I am answering you citate from famous book of Dr. Colbert ” I can do this diet”:
Getting older ushers in many health changes, including losing muscle and gaining fat. As we age, not only do we lose muscle mass, but also most people experience decreased levels of hormones – particularly anabolic hormones, which help build muscle and include testosterone, dehydroepiandrosterone (DHEA), and growth hormone. This hormone imbalance can severely stunt any weight-loss efforts.
DHEA is precursor of Testosterone synthesis and available now in GNS stores across USA.