What is garlic extract?

Garlic extract is a concentrated form of garlic that is made by soaking crushed garlic cloves in a solvent, usually ethanol or water. This process extracts the active compounds found in garlic and creates a potent supplement that can be taken in capsule or liquid form.

How does it work?

Garlic extract is believed to work by producing a chemical called allicin, which is responsible for most of its health benefits. Allicin has been shown to have antimicrobial, antioxidant, and anti-inflammatory properties. Additionally, garlic extract contains other sulfur compounds that may also contribute to its medicinal effects.

What are the active ingredients that are important for its medicinal properties?

The active ingredient in garlic extract is allicin, which is formed when the enzyme alliinase converts alliin to allicin. Other sulfur compounds, such as diallyl sulfide and diallyl disulfide, may also contribute to its health benefits.

What forms does it come in?

Garlic extract is available in a variety of forms, including capsules, tablets, liquid extracts, and oils.

When was it first used for medicinal purposes?

Garlic has been used for medicinal purposes for thousands of years, dating back to ancient Egypt, Persia and Greece.

What does Garlic extract help with?

Garlic extract is made from the garlic bulb. Healers and cooks have used it for more than 5,000 years. It shows up in Ayurvedic, Chinese, Egyptian, Mediterranean and Middle Eastern medicine.

The human evidence is strongest for blood pressure and cholesterol. Other uses rest on smaller studies, on blood markers, or on lab work alone. Our files do not record trial sizes or doses, so none are named below.

• High blood pressure
  Strong evidence — several human clinical trials that agree; sizes and doses not on file. In a number of clinical trials, people taking garlic extract had lower blood pressure. Both the top and bottom numbers fell. The drop was largest in people who started with high readings.
  Evidence grade A · Traditional tier T3
• High cholesterol and blood fats
  Good evidence — human trials on file, with sizes and doses not recorded. In human trials, total and LDL ("bad") cholesterol fell in people taking garlic. Blood fats called triglycerides fell too. HDL, the "good" kind, usually stayed flat or rose a little.
  Evidence grade B · Traditional tier T3
• Catching colds often
  Good evidence — human clinical studies; sizes and doses not on file. In clinical studies, people taking garlic supplements caught fewer colds. Those who did get sick got better faster. In lab work, garlic compounds acted against viruses and bacteria.
  Evidence grade B · Traditional tier T3
• Stiff arteries and heart risk
  Early evidence — small human studies of artery markers, not of heart attacks. Some human studies found less stiffness in artery walls with garlic extract. Early work also suggests it may slow calcium buildup in arteries. These are markers of risk, not counts of heart attacks or strokes.
  Evidence grade C · Traditional tier T3
• Blood sugar in type 2 diabetes
  Early evidence — small or mixed human studies; doses not on file. Some human studies found lower fasting blood sugar in people taking garlic. Insulin sensitivity also improved in parts of this work. It is not a stand-in for diabetes medicine.
  Evidence grade C · Traditional tier T3
• Blood that clots too easily
  Early evidence — human studies measuring platelet clumping, not clot events. In human studies, garlic made platelets slightly less likely to clump. Platelets are the blood cells that start a clot. This mild effect also means care is needed if you take blood thinners.
  Evidence grade C · Traditional tier T3
• Long-term inflammation
  Early evidence — human studies of blood markers only. Studies of aged garlic extract found lower inflammation markers in blood. A compound called SAC mopped up free radicals in lab tests. Better markers do not always mean you feel better.
  Evidence grade C · Traditional tier T3
• Gut balance and feeding good bacteria
  Long traditional use · not yet tested in trials — content analysis and lab work; no human trial on file. Garlic holds prebiotic fibres known as FOS (fructooligosaccharides). In lab studies, helpful gut bacteria feed on fibres of this kind. We hold no human trial on garlic and gut balance.
  Evidence grade insufficient · Traditional tier T3
• Infections that keep coming back
  Long traditional use · not yet tested in trials — lab dish studies of allicin; no human trial on file. In lab dishes, allicin and related compounds acted against many bacteria, fungi and some parasites. Some people take garlic alongside standard care for Candida or H. pylori. Our files hold no human trial showing it clears these infections.
  Evidence grade insufficient · Traditional tier T3

What Garlic extract has not been shown to do

• Garlic has not been shown to raise HDL ("good") cholesterol much; in trials it mostly stayed the same.
• It has not been shown to replace blood pressure medicine.
• It has not been shown to replace diabetes medicine or insulin.
• It has not been shown to cut the number of heart attacks or strokes; the files hold risk markers only.

How to read this:

Each grade covers one use, not the whole herb. A means many human trials that agree. B means at least one good human trial. C means small, mixed or early human work. D means the human evidence is weak or clashes. "Insufficient" means no human study on file, just lab work or custom. This page lists options, not advice. It does not cover dosing, side effects, or who should avoid it. Talk with your doctor, above all if you take medicine for blood pressure, blood sugar or clotting.

What can Garlic extract help prevent?

• Recurrent colds and upper respiratory infections
• Progression of high-normal blood pressure to hypertension
• Cardiovascular disease risk reduction (long-term arterial protection)
• H. pylori-associated gastric complications (adjunctive)

Which foods are rich in it?

Garlic extract is found in fresh garlic, garlic powder, and garlic oil.

What are possible side effects?

Possible side effects of garlic extract may include:

• Bad breath
• Body odor
• Upset stomach
• Heartburn
• Diarrhea
• Allergic reactions
• Bleeding disorders
• Low blood pressure
• Increased risk of bleeding

What's the recommended daily dose?

The recommended daily dose of garlic extract varies depending on the product and concentration. However, doses typically range from 600 to 1200 mg per day.

How many days does it take to work?

The time it takes for garlic extract to work varies depending on the condition being treated and the individual's response. However, some studies have shown that the benefits of garlic extract can be seen within a few weeks.

What time of day is best to take it?

There is no specific time of day that is best to take garlic extract. However, it is recommended to take it with food to reduce the risk of stomach upset.

Is it best to take it with or without food?

It is recommended to take garlic extract with food to reduce the risk of stomach upset.