An advantage of antiperspirants is that they block sweat glands, which helps keep you dry. Unfortunately, natural deodorants don't have the ability to prevent perspiration, only to mask the smell of it.
If you're not used to sweating, you might be a bit uncomfortable. "In the first weeks of using natural deodorants, people complain of a damp feeling," explains Erum Ilyas, MD, FAAD, a dermatologist in Pennsylvania. "The thing to remember is that time will make this feeling disappear." Otherwise, there's not much you can do.