Vinyldithiins

Vinyldithiins at a Glance

The vinyldithiins are not one molecule but a closely related pair: 2-vinyl-4H-1,3-dithiin and 3-vinyl-4H-1,2-dithiin. Both are six-membered sulfur heterocycles carrying a vinyl side chain, and both arise from the same event — the decomposition of allicin after garlic is crushed ^{1,2,14Reference 1Brodnitz MH et al. · 1971Flavor components of garlic extractView study →Reference 2Block E · 1985The chemistry of garlic and onionsView study →Reference 14Bhatwalkar SB et al. · 2021ReviewAntibacterial properties of organosulfur compounds of garlic (Allium sativum)View study →}. The literature treats them as a pair almost without exception, which is why both are covered and names each isomer where a study used one rather than the other.

The most useful thing to know about them is not a pharmacological effect. It is that they are an analytical fingerprint. Vinyldithiins are found only in garlic that has been macerated in vegetable oil — not in fresh cloves, not in garlic powder, not in steam-distilled garlic oil, and not in aged garlic extract ^{4,15Reference 4Lawson LD et al. · 1991Identification and HPLC quantitation of the sulfides and dialk(en)yl thiosulfinates in commercial garlic productsView study →Reference 15Amagase H · 2006ReviewClarifying the real bioactive constituents of garlicView study →}. If a product contains them, you know how it was made.

Their own pharmacology is thin. There is a genuine, if modest, antiplatelet signal, a contested effect on cholesterol synthesis, one human-cell study on fat-cell development, and a surprisingly detailed rodent pharmacokinetic picture — but no human trial has ever tested either isomer, and the compounds carry none of allicin’s antimicrobial punch ^{12Reference 12Nakamoto M et al. · 2020ReviewAntimicrobial properties of hydrophobic compounds in garlic: allicin, vinyldithiin, ajoene and diallyl polysulfidesView study →}.

Two Isomers, One Family

This page deliberately covers a family of two, because that is how the chemistry and the analytical literature handle them.

Isomer	Ring	Also written	What was studied on it
2-vinyl-4H-1,3-dithiin	sulfurs at positions 1 and 3 (dithioacetal)	1,3-vinyldithiin, 2-VD, 2-VDT	Cholesterol-synthesis inhibition 9Reference 9Sendl A et al. · 1992In vitroInhibition of cholesterol synthesis in vitro by extracts and isolated compounds prepared from garlic and wild garlicView study →; more active of the two against M. tuberculosis 13Reference 13Nair SS et al. · 2017In vitroAllium sativum constituents exhibit anti-tubercular activity in vitro and in RAW 264.7 mouse macrophage cells infected with Mycobacterium tuberculosis H37RvView study →; less lipophilic, cleared faster, the only isomer detected in rat liver 6Reference 6Egen-Schwind C et al. · 1992Pharmacokinetics of vinyldithiins, transformation products of allicinView study →
3-vinyl-4H-1,2-dithiin	adjacent sulfurs (cyclic disulfide)	1,2-vinyldithiin, 3-VD, 3-VDT	Anti-adipogenic and anti-inflammatory effects on human preadipocytes 8Reference 8Keophiphath M et al. · 2009Keophiphath M, Priem F, Jacquemond-Collet I, Clément K, Lacasa D (2009). 1,2-vinyldithiin from garlic inhibits differentiation and inflammation of human preadipocytes. The Journal of Nutrition. https://pubmed.ncbi.nlm.nih.gov/19759245/View study →; more lipophilic, accumulates in fat tissue 6Reference 6Egen-Schwind C et al. · 1992Pharmacokinetics of vinyldithiins, transformation products of allicinView study →

Two practical notes follow from this.

The names are widely mangled. Published papers have used “2-vinyl-4H-1,2-dithiin” ^{19Reference 19Sun J et al. · 2019Influence of different frying processes on the flavor characteristics and sensory profile of garlic oilView study →} and swapped the two isomer labels outright ^{12Reference 12Nakamoto M et al. · 2020ReviewAntimicrobial properties of hydrophobic compounds in garlic: allicin, vinyldithiin, ajoene and diallyl polysulfidesView study →}, and a related compound appears as “3,4-dihydro-3-vinyl-1,2-dithiin” ^{17Reference 17Nishimura H et al. · 2000Thermochemical transformation of sulfur compounds in Japanese domestic Allium, Allium victorialis LView study →}. When reading a vinyldithiin claim, check which ring the authors actually drew — the two isomers do not behave identically.

