This hormone is usually thought of as the “male” hormone but both sexes produce testosterone. Signs of deficiency in either sex include: weak or flabby muscles, quick fatigue, lack of stamina during physical activity, lowered libido, and ineffective workouts. Normally, people expect that following a workout program will eventually result in increased muscle strength and/or tone. However, without sufficient Testosterone, the person’s muscles will get tired, but they won’t get stronger, resulting in an ineffective workout. One study showed that, across the board, Testosterone levels have been falling over the decades. Today, a 50-year-old male has less testosterone than that of an 80-year-old who lived 20 years ago!