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  • Retinol: Concentration in a given product

    Posted by suswang8 on March 19, 2024 at 11:01 am

    Hi, all.

    It seems that, at a maximum, a brand will disclose the % of retinol contained in a product. For example, a 1% retinol face oil, such as this one.


    From what I understand, a more important measure of a retinol product’s strength is stated in terms of IU. As an example, for a different product, the manufacturer told me theirs is 0.5% (not mentioned on the label), providing 1500IU. Does anyone know if this conversion rate is “universally true” or does it vary by product? For example, do I assume that all 1% retinol products contain 3000IU of retinol?

    Thank you.

    suswang8 replied 1 month ago 2 Members · 2 Replies
  • 2 Replies
  • Tmas10

    March 19, 2024 at 2:50 pm

    Hello, so the IU is specific to the compound in question. So the retinol IU only applies to retinol, if a product contains a different Vitamin A derivative or a different version of retinol (ex Beta-retinol, retinyl acetate) it will have a different IU. So it would follow the actual ingredient, not products.

    I do not believe IU is exactly what you are looking for however. IU is a measure of the required amount to have a biological effect (i.e. 3 mcg = 1 IU of retinol) it is a specific measurement that is measured for food and supplements, I don’t believe it would be measured for skin effect. This is basically the reason that a company using retinol won’t put an IU, but just the %, compared to a Vitamin A supplement that may put it on there as its more applicable (or the updated “…mcg RAE”). If it helps you think about it more clearly, then by all means, it is just a conversion to a different unit, but I think it is an unnecessary conversion to make in your head.

  • suswang8

    March 20, 2024 at 7:35 pm

    Basically, I am making indirect reference to the study below, which looks at strength based on IU, rather than % concentration, but — yes — I was speaking only of retinol and not other similar derivatives.


    • This reply was modified 1 month ago by  suswang8.

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