ProTestosterone key to a healthy feeling of strength, energy and well-being | Active. Healthy. Well. | Testosterone is the key to a healthy feeling of strength, energy and well-being. When we’re young, we produce a ton of testosterone that gives us the drive and energy of our youth. But as we age, we begin to produce less and less testosterone. That leads us to feeling more worn out, saps our sex drive and weakens us as we age. It’s a horrible feeling and one that happens to every man at some point.