Did you know there are both similarities and differences in the properties of the two major mint essential oils? Their properties do overlap in some areas, but not in others.
Spearmint is sometimes recommended for children as a safer substitute for peppermint. However, while peppermint (and menthol) have positive effects on respiratory symptoms, spearmint has no known benefits in this area and you may be better off using spruce or pine, for example.
On the other hand, it is Peppermint (menthol) and not Spearmint that will give you a nice cooling sensation in hot weather.
But if you’re looking for something to ease pain, nausea or digestive symptoms, either oil could work well for you.