How do SAC and S1PC pharmacokinetics differ between orally administered Kyolic AGE and black garlic preparations in humans?
Executive summary
Orally administered S‑allyl‑L‑cysteine (SAC) and S‑1‑propenyl‑L‑cysteine (S1PC) show high apparent oral availability in preclinical models and are measurable constituents of both Kyolic aged garlic extract (AGE) and black garlic products, but the two product types differ more in starting content and standardization than in demonstrated human pharmacokinetic behavior — because direct, comparative human PK studies are essentially absent from the published record [1] [2]. The pragmatic difference for clinicians and consumers today is dose consistency: Kyolic/AGE products tend to report standardized SAC content while commercial black garlic and black garlic extracts show wide, poorly standardized ranges of SAC and S1PC [2] [3].
1. Product chemistry drives exposure more than imagined metabolic miracles
Kyolic AGE formulations sold as aged garlic extracts are characterized and marketed with specific SAC yields — for example, SAC in two commercial AGE products (Kyolic®, Formula 100™ and One Per Day™) was reported in the 0.34–0.70 mg/g and 0.51–0.93 mg/g ranges respectively, while S1PC is present but at lower and more variable levels across products [2]. By contrast, analyses of black garlic and black garlic extracts showed much broader and sometimes higher ranges for SAC in different matrices — commercial black garlic cloves had SAC in the range 22.28–63.71 mg/100 g, and black garlic extracts showed wide inter‑product variability, meaning that the oral input of SAC and S1PC to a human consumer depends largely on which preparation and dose are taken [2].
2. What is known about absorption, metabolism and excretion — mainly from reviews and animal data
Mechanistic pharmacokinetic reviews report that SAC and S1PC are hydrophilic sulfur‑amino acids with high oral absorption in animal models (bioavailability often reported in the 88–100% range in rats and dogs), and that both compounds are excreted in urine largely as N‑acetylated metabolites, consistent with rapid systemic uptake and renal handling rather than extensive first‑pass disappearance [1] [4]. SAC shows multi‑phase disposition (rapid distribution followed by slower elimination) in animal and limited human work, and SAMC and other volatile sulfur species behave very differently — emphasizing that not all garlic sulfur compounds follow the same PK rules [5] [1].
3. Head‑to‑head human pharmacokinetic evidence is missing
No published study identified in the supplied sources directly compares human plasma or urinary pharmacokinetics of SAC and S1PC after oral administration of Kyolic AGE versus specific black garlic preparations. Clinical trials of Kyolic and optimized AGE report clinical pharmacodynamic outcomes and specify intake amounts of SAC (for instance trials using tablets delivering ~1.25–2.4 mg SAC/day), but these trials do not provide the detailed plasma PK curves or direct S1PC comparisons needed to infer rate constants, Cmax, Tmax or clearance differences between product types in humans [6] [7]. Therefore any statement that one product yields systematically higher human plasma SAC or S1PC concentrations would exceed the cited evidence.
4. Practical implications: standardization, dosing and measurement matter
Analytical work using LC‑MS shows that supplements cluster into “genuine” AGE profiles (with both SAC and S1PC plus precursor peptides) and simpler preparations dominated by SAC alone, highlighting real-world variation in what consumers ingest and what laboratories detect [3]. Because SAC and S1PC are water‑soluble and amenable to urinary N‑acetyl metabolite measurement, well‑designed human PK studies could be done, but until those head‑to‑head data exist, the main pharmacokinetic difference consumers face is variability in starting dose and formulation rather than proven differences in absorption or elimination in humans [3] [1].
5. Alternate interpretations and commercial incentives
Manufacturers of standardized AGE (e.g., Kyolic) have commercial incentives to report consistent SAC yields, which supports claims about reproducible biological effects in clinical trials, while producers of black garlic foods and extracts may not standardize to the same degree, creating heterogeneity in exposure that can be misinterpreted as pharmacokinetic differences [2] [3]. Independent researchers caution that S1PC — once trace in raw garlic but enriched by aging — warrants more PK study because preclinical data suggest potent bioactivity and high bioavailability in animals, yet drug–drug interaction potential appears low based on in vitro CYP tests [4] [1].
6. Bottom line and research gap
SAC and S1PC are well absorbed, renally handled amino‑sulfur compounds whose human excretion patterns (N‑acetylated urine metabolites) and animal bioavailability are established, but direct human comparative PK data between Kyolic‑style AGE and black garlic preparations are not available in the cited literature; therefore differences likely arise from variable content and formulation rather than demonstrated divergent human ADME parameters, and a controlled human PK head‑to‑head study is the critical missing piece [1] [2] [3].