What percentage of TEWL preventing should we aim in a moisturizer?

In a moisturizer occlusive agents prevent TEWL.
So what percentage of TEWL preventing should we aim in a moisturizer product by adding occlusives?

Should we aim to prevent %95-100 TEWL or less? 

What is the normal TEWL rate of a completely young and healthy skin?


Comments

  • abieroseabierose Member
    @Abdullah you really do ask the best questions! I have wondered this very same thing for quite some time.

    I found a lot of interesting articles and publications on TEWL but nothing that specifically answers your question. However I did find a publication about Stratum Corneum Hydration as it relates to TEWL...below is a link to that as well as a screenshot of some of the article...I don't know if any of this will be helpful but I am hoping someone can answer your question because I am interested in knowing this as well.

    https://onlinelibrary.wiley.com/doi/full/10.1111/srt.12711


  • jemolianjemolian Member

    https://www.sciencedirect.com/science/article/pii/S2352647518300133

    Just some relevance for the table, but personally i think the TEWL percentage is mainly theoretical unless you have in vivo testing done. The main thing is that the TEWL reduction with occlusives should be designed based on the type of product you are formulating for the intended customer demographic. If the intended demographic don't need a highly occlusive product, then there's no particular need to really think too much about it. It's more important to get the end user feedback.    
  • AbdullahAbdullah Member
    abierose said:
    @Abdullah you really do ask the best questions! I have wondered this very same thing for quite some time.

    I found a lot of interesting articles and publications on TEWL but nothing that specifically answers your question. However I did find a publication about Stratum Corneum Hydration as it relates to TEWL...below is a link to that as well as a screenshot of some of the article...I don't know if any of this will be helpful but I am hoping someone can answer your question because I am interested in knowing this as well.

    https://onlinelibrary.wiley.com/doi/full/10.1111/srt.12711


    Thanks for the link
  • AbdullahAbdullah Member
    jemolian said:

    https://www.sciencedirect.com/science/article/pii/S2352647518300133

    Just some relevance for the table, but personally i think the TEWL percentage is mainly theoretical unless you have in vivo testing done. The main thing is that the TEWL reduction with occlusives should be designed based on the type of product you are formulating for the intended customer demographic. If the intended demographic don't need a highly occlusive product, then there's no particular need to really think too much about it. It's more important to get the end user feedback.    
    Yes TEWL reduction should be designed differently according to consumer need but how much TEWL reduction do people need? 
    For example i saw in a study that a healthy skin loses 500ml water via TEWL daily. It means TEWL for healthy skin is natural and may be important. So is %100 TEWL reduction necessary?
    Isn't it even harmful long-term? 
  • jemolianjemolian Member
    @Abdullah i think realistically you should have enough material to reduce TEWL, but at the same time balance the preceptive factors (skin feel / feeling after application) of the applied product. Some people might feel that it's overly suffocating due to the amount of occlusives added. It's hard to really reduce TEWL to a large percentage unless you are using petrolatum, which would be the cheapest material with 98% reduction with minimal 5% (https://www.researchgate.net/publication/303091758_Moisturizers_The_Slippery_Road), but you will have to balance the out the rest of the preceptive factors.  

    So far i've only seen that prolong occlusion induces skin damage, though i doubt using an applied material like an occlusive ingredient would be able to do the same inducing that a physical occlusive.  could. https://pubmed.ncbi.nlm.nih.gov/10420139/



  • RedCoastRedCoast Member
    TEWL reduction: it depends.
    Mainly, it depends whether there's a wound involved, bodily location (hands, feet, face, etc), and environmental factors, like the moisturizer being washed off.
    @Abdullah, what location were you thinking of specifically? Face? Feet? Or a "general" or "all-over" moisturizer?
  • AbdullahAbdullah Member
    RedCoast said:
    TEWL reduction: it depends.
    Mainly, it depends whether there's a wound involved, bodily location (hands, feet, face, etc), and environmental factors, like the moisturizer being washed off.
    @Abdullah, what location were you thinking of specifically? Face? Feet? Or a "general" or "all-over" moisturizer?
    For face i think an occlusive agent capable of reducing TEWL by %30 or %40 would be enough. But for hand and foot i don't know how much TEWL reduction should we aim. 
    I have a lotion with %5 petrolatum. Works very good for hand and foot. But for face the same lotion without petrolatum feels better. 
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