Lutein and zeaxanthin: the format matters more than the percentage

A lutein quote can be 5% or 80% and both can be reasonable. The percentage describes the format, not the quality, and the only honest comparison is on cost per gram of actual carotenoid.

The formats

• Oleoresin — the concentrated extract from marigold, high strength, viscous and difficult to dose accurately in a dry blend.
• Oil suspension — the oleoresin diluted into a carrier oil, typically 5% to 20%. Straightforward for softgels.
• Beadlets or cold-water-dispersible powder — the carotenoid encapsulated in a matrix, usually starch or gelatin with antioxidants. Lower strength, typically 5% to 10%, but far more stable and the only practical option for tablets, powders and beverages.

The beadlet is mostly matrix by weight. That is not dilution for its own sake — the matrix is what protects an easily oxidised molecule and lets it disperse in water. It does mean a 5% beadlet and a 20% oil suspension are not remotely comparable per kilo.

Free lutein versus esters

Marigold produces lutein naturally as fatty acid esters. Saponification converts these to free lutein. Both are sold, and the specification must say which, because the ester form carries roughly twice the molecular weight for the same lutein content. A "20% lutein ester" material contains substantially less lutein than "20% free lutein". Check whether the declared percentage refers to total carotenoid, lutein specifically, or lutein esters expressed as free lutein.

The zeaxanthin ratio

Marigold gives roughly a 20:1 lutein to zeaxanthin ratio naturally. Products at 5:1 or 10:1 have been adjusted, usually by adding separately produced zeaxanthin. If your customer's formulation specifies a ratio, it needs to be on the purchase specification with a tolerance, and confirmed by HPLC on each batch rather than assumed from the grade name.

What to put on the specification

• Total carotenoids and lutein specifically, by HPLC, stating whether the figure is free lutein or esters.
• Zeaxanthin content and the resulting ratio.
• Format, and for beadlets the full matrix composition — it becomes part of your ingredient statement.
• Antioxidant system in the formulation, declared with inclusion rates.
• Solvent residues from the extraction, and heavy metals and pesticides on the marigold input.
• Stability data in your intended matrix, since carotenoid degradation is heavily matrix-dependent.

Compare on carotenoid, not on powder

Convert every quote to a price per gram of lutein delivered before you look at them side by side. The ranking usually changes, and it frequently changes in favour of the material that looked expensive per kilo.