The first step in making homemade roll-on deodorant is to mix the magnesium hydroxide with the water. Some of the magnesium may settle, so you'll have time to mix it again later.
Measure all the rest of the ingredients into a bowl and whisk together.
Add the magnesium water and whisk in as well. The arrowroot powder may want to clump up so you may need to work it a bit.
Once it's all mixed, pour into roll-on bottles and secure the top.
To use, shake the bottle and roll onto underarms. You can also use this recipe for under breast sweat, foot sweat and back sweat.
Remember, this is not an antiperspirant so it won't keep you dry, but it will help to minimize odors.