Menthol expiry, does it oxidize like essential oils do?

[Lets_Soap]

Has anyone come across any information describing menthols oxidation rate, expiry and specifically, if the likelihood of sensitization increases with time like many essential oils?

 

[Zany_in_CO]

Menthol Crystals have been discussed many times.
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I usually use them in blends so oxidation and expiration doesn't come into play in that case. The blends last a long time... even years. I've never noticed a decrease in efficacy, if that's your concern?

MENTHOL CRYSTALS USE