Is it safe to use retinols on the labia majora?

Hello, While it is safe to use on any skin, including the labia majora, I do not recommend that the retinol contact your vaginal mucosa.  The product is meant for external use only.  I would apply a small amount of a good quality retinol or tretinoin to a test area on your labia prior to a full application.  In addition, the labia may be less or more sensive to the product than your face.  Only will know once you use it.