Start a sensible weight-lifting program. This is how to naturally increase your testosterone level. You want to start weight lifting with small weights. You don't want to start big because the object is to slowly build the big muscles and the small stabilizer muscles correctly from the start, learning correct form. That's how you get strong and avoid injury. You don't even need weights; you can use your own body weight. Youtube has videos that can get you started. You want balance to keep good posture. Sometimes guys focus on odd muscles. Women don't really admire huge necks. They like nice arms, chests, posture, legs.