YK 11 is a muscle growth credible stimulant and as strong as S23. While others refute YK11 being a sarm, it naturally increases follistatin levels thereby paving way for your body to produce cells needed in muscle growth. However, others have called YK11 a synthetic steroid manufactured to alter the chemical structure of DHT in the body whereas this DHT is a stronger testosterone. Again, with the presence of DHT, YK11 is also known a sex steroid.