All the herbs used in this product are either organic, wild harvested, non-fumigated, non-irradiated, pesticide free and/or non-genetically altered.   

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Gymnema Sylvestre Research Update
Gymnema sylvestre leaf extract: a 52-week dietary toxicity study in Wistar rats
Center for Biological Safety and Research, National Institute of Health Sciences: 1-18-1, Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan.
A 52-week study of oral-repeated-dose toxicity for the extraction powder of Gymnema sylvestre, Indian-native genus, Metaplexis japonica, was conducted in both genders of Wistar rats. The rats were administered a graded dose of Gymnema sylvestre at 0.01, 0.10 and 1.00% of basal powder diet, along with a group fed solely with the basal powder diet without gymnema, for 52 weeks. General conditions were recorded daily. Body weights and food consumptions were recorded weekly up to 12 weeks, and thereafter at longer intervals. At 26 weeks, for an intermediate examination, and 52 weeks, for the final examination, animals were subjected to hematology, serum chemistry, and pathological examination. None of the animals died in the period up to 52 weeks. No exposure-related changes in body-weight, in the food consumption, in the hematological examinations, or in the serum biochemical examinations were recognized. No histopathological alterations were seen. Thus, it was concluded that there was no toxic effect in rats treated with gymnema at up to 1.00% in the diet for 52 weeks. The no-observable-effect level from this study is 1.00% gymnema sylvestre, i.e., 504 mg/kg/day for male and 563 mg/kg/day for female as mean daily intake, for 52 weeks.

Effect of administration with the extract of Gymnema sylvestre R. Br leaves on lipid metabolism in rats.
Biol Pharm Bull. 2001 Jun;24(6):713-7.
Extract of Gymnema sylvestre R. Br leaves was orally administered once a day to rats fed a high fat diet or normal fat diet for 3 weeks to investigate its influence on lipid metabolism. As a result, Gymnema sylvestre did not influence body weight gain or feed intake in both diet groups during the experimental period. The apparent fat digestibility was significantly decreased by Gymnema sylvestre in both diet groups for the last 2 weeks of the experimental period, though not the apparent protein digestibility. In addition, the excretion of neutral sterols and acid steroids into feces was increased by Gymnema sylvestre in both diet groups. Furthermore, Gymnema sylvestre decreased the total cholesterol and triglyceride levels in serum. On the other hand, blood lecithin-cholesterol acyltransferase (LCAT) activity was increased by Gymnema sylvestre. Moreover, it was suggested that Gymnema sylvestre influenced cecal fermentation and that propionic acid and acetic acid contents in cecum were significantly increased by Gymnema. Consequently, it was suggested that gymnema improved serum cholesterol and triglyceride levels through influence over a wide range of lipid metabolism in rats.

Antidiabetic effect of a leaf extract from Gymnema sylvestre in non-insulin-dependent diabetes mellitus patients.
Postgraduate Institute of Basic Medical Sciences Madras, India
J Ethnopharmacol 1990 Oct;30(3):295-300
The effectiveness of GS4, an extract from the leaves of Gymnema sylvestre, in controlling hyperglycaemia was investigated in 22 Type 2 diabetic patients on conventional oral anti-hyperglycaemic agents. Gymnema (400 mg/day) was administered for 18-20 months as a supplement to the conventional oral drugs. During Gymnema supplementation, the patients showed a significant reduction in blood glucose, glycosylated haemoglobin and glycosylated plasma proteins, and conventional drug dosage could be decreased. Five of the 22 diabetic patients were able to discontinue their conventional drug and maintain their blood glucose homeostasis with Gymnema alone. These data suggest that the beta cells may be regenerated/repaired in Type 2 diabetic patients on Gymnema sylvestre supplementation. This is supported by the appearance of raised insulin levels in the serum of patients after Gymnema sylvestre supplementation.