A garlic monograph for the home
Garlic at a glance
Scientific name: Allium sativum
Common names: garlic, elephant garlic, purple garlic
Family name: Amaryllidaceae
Part(s) of the plant used: fresh or dried bulb
Native region and environment: A perennial plant of the Amaryllis family, grown for its flavorful bulbs. Garlic is native to central Asia, but also grows wild in Italy and southern France. It is a classic ingredient in many national cuisines of the region.
This garlic monograph provides basic information about garlic—common names, usefulness and safety, and resources for more information. Browse more herbal monographs.
Garlic has been frequently used in remedies in China since 2700 BC. TCM healers place garlic in the Yang category, for its heating and stimulating effects. Garlic was also used in ancient China to treat depression. In Ayurveda, garlic is a valuable remedy used as a tonic to cure a lack of appetite, common weakness, cough, skin disease, rheumatism, and hemorrhoids. Garlic was brought to the Americas by European settlers in the colonial period. During the influenza pandemic of 1917-1918, some Americans believed so strongly in this herb they wore a necklace of garlic when going out in public.
Garlic constituents & diabetes
The potential health benefits of garlic to support a body with T2DM and metabolic syndrome is enormous. Garlic contains a variety of constituents including organosulfur compounds, saponins, phenols, and polysaccharides. At more than 20 phenolic compounds (including: β-resorcylic acid, gallic acid, rutin, and quercetin) garlic has more phytochemicals than many common vegetables! Garlic has been shown to improve both glucose homeostasis and lower high cholesterol, commonly associated with T2DM. The active phytochemicals of garlic that have been attributed to these beneficial effects are mainly volatile sulfur compounds like alliin and allicin. Garlic has also been shown to improve insulin sensitivity. A clinical trial studying the effect of orally administered raw garlic on T2DM patients demonstrated a significant reduction in blood glucose level, lipid metabolism and significant improvement in antioxidant enzymes in diabetic patients. Several studies have also reported increased insulin secretion upon administration of garlic or garlic extracts/preparations. Researchers have speculated that the higher insulin production is a result of the actions of another constituent, allixin. The total amount of saponins in purple garlic is almost 40 times higher than that in white garlic, which could indicate that purple varieties are better for antidiabetic results. Studies also indicate that raw garlic has strong antioxidant properties and has been shown to exhibit anti-inflammatory properties which are so supportive to people with T2DM.
With a safety rating of 1 and interaction class C, garlic is generally a safe herb to take, but has been shown to have some herb-drug interactions. Garlic, especially fresh garlic, is safe to include in your daily meals. It is suitable for long-term use, but may need to be temporarily stopped before a major surgery.
Potential Drug Interactions
Persons taking heparin, clopidogrel, or aspirin, and doses equivalent to two or more grams daily of fresh garlic should be monitored for abnormal bleeding.
Garlic preparation & dosing
Garlic is readily available in fresh heads at grocery stores. If you are interested in working with a tincture or capsule format, I would recommend you buy this product from a specialty store, like Mountain Rose Herbs.
|Daily Dosage Table: Garlic|
|Fresh||2 cloves||Fresh, minced cloves|
|Tincture||1.5-6 mL||1:1 liquid extract|
|Capsule||500-1000mg||Take with water|
Garlic References Mirunalini, S., Krishnaveni, M., Ambily, V., and Professor, A. (2011). Effects of raw garlic (Allium Sativum) on hyperglycemia in patients with type 2 diabetes mellitus. Pharmacology Online 2, 968–974.
 Eidi, A., Eidi, M., and Esmaeili, E. (2006). Antidiabetic effect of garlic (Allium sativum L.) in normal and streptozotocin-induced diabetic rats. Phytomedicine 13, 624–629. doi: 10.1016/j.phymed.2005.09.010
 Islam, M. S., and Choi, H. (2008). Comparative effects of dietary ginger (Zingiber officinale) and garlic (Allium sativum) investigated in a type 2 diabetes model of rats. J. Med. Food 11, 152–159. doi: 10.1089/jmf.2007.634
 Braun & Cohen (2015) Herbs & Natural Supplements Vol 2. , Elsevier, Sydney Australia