Which one dominates is not firmly established in the sources reviewed here. The one rodent pharmacokinetic study dosed them 3:1 in favour of the 1,3-isomer ^{6Reference 6Egen-Schwind C et al. · 1992Pharmacokinetics of vinyldithiins, transformation products of allicinView study →}, and one isolation paper reported both as the major components of a thiosulfinate-derivative-rich extract ^{13Reference 13Nair SS et al. · 2017In vitroAllium sativum constituents exhibit anti-tubercular activity in vitro and in RAW 264.7 mouse macrophage cells infected with Mycobacterium tuberculosis H37RvView study →}, but no verified quantitative ratio for a commercial oil macerate was found.

The Preparation Fingerprint

This is the compound’s real value. Garlic’s chemistry forks sharply depending on how the bulb is processed, and each fork leaves a different marker set ^{4,15Reference 4Lawson LD et al. · 1991Identification and HPLC quantitation of the sulfides and dialk(en)yl thiosulfinates in commercial garlic productsView study →Reference 15Amagase H · 2006ReviewClarifying the real bioactive constituents of garlicView study →}:

Preparation	Marker compounds	Vinyldithiins present?
Fresh crushed cloves / garlic powder	Allicin and other thiosulfinates (from alliin via alliinase)	No
Steam-distilled garlic oil	Diallyl disulfide, diallyl trisulfide, diallyl sulfide and the methyl-allyl sulfide series	No
Garlic macerated in vegetable oil	Vinyldithiins and ajoene	Yes — exclusively
Aged garlic extract (aqueous alcohol)	S-allylcysteine	No

The definitive analysis measured thiosulfinates, the full sulfide series, both vinyldithiins and both ajoene isomers across commercial garlic products by HPLC. Thiosulfinates were released only from cloves and powder; the vinyldithiins and ajoenes appeared only in oil-macerated products; the diallyl and methyl-allyl sulfide series were exclusive to steam-distilled oils; and products made from garlic aged in aqueous alcohol contained none of these non-ionic sulfur compounds at all ^{4Reference 4Lawson LD et al. · 1991Identification and HPLC quantitation of the sulfides and dialk(en)yl thiosulfinates in commercial garlic productsView study →}.

That analysis also carried a warning that still applies: content varied 4-fold between brands of oil-macerate and 33-fold between steam-distilled oils, which is why the paper argued for analysing garlic products before using them in clinical research ^{4Reference 4Lawson LD et al. · 1991Identification and HPLC quantitation of the sulfides and dialk(en)yl thiosulfinates in commercial garlic productsView study →}. The oil-soluble compounds are also temperature-sensitive in storage — stable at 4 °C over three months, noticeably degraded at 35 °C ^{16Reference 16Yoo M et al. · 2014Validated HPLC method and temperature stabilities for oil-soluble organosulfur compounds in garlic macerated oilView study →}.

Two caveats keep this from being a perfect test. Vinyldithiins also form when garlic is simply cooked: they turn up in boiled garlic extracts ^{18Reference 18Tocmo R et al. · 2017Data on the effect of boiling on the organosulfides and the hydrogen sulfide-releasing activity of garlicView study →} and among the dominant heterocycles of fried garlic oil ^{19Reference 19Sun J et al. · 2019Influence of different frying processes on the flavor characteristics and sensory profile of garlic oilView study →}. And oil-macerated products were, in the same survey, the weakest garlic preparation class for antiplatelet activity — roughly 12% of the activity of a fresh clove homogenate ^{5Reference 5Lawson LD et al. · 1992Inhibition of whole blood platelet-aggregation by compounds in garlic clove extracts and commercial garlic productsView study →}. A vinyldithiin-rich product is a well-identified product, not necessarily a potent one.

How They Form

Vinyldithiins are not made by the garlic plant. Intact cloves store the odourless precursor alliin; crushing brings alliinase into contact with it and produces allicin ^{14Reference 14Bhatwalkar SB et al. · 2021ReviewAntibacterial properties of organosulfur compounds of garlic (Allium sativum)View study →}. Allicin is unstable, and its decomposition route depends on the solvent it lands in.

