For some, a relatively toned physique just won't cut it. Enter muscle implants. Solid silicone implants are placed under or in between muscles to help boost areas that are underdeveloped. Calf and pectoral implants are apparently pretty common for men, and gluteal and bicep implants are gaining traction, too. So, who’s getting these muscle enhancements? “People that do these things are actually in very great shape normally," says Saeed Marefat, M.D. "They’re athletes, they work out, they have almost perfect bodies, but they are perfectionists. They want the best. It’s not the person who’s a couch potato without any muscle at all—it’s the opposite."