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Anti-oxidants in Cosmetic Formulation
Hi,
I was wondering what specifically the anti-oxidants are doing in a cosmetic formula to improve on stability. I understand that they are donating electrons to whatever free radicals are being formed, but what free radicals are they? Is it specific to each formula? Is it mainly preventing peroxide formation?As a follow up question what does the peroxide do to the formula that is so damaging?Forgive me if some of my questions are basic. I’m basically self taught in cosmetic chemistry and there are some gaps in knowledge.Thanks in advance. -
6 Replies
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The answer depends on what ingredients are in your formula so it’s difficult to give you an exact chemical reaction that an antioxidant is supposed to prevent. I think you’ll find in cosmetic chemistry that practices are derived more through empirical knowledge than from theoretical pondering.
The reason that antioxidants are added to cosmetics is because they prevent things like color changes and odor changes.Rather than figure out exactly why any specific antioxidant works a cosmetic formulator will figure that if there is an odor change or color change then adding an antioxidant is something you try. If that stops the destabilizing process then you move on to your next problem. It’s rare that anyone gets much chance to ponder why an antioxidant worked or what chemical reaction it prevented.The lack of theoretical knowledge in cosmetic chemistry was one of the most surprising things to me when I entered this industry. In college chemistry you learn all sorts of theoretical stuff and chemical reactions, but in formulating you focus on what substances do & not so much on why. -
One reason to add antioxidants is to prevent rancidity due to the inherent instability of double bonds in fatty acids.
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For example, I made 2 simple olive oil lip balms. One with tocopherol and the other without. After about 1 year, that without toco gained a rather unpleasant weak smell. The olive oil was extra virgin, but if it was not, maybe it would had gained the smell in less than a year.
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Thank you for the responses.
Perry: Unfortunately, my experiences have run similar to your own in regards to the lack of theoretical knowledge.
Having been self-taught I’m a firm believer in the value of testing and empirical knowledge. I have had the fortune to create formulas for some of the biggest companies out there, L’Oreal, Estee Lauder, LVMH, Chanel to name a few. I usually work at high fragrance loads (anywhere from 8% to 35% !). I’m well aware of what results from oils, fats, and lipids, without anti-oxidants. However, most of these companies really want the neatest formulas possible for their fragrances so I was looking at trying to focus on the chemistry of why rather then just trying to stop the result.
If anything new comes along in terms of theoretical knowledge, I love to hear it, Perry.
Thanks again, everyone.
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While this site is a great resource, I think in this is probably more of an area to read about and study offline. It is simply to broad and like many topics, new knowledge will lead to additional questions. I will share that some of the best advice on anti-oxidants and ROS has come from Chemists with experience in the Food Industry. This is a huge topic for that sector.
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Is it safe for me to summarize like this: anti-oxidants are really in products to deal with oxidation of substances in the product, not to deal with what is going on inside a skin cell or w/DNA (as marketing leads consumers to believe) i.e. they think these are “anti-aging products” protecting their skin from free radicals.
I do not believe there is any data to show that anything put on the skin actually has a real affect in vivo. Some do in theory.
An example is the current obsession I hear with Vitamin C serums. Where Ascorbic Acid applied topically is supposed to to wonderous things for aging skin. I have not been able to find any concrete data to demonstrate that one can take ascorbic acid, get in into the skin where in will do anything, and then have it in the proper form to do what it is supposed to do.
Anyone who can enlighten me further, I thank in advance!
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