What is garlic extract?
Garlic (Allium sativum) is a plant in the Allium family that has been used both as food and in folk medicine for thousands of years. From ancient Egypt to Greece, from China to India β garlic has been a traditional health supporter across many cultures.
Garlic extract is a concentrated form of garlic's bioactive compounds. The key compounds of interest are:
- Allicin β an unstable sulphur compound formed when garlic is crushed, responsible for its characteristic odour
- Alliin β the stable precursor to allicin
- S-allylcysteine (SAC) β a water-soluble sulphur compound particularly abundant in aged garlic extract
- Ajoene and vinyl dithiins β other sulphur compounds
The type of extract affects its composition: fresh garlic extract contains allicin, while aged extract contains more SAC.
How does garlic extract work?
Garlic's bioactive sulphur compounds work through several mechanisms:
- Allicin is formed by the enzyme alliinase when garlic cells are crushed. It is chemically unstable and quickly breaks down into other sulphur compounds
- S-allylcysteine is more stable and well absorbed from the digestive tract. It is considered the primary bioactive compound in aged garlic extract
- Sulphur compounds have shown antioxidant properties and effects on nitric oxide (NO) metabolism in research (Banerjee et al., 2003)
Garlic extract research has primarily focused on two areas: cardiovascular health and the immune system.
Evidence and research
Important note: The European Food Safety Authority (EFSA) has not approved specific health claims for garlic extract supplements. Several claims have been submitted and rejected or are pending. These included claims about blood pressure, cholesterol, immunity and antioxidant properties.
What the scientific literature shows:
- Garlic has a long history in traditional medicine across various cultures
- Meta-analyses have examined garlic's effects on blood pressure and lipid profiles, with modest results (Ried et al., 2013; Reinhart et al., 2009)
- Garlic's sulphur compounds have demonstrated antioxidant properties in in vitro settings
- Aged garlic extract (AGE) is the most studied form in long-term clinical trials (Budoff et al., 2009)
- Study results have been variable β partly due to differences in extract types and dosages
Since there are no approved EFSA claims, we cannot state that garlic extract treats, prevents or alleviates any disease.
How to take garlic extract
Garlic extract is available in several forms:
- Aged garlic extract (AGE) β produced by long-term soaking of garlic, contains stable sulphur compounds, odourless
- Garlic powder β dried and ground garlic, retains alliin
- Garlic oil β distilled or macerated oil, contains various sulphur compounds
- Allicin-standardised extract β higher allicin content, but allicin is unstable
Typical dosages in the literature have been 600β1200 mg AGE per day or 2β5 mg allicin per day.
Recommendations:
- Choose based on your preference β aged extract is odourless and well tolerated
- Take with food to reduce digestive discomfort
- Start with a lower dose and increase gradually
Who might benefit from garlic extract?
- People interested in cardiovascular health β garlic is a traditional heart health supporter
- Those seeking immune system support β garlic is a traditional immune supporter
- People who don't eat enough garlic β extract provides a more concentrated dose
- Those who want garlic's benefits without the odour β aged extract is odourless
Warning: Garlic extract may affect blood clotting. Do not use before surgery or alongside blood-thinning medications without consulting your doctor.
Frequently asked questions
Is eating raw garlic better than taking extracts? Crushing fresh garlic activates allicin, but it breaks down quickly. Aged extract offers more stable compounds (SAC). Both have their own advantages.
Does garlic extract lower blood pressure? EFSA has not approved garlic's blood pressure claim. Some studies have shown modest trends, but the evidence is insufficient for an approved health claim.
Is aged garlic extract better than regular? Ageing converts allicin into more stable compounds (SAC, S-allylmercaptocysteine). AGE is the most studied form in long-term trials and is well tolerated.
Is garlic extract safe? Generally yes, at typical doses. The most common side effects are digestive discomfort, bloating and garlic odour (less with aged forms). Consult your doctor if you take medications.
How much garlic should you eat daily? Traditional recommendations suggest 1β2 cloves per day. Extract provides a standardised and more controllable dose.
References
- Ried K, Toben C, Fakler P. (2013). Effect of garlic on serum lipids: an updated meta-analysis. Nutrition Reviews, 71(5), 282-299.
- Reinhart KM, Coleman CI, Teevan C, Vachhani P, White CM. (2009). Effects of garlic on blood pressure in patients with and without systolic hypertension: a meta-analysis. Annals of Pharmacotherapy, 43(12), 1982-1991.
- Budoff MJ, Takasu J, Flores FR, et al. (2009). Inhibiting progression of coronary calcification using Aged Garlic Extract in patients receiving statin therapy. Preventive Medicine, 49(2-3), 101-107.
- Banerjee SK, Mukherjee PK, Maulik SK. (2003). Garlic as an antioxidant: the good, the bad and the ugly. Phytotherapy Research, 17(2), 97-106.
See also:
Disclaimer
A food supplement is not a substitute for a varied and balanced diet and a healthy lifestyle.
