its air-oxidized derivatives (limonene-1,2-oxide, limonene hydroperoxides) are among the most common causes of occupational fragrance-related allergic contact dermatitis. The EU Cosmetics Regulation requires labeling of D-limonene in leave-on products at ≥0.001% and rinse-off products at ≥0.01%. Sensitized individuals develop dermatitis upon re-exposure at concentrations far below irritant thresholds. The occupational risk is highest in cleaning service workers, aromatherapy practitioners, and citrus processing industry workers with prolonged skin contact with D-limonene-containing materials. For non-sensitized individuals, brief consumer product use produces minimal skin risk, though frequent unprotected contact with concentrated products should be avoided.

What is d-limonene?

The IUPAC name is (4R)-1-methyl-4-prop-1-en-2-ylcyclohexene.

Also known as: (4R)-1-methyl-4-prop-1-en-2-ylcyclohexene, (+)-Limonene, (R)-(+)-Limonene, (D)-Limonene.

IUPAC name
(4R)-1-methyl-4-prop-1-en-2-ylcyclohexene
CAS number
5989-27-5
Molecular formula
C10H16
Molecular weight
136.23 g/mol
SMILES
CC1=CCC(CC1)C(=C)C
PubChem CID
440917

Risk for people

Moderate risk

Dermal exposure to D-limonene occurs through direct contact with citrus-based cleaning products, personal care products containing citrus fragrance, and occupational handling of concentrated D-limonene or citrus peel oil. The primary dermal concern is sensitization rather than systemic toxicity: D-limonene and its air-oxidized derivatives (limonene-1,2-oxide, limonene hydroperoxides) are among the most common causes of occupational fragrance-related allergic contact dermatitis. The EU Cosmetics Regulation requires labeling of D-limonene in leave-on products at ≥0.001% and rinse-off products at ≥0.01%. Sensitized individuals develop dermatitis upon re-exposure at concentrations far below irritant thresholds. The occupational risk is highest in cleaning service workers, aromatherapy practitioners, and citrus processing industry workers with prolonged skin contact with D-limonene-containing materials. For non-sensitized individuals, brief consumer product use produces minimal skin risk, though frequent unprotected contact with concentrated products should be avoided.

Regulatory consensus

18 regulatory and scientific bodies have classified D-Limonene. The classifications differ — that's the data.

AgencyYearClassificationNotes
EPA CTX / IARC—Group 3 - Not classifiable as to its carcinogenicity to humans
EPA CTX / Genetox—Genotoxicity: positive (Ames: positive, 8 positive / 7 negative reports)
EPA CTX / Genetox—Genotoxicity: positive (Ames: positive, 8 positive / 7 negative reports)
EPA CTX / Skin-Eye—Skin Irritation: Skin Irrit. 2 (score: high)
EPA CTX / Skin-Eye—Skin Sensitization: Skin Sens. 1 (score: high)
EPA CTX / Skin-Eye—Skin Sensitization: Sh (score: high)
EPA CTX / Skin-Eye—Skin Irritation: Skin irritation - category 2 (score: high)
EPA CTX / Skin-Eye—Skin Sensitization: Skin sensitisation - category 1 (score: high)
EPA CTX / Skin-Eye—Skin Irritation: Skin corrosion/irritation - Category 2 (score: high)
EPA CTX / Skin-Eye—Skin Sensitization: Skin sensitization - Category 1 (score: high)
EPA CTX / Skin-Eye—Skin Irritation: Category 2 (score: high)
EPA CTX / Skin-Eye—Skin Sensitization: Category 1 (score: high)
EPA CTX / Skin-Eye—Eye Irritation: Category 6.4A (Category 2A) (score: high)
EPA CTX / Skin-Eye—Skin Irritation: Category 6.3B (Category 3) (score: moderate)
EPA CTX / Skin-Eye—Skin Sensitization: Category 6.5B (Category 1) (score: moderate)
EPA CTX / Skin-Eye—skin sensitisation: in vivo (LLNA): High Frequency of Sensitization (score: high)
EPA CTX / Skin-Eye—eye irritation: in vivo: Studies Indicate No Significant Irritation (score: low)
EPA CTX / Skin-Eye—skin irritation: in vivo: Studies Indicate No Significant Irritation (score: low)

Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.

Where you encounter d-limonene

  • Industrial Facilities — Manufacturing plants, Chemical storage areas, Waste treatment sites
  • Occupational Environments — Factories, Warehouses, Transportation vehicles
  • Fragrance — perfume, cologne, scented personal care products, household fragrance products, candles
    Identified in Fragrance Ingredient Safety Priority Research database (2,325 ingredients)

Safer alternatives

Lower-risk approaches that achieve a similar outcome to D-Limonene:

  • Fragrance-free formulations
    Trade-offs: Consumer preference for scented products
    Relative cost: Lower (ingredient elimination)
  • Essential oil-based fragrances (with disclosure)
    Trade-offs: Natural does not mean safe — many essential oils are skin sensitizers
    Relative cost: 2-5× conventional

Frequently asked questions

Is d-limonene safe for you?

Dermal exposure to D-limonene occurs through direct contact with citrus-based cleaning products, personal care products containing citrus fragrance, and occupational handling of concentrated D-limonene or citrus peel oil. The primary dermal concern is sensitization rather than systemic toxicity: D-limonene and its air-oxidized derivatives (limonene-1,2-oxide, limonene hydroperoxides) are among the most common causes of occupational fragrance-related allergic contact dermatitis. The EU Cosmetics Regulation requires labeling of D-limonene in leave-on products at ≥0.001% and rinse-off products at ≥0.01%. Sensitized individuals develop dermatitis upon re-exposure at concentrations far below irritant thresholds. The occupational risk is highest in cleaning service workers, aromatherapy practitioners, and citrus processing industry workers with prolonged skin contact with D-limonene-containing materials. For non-sensitized individuals, brief consumer product use produces minimal skin risk, though frequent unprotected contact with concentrated products should be avoided.

What products contain d-limonene?

D-Limonene appears in: Manufacturing plants (Industrial facilities); Chemical storage areas (Industrial facilities); Factories (Occupational environments); Warehouses (Occupational environments); perfume (Fragrance).

Why do regulators disagree about d-limonene?

D-Limonene has been classified by 18 agencies including EPA CTX / IARC, EPA CTX / Genetox, EPA CTX / Genetox, EPA CTX / Skin-Eye, EPA CTX / Skin-Eye, with differing conclusions. Regulators apply different standards of evidence (animal data weighting, exposure-pattern assumptions, epidemiological power thresholds), which is why two scientific bodies can review the same data and reach different conclusions. See the regulatory consensus table on this page for the full picture.

See D-Limonene in the body app

Look up products containing d-limonene, compare to alternatives, and explore the full data record.

Open in body View raw API data

Sources (2)
  1. US FDA: D-Limonene — GRAS Determination, Food Additive Status, and Flavor Safety Assessment (2018) — regulatory
  2. ASPCA Animal Poison Control Center: D-Limonene and Citrus Oil Toxicosis — Clinical Management in Dogs and Cats (2022) — veterinary

Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →