Devil's Club and Diabetes

I am 43 years old and I have diabetes. I have read that devil's claw root is good for this condition.The books that I have do not specify the daily dosage. Can you please help me with this. Thank you very much.

Devil's Claw (Harpagophytum procumbens) is used for pain and inflammation in arthritis and for gall bladder & liver complaints. Devil's Club root bark (Oplopanax horridus) is used in diabetes to support the adrenal glands and the endocrine system. It is a member of the Ginseng family, so helpful for increasing vitality. Stephen Harrold Buhner in "Sacred Plant Medicine" (Roberts Rinehart Publishers) recommends taking 30 drops, three times a day, for 6 months to a year.