Whatever 'youthening' effect l-dope has is considered by many to relate to its antagonism to serotonin, a substance used in the body in nervous system activities, but which tends to accumulate with age. There are theories which relate the accumulation of serotonin with a 'death hormone' release, and the benefits of l-dope with its suppression of excessive buildup of levels of serotonin. Serotonin accumulates more rapidly with age, more rapidly on a very high protein diet, and also more rapidly when atmospheric conditions tilt towards an excessive level of positive ions in the air.

'The amino acid l-dope is present in only one species of plant, and it is easily oxidized. Two or three days after harvest it declines and is absent by the time the plant finishes its growing period and starts to get dry.' Two cupfuls (200 grams) of pods and seeds contain around 600 milligrams of 1-dope when picked fresh. Three days later this is down to 400 milligrams, and by the time they are marketed 200 grams of beans contain under 90 milligrams.

These beans are now commonly used as a 'natural' treatment of Parkinsorls disease, at which time youth enhancing/anti-ageing characteristics are said to be evident. Dr Beth-EI states: 'A constant daily inclusion of natural l-dope in meals will avoid exhaustion and later atrophy of the human brain dopaminergic system . . . prolonging the youth period of human life, and at the same time adding strength and capabilities to many body functions.'

This extremely useful and apparently valid approach seems to help maintain youth, an outcome which is highly desirable but which is not the same as the achievement of life extension.