Propylene glycol, AKA PG, is found in different kinds of liquid skincare products. Crazily enough, it’s also found in things like antifreeze, brake fluid, and paints. Yes, this ingredient is in our skincare AND car products. Yikes. PG is known to be able to allow harmful chemicals to sink deeper into your skin and bloodstream than they could otherwise do on their own.
PG’s side effects include skin inflammation and irritation. PG prevents moisture loss by creating a seal over your skin but can also make your skin drier by drawing moisture from the deeper layers of your skin towards the top-most layers.
An alternative people use is Vegetable glycerin.
Another alternative, but not so great, is Propanediol, AKA 1,3 propylene glycol. It’s safety depends on its manufacturing process.