vitalys
Forum Replies Created
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@Abdullah Any chemical peeling causes various degree of skin injuries and hence inflammatory response - it is the only way to get regeneration or rejuvination, etc. Most people associate inflammation with diseases or something bad and unpleasant but in fact inflammation is a double-edged sword. We can not treat any disease or condition without inflammatory process. The theory of inflammation is a cornerstone in medical sciences, including dermatology and cosmetology. The only purpose of chemical peelings is inducing the controled injury and inflammation and then the healing process, which results in skin regeneration at the area of injury with all aesthetic benefits . Generally, more tissue damage = more severe inflammation = more pronounced cosmetic effects in the end of the healing process. You may cause a single, but severe injury with free acid at high concentration (50-70% and even higher) or use diluted less concentrated solutions (or neutralized forms) repeatedly to get lesser inflammatory response and hence the moderate or even comparable cosmetic effects with time. (slowly but surely). However, continuous use of the diluted solutions (read the prolonged mild inflammation) may lead to unwanted permanent effects such as changing of a skin type, oiliness, dryness etc. In the latter case every time you apply the acid solution you induce the inflammatory response, which could be unnoticeable or insignificant, because the damage you create is insignificant.
It is very important to note that the strength of an acid solution is not so important as its pH. So pH defines the strength of the peeling solution, not a concentration intself. The same concentration of the acid, for instance 70% may have pH 0.1/0.2 or 2.0 or 3.5 and even higher.
10% of free lactic acid solution is often used as pretreatment before the serious medical grade peelings with highly concentrated acids or acid combinations. So, I assume this concentration is relatively high for every day continuous use unless you create the partially neutralized solution at the same concentration with higher pH.
@Mayday Yes, some peelings may cause severe systemic responses. For instance, phenolic peelings can be provided only in clinics with a control of heart and lungs functions to avoid the heart failure. -
@PhilGeis Yes, it is but this book can not be inexpensive. I have read 3d edition too
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@PhilGeis You shared just an invaluable book, I would say literally a text book. I think anyone in the world of cosmetic formulating should read it and learn from cover to cover.
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@Graillotion I would play with Olive squalane wax - it should be rewarding in the stick formulations (Don’t confuse with Olive wax, which is just hydrogenated olive oil)
Re: Triclosan. As soon as our laboratory has recently looked for Triclosan efficient and safe replacement, we studied O-Cymen-5-Ol. This ingredient has become a leader in tests, including “sniff tests”. It shows excellent deodorizing efficacy at 0.1-0.3%. If you couple it with Triethyl citrate, Ethylhexylglycerin and Trehalose you will achieve even more pronounced effect. -
@Abdullah The Stratum Corneum is a pretty strong shield against sunbeams. When SC gets damaged or altered with any chemical or mechanical agent the shield becomes weak or thin, which makes lively skin cells vulnerable to solar radiation. The latter induces inflammatory reactions as well as the alterations from the damaging factors (e.g. acid peelings).
Abdullah said:And is this sensitivity only when AHA is on top of skin or even after some time when it is rinsed off?The hypersensitivity will last until the skin barriers are completely restored and inflammation is eliminated.
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The following events occur:
Acid application > Damage to the corneocytes > Cytokines production begins > Initial stages of inflammation > Activation of all lively cells in the basal layer, including melanocytes, immune cells and fibroblasts > Activated melanocytes start to produce melanin.
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I doubt the typical ratios exist.
Personally, I prefer to use a pure weak acid (e.g. Citric acid) and a pure strong base (e.g. 50% NaOH solution) to create a buffing system in situ and adjust pH to the required level in the system. -
Congratulations, Perry!
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It is very difficult (almost impossible) to tell how much you need to employ in your system - it all depends (water, urea purity, etc). You need to choose the buffing system, which would be able to maintain the pH at the particular level for a long period of time. Urea is most stable at pH 6-6.2, so you need to adjust the pH of your solution manually by adding components of the buffer literally drop by drop and then you will find out the % for your system precisely.
