Medicinal Plants and Herbs for Diabetes


Throughout history, many cultures have relied heavily on plants and herbs for medicinal purposes. Modern medicine is now looking at how these traditional sources can be used to treat and manage diabetes either along with conventional medications or on their own. The source and purity of an herb is crucial for effectiveness and to minimize any possible side effects. Professional guidance is always advised when using herbal remedies. Research has been conducted on many sources of medicinal herbs including the following:


American ginseng (Panax quinquefolium)  American ginseng appears to lower blood glucose levels by enhancing insulin secretion (1). One study found that people with type 2 diabetes who took American ginseng before or with their meal experienced a moderate reduction in glucose levels after the meal (2).


Bay (Laurus nobilis)  Bay leaf is demonstrated to help the body use insulin more efficiently at levels as low as 500 mg which is less than half a teaspoon. Other spices like cinnamon, cloves, turmeric, coriander, and cumin are also good at controlling blood sugar levels (3).


Berberine – Research has shown that 500mg of Berberine taken 2-3 times daily was able to control blood sugar and lipid metabolism as effectively as metformin (4).


Bitter Gourd (Momordica charantia)  This particular plant, also known as bitter melon, has attracted considerable interest for its ability to regulate blood sugar (5).


Cayenne (Capsicum frutescens)  This is another herb used in alleviating pain associated with diabetic neuropathy. It is commonly called chili pepper and is used in the form of an external cream.


Cinnamon  This popular spice has demonstrated an ability to increase insulin sensitivity and reduce both blood glucose and cholesterol levels in people with Type 2 diabetes (6,7). Diabetes Action funded research by Dr. Richard Anderson’s lab discovered that a new water-soluble polyphenol type-A polymer was the most effective and safe ingredient (8). Because whole cinnamon includes fat soluble components such as coumarin, which may be toxic at high doses, only the water soluble extract with patented names such as Cinnulin PF or CinnSulin should be used. Additional studies funded by Diabetes Action found this same cinnamon extract has shown neuroprotective effects on the brain which can lead to improved prevention and treatment of Alzheimer’s disease (9). Many researchers are now calling Alzheimer’s Type 3 Diabetes.


Curcumin (Turmeric) – A commonly used food spice that has been traditionally used for pain and wound healing but also appears to inhibit autoimmune disease by regulating inflammatory cytokines. Research has shown that curcumin may be 400 times more powerful than the common diabetes drug Metformin in improving insulin sensitivity and helping to reverse type 2 diabetes (10).


Evening Primrose Oil (Gamma linolenic acid or GLA)  Defective fatty acid metabolism in diabetes may lead to impaired nerve function and can contribute to the development of peripheral neuropathy. Initial studies suggest that evening primrose oil, which is rich in gamma linolenic acid, improves blood flow and nerve function (11).


Fenugreek (Trigonella foenum-graecum) – Fenugreek, a common ingredient in Indian and Middle Eastern cuisine, has been shown to help regulate blood sugar levels and increase good (HDL) cholesterol while lowering total cholesterol (12). In addition, fenugreek seeds are a good source of soluble fiber.


Flax (Linum usitatiisimum)  Flax seed is one of nature’s richest sources of soluble fiber. Research has shown a significant improvement in glucose values by the intake of flax fiber (13). In addition, flax oil is an excellent source of alpha linolenic acid (omega-3 fatty acid). Either ground flax seed or its oil can be used in bread or muffins.


Ginger (Zingiber officinale)  Most commonly used as a flavoring for food, ginger may also be taken orally in higher amounts for various kinds of digestive relief. Limited studies in animals with diabetes show that ginger may reduce blood levels of sugar and cholesterol (14,15,16).


Ginko Biloba – For patients with type 2 diabetes who were poorly managed on metformin, the addition of a Ginkgo Biloba extract was effective in improving treatment outcomes. (17)


Gurmar (Gymnema sylvestre) – In a 2000 study conducted by Diabetes Educators, 65 patients showed a significant reduction in A1C levels when they took a commercial supplement that contained 400 mg of gymnema sylvestre leaf extract (18).


Hydroxycitric Acid (HCA) – This herbal compound found naturally in the grindle berry, Garcinia Cambogia, may play an essential role in lowering cholesterol and for weight reduction by suppressing appetite. Mixed results and potential side effects show the need for further research. HCA should not be used by anyone taking either cholesterol or diabetes medications (19).


Lagerstoemia speciosa  This plant is commonly called Banaba in the Philippines, also known as Crepe Myrtle, Queen’s Flower or Pride of India. It has been shown to regulate blood glucose levels by increasing insulin action (20).


Nopal (Opuntia fulignosa)  Nopal, also called the prickly pear cactus, is a popular food in Latin America. Numerous studies regarding its role in controlling and lowering blood sugar have been conducted. An Austrian study showed that opuntia decreased blood lipids, blood glucose, and increased insulin sensitivity in people without diabetes (21).


