What Is Garlic Oil?
Garlic oil is an essential oil produced by distilling the cloves of garlic (Allium sativum). It contains garlic's bioactive sulfur compounds in concentrated form — primarily allicin and its derivatives such as diallyl disulfide and diallyl trisulfide.
Garlic's active compounds form when a clove is crushed, cut, or chewed — this triggers the enzyme alliinase, which converts alliin into allicin. Garlic oil captures these compounds in concentrated form.
Natural Food Sources of Garlic Oil
Garlic oil itself does not occur naturally in foods — it is a distilled product. However, garlic's bioactive sulfur compounds are present in:
Raw Garlic
A raw garlic clove is the primary natural source of allicin. When crushed, allicin forms rapidly but is unstable and breaks down within minutes into further sulfur compounds. Eating raw garlic provides the highest level of active sulfur compounds.
Other Allium Family Plants
| Food | Allicin / sulfur compound presence |
|---|---|
| Raw garlic | Highest |
| Raw onion | Moderate |
| Leeks | Low |
| Chives | Low |
| Shallots | Moderate |
Garlic-Infused Foods
Garlic bioactives are present in garlic-infused olive oil, pickled garlic, and garlic pastes used in Asian cuisine. However, heating and processing significantly reduce allicin activity.
Bioavailability: Food vs. Supplement
The bioavailability of allicin and garlic sulfur compounds from food depends on several factors:
- Eating raw garlic: maximum allicin formation occurs after crushing; swallowing a whole clove produces considerably less
- Heating: allicin activity drops rapidly during boiling and frying — brief heating preserves more sulfur compounds than prolonged cooking
- Stomach acidity: allicin is acid-sensitive; enteric-coated supplements protect allicin from stomach acid
Garlic oil supplements (typically soft capsules) are often enteric-coated to ensure allicin and its derivatives reach the small intestine, where they are absorbed (Lawson & Wang, 2001).
Daily Targets from Diet
Garlic oil has no official daily reference intake. For garlic itself, an intake of one to four cloves of fresh garlic per day has been suggested as an approximate reference in nutritional literature.
In Estonia, garlic is widely used as a cooking ingredient but is rarely consumed raw in supplement-equivalent amounts.
The Benefits of Garlic Oil
Garlic has well-studied antimicrobial properties. Studies have observed that allicin from garlic inhibits various bacteria and fungi under in vitro conditions (Ankri & Mirelman, 1999). Garlic-related health benefits have also been examined in the context of cardiovascular health.
Cooking and Storage Effects
- Raw: for maximum allicin, crush garlic and let it stand for 5–10 minutes before heating — this gives the enzyme alliinase time to produce allicin
- Heating: the shorter the heating, the more is preserved; adding garlic near the end of cooking retains more active compounds than boiling it from the start
- Storage: raw garlic keeps in a cool dry place; opened garlic oil products should be refrigerated
Cardiovascular Research on Garlic
Garlic has been studied in the context of cardiovascular health. Several meta-analyses have examined whether garlic supplements affect blood pressure and lipid profiles. The evidence suggests a modest effect on blood pressure in people with elevated levels, though results across trials are variable and effect sizes are generally small.
Garlic's cardiovascular effects are attributed primarily to allicin-derived sulfur compounds acting on vascular tone and platelet function. It is worth noting that the studies showing the most consistent effects used standardised allicin-yielding supplements, not raw garlic portions.
Garlic Oil vs. Aged Garlic Extract — Which Is Better?
These two product types contain different active compounds:
| Product type | Primary active compounds | Odour |
|---|---|---|
| Garlic oil (distillation) | Diallyl disulfide, diallyl trisulfide | Moderate |
| Aged garlic extract (fermentation) | S-allylcysteine, S-allylmercaptocysteine | Low |
Aged garlic extract (AGE) is water-soluble and generally considered better tolerated. Garlic oil in enteric-coated capsules is a good choice for those who want the classic allicin-pathway compounds with minimal odour. The choice depends on your personal goals and tolerance.
When Does a Supplement Make Sense?
Those who cannot tolerate the taste or smell of garlic, or who want a standardised dose of garlic actives, find supplements the most practical option. Enteric-coated capsules ensure that allicin reaches the absorption site without breaking down in stomach acid.
NOW Garlic Oil 1500mg 250 softgels and NOW Garlic Oil 1500mg 100 softgels are available at maxfit.ee and provide concentrated garlic oil in enteric-coated capsules. Browse the garlic oil supplement range at /en/category/kuuslauguoli.
Practical Tips for Maximising Garlic Benefits
To maximise the benefit you get from garlic in food:
- Crush, do not just chop: crushing activates the alliinase enzyme that produces allicin; chopping alone produces less
- Wait 5–10 minutes before heating — this time allows the enzyme to function and allicin to form
- Add garlic later: in cooking, add garlic closer to the end rather than the beginning
- Raw garlic applications: in short-exposure preparations (salad dressings, dips), raw garlic retains the most active compounds
For people who have difficulty digesting garlic, garlic oil capsules are a good alternative, providing allicin equivalents without gastrointestinal irritation.
FAQ
Is garlic oil the same as garlic extract?
They are different products. Garlic oil is produced by steam distillation and contains primarily diallyl disulfide. Garlic extract (such as aged garlic extract) retains other bioactive compounds such as S-allylcysteine. Both have distinct compound profiles.
Does garlic oil cause breath odour?
Garlic oil capsules cause less breath odour than eating raw garlic, because the enteric coating delays the release of active compounds. However, breath odour is not completely avoided, as diallyl disulfide is excreted via the lungs.
Is garlic oil suitable for vegans?
Most garlic oil capsules are soft gelatin capsules, which are not vegan. Look specifically for a vegan capsule label if that matters to you.
References
- Ankri, S. & Mirelman, D. (1999). Antimicrobial properties of allicin from garlic. Microbes and Infection, 1(2), 125–129. https://pubmed.ncbi.nlm.nih.gov/10594976/
- Lawson, L.D. & Wang, Z.J. (2001). Low allicin release from garlic supplements: a major problem due to the sensitivities of alliinase activity. Journal of Agricultural and Food Chemistry, 49(5), 2592–2599. https://pubmed.ncbi.nlm.nih.gov/11368641/
- Iciek, M. et al. (2009). Biological properties of garlic and garlic-derived organosulfur compounds. Environmental and Molecular Mutagenesis, 50(3), 247–265. https://pubmed.ncbi.nlm.nih.gov/19253339/
