Reputable lab, well I thought they were, it touting Sodium Ascrorbyl Phosphate is better than

L ascorbic acid for as far as topical vitamin C goes for the skin. Thoughts?


  • PerryPerry Administrator, Professional Chemist
    Marketers are gonna market.

    If a company profits from making you believe something is true, you should discount what that companies says.  This doesn't mean they are necessarily lying. But it does mean that they probably aren't telling you the whole truth.
  • Better is relative, right?

    Since L-Ascorbic Acid is super unstable, one could say Sodium Ascorbyl Phosphate is better because it will remain viable for longer in a product. It’s also less irritant/stings less, and you can use a lower percentage because it won’t readily oxidize.

    From a visible results standpoint, not sure. I read a paper somewhere that claimed 10% MAP and 10% SAP had similar results to L-Ascorbic Acid, without the stability issues. So maybe not better in terms of effectiveness (assuming LAA hasn’t oxidized in a product).

    Maybe the lab just doesn’t want the headache of working with LAA.

  • PharmaPharma Member, Pharmacist
    Skin penetration of SAP (and MAP) is very likely poorer than for LAA.
    The 10% comparison is not always evident: Is it 10% by weight or by mol (= 10% relative to the AA part)?
    Cellular uptake of AA is also better than for SAP/MAP. The latter requires to be taken up to be split into free and active AA.
    You would have to dig through scientific literature to see whether someone actually bothered to compare the two forms in a skin test. I doubt you'll find much...
  • MarkBroussardMarkBroussard Member, Professional Chemist
    "Better" is a relative term ... "Better" in what context?

    "Better" meaning it is more effective?  Or, easier to incorporate into a formula?  Or, more stable?

    Depending on your product format, say a cream ... then, Yes, SAP would be better than LAA in terms of your cream not discoloring so quickly.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    See website for details
  • @Pharma agree with all that. I think for the most part we can all assume that a bioactive compound will be easier to absorb/utilize vs one that needs an enzyme to “activate” it like MAP or SAP. 

    For a qualitative analysis like that on skin texture and color improvement, considering that cosmetic formulas are percent by weight, I think comparing effectiveness of a given percentage of two compounds is sufficient. After all you just want to know if a consumer will see the same or similar results with either one of the compounds (or if you need more of less of one to achieve the same). The study I read was in vivo, and qualitative. From an academic standpoint, I know it doesn’t mean much in terms of the pharmacokinetics of each form of AA.
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