In a lipid environment, allicin undergoes a Cope-type elimination to give 2-propenesulfenic acid and its rearrangement partner thioacrolein — a highly reactive, transient thioaldehyde ^{3Reference 3Yoneda T et al. · 2021Construction of sulfur-containing compounds with anti-cancer stem cell activity using thioacrolein derived from garlic based on nature-inspired scaffoldsView study →}. Two thioacrolein molecules then combine in a Diels-Alder cycloaddition, and that self-condensation is what closes the six-membered ring: one regiochemistry gives the 1,3-dithiin, the other the 1,2-dithiin ^{2,3Reference 2Block E · 1985The chemistry of garlic and onionsView study →Reference 3Yoneda T et al. · 2021Construction of sulfur-containing compounds with anti-cancer stem cell activity using thioacrolein derived from garlic based on nature-inspired scaffoldsView study →}. Because the reaction is a dimerisation of a single fragment, one vinyldithiin comes from one allicin molecule ^{12Reference 12Nakamoto M et al. · 2020ReviewAntimicrobial properties of hydrophobic compounds in garlic: allicin, vinyldithiin, ajoene and diallyl polysulfidesView study →} — in contrast to ajoene, which requires three.

Thioacrolein’s usefulness as a Diels-Alder partner has since been exploited synthetically: chemists have used allicin-derived thioacrolein in a sequential double Diels-Alder reaction to build thiopyranone scaffolds with anti-cancer-stem-cell activity matching or exceeding (Z)-ajoene ^{3Reference 3Yoneda T et al. · 2021Construction of sulfur-containing compounds with anti-cancer stem cell activity using thioacrolein derived from garlic based on nature-inspired scaffoldsView study →}.

The practical consequence is straightforward. Steam distillation drives allicin toward the volatile allyl sulfides; aqueous alcohol ageing bypasses the allicin route toward S-allylcysteine; only maceration in oil lets thioacrolein dimerise in bulk, so only oil macerates accumulate vinyldithiins ^{4,15Reference 4Lawson LD et al. · 1991Identification and HPLC quantitation of the sulfides and dialk(en)yl thiosulfinates in commercial garlic productsView study →Reference 15Amagase H · 2006ReviewClarifying the real bioactive constituents of garlicView study →}. Review-level accounts describe the dithiins as the principal oil-soluble product of allicin breakdown, ahead of ajoene and the sulfides ^{21Reference 21Tedeschi P et al. · 2022ReviewTherapeutic potential of allicin and aged garlic extract in Alzheimer’s diseaseView study →}.

What It's Used For

The isolate literature is small, old, and mostly in vitro. It is worth reading for what it rules out as much as for what it supports.

Evidence by IndicationStrength of support · Beta

Support is an experimental score — weighted by study type (human > animal > in vitro) and volume. A beta, not a validated metric. Every row here is preclinical isolate work; nothing rises above in vitro plus one rodent pharmacokinetic study, so the whole table sits low by design.

01Antiplatelet activityShaky32%Whole-blood aggregometry of quantified isolates; the main active in oil-macerates ^{5,17Reference 5Lawson LD et al. · 1992Inhibition of whole blood platelet-aggregation by compounds in garlic clove extracts and commercial garlic productsView study →Reference 17Nishimura H et al. · 2000Thermochemical transformation of sulfur compounds in Japanese domestic Allium, Allium victorialis LView study →}

02Cholesterol synthesisShaky26%Three in-vitro systems that disagree ^{9,10,11Reference 9Sendl A et al. · 1992In vitroInhibition of cholesterol synthesis in vitro by extracts and isolated compounds prepared from garlic and wild garlicView study →Reference 10Gebhardt R · 1996AnimalDifferential inhibitory effects of garlic-derived organosulfur compounds on cholesterol biosynthesis in primary rat hepatocyte culturesView study →Reference 11Cho BH · 2000Effects of allyl mercaptan and various allium-derived compounds on cholesterol synthesis and secretion in Hep-G2 cellsView study →}

03Adipogenesis and adipose inflammationShaky20%One human primary-cell study of the 1,2-isomer at 100 µM ^{8Reference 8Keophiphath M et al. · 2009Keophiphath M, Priem F, Jacquemond-Collet I, Clément K, Lacasa D (2009). 1,2-vinyldithiin from garlic inhibits differentiation and inflammation of human preadipocytes. The Journal of Nutrition. https://pubmed.ncbi.nlm.nih.gov/19759245/View study →}

