Human Studies
Numerous human studies with dihydroquercetin (taxifolin) from larch wood have been conducted on people with different pathological conditions.


A randomized, double-blind, placebo-control study was conducted on 100 hypertensive patients with atherosclerosis. The average age of patients was 61.6±1.18 years (50-70 years old). The study evaluated the effect of dihydroquercetin (taxifolin) on hemodynamic and biochemical parameters, endothelial function, and neurological status.

68 patients received dihydroquercetin (taxifolin) 80 mg/day + standard therapy, while the remaining patients received placebo + standard therapy for 12 weeks. At the end of the study, there was a significant decrease in the frequency of headaches by 52% in the group receiving dihydroquercetin (taxifolin), while the decrease reached 25%. Additionally, there was a 41% decrease in the number of complaints on a disturbance in coordination, while no changes were observed in the placebo group. Positive effects on lipid metabolism and improved cerebral microcirculation were observed in the group on dihydroquercetin (taxifolin).
There were no side effects in the group on dihydroquercetin (taxifolin) (Britov & Aparina, 2006).


42 patients (50-76 years old) with chronic microcirculatory disturbances due to arterial hypertension, atherosclerosis and ischemic heart disease, diabetes, etc. received basic therapy + dihydroquercetin (taxifolin) (28 patients) at 0.75 g/day or basic therapy + placebo (14 patients) for 3 months. The treatment with dihydroquercetin (taxifolin) resulted in positive changes in the blood microcirculation, improved rheological indices, increased the rate of blood circulation, and strengthened the capillary walls.
There were no side effects in the group on dihydroquercetin (taxifolin) (Kozlov, et al. 2006).

60 patients (39-75 years old) with atherosclerosis of lower extremities received either basic therapy + placebo (20 patients), or basic therapy dihydroquercetin (taxifolin)  (60 mg/d)- 20 patients, or basic therapy dihydroquercetin (taxifolin) (60 mg/d) + dihydroquercetin (taxifolin) based cream (20 patients) for 2 months. In both groups receiving dihydroquercetin (taxifolin), there was a significant improvement in the ability to walk longer distances without pain, a decrease in the ischemic pain in the damaged extremity, and improved microcirculation.
There were no side effects in the groups on dihydroquercetin (taxifolin) (Koshkin & Nastavweva, 2008).

30 patients (32-68 years old) with ischemic heart disease after aorta-coronary shunting surgery received either basic rehabilitation therapy (10 patients) or basic rehabilitation therapy + dihydroquercetin (taxifolin) (60 mg/day). Administration of dihydroquercetin (taxifolin) as an adjunct therapy significantly improved microcirculation, central and peripheral hemodynamic, improved blood oxygenation, and improved psycho-emotional conditions.
There were no side effects in the group on dihydroquercetin (taxifolin) (Shakula, et al. 2007).


15 patients with chronic venous insufficiency [52.4±2.5 years and 56.3±4.3 years, median age of men and women, respectively] and 15 patients with atherosclerosis [61.3±4.4 years and 64.5±2.3 years, median age of men and women, respecviely] received basic therapy + dihydroquercetin (taxifolin) 30 mg + Ascorbic acid, 70 mg), while 20 patients with chronic venous insufficiency and 10 patients with atherosclerosis received basic therapy for 30 days. Administration of dihydroquercetin (taxifolin) resulted in positive changes in hemodynamic indices, rheological blood parameters, and normalization of parameters of cholesterol metabolism.
There were no side effects in the group on dihydroquercetin (taxifolin) (Tikhonov, 2008).


48 patients with arterial hypertension of the II & III degree received basic therapy + dihydroquercetin (taxifolin), or basic therapy only. 10 healthy controls were also evaluated. The treatment with Adihydroquercetin (taxifolin) resulted in a significant decrease in blood viscosity, an increase in the time of erythrocyte aggregation, an increase in the index of erythrocyte deformability, an increase in the erythrocyte aggregation period, decrease in blood pressure, increase in the systolic index, and significant decrease in the levels of the primary and secondary products of lipid peroxidation.
Safety Result:
There were no side effects in the group on Ascovertin (Plotnikov, et al. 2005).


51 patients w/ischemic heart disease received basic therapy + dihydroquercetin (taxifolin), or basic therapy only. 10 healthy controls were also evaluated. The treatment with dihydroquercetin (taxifolin) resulted in an increase in deformation of erythrocytes, a decrease in the level of fibrinogen, a decrease in the number of episodes of stenocardia, decrease in the number of administered nitroglyceride, increase intolerability to physical exercise, and a decrease in the levels of the primary and secondary products of lipid peroxidation.
Safety Result:
There were no side effects in the group on Ascovertin (Plotnikov, et al. 2005).


40 patients with ischemic heart disease, received basic therapy + dihydroquercetin (taxifolin), or basic therapy+placebo [20 patients] for 3 months. The treatment with dihydroquercetin (taxifolin) has positive effects on the hemorheological status and significantly decreased anginal episodes/week.
There were no side effects in the group on Ascovertin (Tyukavkina, et al. 2001).


29 patients 56-78 years old with discirculatory encephalopathy received basic therapy + Capilar (80 mg/d) for 18-21 days. The administration of dihydroquercetin (taxifolin) showed significant improvements in the psychoemotional conditions of the patients.
There were no side effects observed (Zavolokov, Ilyuhina, 2001).


