Table of ContentsView AllTable of ContentsCurrent EvidenceWhich Form Is Best?Dosage and How to TakePossible Side EffectsDrug InteractionsFrequently Asked Questions
Table of ContentsView All
View All
Table of Contents
Current Evidence
Which Form Is Best?
Dosage and How to Take
Possible Side Effects
Drug Interactions
Frequently Asked Questions
Although more research is needed, there is evidence thatgarlic(Allium sativum) can help lowercholesterol. Garlic contains a bioactive compound calledallicinthat is thought to contribute to this effect.
The cholesterol-lowering effects add to the other reported benefits of garlic, including improvedimmunity, reducedblood pressure, and antioxidant properties.
This article takes an unbiased look at research investigating the use of garlic in lowering cholesterol. It also examines which form of garlic is “best” at bringing down cholesterol as well as the possible risks and side effects.
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Garlic and High Cholesterol: Current Research
There have been numerous studies investigating the effects of garlic on blood cholesterol levels. While much of the evidence has been positive, the results remain far from consistent.
Allicin, a sulfur-based compound found in garlic, is attributed to the cholesterol-lowering effects. Even so, the exactmechanism of actionremains under debate.
The investigators further reported that, of the 39 clinical trials included in the review, 26 showed significant reductions in LDL levels. The effects of garlic were largely dose-dependent, meaning that higher doses corresponded to greater drops in LDL. Moreover, the cholesterol-lowering effects tended to increase the longer that a person was on treatment.
Even so, the reductions in LDL levels (between 6% and 9%) were not enough to suggest that garlic alone can treat high cholesterol. The effects also do not appear to be lasting, with LDL levels returning to their baseline levels once treatment is stopped.
Not all of the studies in the review agreed with these findings. Thirteen of the 39 studies reported no significant changes in LDL or total cholesterol levels, while others found that the cholesterol-lowering effects of garlic were only temporary.Further research is needed.
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Which Form of Garlic Is Best for Cholesterol?
Garlic comes in many different forms: fresh, powders, oils, extracts, freeze-dried, and a variety ofdietary supplements. There is currently no clear consensus as to which works best at lowering cholesterol and at what dose.
The 2013 review from the University of Adelaide suggested that garlic powder delivers the most consistent results, although the investigators did not include tablets or supplements in their review.
In 2020, researchers from the University of Vigo in Italy performed an allicin bioavailability study, analyzing how much allicin circulates in the bloodstream after consuming garlic in different forms. Of the 13 garlic supplements and nine garlic preparations (crushed, boiled, roasted, etc.), supplements overwhelmingly delivered the highest level of allicin into the bloodstream.
Although fresh crushed garlic achieved the highest spike overall, the effect was short-lasting, often dissipating within minutes.
Of the supplements, non-enteric-coated tablets performed best, delivering allicin at consistent blood levels for hours rather than minutes. Enteric-coated tablets were nearly as effective, although the bioavailability dropped significantly when taken with a high-protein meal. Garlic capsules performed similarly to enteric-coated tablets irrespective of food.
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Most studies that examined the effectiveness of garlic in lowering cholesterol involved doses of between 500 to 1,000 milligrams (mg) per day. Raw garlic was generally prescribed as one to two cloves per day.
Garlic can be taken with or without food (although you may want to avoid taking enteric-coated garlic tablets with a high-protein meal as it may reduce its effectiveness).
As with all drugs or supplements, garlic can cause side effects. Most are generally mild and tend to occur at higher doses.
The possible side effects of garlic supplementation include:
Garlic also has mildanticoagulant(blood-thinning) properties that may not be appropriate for people withbleeding disorders.
Similarly, garlic supplements should be stopped before scheduled surgery (including dental surgery) as they can potentially cause excessive bleeding.
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There are certain risks associated with the use of garlic supplements, not least of which include drug interactions. For this reason, you should speak with your healthcare provider before starting treatment, especially if you are on long-term medications.
