DL-menthol

Endpoint summary

Description of key information

Menthol isomers were tested for skin irritation in rabbits according to the current OECD-guideline 404. All isomers were tested undiluted and in 50, 25, 5 and 1% concentrations. Diethylphthalate (DEP) was used as diluent. The investigations were performed in the same laboratories, using the same protocol.
Menthol in diethylphahtalate (DEP) was tested for eye irritation according to the current OECD-guideline 405. 

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Additional information

The undiluted compounds were irritating to the skin. Under the experimental conditions the mean score for erythema and edema was 3.

The test article formulation (menthol as 40% solution in DEP as vehicle) and the vehicle (DEP - dieethylphthalate) had almost the same eye-irritating potential. Menthol in a 40% solution is therefore not irritating to the eye.

According to the results from the skin irritation key-study a classification as Xi, R38 (erythema and edema socre: both 3) is justified. GHS: skin irrit. 2, H315).

For eye-irritation no classification required according DSD-DPD, according GHS due to the cornea score = 2.1 a classification as cat.2, H319 is adequate.

Other isomers and concentrations were also studied by the same testing laboratory.

A 29% solution of L-menthol had the following scores: cornea opacity 0.2; redness 0.6; chemnosis 0.1.

A 29% solution of D-menthol had the following scores: cornea opacity 0.4; redness 1.3; chemnosis 0.4.

(OECD SIDS for menthols, UNEP Publications).

Effects on skin irritation/corrosion: irritating

Effect level: empty Endpoint conclusion: Adverse effect observed

Justification for classification or non-classification

Skin irritation:D/L-menthol meets the criteria for classification and labelling for this endpoint, as set out in Regulation (EC) No. 1272/2008. Based on a valid key study performed according to OECD 404 protocol, the substance showed irritating properties with a maximum draize score of 3 that were reversible although not fully reversed at the highest concentration of 100% but the underlying skin remained intact. At concentrations below 50% menthol, the test data did not meet the criteria for classification as skin irritant. Consequently, a specific concentration limit for skin irritation Category 2 is set to ">25% by weight".

Eye irritation:According to CLP classification criteria, the substance meets the criteria for eye irritant category 2. However it does not need to be classified under Directive 67/548/EEC, as all scores were below the limits specified for eye irritation as set out in Directive 67/548/EEC.

Although 40% L-menthol in DEP when tested showed very slight irritation of the eye the results from testing 29% D- and L-menthol and 5% L-menthol clearly indicated no need for classification applying CLP criteria. Consequently, a specific concentration limit for eye irritation Category 2 is set to ">25% by weight".