04Antimicrobial activityShaky16%Active against M. tuberculosis in vitro ^{13Reference 13Nair SS et al. · 2017In vitroAllium sativum constituents exhibit anti-tubercular activity in vitro and in RAW 264.7 mouse macrophage cells infected with Mycobacterium tuberculosis H37RvView study →}; no activity against bacteria generally ^{12Reference 12Nakamoto M et al. · 2020ReviewAntimicrobial properties of hydrophobic compounds in garlic: allicin, vinyldithiin, ajoene and diallyl polysulfidesView study →}

Mechanisms

The load-bearing entry is the negative one. Allicin and the ajoenes work on microbes by attacking thiol groups; closing the sulfur into a stable ring removes that chemistry. Whatever the vinyldithiins do, they do not do what allicin does.

Pharmacokinetics

Unusually for such a thinly studied molecule, the pharmacokinetics are the best-characterised part of the file — in rats.

Given orally at 27 mg of 2-vinyl-4H-1,3-dithiin and 9 mg of 3-vinyl-4H-1,2-dithiin, both isomers were detectable by GC-MS in serum, kidney and fat tissue for 24 hours, but only the 1,3-isomer reached the liver. The two diverge on lipophilicity: 1,3-vinyldithiin is less lipophilic and clears rapidly from serum, kidney and fat, while 1,2-vinyldithiin is more lipophilic and tends to accumulate in fat tissue. Liver-homogenate experiments confirmed different degradation rates for the two, and showed that allicin is metabolised faster than either vinyldithiin — the dithiins are the more persistent species ^{6Reference 6Egen-Schwind C et al. · 1992Pharmacokinetics of vinyldithiins, transformation products of allicinView study →}.

A ³⁵S-labelled study filled in the disposition. After an 8 mg/kg oral dose in an oil macerate, peak blood radioactivity came at 120 minutes (versus 10 minutes for alliin and 30–60 minutes for allicin), and blood levels above 1,000 ng-equivalents/mL were still present at 72 hours. Total urinary plus faecal recovery was 92.3%, implying a minimum absorption of ~73%. Almost nothing appeared in exhaled air, though autoradiography showed enrichment in airway and pharyngeal mucosa and deposition mainly in the cartilage of the vertebral column and ribs. Crucially, no unchanged vinyldithiin was found in urine — metabolism is extensive, and the metabolites are very polar acids that are neither sulfate nor glucuronide conjugates. Organ distribution was indistinguishable from allicin’s ^{7Reference 7Lachmann G et al. · 1994Lachmann G, Lorenz D, Radeck W, Steiper M (1994). [The pharmacokinetics of the ³⁵S-labelled garlic constituents alliin, allicin and vinyldithiine]. Arzneimittel-Forschung. https://pubmed.ncbi.nlm.nih.gov/8053972/View study →}.

The honest reading: the vinyldithiins are well absorbed, slowly cleared, fat-partitioning, and completely metabolised to unidentified polar acids. That last point undercuts every in-vitro result above, because whatever reaches tissue is not the parent compound. A frequently repeated review-level claim holds that oil-soluble garlic organosulfurs — vinyldithiins included — cannot be detected in human blood or urine even after a large garlic intake ^{21Reference 21Tedeschi P et al. · 2022ReviewTherapeutic potential of allicin and aged garlic extract in Alzheimer’s diseaseView study →}; that statement traces to a review rather than a primary human assay, and no human pharmacokinetic study of either isomer exists.

Clinical Trials

There are none. No completed, ongoing or terminated human trial has administered 2-vinyl-4H-1,3-dithiin or 3-vinyl-4H-1,2-dithiin. Human garlic trials use whole preparations — powder tablets standardised to allicin yield, aged garlic extract standardised to S-allylcysteine, or steam-distilled oil — and oil-macerated garlic, the only vinyldithiin-bearing category, is the least-trialled of them ^{4,20Reference 4Lawson LD et al. · 1991Identification and HPLC quantitation of the sulfides and dialk(en)yl thiosulfinates in commercial garlic productsView study →Reference 20Lawson LD · 2018Allicin bioavailability and bioequivalence from garlic supplements and garlic foodsView study →}.

Last checked: July 2026.

