deodorant but what deodorant to use. I have done a lot of research on when kids should start using deodorant. In my opinion if the kids are using a safe natural deodorant it should be whenever the children begin to develop odor that showering once a day will not contain. This can be 5 years old or earlier in some cases.0 most extreme places on Earth. Children begin to start producing body odor around the same time that they begin puberty. Age of puberty onset varies, and may be from 8 to 14 in girls and about 9 to 15 in boys.