Another option is use esters of such acids as Citric, Lactic, etc. - Triethyl Citrate, Triacetin, Ethyl Lactate. They also effectively prevent the pH drift of urea solutions. -
The buffer is necessary if you want to extend Urea stability in the water solution.
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I don’t see any obstacles with this combination if you utilize the mixture within a week.
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@DaveStone 10% Urea is too much here. Usually, 10% Urea is used for “thick” skin type (palms and soles). Of course, it depends on the purpose of your formulation, but I would employ 3-5% of Urea.
The concentration of Salicylic acid also depends on the purpose of the formulation. Usually 0,5 - 2%. The higher concentrations bring your product into OTC category (For example, the preparations against acne) -
Urea and hydroxy acids affect the protein structures differently. Acids coagulates the proteins, so the process of exfoliation is slower (If you use the recommended % of an acid or an acid mixture).
You don’t need to use 40% Urea solution to exfoliate the callused skin. 25-30% will suffice to remove it quickly and safely.
Another option is 3.5-5% KOH solutions, which are also known as ” cuticle and callus removers” , manufactured in a form of gels and used in the salon industry and by foot care specialists. If you use the KOH as exfoliating remedy, it is highly recommended to apply efficient moisturizer to recover the skin barriers, because alkaline preparations destroy the skin proteins as well as the skin lipids (cell membranes, etc). -
@Perry Actually, they are comparable in their effect, but still different. These two substances can apparently complement each other in different preparations. It also depends on a formulation and its purpose. However, there are plenty of formulations where Urea shows more pronounced and prolonged effect. For example, the special formulations for hand and foot care. I completely agree with @ngarayeva001 that urea is the best component to improve dry skin conditions. I can say the same about feet, atopic skin conditions, severe ichthyosis, hyperkeratosis, etc
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40% Urea is one of the strongest keratolytics, as @chemicalmatt mentioned, but at the concentration of 5-7% it becomes one of the most powerful humectants ( I would say the best one).
@DaveStone Yes, 40% Urea will dissolve a healthy nail too. -
The form of a topical preparations along with the concentration of the active in it define the properties, penetration and activity
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@CHarley Candida and Aspergillus are not bacteria. Thus, you need to fortify your antifungal spectrum of the preservative system.
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@Pharma, Excellent input! Indeed it merely can’t work topically.
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@Abdullah , @ketchito explained it perfectly regarding the barriers.
The skin barriers determine the key function of the human skin - protection of the entire body. In fact it is like a State boarder with all its soldiers, officers, boarder control, security systems, customs, etc. Thus, so called protectants fortify the boarder forces. -
@Abdullah A skin protectant is a substance or a mix of substances that maintain the skin barriers.
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It can be overhydrated when the skin is exposed to water, for example shower or foot baths. Hyaluronic acid works only on the surface while you need to enhance water retention in the Stratum Corneum. Components of the natural moisturizing factor, such as Lactic acid, Urea, etc would be highly efficient along with polyols, sugar alcohols, etc.
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@DaveStone Mandelic acid may work great. However, it is quite difficult to recommend something particular distantly. I assume you may want to see your dermatologist to determine the exact skin condition.
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@ngarayeva001 This article summarizes sex-related differences in the skin.
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@Abdullah It doesn’t compete, but works in synergy with other components.
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@DaveStone Dry skin and dehydrated skin conditions are not interchangeable meanings. Dehydrated skin - is water deficiency ( when skin is losing its ability to retain water) while dry skin is a sign of the decreased or abnormal lipid synthesis in the skin. TEWL takes place in both conditions.
If your moisturizers and occlusive preparations are obviously useless, it might be the dry skin condition. There are plenty of methods to maintain the lipid content and production in the epidermis. Light acid peels and Nicotinamide, for instance, show good results.
Be careful with Tretinoin. I would use it only after the consultation with a dermatologist.