Isolate vs. Plant Studies

This molecule family inverts the usual pattern in an awkward way. All of the pharmacology is isolate work — purified, structurally confirmed 2-VD and 3-VD in aggregometry, hepatocyte, preadipocyte and mycobacterial assays ^{5,8,10,13Reference 5Lawson LD et al. · 1992Inhibition of whole blood platelet-aggregation by compounds in garlic clove extracts and commercial garlic productsView study →Reference 8Keophiphath M et al. · 2009Keophiphath M, Priem F, Jacquemond-Collet I, Clément K, Lacasa D (2009). 1,2-vinyldithiin from garlic inhibits differentiation and inflammation of human preadipocytes. The Journal of Nutrition. https://pubmed.ncbi.nlm.nih.gov/19759245/View study →Reference 10Gebhardt R · 1996AnimalDifferential inhibitory effects of garlic-derived organosulfur compounds on cholesterol biosynthesis in primary rat hepatocyte culturesView study →Reference 13Nair SS et al. · 2017In vitroAllium sativum constituents exhibit anti-tubercular activity in vitro and in RAW 264.7 mouse macrophage cells infected with Mycobacterium tuberculosis H37RvView study →}. That would normally be a strength. Here it is offset by the fact that all of the human evidence is at the product level, and the products in question are oil-macerated garlic supplements, which performed worst of all garlic preparation types in the one experiment that compared them directly ^{5Reference 5Lawson LD et al. · 1992Inhibition of whole blood platelet-aggregation by compounds in garlic clove extracts and commercial garlic productsView study →}.

There is also no “whole plant” to fall back on. Vinyldithiins are absent from the intact bulb; the “plant vehicle” is a manufacturing process, not a botanical extract. So the transferability question is not the usual isolate-versus-extract one — it is whether a compound that exists only because of how a product was made contributes anything to that product’s effect. On present evidence the answer is: measurably, for platelet aggregation in a test tube ^{5Reference 5Lawson LD et al. · 1992Inhibition of whole blood platelet-aggregation by compounds in garlic clove extracts and commercial garlic productsView study →}; not demonstrated, for anything a person would notice.

Prevalence in Nature

Strictly speaking, the vinyldithiins are not natural products of a living plant. No intact Allium tissue contains them; they appear only after cell disruption releases alliinase, allicin forms, and allicin then decomposes in a lipid environment ^{1,2,14Reference 1Brodnitz MH et al. · 1971Flavor components of garlic extractView study →Reference 2Block E · 1985The chemistry of garlic and onionsView study →Reference 14Bhatwalkar SB et al. · 2021ReviewAntibacterial properties of organosulfur compounds of garlic (Allium sativum)View study →}. They have no known role in plant defence or signalling, because the plant never assembles them — the defence chemistry belongs to alliin, alliinase and allicin.

Where they do turn up:

• Oil-macerated garlic products — the defining source, and the only commercial garlic category that contains them ^{4Reference 4Lawson LD et al. · 1991Identification and HPLC quantitation of the sulfides and dialk(en)yl thiosulfinates in commercial garlic productsView study →}.
• Cooked garlic — boiled crushed garlic extracts contain both isomers ^{18Reference 18Tocmo R et al. · 2017Data on the effect of boiling on the organosulfides and the hydrogen sulfide-releasing activity of garlicView study →}, and a vinyldithiin ranks among the dominant heterocycles of fried garlic oil, alongside dimethyl trisulfide and diallyl disulfide ^{19Reference 19Sun J et al. · 2019Influence of different frying processes on the flavor characteristics and sensory profile of garlic oilView study →}.
• Allium victorialis (victory onion, “gyoja-ninniku”) — 2-vinyl-4H-1,3-dithiin and a 3-vinyl-1,2-dithiin were identified in a dichloromethane extract of this Japanese wild Allium, and pan-frying increased the dithiin fraction ^{17Reference 17Nishimura H et al. · 2000Thermochemical transformation of sulfur compounds in Japanese domestic Allium, Allium victorialis LView study →}. The same thermochemical route runs in wild garlic relatives, whose extracts inhibit cholesterol synthesis about as well as garlic’s ^{9Reference 9Sendl A et al. · 1992In vitroInhibition of cholesterol synthesis in vitro by extracts and isolated compounds prepared from garlic and wild garlicView study →}.

