Garlic has been linked to healthy immune function, reduced blood pressure and a lower risk of heart disease. But what about garlic oil pills and other such dietary supplements?
Depending on the ingredients used, these products may have some health benefits. But there are also some safety concerns to keep in mind before you buy a bottle.
Is Garlic Really That Healthy?
Garlic has been used as food and medicine for centuries thanks to its taste as well as its connection to shorter colds and lower risk of heart disease, according to a December 2011 review in BioMedicine.
Many of its healing properties are attributed to sulfuric compounds in the spice like allicin, diallyl sulfide, diallyl disulfide, diallyl trisulfide and allylmethyl sulfide, per the BioMedicine review. Allicin, however, is an unstable compound, which means it only stays intact for a short period of time after chopping or crushing fresh garlic, according to the Linus Pauling Institute.
As a result, garlic oil is richer in the other compounds. They're captured through a process called steam distillation, which renders raw cloves into oil, according to the Linus Pauling Institute.
You can then eat garlic oil by adding it to food or taking it as a supplement, the varieties of which are widely available in health stores, pharmacies and online.
Just be sure to confirm that your supplement of choice contains garlic oil, because some pills are made with garlic extract or powder instead, per the Linus Pauling Institute.
Garlic supplements, including garlic oil pills, are touted as a cure-all. However, their potential benefits are subject to debate. The compounds in garlic pills may differ in composition and dosage from those in fresh garlic.
5 Possible Benefits of Garlic Oil Pills
Garlic pills are good for many of the same benefits as the plant itself. However, the actual effects of garlic oil supplements can vary from type to type, according to July 2018 research in Nutrients.
And some research touting garlic oil softgels' benefits is insufficient or inconclusive, per the National Center for Complementary and Integrative Health (NCCIH). Some studies have been conducted on mice and other rodents, so it's hard to say how they apply to humans. Garlic supplements' long-term safety requires further investigation as well.
Nonetheless, some evidence suggests there are certain perks to popping garlic oil capsules:
1. They're Antimicrobial
Allicin may have bacteria- and fungus-fighting capabilities, according to April 2018 research in Scientific Reports. It may deactivate viruses like the flu or herpes, help fight fungal infections like yeast and aid in battling certain parasites, per the American Society for Microbiology. However, garlic isn't recognized by the medical community as a treatment for these conditions, so make sure to visit your doctor if you're sick.
What's more, most of these studies have been conducted in controlled laboratory environments, so it's hard to say whether or not the promising findings will be replicated in humans, according to a June 2016 review in Trends in Food Science & Technology.
Allicin is also best consumed through freshly crushed garlic or garlic powder, so you may opt for those preparations over garlic oil capsules for this particular perk, according to the Linus Pauling Institute.
2. They May Support Immune Function
Garlic softgels might aid in the defense against common ailments like colds and flus, according to the BioMedicine review. A January 2012 study in Clinical Nutrition found that people who took daily garlic supplements had milder and fewer colds and flus overall than those who took a placebo pill.
That said, researchers note that evidence is still lacking and more research is needed to confirm garlic's immune-supportive properties, per a November 2014 review in the Cochrane Database of Systematic Reviews.
As a result, don't rely on garlic alone to remedy seasonal sickness. Common treatments like decongestants and painkillers may still be the best bet for relieving symptoms, according to a February 2014 review in CMAJ.
Some claim that putting garlic in your ear or nose can help with similar issues like sinus infections, sinus pressure, congestion or ear pain. However, there's no research to support these home remedies. Rather, you should visit your doctor if you're having ear or sinus problems.
3. They Have Antioxidant and Anti-Inflammatory Properties
Oxidative stress occurs when molecules called free radicals harm your body's cells, which can lead to inflammation and DNA damage, according to June 2015 research in the European Journal of Medicinal Chemistry. It can also play a role in developing conditions like heart disease and cancer, per the BioMedicine review.
Antioxidants can help protect us from oxidative stress. And garlic — particularly aged garlic — is a solid source of the stuff, according to a July 2020 review in Antioxidants.
Garlic may also help quell inflammation specifically, which could ease symptoms of conditions like arthritis, per the Cleveland Clinic.
The sulfur in garlic oil supplements is tied to a lower risk for high blood pressure, according to a December 2014 review in Integrated Blood Pressure Control. That's because it may encourage blood vessels to widen, so blood can flow with less constriction.
