Some formulations include as much as 2 percent or more retinol, which is greater than the average for over-the-counter retinol creams. Important to remember is that retinol concentrations less than 0.25 percent will not provide any benefit. Manufacturers are not obligated to reveal the amount of retinol included in their products, and many choose to keep this information confidential as part of their trade secret formulation. Having said that, if a product’s concentration is not listed on the label, you may wish to check with the manufacturer to verify the product is effective.