No verified concentration figure — mg/g, % of oil, or isomer ratio — was found for any of these sources in the literature reviewed here. The available quantitative work reports relative content across product types and a 4-fold spread between brands of oil-macerate ^{4Reference 4Lawson LD et al. · 1991Identification and HPLC quantitation of the sulfides and dialk(en)yl thiosulfinates in commercial garlic productsView study →}, not absolute levels.

Discovery & Synthesis

The vinyldithiins were first identified in 1971, when Brodnitz, Pascale and Van Derslice analysed the flavour components of garlic extract and characterised the two vinyl dithiin isomers among them ^{1Reference 1Brodnitz MH et al. · 1971Flavor components of garlic extractView study →}. Through the following decade the formation mechanism was worked out: allicin undergoes Cope elimination to 2-propenesulfenic acid and thioacrolein, and two thioacrolein units undergo a Diels-Alder cycloaddition to close the dithiin ring — chemistry popularised in Eric Block’s account of garlic and onion chemistry ^{2Reference 2Block E · 1985The chemistry of garlic and onionsView study →} and since used deliberately in synthesis ^{3Reference 3Yoneda T et al. · 2021Construction of sulfur-containing compounds with anti-cancer stem cell activity using thioacrolein derived from garlic based on nature-inspired scaffoldsView study →}.

Manufacture today is not really a manufacture at all. The compounds are not produced or sold as isolated ingredients; they are generated in situ whenever garlic is macerated in oil, and the “production method” is the maceration process itself ^{4,15Reference 4Lawson LD et al. · 1991Identification and HPLC quantitation of the sulfides and dialk(en)yl thiosulfinates in commercial garlic productsView study →Reference 15Amagase H · 2006ReviewClarifying the real bioactive constituents of garlicView study →}. Research-grade material is obtained either by isolation from a thiosulfinate-derivative-rich garlic extract by flash chromatography ^{13Reference 13Nair SS et al. · 2017In vitroAllium sativum constituents exhibit anti-tubercular activity in vitro and in RAW 264.7 mouse macrophage cells infected with Mycobacterium tuberculosis H37RvView study →} or by semi-preparative HPLC from garlic extracts ^{18Reference 18Tocmo R et al. · 2017Data on the effect of boiling on the organosulfides and the hydrogen sulfide-releasing activity of garlicView study →}, rather than by total synthesis. Analytical methods — normal-phase HPLC for the oil-soluble organosulfur set — exist chiefly for quality control of garlic macerated oils, which is the commercial context that actually cares about these molecules ^{16Reference 16Yoo M et al. · 2014Validated HPLC method and temperature stabilities for oil-soluble organosulfur compounds in garlic macerated oilView study →}.

Patents: not yet researched.

Toxicity & Safety

There is no dedicated toxicology for either isomer — no genotoxicity package, no repeat-dose study, no reproductive or developmental data, no human exposure record. The low badge here rests on two things: oil-macerated and fried garlic are long-standing foods, and nothing adverse has been reported for the isolated compounds. It does not rest on a safety dataset, and the absence of findings should not be read as a finding of absence.

What is documented is limited and reassuring as far as it goes. In primary rat hepatocytes, cytotoxicity measured by lactate-dehydrogenase leakage was slightly higher for the two vinyldithiins than for diallyl disulfide or allyl mercaptan, but only appeared above 10 mM — far beyond any concentration relevant to intake ^{10Reference 10Gebhardt R · 1996AnimalDifferential inhibitory effects of garlic-derived organosulfur compounds on cholesterol biosynthesis in primary rat hepatocyte culturesView study →}. In Hep-G2 cells, vinyl-dithiin oil showed no significant cytotoxicity up to 50 µg/mL, with viability falling sharply above 250 µg/mL for every garlic compound tested including the sulfides ^{11Reference 11Cho BH · 2000Effects of allyl mercaptan and various allium-derived compounds on cholesterol synthesis and secretion in Hep-G2 cellsView study →}. Rat pharmacokinetic studies at 8 mg/kg orally reported no toxicity signal ^{6,7Reference 6Egen-Schwind C et al. · 1992Pharmacokinetics of vinyldithiins, transformation products of allicinView study →Reference 7Lachmann G et al. · 1994Lachmann G, Lorenz D, Radeck W, Steiper M (1994). [The pharmacokinetics of the ³⁵S-labelled garlic constituents alliin, allicin and vinyldithiine]. Arzneimittel-Forschung. https://pubmed.ncbi.nlm.nih.gov/8053972/View study →}.