Onions and Garlic (Allium cepa and Allium sativum)  The use of onions and garlic to reduce blood sugar levels has been popular in Asia, Europe and the Middle East. These plants contain the sulfur compounds allicin and allyl propyl di sulphide which have chemical structures similar to insulin, and therefore are believed to reduce blood sugar.


Pomegranate (Punica granatum)  This delicious fruit contains many beneficial substances such as polyphenols, that have antioxidant, anti-viral, and anti-tumor properties. Its cinical role is being explored now with encouraging initial results in lowering lipid levels in people with diabetes (21) and improving blood flow to the heart (23).


Pycogenol – This extract of pine bark has been used in some countries to treat diabetic retinopathy and diabetic ulcers. A German study showed a positive effect on lowering glucose levels (24).


Red Yeast Rice (monascus purpureus) – Although many doctors prescribe statin drugs to lower LDL cholesterol levels, research has shown similar anti inflammatory and lipid lowering effects from taking red yeast rice. However, this should only be taken under medical supervision as the red yeast rice extract does contain the same chemicals as the prescription drug lovastatin (25).


Resveratrol – This polyphenolic compound is found in various plants such as grapes and berries. There has been compelling evidence on the strong anti-inflammatory potential of Resveratrol as an anti-aging agent (26).


Silymarin (Milk Thistle) – This herb has been used to treat liver diseases for many years. Recent research has shown that silymarin reduces insulin resistance and significantly decreases fasting insulin levels and lowering liver enzyme levels better than patients taking metformin  (27).


Sulforaphane – This phytochemical is found in cruciferous vegetables such as broccoli, kale, and cabbage. It has not only shown strong cancer preventive actions, but has been able to show a reduction of blood sugars by 10% (28).


Tea (camellia senensis)  Due to its high antioxidant polyphenol content, in traditional Chinese and Indian medicine, green tea has been used successfully in promoting digestion, wound healing, lowering blood glucose, and improving heart health. Research shows that black, green, and oolong teas increase insulin sensitivity (29). However, herbal teas were not effective because they do not contain camellia senensis.



1.     Vuksan V, Sievenpiper JL, Xu Z, et al. “Konjac-Mannan and American ginsing: emerging alternative therapies for type 2 diabetes mellitus.” Am Coll Nutr, 2001. 20 (5 Suppl): 370S-380S.

2.     Vuksan V, Sievenpiper JL, Koo VY, et al. “American ginseng (Panax quinquefolius L) reduces postprandial glycemia in nondiabetic subjects and subjects with type 2 diabetes mellitus.” Arch Intern Med., 2000. 160(7):1009-13.

3.     Khan, A., Bryden, N.A., Polansky, M.M, and Anderson, R.A. “Insulin potentiating factor and chromium content of selected spices.” Biol Trace Elem Res., 1990. 24: 183-188.

4. Lan J, Zhao Y, Dong F, Yan Z, Zheng W, Fan J, Sun G. Meta-analysis of the effect and safety of berberine in the treatment of type 2 diabetes mellitus, hyperlipemia and hypertension. J Ethnopharmacol. 2015 Feb 23;161:69-81. 

5.     Abascal, K., Yarnell, E. “Using bittermelon to treat diabetes.” Altern Complemen Ther, 11(4): 179-184.

6.     McBride, J., “Cinnamon extracts boost insulin sensitivity.” Agricultural Research, 2000. 48(7): 21.

7.     Khan, A., Safdar, M., Ali, Khan M.M., Khattak, K.N., Anderson, R.A. “Cinnamon improves glucose and lipids of people with type 2 diabetes”. Diabetes Care, 2003. 26(12):3215-8.

8.     Anderson, R., Broadhurst, C.L., Polansky, M.M., et al. “Isolation and characterization of polyphenol type-A polymers from cinnamon with insulin-like biological activity.” J Agric Food Chem, 2004. 52(1):65-70.

9.     Peterson, Dylan W., Anderson, Richard A., et al. “Cinnamon extract inhibits tau aggregation associated with Alzheimer’s disease in vitro.” Journal of Alzheimer’s Disease. 2009: 17(3): 457-467.

10.  Kim T, Davis J, Zhang AJ, He X, Mathews ST. Curcumin activates AMPK and suppresses gluconeogenic gene expression in hepatoma cells. Biochem Biophys Res Commun. 2009 Oct 16;388(2):377-82.

11.  Ford, I., Cotter, M.A., Cameron, N.E., Greaves, M. “The effects of treatment with alpha- lipoic acid or evening primrose oil on vascular hemostatic and lipid risk factors, blood flow, and peripheral nerve conduction in the streptozotocin-diabetic rat.” Metabolism, 2001. 50(8):868-75.

