About Testosterone Testosterone is the male hormone that gives men lower voices, facial hair, and sexual interest. Testosterone does been to decline gradually in men after the age of 30, but a sharp decline in testosterone is not normal, and can be a precursor to some more serious illnesses. It can also be hard to diagnose or for men to even recognize as a problem because the symptoms closely mirror the symptoms of things like depression and high blood pressure. Symptoms As previously stated, there are many symptoms of low Testosterone , and they can indicate other things such as depression or high blood pressure. However, if a man is experiencing several of these symptoms together, it is very important that he consult his doctor for further testing: Lowered libido – Although a man’s sex drive will decrease as he becomes older, a marked disinterest in sex can be an indicator of low testosterone. Lack of energy – Low testosterone has also been linked to lower energy and becoming tired ...