Blood Pressure and Garlic
People often read that garlic can lower high blood pressure. Should patients with hypertension really start using the pungent bulbor the powders and granules made from itmore often?
In 2008, eleven different studies on lowering blood pressure with garlic were analyzed. Some studies did show better blood-pressure reductions with garlic compared with placebos (the higher the starting blood pressure, the larger the possible reduction), but no consistent results were found. This was partly due to insufficient methodological quality in some studies. For example, many did not report how blood pressure was measured during the study period.
In 2010, Australian researchers examined the effect of so-called black garlic in patients with hard-to-control high blood pressure. Black garlic is regular garlic that's been "aged" by fermentation. The 50 participants took four capsules daily for twelve weeks containing black garlic extract (960 mg with 2.4 mg S-allylcysteine) or a matching placebo. The results showed a reduction in blood pressure, but it was not statistically significant.
A 2016 meta-analysis also showed a reduction in blood pressure values, but about one third of the study participants did not respond to garlic.
In 2019 another meta-analysis was published that looked at 12 studies in which participants took garlic as a powder or capsule, or in the form of aged garlic.
This analysis found that garlic lowered participants' systolic blood pressure by an average of 810 mmHg and diastolic pressure by about 56 mmHg. However, this did not occur in all participantssome fell below these average effects, meaning their blood pressure dropped less. This is thought to be related to how well each person is supplied with B vitamins.
It was also shown that aged garlic has a positive effect on the arteries, specifically on arterial stiffness. It was further found that aged garlic, like other garlic products, has a blood-thinning effect, but does not increase the bleeding risk.
In 2019 another meta-analysis was published that looked at 12 studies in which participants took garlic as a powder or capsule, or in the form of aged garlic.
This analysis found that garlic lowered participants' systolic blood pressure by an average of 810 mmHg and diastolic pressure by about 56 mmHg. However, this did not occur in all participantssome fell below these average effects, meaning their blood pressure dropped less. This is thought to be related to how well each person is supplied with B vitamins.
It was also shown that aged garlic has a positive effect on the arteries, specifically on arterial stiffness. It was further found that aged garlic, like other garlic products, has a blood-thinning effect, but does not increase the bleeding risk.
It's important to mention that garlic can interact with various medications. It can enhance the antiplatelet ("blood-thinning") effect of platelet aggregation inhibitors, such as aspirin. Because an increased bleeding tendency may also occur when taken with oral anticoagulants like Marcumar, and with newer agents such as Xarelto, Eliquis, etc., garlic supplements are not recommended in these situations. On the other hand, garlic can reduce the effectiveness of protease inhibitors in people with HIV.
The 2019 meta-analysis confirmed a blood-pressure-lowering effect of garlic. However, this was not seen in all participants. Some people respond to garlic with lower blood pressure, others do not. As that meta-analysis suggested, this may depend on B-vitamin status. Considering the possible interactions mentioned, you can enjoy fresh garlic as a food. Whether to use a garlic supplement to lower blood pressure should, however, be discussed with your treating doctor firstespecially if you are already taking medication for high blood pressure.
Sources:
- https://www.thieme-connect.com/products/ejournals/abstract/10.1055/a-0659-7629
- https://www.aerzteblatt.de/blog/43556/Knoblauch-Dufte-fuer-den-Blutdruck
- https://www.maturitas.org/article/S0378-5122%2810%2900227-6/abstract
- https://www.ncbi.nlm.nih.gov/pubmed/22895963
- https://www.aerzteblatt.de/nachrichten/73371/Pflanzliche-Praeparate-Diese-Wechselwirkungen-sollten-Kardiologen-kennen
- https://www.jacc.org/doi/10.1016/j.jacc.2016.11.078
- https://pubmed.ncbi.nlm.nih.gov/32010325/
- https://www.spandidos-publications.com/10.3892/etm.2019.8374
This article comes from BloodPressureDB – the leading app since 2011 that helps hundreds of thousands of people monitor their blood pressure every day.
Our content is based on carefully researched, evidence-based information and is continuously updated (as of 12/2025).
Author Sabine Croci is a certified medical assistant with many years of experience in internal medicine and cardiology practices as well as in outpatient care. Since 2015 she has led the editorial team at BloodPressureDB. With additional qualifications as a paramedic, first responder, and training in various therapy and emergency areas, she provides well-founded, practical, and reliably reviewed information.
Author Sabine Croci is a certified medical assistant with many years of experience in internal medicine and cardiology practices as well as in outpatient care. Since 2015 she has led the editorial team at BloodPressureDB. With additional qualifications as a paramedic, first responder, and training in various therapy and emergency areas, she provides well-founded, practical, and reliably reviewed information.