12.  Vijayakumar, M.V. ,Singh, S., Chhipa, R.R., Bhat, M.K. “The hypoglycemic activity of fenugreek seed extract is mediated through the stimulation of an insulin signalling pathway.” Br J Pharmacol, 2005. 146(1):41-8.

13.  Dahl, W.J.,.Lockert, E.A., Cammer, A.L., Whiting, S.J. “Effects of flax fiber on laxation and glycemic response in healthy volunteers.” J Med Food, 2005. 8(4):508-11.

14.  Akhani SP, Vishwakarma SL, Goyal RK. Anti-diabetic activity of Zingiber officinale in streptozotocin-induced type I diabetic rats J Pharm Pharmacol. 2004 Jan;56(1):101-5.

15.  Bhandari U, Kanojia R, Pillai KK. Effect of ethanolic extract of Zingiber officinale on dyslipidaemia in diabetic ratsJ Ethnopharmacol. 2005 Feb 28;97(2):227-30.

16.  Srinivasan K. Plant foods in the management of diabetes mellitus: spices as beneficial antidiabetic food adjuncts. Int J Food Sci Nutr. 2005 Sep;56(6):399-414.

17.  Aziz TA, Hussain SA, Mahwi TO, Ahmed ZA, Rahman HS, Rasedee A. The efficacy and safety of Ginkgo biloba extract as an adjuvant in type 2 diabetes mellitus patients ineffectively managed with metformin: a double-blind, randomized, placebo-controlled trial. Drug Des Devel Ther. 2018 Apr 5;12:735-742.

18.  Joffe, D.J., Freed, S.H. “Effect of extended release gymnema sylvestre leaf extract (Beta Fast GXR) alone or in combination with oral hypoglycemics or insulin regimens for type 1 and type 2 diabetes.” Diabetes In Control Newsletter, 2001. 76(1).

19.  Onakpoya I, Hung SK, Perry R, Wider B, Ernst E. The Use of Garcinia Extract (Hydroxycitric Acid) as a Weight loss Supplement: A Systematic Review and Meta-Analysis of Randomised Clinical Trials. J Obes. 2011;2011:509038.

20.  Hattori K, Sukenobu N, Sasaki T, Takasuga S, Hayashi T, Kasai R, Yamasaki K, Hazeki O. Activation of insulin receptors by lagerstroemin.J Pharmacol Sci. 2003 Sep;93(1):69-73.

21.  Wolfram RM, Kritz H, Efthimiou Y, Stomatopoulos J, Sinzinger H. Effect of prickly pear (Opuntia robusta) on glucose- and lipid-metabolism in non-diabetics with hyperlipidemia--a pilot study. Wien Klin Wochenschr. 2002 Oct 31;114(19-20):840-6.

22.  Esmaillzadeh A, Tahbaz F, Gaieni I, Alavi-Majd H, Azadbakht L. “Concentrated pomegranate juice improves lipid profiles in diabetic patients with hyperlipidemia.” J Med Food. 2004 Fall;7(3):305-8.

23.  Sumner, M.D., et al. “Effects of pomegranate juice consumption on myocardial perfusion in patients with coronary heart disease.” Am Jrnl Cardiology, 2005 96(6): 810-814.

24.  Liu, Ximing, MD et al. “French Maritime Bark Extract Pycnogenol Dose-Dependently Lowers Glucose in Type 2 Diabetic Patients.” Diabetes Care. 2004 (3) vol. 27 pg. 839.

25.  Becker, David J., M.D., et al. “Red yeast rice for dyslipidemia in statin intolerant patients: a randomized trial.” Annals of Internal Medicine. 2009; 150: 830-839.

26.  Alarcon de la Lastra, Catalina “Resveratrol as an anti inflammatory and anti-aging agent: mechanisms and clinical implications.” Molecular Nutrition & Food Research. 2005 (5) Vol 49:405-430.

27.  Ebrahimpour-Koujan S, Gargari BP, Mobasseri M, Valizadeh H, Asghari-Jafarabadi M. Lower glycemic indices and lipid profile among type 2 diabetes mellitus patients who received novel dose of Silybum marianum (L.) Gaertn. (silymarin) extract supplement: A Triple-blinded randomized controlled clinical trial. Phytomedicine. 2018 May 15;44:39-44.

28.  Axelsson AS, Tubbs E, Mecham B, Chacko S, Nenonen HA, Tang Y, Fahey JW, Derry  JMJ, Wollheim CB, Wierup N, Haymond MW, Friend SH, Mulder H, Rosengren AH. Sulforaphane reduces hepatic glucose production and improves glucose control in patients with type 2 diabetes. Sci Transl Med. 2017 Jun 14;9(394).

29.  Anderson, R.A., Polansky, M. “Tea enhances insulin activity.” J Agric Food Chem, 2002. 50(24): 7182-7186.