Patient QI found the following herbal medicines had evidence for a positive effect on lowering blood pressure.
Hawthorn (Crategus oxycantha, C. monogyna, C. curvisepala)
Patient QI found two studies that show a clear effect of hawthorn on hypertension. Study One randomly assigned participants to a daily supplement for 10 weeks of either: (a) 600 mg Magnesium, (b) 500 mg hawthorn extract, (c) a combination of (a) and (b), (d) placebo. Results showed a reduction in the resting diastolic blood pressure at week 10 in the 19 subjects who were assigned to the hawthorn extract, compared with the other groups. A reduction in anxiety was also observed in those taking hawthorn compared with the other groups.
Study Two investigated the antihypertensive effects of Iranian Hawthorn (C. curvisepala) on 92 patients with primary mild hypertension, aged 40-60 years. Results showed a significant decrease in both systolic and diastolic Blood Pressure after 3 months.
A further study in 2013 investigated the affect of Hawthorn dosage on blood pressure reduction but could find no clear connection between the dose taken and the degree of reduction in blood pressure.
Maitake mushrooms (Grifola frondosa)
Patient QI found many studies exist on the effects of maitake as a cancer or HIV treatment but very little relating maitake to high blood pressure. A 2010 study did assess the ability of edible maitake mushroom to overcome age-associated hypertension amongst other age associated factors and concluded that maitake mushroom fractions lessen age-related hypertension, enhance insulin sensitivity; and reduce some aspects of inflammation.
Olive leaf extract (Olea europea)
Patient QI looked at 3 studies of olive leaf extract supplements to treat high blood pressure.
Study 1 compared a dose of 500mg of olive leaf extract twice a day to a conventional medicine in the ACE inhibitor category. Results showed that the olive leaf worked equally as well as the ACE inhibitor in reducing blood pressure but also reduced triglyceride levels whereas the ACE inhibitor did not.
Study 2 compared doses of 500mg/day, 1000mg per day and change in lifestyle in 40 sets of identical twins suffering from high blood pressure. After 8 weeks the blood pressure had decreased for the 500mg olive leaf extract per day group, significantly decreased in the 1000mg olive leaf extract per day group and the cholesterol levels had decreased for all the groups but by more in the 1000mg/ day group.
Study 3 (paper is published in French) looked at the effects of Olea europaea L. aqueous extract on two groups of patients suffering with essential hypertension. Group 1 were newly diagnosed and Group 2 were already on treatment for hypertension. There was a significant decrease of blood pressure for both groups and no side effects.
Reishi mushrooms (Ganoderma lucidum).
Patient QI found no recent studies which clearly showed that Reishi is effective in lowering blood pressure however a 2012 controlled study indicated that it may have a mild antidiabetic effect and potentially improve the dyslipidaemia of diabetes which can contribute to high blood pressure.
Tribulus terrestris is an Indian herb that is used in Ayurveda medicine for its ability to reduce blood pressure. Patient QI research found only one recent study published in a peer reviewed journal that investigated the anti hypertensive effect of Tribulus terrestris. and results showed that the systolic blood pressure was significantly decreased compared to controls.
Turmeric (Curcuma longa)
Patient QI found a wealth of studies on the anti-inflammatory effects of curcuma and it is currently under investigation for anti cancer properties and its ability to interfere with the replication of viruses. The most recent study that we found on the effect of curcuma on blood pressure was a 2009 study which concluded that their results demonstrated the hypotensive and bradycardic effects of curcuma, as well as a potent vasodilation of mesenteric arteries.
Yerba mate (Ilex paraguariensis)
Yerba mate has traditionally been used in South America for its effect in lowering high blood pressure and overcoming fatigue due to stress. Patient QI found some recent studies published in peer reviewed medical journals on its effects on weight loss and hyperglycemia but no studies specific to reduction of blood pressure.
Patient QI recommends that you always discuss any treatments that you intend to use with your coordinating therapist or a qualified medical herbalist / phytotherapist.