In one small study of 79 people, taking garlic extract for three months seemed to help lower blood pressure numbers for those with hypertension, according to November 2012 research in the European Journal of Clinical Nutrition. The study was small, though, so its results require further investigation.
5. They're Tied to Lower Cholesterol
One research analysis found that taking garlic extract for more than two months helped lower total and low-density lipoprotein (the "bad") cholesterol in people with high levels, according to a May 2013 review in Nutrition Reviews.
It may also help reduce plaque buildup in the arteries, which can lead to complications like heart attack or stroke, per February 2016 research in The Journal of Nutrition.
The end result of lower cholesterol and blood pressure? Better heart health overall. In fact, studies have shown that garlic is linked to a lower risk for heart disease, according to July 2016 research in the International Journal of Preventative Medicine.
Are Garlic Oil Pills Safe?
Garlic is a naturally occurring ingredient, which means a pure version of the spice is typically safe to consume unless you have a known allergy, according to the NCCIH.
Just remember that the FDA does not require supplements to be proven safe or effective before they are sold, so there's no guarantee that any supplement you take is safe, contains the ingredients it says it does or produces the effects it claims.
With that in mind, here are some things to consider if you're thinking about taking garlic oil pills.
1. Side Effects
These products may cause adverse reactions like upset stomach, heartburn, bad breath and body odor, according to the NCCIH.
The NCCIH also reports that these supplements may increase your risk for bleeding, so they might not be safe for people who take blood thinners or those who are preparing for surgery.
Garlic supplements may increase the risk of bleeding and should not be used by those taking blood thinners or preparing for surgery.
Garlic can also cause allergic reactions, according to the NCCIH. If that's the case, you may experience trouble breathing, swelling, vomiting or itching, among other symptoms, per the U.S. National Library of Medicine. Severe allergic reactions, called anaphylaxis, require emergency care.
The good news is that spice allergies account for only 2 percent of all food allergy cases, as reported by the University of Manchester. However, if you're allergic to raw garlic, it's recommended to steer clear of all supplement forms of the spice as well.
3. Drug Interactions
You may also want to hold off on garlic oil capsules if you're taking HIV drugs, blood-thinning medication or other supplements, according to the NCCIH.
To be safe, consult with your doctor before starting any supplement regimen.
- NCBI: "Potential of Garlic (Allium sativum) in Lowering High Blood Pressure: Mechanisms of Action and Clinical Relevance"
- Avicenna Journal of Phytomedicine: "Garlic: A Review of Potential Therapeutic Effects"
- NIH: "Garlic"
- Trends in Food Science & Technology: "Antifungal and Antibacterial Activities of Allicin: A Review"
- National Cancer Institute: "In Vitro"
- BioMedicine: "Garlic: Health Benefits and Actions"
- NCBI: "Oxidative Stress, Aging, and Diseases"
- University of Manchester: "Allergy Information For: Garlic (Allium sativum)"
- Scientific Reports: "A Comparison of the Antibacterial and Antifungal Activities of Thiosulfinate Analogues of Allicin"
- American Society for Microbiology: "Old Wives’ Tales and Garlic as an Antibiotic: Are Microbial Myths Fact or Fiction?"
- Clinical Nutrition: "Supplementation with aged garlic extract improves both NK and γδ-T cell function and reduces the severity of cold and flu symptoms: a randomized, double-blind, placebo-controlled nutrition intervention"
- Cochrane Database of Systematic Reviews: "Garlic for the common cold"
- European Journal of Clinical Nutrition: "Aged garlic extract reduces blood pressure in hypertensives: a dose-response trial"
- Nutrition Reviews: "Effect of garlic on serum lipids: an updated meta-analysis"
- International Journal of Preventative Medicine: "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" "
- The Journal of Nutrition: "Garlic and Heart Disease"
- European Journal of Medicinal Chemistry: "The role of antioxidants in the chemistry of oxidative stress: A review"
- Antioxidants: "Potential Health Benefit of Garlic Based on Human Intervention Studies: A Brief Overview"
- National Center for Complementary and Integrative Health: "Garlic"
- U.S. National Library of Medicine: "Allergy"
- Nutrients: "Allicin Bioavailability and Bioequivalence from Garlic Supplements and Garlic Foods"
- Linus Pauling Institute: "Garlic and Organosulfur Compounds"
- Cleveland Clinic: "6 Surprising Ways Garlic Boosts Your Health"
- CMAJ: "Prevention and treatment of the common cold: making sense of the evidence"
- FDA: "FDA 101: Dietary Supplements"