Two things are worth flagging in the absence of data. First, the 1,2-isomer accumulates in fat tissue in rats and clearance from blood is slow — radioactivity was still measurable at 72 hours ^{6,7Reference 6Egen-Schwind C et al. · 1992Pharmacokinetics of vinyldithiins, transformation products of allicinView study →Reference 7Lachmann G et al. · 1994Lachmann G, Lorenz D, Radeck W, Steiper M (1994). [The pharmacokinetics of the ³⁵S-labelled garlic constituents alliin, allicin and vinyldithiine]. Arzneimittel-Forschung. https://pubmed.ncbi.nlm.nih.gov/8053972/View study →} — so repeated intake would not behave like a rapidly cleared compound. Second, the vinyldithiins sit inside the garlic antiplatelet class, and while their own specific activity is low, they were the main anti-aggregatory contributor in oil-macerated products ^{5Reference 5Lawson LD et al. · 1992Inhibition of whole blood platelet-aggregation by compounds in garlic clove extracts and commercial garlic productsView study →}; the standard garlic caution around anticoagulant and antiplatelet medication and around surgery applies to the product, whatever the individual molecule does. No enzyme- or transporter-level drug-interaction work (CYP isoforms, P-glycoprotein) has been done on either isomer.

Safety at a Glance

✅ Low / no toxicity

• Long dietary history in the source form. Oil-macerated and cooked garlic are foods; no adverse effect has been attributed to the vinyldithiins specifically.
• Cytotoxicity only at implausible concentrations. Hepatocyte toxicity appeared above 10 mM, thousands of times higher than any dietary exposure.
• No isolate toxicology at all. No genotoxicity, repeat-dose, reproductive or human-exposure data exists for either isomer — the badge reflects missing data, not demonstrated safety.
• Garlic antiplatelet class. In oil-macerated products the vinyldithiins are the main anti-aggregatory component; the usual caution with anticoagulant/antiplatelet drugs and before surgery applies to the product.
• Slow clearance and fat accumulation. The 1,2-isomer partitions into fat in rats and blood radioactivity persists for at least 72 hours; the behaviour of repeated intake is uncharacterised.

Dosage

There is no human dose for either vinyldithiin, and nothing here should be read as one. The figures that exist are laboratory quantities:

Human exposure is indirect and unmeasured: it comes from eating or supplementing oil-macerated garlic, whose vinyldithiin content varies up to 4-fold between brands and degrades in warm storage ^{4,16Reference 4Lawson LD et al. · 1991Identification and HPLC quantitation of the sulfides and dialk(en)yl thiosulfinates in commercial garlic productsView study →Reference 16Yoo M et al. · 2014Validated HPLC method and temperature stabilities for oil-soluble organosulfur compounds in garlic macerated oilView study →}. Garlic supplements are dosed and standardised on allicin yield or on S-allylcysteine, never on vinyldithiins ^{20Reference 20Lawson LD · 2018Allicin bioavailability and bioequivalence from garlic supplements and garlic foodsView study →}. These are research figures, not a personal recommendation.

