Hydroxypropyl Tetrahydropyrantriol

This ingredient is often marketed as Pro-Xylane. It was developed by L'Oreal in 2006 and comes from xylose, a natural sugar extracted from beech wood.

In L'Oreal's published chemistry work, this ingredient was identified as a strong activator of sulfated glycosaminoglycan (GAG) biosynthesis.

This ingredient helped skin make more of its own natural “water-holding” molecules (called GAGs) in lab studies and skin models, which are important for keeping skin plump and hydrated. It also supported proteins that help anchor and support the skin’s layers.

Most human studies look at full skincare formulas rather than the ingredient on its own.

In one 12-week study, a facial serum containing Pro-Xylane was linked to improvements in skin hydration, firmness, and the appearance of sun-damaged skin.

In a more recent study, a product with hydroxypropyl tetrahydropyrantriol plus niacinamide was used after laser treatments and showed visible improvements in fine lines, wrinkles, and overall skin appearance within about 8 weeks, along with signs that the skin was calming and repairing itself.