HYALURONIC ACID
IT DOES NOT PUT WATER INTO YOUR SKIN.
IT STOPS THE WATER ALREADY THERE FROM LEAVING.
WHAT IT
HOLDS
HYALURONIC ACID IS A HUMECTANT: A MOLECULE THAT BINDS WATER AND KEEPS IT IN THE UPPER LAYERS OF THE SKIN. IT HOLDS SEVERAL HUNDRED TIMES ITS OWN WEIGHT. SKIN LOOKS PLUMPER BECAUSE IT IS HYDRATED, NOT BECAUSE ANYTHING HAS BEEN FILLED IN.
THEY ARE NOT
ALL THE SAME
MOLECULAR WEIGHT DECIDES EVERYTHING. A LARGE MOLECULE STAYS ON THE SURFACE AND FORMS A FILM THAT SLOWS EVAPORATION. A SMALL ONE TRAVELS FURTHER INTO THE STRATUM CORNEUM. MOST LABELS SAY “HYALURONIC ACID” WITHOUT SAYING WHICH — WHICH AMOUNTS TO SAYING NOTHING.
A HUMECTANT
NEEDS WATER
IF IT CANNOT FIND ANY IN THE AIR, IT DRAWS IT FROM DEEPER IN YOUR SKIN. IN DRY WEATHER, APPLIED TO DRY SKIN AND LEFT BARE, IT CAN THEREFORE DEHYDRATE RATHER THAN HYDRATE. THE RULE IS SIMPLE: DAMP SKIN, THEN SOMETHING OVER THE TOP TO HOLD IT ALL IN.
WHAT TO PAIR
IT WITH
ANYTHING — THAT IS ITS PARTICULARITY: HYALURONIC ACID HAS NO PREFERRED pH AND CONFLICTS WITH NO OTHER ACTIVE. IT IS THE ONE YOU ADD WHEN ANOTHER DRIES YOU OUT — AFTER A RETINOID, AFTER AN ACID. THE ONLY RULE IS ORDER: DAMP SKIN, THEN SOMETHING OVER THE TOP TO HOLD IN WHAT IT HAS BOUND. ALONE IN DRY AIR, IT WORKS AGAINST YOU.