Garlic can lower high blood pressure.
Garlic has been used in folk medicine for millenia for its health benefits as well as an antiseptic. The Ancient Greeks and Romans also used garlic as an aid to strength and endurance and was fed to their soldiers and sailors. Garlic was even given to the original olympic athletes in Greece, as perhaps one of the earliest “performance enhancing” agents.
Cardiovascular diseases such as heart attack and stroke are responsible for more deaths than almost any other condition 1. High blood pressure (hypertension) is one of the most important factors that may lead to these events.
Human studies have found garlic supplements to have a significant impact on reducing blood pressure in people with hypertension 2 3.
How effective is garlic at lowering high blood pressure?
In one study on the effects of garlic on systolic and diastolic blood pressure in patients with essential hypertension, doses of between 600–1,500 mg of aged garlic extract were found to be just as effective as the drug Atenolol at reducing blood pressure over a 24-week period 4. Atenolol is a beta blocker medicine, used to treat hypertension and irregular heartbeats (arrhythmia).
A review and meta-analysis by Karin Ried 3, published in 2019, found that garlic lowers blood pressure in hypertensive subjects, improves arterial stiffness and gut microbiota. Karin’s meta-analysis of 12 trials and 553 hypertensive participants confirmed that garlic supplements lower systolic blood pressure by an average of 8.3 ± 1.9 mmHg and diastolic blood pressure by 5.5 ± 1.9 mmHg, similarly to standard anti-hypertensive medications.
Furthermore, this reduction in blood pressure was associated with a 16-40% reduction in the risk of suffering from cardiovascular events.
Karin’s findings are supported by a study by Toshiaki Matsutomo, published in 2020 5.
How does garlic lower high blood pressure?
Allicin is a major active ingredient in garlic supplementation as it has been reported to exert angiotensin II-inhibiting and vasodilating effects. In addition to allicin, γ-glutamyl-S-allylcysteine (GSAC) may contribute to the effects by inhibiting the angiotensin converting enzyme (ACE) and inducing endothelium-dependent and -independent relaxation 5.
Put another way, the active ingredients in garlic act as an ACE inhibitor and a vascular relaxant.
How much garlic should you eat?
There’s no official recommended dosage for garlic. Most studies have found that around 1–2 cloves per day could be beneficial. However, a report in the Times of India recommends eating four cloves of raw garlic daily to “cure” hypertension 6 7.
It should be noted that garlic cloves vary in size, which will affect the amount of allicin they contain.
Raw garlic also contains more allicin, which is the sulfur-containing compound responsible for many of garlic’s beneficial health effects, than cooked garlic. So, you will need to eat more cooked garlic to consume the same amount of allicin.
In supplement form, doses of up to 3,600 mg of aged garlic extract have also been shown to be effective 8.
Raw garlic has anticoagulent properties. While enjoying raw garlic in moderation is unlikely to cause any issues for most healthy adults, people taking blood thinners should check with their doctor before consuming large amounts of garlic or using a garlic supplement.
See medical caveat page for more information
If you are trying to lower your blood pressure to normal levels using natural methods, eating up to four cloves of raw garlic a day or taking a good quality garlic supplement can help you achieve your goal.