Some of the drugs garlic can possibly interact with include:
Can Garlic Lower Blood Pressure?
Summary
Other studies contend that garlic supplements are more effective in lowering cholesterol than fresh or prepared garlic. Further research is needed,
Although garlic is generally regarded as safe, speak with a healthcare provider before starting treatment to avoid drug interactions and other possible harms.
A Word From Verywell
As promising as some of the evidence may sound, self-treating a condition like high cholesterol is likely to cause more harm than good. It is important to remember that just because a product is “natural” does not mean that it is either safe or effective.
Cholesterol Doctor Discussion GuideGet our printable guide for your next doctor’s appointment to help you ask the right questions.Download PDFEmail AddressSign UpThank you, {{form.email}}, for signing up.There was an error. Please try again.
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Some studies on garlic and cholesterol levels reported that it can lower “bad” LDL cholesterol levels in as little as eight weeks.
Studies suggest that heating garlic may reduce its cholesterol-lowering effects. Allicin, the cholesterol-lowering compound in garlic, is destroyed at temperatures above 140 degrees F.
9 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Ried K, Toben C, Fakler P.Effect of garlic on serum lipids: an updated meta-analysis.Nutr Rev. 2013;71(5):282-99. doi:10.1111/nure.12012Bayan L, Koulivand PH, Gorji A.Garlic: a review of potential therapeutic effects.Avicenna J Phytomed. 2014;4(1):1–14.Lu Y, He Z, Shen X, et al.Cholesterol-lowering effect of allicin on hypercholesterolemic ICR mice.Oxid Med Cell Longev.2012;2012:489690. doi:10.1155/2012/489690Gonen A, Harats D, Rabinkov A, et al.The antiatherogenic effect of allicin: possible mode of action.Pathobiology,2005;72(6):325-34. doi:10.1159/000091330Ansary J, Forbes-Hernandez TY, Gil E, et al.Potential health benefit of garlic based on human intervention studies: a brief overview.Antioxidants (Basel).2020 Jul;9(7):619. doi:10.3390/antiox9070619U.S. Food and Drug Administration.CFR - Code of Federal Regulations Title 21.Berginc K, Kristl A.The mechanisms responsible for garlic - drug interactions and their in vivo relevance.Curr Drug Metab. 2013 Jan;14(1):90-101.Aslani N, Entezari MH, Askari G, Maghsoudi Z, Maracy MR.Effect of garlic and lemon juice mixture on lipid profile and some cardiovascular risk factors in people 30–60 years old with moderate hyperlipidaemia: a randomized clinical trial.Int J Prev Med. 2016;7:95. doi:10.4103/2008-7802.187248Lawson L, Hunsaker S.Allicin bioavailability and bioequivalence from garlic supplements and garlic foods.Nutrients. 2018;10(7):812.
9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Ried K, Toben C, Fakler P.Effect of garlic on serum lipids: an updated meta-analysis.Nutr Rev. 2013;71(5):282-99. doi:10.1111/nure.12012Bayan L, Koulivand PH, Gorji A.Garlic: a review of potential therapeutic effects.Avicenna J Phytomed. 2014;4(1):1–14.Lu Y, He Z, Shen X, et al.Cholesterol-lowering effect of allicin on hypercholesterolemic ICR mice.Oxid Med Cell Longev.2012;2012:489690. doi:10.1155/2012/489690Gonen A, Harats D, Rabinkov A, et al.The antiatherogenic effect of allicin: possible mode of action.Pathobiology,2005;72(6):325-34. doi:10.1159/000091330Ansary J, Forbes-Hernandez TY, Gil E, et al.Potential health benefit of garlic based on human intervention studies: a brief overview.Antioxidants (Basel).2020 Jul;9(7):619. doi:10.3390/antiox9070619U.S. Food and Drug Administration.CFR - Code of Federal Regulations Title 21.Berginc K, Kristl A.The mechanisms responsible for garlic - drug interactions and their in vivo relevance.Curr Drug Metab. 