References

1. Brodnitz MH, Pascale JV, Van Derslice L (1971). Flavor components of garlic extract. Journal of Agricultural and Food Chemistry. https://doi.org/10.1021/jf60174a007
2. Block E (1985). The chemistry of garlic and onions. Scientific American. https://pubmed.ncbi.nlm.nih.gov/3975593/
3. Yoneda T, Kojima N, Matsumoto T, et al. (2021). Construction of sulfur-containing compounds with anti-cancer stem cell activity using thioacrolein derived from garlic based on nature-inspired scaffolds. Organic & Biomolecular Chemistry. https://pubmed.ncbi.nlm.nih.gov/34878480/
4. Lawson LD, Wang ZJ, Hughes BG (1991). Identification and HPLC quantitation of the sulfides and dialk(en)yl thiosulfinates in commercial garlic products. Planta Medica. https://pubmed.ncbi.nlm.nih.gov/1775579/
5. Lawson LD, Ransom DK, Hughes BG (1992). Inhibition of whole blood platelet-aggregation by compounds in garlic clove extracts and commercial garlic products. Thrombosis Research. https://pubmed.ncbi.nlm.nih.gov/1579891/
6. Egen-Schwind C, Eckard R, Jekat FW, Winterhoff H (1992). Pharmacokinetics of vinyldithiins, transformation products of allicin. Planta Medica. https://pubmed.ncbi.nlm.nih.gov/1620748/
7. Lachmann G, Lorenz D, Radeck W, Steiper M (1994). [The pharmacokinetics of the ³⁵S-labelled garlic constituents alliin, allicin and vinyldithiine]. Arzneimittel-Forschung. https://pubmed.ncbi.nlm.nih.gov/8053972/
8. Keophiphath M, Priem F, Jacquemond-Collet I, Clément K, Lacasa D (2009). 1,2-vinyldithiin from garlic inhibits differentiation and inflammation of human preadipocytes. The Journal of Nutrition. https://pubmed.ncbi.nlm.nih.gov/19759245/
9. Sendl A, Schliack M, Löser R, Stanislaus F, Wagner H (1992). Inhibition of cholesterol synthesis in vitro by extracts and isolated compounds prepared from garlic and wild garlic. Atherosclerosis. https://pubmed.ncbi.nlm.nih.gov/1632861/
10. Gebhardt R, Beck H (1996). Differential inhibitory effects of garlic-derived organosulfur compounds on cholesterol biosynthesis in primary rat hepatocyte cultures. Lipids. https://pubmed.ncbi.nlm.nih.gov/8972460/
11. Cho BH, Xu S (2000). Effects of allyl mercaptan and various allium-derived compounds on cholesterol synthesis and secretion in Hep-G2 cells. Comparative Biochemistry and Physiology Part C. https://pubmed.ncbi.nlm.nih.gov/11050691/
12. Nakamoto M, Kunimura K, Suzuki JI, Kodera Y (2020). Antimicrobial properties of hydrophobic compounds in garlic: allicin, vinyldithiin, ajoene and diallyl polysulfides. Experimental and Therapeutic Medicine (review). https://pubmed.ncbi.nlm.nih.gov/32010337/
13. Nair SS, Gaikwad SS, Kulkarni SP, Mukne AP (2017). Allium sativum constituents exhibit anti-tubercular activity in vitro and in RAW 264.7 mouse macrophage cells infected with Mycobacterium tuberculosis H37Rv. Pharmacognosy Magazine. https://pubmed.ncbi.nlm.nih.gov/28808382/
14. Bhatwalkar SB, Mondal R, Krishna SBN, et al. (2021). Antibacterial properties of organosulfur compounds of garlic (Allium sativum). Frontiers in Microbiology (review). https://pubmed.ncbi.nlm.nih.gov/34394014/
15. Amagase H (2006). Clarifying the real bioactive constituents of garlic. The Journal of Nutrition (review). https://pubmed.ncbi.nlm.nih.gov/16484550/
16. Yoo M, Kim S, Lee S, Shin D (2014). Validated HPLC method and temperature stabilities for oil-soluble organosulfur compounds in garlic macerated oil. Journal of Chromatographic Science. https://pubmed.ncbi.nlm.nih.gov/24243685/
17. Nishimura H, Takahashi T, Wijaya CH, Satoh A, Ariga T (2000). Thermochemical transformation of sulfur compounds in Japanese domestic Allium, Allium victorialis L. BioFactors. https://pubmed.ncbi.nlm.nih.gov/11237191/
18. Tocmo R, Wu Y, Liang D, Fogliano V, Huang D (2017). Data on the effect of boiling on the organosulfides and the hydrogen sulfide-releasing activity of garlic. Data in Brief. https://pubmed.ncbi.nlm.nih.gov/27995158/
19. Sun J, Sun B, Ren F, Chen H, Zhang N, Zhang Y (2019). Influence of different frying processes on the flavor characteristics and sensory profile of garlic oil. Molecules. https://pubmed.ncbi.nlm.nih.gov/31817376/
20. Lawson LD, Hunsaker SM (2018). Allicin bioavailability and bioequivalence from garlic supplements and garlic foods. Nutrients. https://pubmed.ncbi.nlm.nih.gov/29937536/
21. Tedeschi P, Nigro M, Travagli A, et al. (2022). Therapeutic potential of allicin and aged garlic extract in Alzheimer’s disease. International Journal of Molecular Sciences (review). https://pubmed.ncbi.nlm.nih.gov/35805955/

View all 21 references▾