31 patients with cerebral atherosclerosis received basic therapy + dihydroquercetin (taxifolin) 20 mg, Ascorbic acid, 50 mg), or basic therapy only. 10 healthy controls were also evaluated. The treatment with dihydroquercetin (taxifolin) resulted in a significant decrease in blood viscosity; an increase in the time of erythrocyte aggregation, improvement in short-term memory and ability to concentrate, and a significant decrease in the primary and secondary products of lipid peroxidation.
Safety Result:
There were no side effects in the group on Ascovertin (Plotnikov, et al. 2005).


40 patients, median age 56.2±8.5 years old, with diabetes mellitus received basic therapy + dihydroquercetin (taxifolin) (120 mg/day) or basic therapy + placebo for 12 weeks. 20 healthy volunteers comprised the control group. Administration of dihydroquercetin (taxifolin) resulted in a significant decrease in HbA1x levels and improved sensitivity to insulin.
There were no side effects in the group on Diquertin (Nedosugova, 2006).


37 patients 30-68 years old with diabetes-related onychomycosis of feet and hands received basic therapy (20 patients) or basic therapy+ dihydroquercetin (taxifolin) (120 mg/day) for 12-16 weeks. The treatment with dihydroquercetin (taxifolin) significantly decreased MDA levels and coefficient of intoxication, as determined by the level and value of oligopeptides. There were no side effects in the group on Diquertin (Davudova & Zoloeva, 2009).


29 patients with NIDDM received basic therapy + dihydroquercetin (taxifolin) or basic therapy only. 10 healthy controls were also evaluated. A significant decrease in blood viscosity; an increase in the time of erythrocyte aggregation and in the index of their deformability, a decrease in blood pressure, an increase in the systolic index, and a significant decrease in the levels of the primary and secondary products of lipid peroxidation were observed. There was an improvement in the subjective evaluation by the patients.
Safety Result:
There were no side effects in the group on Ascovertin (Plotnikov, et al. 2005).


43 women with Lyme disease were treated with a basic therapy + dihydroquercetin (taxifolin) + other vitamins, or as control only with the basic therapy. There was an increase in levels of the endogenous antioxidants, and a decrease in the levels of the primary products of lipid peroxidation, as well as a normalization of the menstrual cycle in the taxifolin group.
Safety Result:
There were no side effects in the group on taxifolin (Plotnikov, et al. 2005).


48 women that would undergo an operation on the ovaries were treated with a basic therapy + dihydroquercetin (taxifolin) + vitamin C, or as control only with the basic therapy. The MDA level was much lower in the taxifolin treated group than in the group on basic therapy only, while the levels of catalase and SOD were significantly higher. The amplitude of the uterus muscle contractions 1 month after the operation in the taxifolin-supplemented group was similar to that of the control group.
Safety Result:
There were no side effects in the group on taxifolin (Plotnikov, et al. 2005).


40 male patients with chronic pulmonary obstructive disease, aged 30 to 65 years old (mean age 50.4±2.5), received standard therapy (the control group) or standard therapy plus dihydroquercetin (taxifolin) at 80 mg/day (20 patients in each group) for 18-21 days. At the end of the study, patients in the Taxifolin group showed normalization of the indices of tissue and organs’ microcirculation, increased blood oxygenation, improved rheological blood parameters, increased tolerance to physical exercise, and improved functioning of the respiratory and cardiovascular systems.
There were no side effects in the group on dihydroquercetin (taxifolin)(Shakula, et al. 2008).


56 patients with out-of-hospital-acquired pneumonia received standard therapy or standard therapy+Derinat or standard therapy + dihydroquercetin (taxifolin) 160 mg/d (n=14 patients) or standard therapy + Derinat + dihydroquercetin (taxifolin), 160 mg/d (n=14 patients). 12 healthy subjects composed the control group. dihydroquercetin (taxifolin) rendered the correcting effects on oxygen activity of granulocytes, the concentration of TNF-alpha, IL-1beta, IL-8, GSF-Gi, IL-10, while Derinat- on the content of lymphocytes examined, products of lipid peroxidation, and catalyze activity. The maximal positive effects on the immune responses and oxidant status parameters were found in the application of both preparations.
There were no side effects in the groups on Diquertin (Serikova, et al.).

The effectiveness of supplemental taxifolin in patients with acute pneumonia was investigated. 112 male patients were divided into three groups: the first control group (n=50), which received standard therapy without antioxidants; the second comparative group (n=32) received composite therapy including the standard therapy plus the antioxidative complex of a-tocopherol acetate, 100 mg in pills four times a day, and intravenous administration of 10 ml of 10% solution of sodium thiosulfate two times a day; the third experimental group (n=30), which in addition to the standard therapy received 40-60 mg of dihydroquercetin (taxifolin) four times a day. The antioxidant therapy was administered for 2 weeks following hospitalization. The observation period lasted until day 25.
It was established that the patients of the third group, receiving taxifolin, had a faster recovery from symptoms of pneumonitis and lower the content of TBARS [thiobarbituric acid reactive substances] in blood plasma compared with patients of the first group. Also, patients in the third group showed a more complete X-ray restoration of lung tissue (1.8 times) and a decrease of pulmonary fibrosis (3.6 times) (p<0.05). There was no essential difference between the clinical effectiveness of taxifolin and the antioxidant complex.
Safety Result:
There were no side effects in the group on taxifolin (Teselkin, et al. 1998 and 1998a; Kolhir, 1998).

Human study summary

Altogether, 507 patients were treated with dihydroquercetin (taxifolin) from larch wood (40-120 mg/day) for 2 weeks – 3 months. No side effects were connected with the administration of taxifolin during any of the studies.