Trans-Zeaxanthin (dietary isomer) vs. Meso-Zeaxanthin
Among 385 on-market zeaxanthin products with an identifiable primary form, 19.5% use Trans-Zeaxanthin (dietary isomer) (75 products) and 9.1% use Meso-Zeaxanthin (35).
| Trans-Zeaxanthin (dietary isomer) | Meso-Zeaxanthin | |
|---|---|---|
| Quality tier | Unrated | Tier 2 |
| Zeaxanthin by weight | — | — |
| Share of market | 19.5% | 9.1% |
| On-market products | 75 | 35 |
| Median declared dose | 0.15 mg middle half: 0.15–0.47 | 4 mg middle half: 4–8.5 |
| Most common brands | Life Extension | Life Extension, Higher Nature, Doctors' Preferred |
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 Trans-Zeaxanthin (dietary isomer) is unrated
The isomer naturally present in diet and macular pigment; it was a co-component (2 mg) in every verified trial and never tested alone at a defined dose, so it is not ranked.
Source: Sabour-Pickett S et al. 2014, Retina 34(9):1757-1766, PMID 24887490
Why Meso-Zeaxanthin is tier 2
Human RCT evidence at supplemental doses: in 52 early-AMD patients, formulations containing 10 or 17 mg/day meso-zeaxanthin (with lutein and zeaxanthin) raised macular pigment optical density across more eccentricities than lutein 20 mg + zeaxanthin 2 mg, and the 17 mg arm improved contrast sensitivity most; a separate RCT (n=44) showed serum and central MPOD increases. Evidence is from small trials by one research group with no disease-progression endpoint, hence tier 2 rather than 1.
Source: Sabour-Pickett S et al. 2014, Retina 34(9):1757-1766, PMID 24887490; Connolly EE et al. 2011, Invest Ophthalmol Vis Sci 52(12):9207-9217, PMID 21979997