YK11, also known as YK-11, is a potent selective androgen receptor modulator (SARM) designed to boost muscle growth and physical performance. Unlike traditional anabolic steroids, YK11 inhibits myostatin, a protein that limits muscle development, leading to enhanced muscle mass and strength. Additionally, YK11 may improve bone density and strength. Its selective action reduces common steroid side effects, offering a safer alternative for achieving superior gains.