Bracelets are unisex in nature as both men and women wear and adorn them with various garments and so on. However, with increasing fashion industry, these have also been segregated into gender biased designs. They are based on taste, preference, color, personality, precious gems and so on. Some cater well for women, whereas other for men. Thus men bead bracelets are a separate category of items, often sold at individual websites of boutiques or at larger e-commerce sites.
The difference between women and men's bracelet designs in mostly in the color, choice of material, size, shape and so on. It is a wise decision to keep them thicker than having smaller beads that might be more suitable for women. Now, this has nothing to do with the thinking, but has been followed for centuries in the fashion department, and some things like color etc. don't change. The bead bracelets are often marketed with accessories like leather, are heavy, are larger in size and might also contain metal parts. These attract men more often than slender and sleek designs, and this is a psychology that caters to the way the designs are segregated into two genders. Then, it is also based on research that men have wider wrists than most women and the thinner and slimmer lines work well on women than men. There are also other details like using of stones and gems in beads and their color that suits one gender little more than the other. Similar things get into designing men's bracelets and are contemporary too, that can change but not too much.