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Description of key information

Short description of key information on bioaccumulation potential result: 
L-, DL, and unspecified Menthol isomers were well absorbed via the oral (dermal 100 % assumtion) route of exposure. They were mainly excreted as glucuronic acid conjugates. In rats an extensive enterohepatic circulation leads in addition to various hydoxylated degradation products. Glucuronides and degradation products were mainly eliminated via urine, minor quantities via the faeces. Thus, both in animals and humans menthol seems to be metabolized in a similar way, being rapidly glucuronidated and excreted mainly via urine.

Key value for chemical safety assessment

Bioaccumulation potential:
no bioaccumulation potential

Additional information

L-, DL, and unspecified Menthol isomers were well absorbed via the oral rout and as a worst case assumption also by dermal route. They were mainly excreted as glucuronic acid conjugates. Glucuronides and degradation products were fast eliminated mainly via urine, minor quantities via the faces. In one study reliable 1 study the total excretion in rats was after 17 h was 56,5% of given dose correlating to about 90% of the recoverd Menthol activity. Additional recovered activity was found in ileum 3.5%, fat 2.1 %, liver 0.8%, Serum 0.31%,Kidney 0.2%, Brain < 0.1%, Testis < 0.1%. Administrated menthol in soft gelatine capsuls to human probands was fast absorbed and excreted (halflife of excetrion 2 -4h).

Menthol glycuronic acid appeared in the urine of rabbits in less than an hour after gavage dosing menthol, and 90 per cent of the conjugated acid was found to be excreted in 6 hours when 2 g of menthol were feed. Even when larger doses were given over 90 per cent of the total amount excreted appeared in the urine during the first 24 hours.

Thus, both in animals and humans the Menthols can be metabolized in similar way, being rapidly glucuronidated and excreted mainly via urine.

A toxicokinetic assessment in more detail is presented in attachment MentholsTK_Assessment_Final.pdf of section Basic toxicokinetics.