2013 Jan;14(1):90-101.Aslani N, Entezari MH, Askari G, Maghsoudi Z, Maracy MR.Effect of garlic and lemon juice mixture on lipid profile and some cardiovascular risk factors in people 30–60 years old with moderate hyperlipidaemia: a randomized clinical trial.Int J Prev Med. 2016;7:95. doi:10.4103/2008-7802.187248Lawson L, Hunsaker S.Allicin bioavailability and bioequivalence from garlic supplements and garlic foods.Nutrients. 2018;10(7):812.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Ried K, Toben C, Fakler P.Effect of garlic on serum lipids: an updated meta-analysis.Nutr Rev. 2013;71(5):282-99. doi:10.1111/nure.12012Bayan L, Koulivand PH, Gorji A.Garlic: a review of potential therapeutic effects.Avicenna J Phytomed. 2014;4(1):1–14.Lu Y, He Z, Shen X, et al.Cholesterol-lowering effect of allicin on hypercholesterolemic ICR mice.Oxid Med Cell Longev.2012;2012:489690. doi:10.1155/2012/489690Gonen A, Harats D, Rabinkov A, et al.The antiatherogenic effect of allicin: possible mode of action.Pathobiology,2005;72(6):325-34. doi:10.1159/000091330Ansary J, Forbes-Hernandez TY, Gil E, et al.Potential health benefit of garlic based on human intervention studies: a brief overview.Antioxidants (Basel).2020 Jul;9(7):619. doi:10.3390/antiox9070619U.S. Food and Drug Administration.CFR - Code of Federal Regulations Title 21.Berginc K, Kristl A.The mechanisms responsible for garlic - drug interactions and their in vivo relevance.Curr Drug Metab. 2013 Jan;14(1):90-101.Aslani N, Entezari MH, Askari G, Maghsoudi Z, Maracy MR.Effect of garlic and lemon juice mixture on lipid profile and some cardiovascular risk factors in people 30–60 years old with moderate hyperlipidaemia: a randomized clinical trial.Int J Prev Med. 2016;7:95. doi:10.4103/2008-7802.187248Lawson L, Hunsaker S.Allicin bioavailability and bioequivalence from garlic supplements and garlic foods.Nutrients. 2018;10(7):812.
Ried K, Toben C, Fakler P.Effect of garlic on serum lipids: an updated meta-analysis.Nutr Rev. 2013;71(5):282-99. doi:10.1111/nure.12012
Bayan L, Koulivand PH, Gorji A.Garlic: a review of potential therapeutic effects.Avicenna J Phytomed. 2014;4(1):1–14.
Lu Y, He Z, Shen X, et al.Cholesterol-lowering effect of allicin on hypercholesterolemic ICR mice.Oxid Med Cell Longev.2012;2012:489690. doi:10.1155/2012/489690
Gonen A, Harats D, Rabinkov A, et al.The antiatherogenic effect of allicin: possible mode of action.Pathobiology,2005;72(6):325-34. doi:10.1159/000091330
Ansary J, Forbes-Hernandez TY, Gil E, et al.Potential health benefit of garlic based on human intervention studies: a brief overview.Antioxidants (Basel).2020 Jul;9(7):619. doi:10.3390/antiox9070619
U.S. Food and Drug Administration.CFR - Code of Federal Regulations Title 21.
Berginc K, Kristl A.The mechanisms responsible for garlic - drug interactions and their in vivo relevance.Curr Drug Metab. 2013 Jan;14(1):90-101.
Aslani N, Entezari MH, Askari G, Maghsoudi Z, Maracy MR.Effect of garlic and lemon juice mixture on lipid profile and some cardiovascular risk factors in people 30–60 years old with moderate hyperlipidaemia: a randomized clinical trial.Int J Prev Med. 2016;7:95. doi:10.4103/2008-7802.187248
Lawson L, Hunsaker S.Allicin bioavailability and bioequivalence from garlic supplements and garlic foods.Nutrients. 2018;10(7):812.
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