Melatonin pills. Collection of pills of melatonin, a hormone which controls the biological clock and induces sleep, and is claimed to slow aging. Melatonin is produced naturally by the pineal gland in the brain. Secreted at night, it helps to control sleep and set the biological clock. In middle age, melatonin secretion drops off and may be responsible for symptoms of aging like insomnia and irritability. As a drug melatonin can be taken by people aged over 40 just before they go to bed. By assisting the rhythm of sleep, the body is more rested when awake. In this way it is thought that the aging process may be slowed. Melatonin is also used successfully to prevent jetlag.