Molecules with a molecular weight less than 500 g/mol, like linoleic acid, can penetrate human skin.

“any molecule with a molecular weight less than 500 grams per mole can penetrate the human skin especially a lipid molecule like linoleic acid so linoleic acid I think is 250 grams per mole clearly within the range of molecule size that could go into your skin from your skin if you apply it onto the outside of your skin”