When it first came into the world, natural deodorant reeked of issues. They weren't particularly easy to use, nor were they able to keep you smelling fresh until the end of the day. But after years of research, cosmetic chemists kept chugging until they found formulas that are just as good as the other deodorants you know and love. (A quick refresher: Natural deodorants contain no aluminum, which is what antiperspirants use to prevent your body from producing sweat.) Still, there's nothing worse than taking a chance on a natural deodorant to have it to melt down at the most inopportune time—which is why we called on Glamour staffers to sweat the problem for you. We tested dozens of options to narrow down which aluminum-free deodorants hold up to their claims. Here are the ones that withstood the heat.