Polygonum cuspidatum (Japanese knotweed) root extract-sourced resveratrol vs. Trans-Resveratrol
Among 1,277 on-market resveratrol products with an identifiable primary form, 50.1% use Polygonum cuspidatum (Japanese knotweed) root extract-sourced resveratrol (640 products) and 49.9% use Trans-Resveratrol (637).
| Polygonum cuspidatum (Japanese knotweed) root extract-sourced resveratrol | Trans-Resveratrol | |
|---|---|---|
| Quality tier | Unrated | Unrated |
| Resveratrol by weight | — | — |
| Share of market | 50.1% | 49.9% |
| On-market products | 640 | 637 |
| Median declared dose | 50 mg middle half: 10–160 | 30 mg middle half: 20–100 |
| Most common brands | ProCaps Laboratories, Vitamin World, Metagenics | Pure Encapsulations, Dr. Sinatra, Source Naturals |
Doses are declared per serving in mg. “By weight” is the share of the ingredient that is the nutrient itself (e.g. elemental magnesium in a magnesium salt).
Why Polygonum cuspidatum (Japanese knotweed) root extract-sourced resveratrol is unrated
Botanical-source descriptor (the dominant commercial source -- several hundred on-market rows name it in raw_form) rather than a distinct delivery form; standardization varies widely and no human comparison against synthetic/fermented resveratrol was verified, so it is not ranked. A row whose own name is the plant source (e.g. "Japanese Knotweed Root Extract") declares extract mass, not resveratrol, and is kept unresolved; a "Resveratrol" row that merely lists the plant in raw_form keeps its declared mg.
Why Trans-Resveratrol is unrated
The biologically relevant isomer and what most products declare, but the human trials verified here report "resveratrol" without isomer detail in the abstract, and trans vs unspecified was not compared; not ranked. Human exposure to free resveratrol is low relative to its glucuronide/sulfate conjugates (up to ~20-fold higher AUC for metabolites at 0.5-5 g/day).
Source: Brown VA et al. 2010, Cancer Res 70(22):9003-9011, PMID 20935227