Topical Amino acids - What's the point?

ZinkZink Member
edited December 2014 in Formulating
To start things off, let's look at the paper "Anatomical and Physiological Basis for Corneotrophic Care of the Skin"

'Amino acids. Some amino acids can be absorbed from the skin and may aid in tissue repair and regeneration. Altering cellular osmolality to a hyperosmotic state results in a decrease in ATP allied with oncosis and resultant necrosis. The following components discussed are ingredients in Olivamine.

Glycine (<100 d) protects ATP-depleted cells by low affinity interactions with multimeric channel protein, stabilization of which may otherwise lead to formation of pathological pores. Such porous defects in membranes of ATP-depleted cells have been characterized recently, showing definable exclusion limits for molecules of increasing sizes.23 Glycine provided during ATP depletion blocked the development of membranous pores completely. 24 The relationship between necrosis and an extracellular depletion of ATP makes its protection and restoration imperative during the pre lethal stages of necrosis or early necrosis. 

l-Taurine (<200 d) can act as a direct antioxidant that scavenges or quenches oxygen-free radicals intracellularly to block ROS-mediated cell death. The beneficial effects of the ROS-scavenging capacity of l-taurine include attenuation of lipid peroxidation, reduction of membrane permeability, and inhibition of intracellular oxidation in different cells. 25 Apart from its effect on antioxidant defense, l-taurine also functions in osmoregulation and modulation of intracellular Ca 2+ concentration. Taurine prevents high glucose–induced apoptosis in endothelial cells through ROS inhibition and stabilization of intracellular calcium. 26

N-acetyl l-cysteine (NAC) is an antioxidant, particularly working against hydrogen peroxide. The hypothesis that NAC-induced free-radical signaling delays G 0 /G 1 cell progression to S phase by regulating the cell cycle regulatory protein cyclin D 1 and the free radical–scavenging enzyme manganese superoxide dismutase (MnSOD) has been investigated. Treatment with NAC (<200 d) resulted in increased cellular glutathione levels, indicating a shift to a more reducing environment. This shift in cellular redox environment was associated with delayed progression from G 0 /G 1 to S. NAC treatment resulted in a decrease in cyclin D 1 and an increase in MnSOD protein levels. The absence of a NAC- induced G 1 arrest in fibroblasts overexpressing cyclin D 1 (or a nondegradable mutant of cyclin D 1 V T286A) indicates that cyclin D 1 regulates this delay in G 0 /G 1 to S progression. These results support the hypothesis that cellular redox environment regulates cellular proliferation via regulating cell cycle regulatory protein levels. 27 Furthermore, in the authors’ opinion, the results also suggest that inclusion of NAC in skin care formulations might help in appropriate
wound healing by controlling proliferation and preventing scarring.'

Cont..

Comments

  • DNA synthesis is a vital part of cell life. In studies done in vivo and in vitro, 
    l-proline (<200 d) was found to be the only amino acid that was involved in the stimulation of DNA synthesis. 28 Furthermore, EGF elicited no response without the addition of l-proline. Proline-deficient media such as Leibovitz L-15, Eagle minimal essential, and Dulbecco modified minimal essential did not induce DNA synthesis. However, using media such as Williams E, McCoy’s 5A, and Ham’s F-12, which are rich in l-proline, there was DNA synthesis and marked proliferation. 29
    l-Proline is essential for the induction of cellular proliferation in vivo and in vitro through its effect on synthesis of intracellular collagen.

    So, are any of you (not) using amino acids in your formulations, and if, why/why not?
  • PerryPerry Administrator, Professional Chemist
    I see very little evidence of much benefit (beyond marketing) of using amino acids in topical formulations. There are lots of questions that occur to me from the information posted.  

    The paper sited starts with a really weak marketing claim."Some amino acids can be absorbed from the skin and may aid in tissue repair and regeneration. "

    I guess the amino acids being discussed include Proline, Glycine, Taurine, and Cysteine.  Does this mean the other 16 amino acids were investigated and found not to be effective?

    Also what does "may aid" mean?  Does that mean 90% of the time, 50% of the time, 1% of the time or there's one chance in a million it will aid?  Wouldn't that also mean that it "may not aid" in tissue repair and regeneration?  What determines whether it's going to help or not?

    And what specifically is meant by tissue repair and regeneration?  Do these amino acids convert scar tissue to normal skin?  Do they regenerate skin so there is extra skin?  What does this mean?  Is there a study showing scar tissue is regenerated when these amino acids are applied?

    If Taurine works as an antioxidant wouldn't other, better antioxidants be preferred to have a superior effect?  What makes taurine a better choice as an antioxidant over other molecules?  And why would you need two antioxidants (taurine and cysteine)?

    If proline is involved in the stimulation of DNA synthesis wouldn't this be a potential problem in the event that someone had skin cancer?  Stimulating the production of more cancerous DNA doesn't sound like a good idea.  Have they shown that proline stimulates DNA synthesis for only non-cancerous DNA?

    There is some interesting stuff here and the technology of amino acids shows some potential however, there are so many unanswered questions and vague claims that there is little reason to use these ingredients (except for marketing purposes).  And based on the hypotheses provided (stimulating DNA synthesis, preventing cell apoptosis) it may be downright dangerous to use amino acids in topical skin care products.  
  • pmapma Member
    edited December 2014
    The topical application of some amino acids can improve the skin's barrier function. But even petrolatum can do this... Anyway, from amino acids you can develop wonderful new raw materials, like mild and effective surfactants, extremely smooth powders for makeup etc. 
  • I doubt amino acids are able to penetrate the skin barrier and even it may be possible - what are they supposed to do in the skin layers? However, I have got an experience of working with them in some formulations using their properties. For instance, L-Arginine appears to be a nice neutralizer for Carbopols giving the final products very pleasant sensorial feeling and additional conditioning effect especially in nail and hair formulations. It's also widely known as a functional ingredient in acid based peels for the professional cosmetic practice. Glycine is able to improve the quality and some properties in hand made soaps.
  • pmapma Member
    Topical arginine HCL may be useful:

    [Topically applied arginine hydrochloride. Effect on urea content of stratum corneum and skin hydration in atopic eczema and skin aging].


  • pmapma Member
    Speaking in amino acids, the new trending in China and Japan are D-amino acids. In China in creams/cosmetics and in Japan in drinks/oral.

    But I haven't found any relevant study for cosmetic applications of D-amino acids. Just thinks like that:

  • @pma Thank you for the article. It comes along with my own studies with formulations I have made for atopical skin conditions. Indeed, as I could scrutinized adding 5-10% of L-Arginine to the formulation significantly helps to treat some skin conditions. However, I didn't correlate those results with Krebs cycle at all. I still have no any evidences amino acids are able to penetrate the barrier.
  • Hi @vitalys - can you tell us what skin conditions you tried it for? :)
  • eczema, atopic dermatitis, psoriasis. But please, don't assume this is a remedy - as I have mentioned -" It helps to treat" and products which contain this amino acid show the obvious results diminishing some symptoms making the life of the patients easier.
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