Curcuminoids are extracted from the rhizomes of curcuma longa (turmeric) and have great antioxidant and anti-irritation properties that make them almost ideal ingredients for skin care. Their molecular structure is the reason for the potent antioxidant properties they possess, but because of their low solubility and poor bio-availability, very high concentrations are required to obtain the desired effects. Scientists realized that the small amounts that were absorbed and used were eventually converted by the body into a much better chemical, tetrahydrocurcuminoids (THCs).
Tetrahydrocurcuminoids keep the superior antioxidant and anti-irritation properties of curcuminoids, but are easier to use in skin care products. In addition to being a powerful antioxidant, tetrahydrocurcuminoids are commonly used in skin brightening products combined with other actives to reduce the appearance of dark spots and uneven skin tone.