AYU Sunless FAQs.

AYU Sunless FAQs.

DHA (Dihydroxyacetone) is a three-carbon reducing sugar and the principal color-developing ingredient used in most sunless tanning formulas. It reacts with amino groups in free amino acids, peptides and proteins within the stratum corneum through a nonenzymatic browning process commonly described as the Maillard reaction. This reaction forms colored compounds called melanoidins without stimulating melanin or requiring UV exposure.

Visible DHA-developed color begins forming within several hours and can continue developing after the first rinse. The timing and depth depend on the DHA concentration, complete formulation, amount applied, development time and condition of the skin. The color gradually fades as the colored cells of the stratum corneum naturally shed.

Erythrulose is a four-carbon reducing sugar that participates in a similar reaction but develops more gradually, commonly over 24 to 48 hours. When used alone, it generally produces lighter color, which is why formulators often combine it with DHA.

In a carefully balanced formula, DHA contributes earlier color development while erythrulose contributes more gradually. This broadens the development profile and can support a smoother progression of color and fade. Erythrulose does not independently guarantee a deeper, more even or longer-lasting tan. Its performance depends on its concentration, its ratio with DHA, the complete formulation and the client's skin.

At AYU Sunless, DHA is the primary tanning active, and erythrulose is incorporated into selected formulas when its slower development profile supports the intended performance. We evaluate the tanning actives, pH, delivery system, skin-conditioning ingredients and development schedule as one complete formulation system.

For a deeper explanation, read How Sunless Tanning Actually Works on Skin.