Yoga Makes You Younger -The Third Eye and it's effects on the pineal gland's production of melatonin The pineal gland is considered one of the body's greatest mysteries. Today we know that it is an endocrine gland which secrets the hormone melatonin. Western science has mainly ignored this gland and considered it more or less useless. It is not until the last 50 years that science has started to uncover some of the pineal glands great secrets.