Damiana Tea for High Blood Pressure?

How much dried damiana is used in a tea for high blood pressure? I'm not sure if this is Chinese? Have heard this is also good for diabetes and migraine. Is gugul good for high cholesterol?

Damiana (Turnera diffusa) is used to strengthen the nervous system, which in many cases can help to reduce blood pressure. It is also used in depression, anxiety and nervous exhaustion. I do not know of its use in diabetes. In migraine, it may be useful if the cause of the migraine is related to nervous exhaustion, stress or emotional disturbances. Migraine is sometimes triggered by certain foods, by poor digestion, by liver or kidney problems or by menstruation.
To make a tea, pour one cup of water over one teaspoon of dried herb in a ceramic pot or cup. Cover and steep for 10-15 minutes. Strain. Drink 3 times a day.
Damiana is not Chinese; it is a Mexican herb.