What it is
1,3-Propanediol, also called 1,3-Dihydroxypropane, can be derived synthetically from oil, or from corn sugar.
What it does
1,3-Propanediol is a humectant: it can attract water from the environment into the skin, thus helping to keep it hydrated.
In addition, it is also used as a solvent to dissolve other substances.
1,3-Propanediol is a relatively-new ingredients so very few studies have been so far conducted to determine both its efficacy and side effects. However, it is generally considered to be safe.