Spearmint is peppermint's milder relative. Both come from the mint family and both carry menthol, but spearmint holds only a fraction of it — which is exactly why it is worth keeping separate on the shelf. Peppermint hits cold and sharp. Spearmint cools without the sting, and that makes it the better choice for thin, tender, or already irritated skin.
Its usefulness on feet is twofold. The antiseptic compounds in the oil discourage the bacteria that turn ordinary foot sweat into foot odour, and the mild menthol gives a cooling sensation that takes the edge off hot, tired feet at the end of a long day.
If peppermint has ever felt too strong on your skin — a burning rather than a cooling — spearmint is the substitution to make.
