Aged Garlic vs Fresh Garlic vs Garlic Oil: Allicin, SAC and the Odour Question (2026 Australian Guide)

Four garlic preparations, four different chemistries. Why allicin does not exist in an intact clove, what aged garlic extract is standardised to instead, what allicin yield potential means on a label, and why odourless is a processing outcome.

By Health & Heal

October 22, 2026 5 min read

Four products, one plant, four different chemistries

Garlic supplements are an unusually confusing category, because "garlic" on a label can mean four genuinely different preparations with different marker compounds, different standardisation and different odour.

The four:

Garlic powder — dried, milled clove
Aged garlic extract — clove aged in solution, typically for many months
Garlic oil — steam-distilled, or macerated in a carrier oil
Garlic oil macerate — crushed clove held in oil

They are not interchangeable, and the number on the front of the pack means something different in each case.

The thing most people get wrong: allicin is not in garlic

An intact garlic clove contains no allicin whatsoever.

What it contains is alliin, a stable sulphur compound, kept physically separate from an enzyme called alliinase. When the clove is crushed, cut or chewed, the two meet and alliinase converts alliin into allicin.

Allicin is then highly unstable. It begins breaking down within minutes at room temperature, degrading into other sulphur compounds — diallyl disulphide, diallyl trisulphide, ajoene, vinyldithiins. These are what garlic oil actually contains.

Two consequences that explain most of the label confusion:

A supplement cannot meaningfully contain stable, measured allicin sitting in the bottle
Alliinase is destroyed by stomach acid, which is why serious garlic powder tablets are enteric coated — to get the enzyme and substrate into the small intestine intact

What "allicin yield potential" means

Better garlic powder labels do not claim an allicin content. They state an allicin yield potential or allicin releasing potential — how much allicin the product could generate under standardised laboratory conditions.

That is the honest way to express it. A label claiming a fixed milligram quantity of allicin present in the capsule is describing something that is chemically difficult to sustain.

Aged garlic extract: a different marker entirely

Aged garlic extract is made by holding sliced clove in an aqueous ethanol solution, typically for up to around 20 months. The ageing converts the harsh, volatile sulphur compounds into stable, water-soluble ones.

The result is standardised not to allicin but to S-allyl cysteine (SAC) — a stable, water-soluble, well-characterised marker compound. SAC is the standard reference point for aged garlic preparations because, unlike allicin, it can actually be measured consistently in a finished product.

Aged garlic is also where "odourless" genuinely comes from. The ageing process removes the volatile compounds responsible for garlic breath. That is a chemical outcome of the processing, not a coating or an additive.

Garlic oil: two quite different things under one name

Steam-distilled garlic oil

Highly concentrated. Contains the sulphide breakdown products of allicin — diallyl disulphide and related compounds — and no alliin or allicin. Roughly 1kg of garlic yields only a few grams of oil, which is why doses are small.

Garlic oil macerate

Crushed garlic steeped in a vegetable oil. Much weaker, and a very different composition — dominated by vinyldithiins.

Both are usually labelled "garlic oil". If a softgel lists a large milligram figure, it is almost certainly a macerate or an oil-garlic blend, not distilled oil. Check whether the label gives a concentration ratio. The same softgel-versus-drops question comes up with oregano oil and its carvacrol percentage.

Reading the ratio on the label

Garlic labels lean heavily on equivalence claims. Two to decode:

Extract ratios — "10:1" means ten parts raw material produced one part extract. So 100mg of a 10:1 extract derives from 1,000mg of clove. A 300mg capsule of 10:1 extract is not comparable to a 300mg capsule of plain powder. We unpack this properly in what does 10:1 extract mean.

Fresh clove equivalence — "equivalent to 1,000mg fresh garlic" is a calculated figure, based on a conversion the manufacturer has applied. It is useful for rough orientation and not a measurement of anything in the capsule.

Standardisation percentages — "standardised to 1% SAC" or "standardised to 1.3% alliin" is the more informative statement, because it tells you about the actual material rather than its ancestry. Our saw palmetto standardisation guide works through the same maths on a different botanical.

The odour question, honestly

Garlic odour comes from volatile sulphur compounds, principally allyl methyl sulphide, which is absorbed and then released through the lungs over hours. It is not coming from your mouth, which is why brushing your teeth does little.

What each format does:

Aged garlic extract	Genuinely low odour. The volatiles are converted during ageing
Enteric-coated powder	Reduces odour by delaying release past the stomach. Reduced, not eliminated
Garlic oil softgels	The compounds responsible are concentrated in the oil. Expect odour
Plain garlic powder	Expect odour

A product marketed as odourless that is a plain powder or an oil has, at most, coated the capsule. The compounds are still going to be absorbed.

Enteric coating: when it matters

For garlic powder products it matters a great deal, because the whole mechanism depends on alliinase surviving the stomach. An uncoated garlic powder tablet loses much of its conversion capability to stomach acid.

For aged garlic extract it is largely irrelevant — SAC is stable and water-soluble, with no enzyme to protect.

So "enteric coated" is a meaningful quality signal on a powder and a marketing flourish on an aged extract.

Five things to check on a garlic label

1. Which preparation is it? Powder, aged extract, distilled oil or macerate. The front of the pack often does not say clearly — check the ingredients line.

2. What is it standardised to? Alliin or allicin yield potential for powder. SAC for aged extract. Nothing stated means nothing guaranteed.

3. Is a fixed allicin content claimed? Treat that with scepticism. Yield potential is the defensible claim.

4. Is it enteric coated, and does that matter here? Important for powder, not for aged extract.

5. Is the milligram figure extract or raw equivalent? A 10:1 extract and a raw powder at the same milligram weight are very different products.

One practical caution

Garlic in concentrated supplement form is not nutritionally equivalent to garlic as a food, and it can interact with some prescription medicines — blood-thinning medication in particular. It is also commonly asked about before surgery.

If you take prescription medication or have a procedure coming up, raise garlic supplements with your doctor or pharmacist specifically. It is one of the more frequently relevant interactions in the supplement aisle, and it is worth a conversation rather than an assumption.

The short version

An intact clove has no allicin — it has alliin plus an enzyme, and crushing makes allicin, which then degrades quickly. So garlic powder is standardised to alliin or allicin yield potential and benefits from enteric coating. Aged garlic extract is standardised to SAC, is stable, and is genuinely low odour. Garlic oil contains the breakdown products and will be noticeable.

Work out which of the four you are holding before comparing any numbers on the front of the pack.