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Retinol and retinyl palmitate are among the most widely used active ingredients in skin care products. Unfortunately, there is much confusion about how they work, what results they can deliver and what their optimal usage is. This article will help clarify these issues.
First, let me explain the basics. Both retinol and retinyl palmitate are forms of vitamin A (along with yet another form retinaldehyde). As opposed to many other vitamins, vitamin A does not have much of a direct biological effect. It works via its active metabolite (biochemical derivative) called retinoic acid. Only retinoic acid and its analogs collectively called retinoids have direct effect on skin cells and can adjust their physiology toward a more youthful state. In fact, retinoic acid a.k.a. tretinoin is the active ingredient in Retin A and Renova - some of the best-known anti-wrinkle creams (see our article on tretinoin). However, topical retinoic acid often causes skin irritation and other side effects, which limit its use, especially in sensitive individuals.
The good news is that skin cells have the "equipment" (specialized enzymes) converting various forms of vitamin A into retinoic acid. Indeed, if sufficient amounts of retinol, retinyl palmitate or retinaldehyde are added to the culture of skin cells, the amount of retinoic acid in the cells increases. Therefore, at least in theory, topical vitamin A may deliver at least some of the well-established skin benefits of retinoic acid while producing fewer side effects.
Not all forms of vitamin A are created equal. Some are more easily converted to retinoic acid than others. A typical conversion pathway looks like this:
It takes two and three metabolic steps, correspondingly, to convert retinol and retinyl palmitate to retinoic acid. The overall rate of conversion of retinol to retinoic acid is low and that of retinyl palmitate is lower still. Therefore a relatively large amount of retinol and even larger amount of retinyl palmitate needs to be delivered into a cell to boost retinoic acid levels and produce clinically meaningful effects. Numerous products with retinol and retinyl palmitate are touted as equivalent to retinoic acid (tretinoin, Retin A) in effectiveness yet devoid of its side effects. The reality is a bit more complicated. Many of these products contain too little retinol / retinyl palmitate to have any noticeable effect. Simply the fact that these agents are in the list of ingredients is not enough. The products with high concentrations do exist but may still not deliver the purported benefits for a number of reasons. In particular, a product with highly concentrated retinol may cause skin irritation, especially in people with sensitive skin. Highly concentrated retinyl palmitate is less irritating than retinol (at equivalent levels) but is also less effective. (After all retinyl palmitate is the farthest away from retinoic acid in the metabolic pathway.) Furthermore, conversion rates of various forms of vitamin A to retinoic acid vary among individuals - the same product/concentration may yield visible benefits in some people and little or none in others. Further still, retinol, and to a lesser degree retinyl palmitate, can be degraded by oxidation if formulated, stored and/or used improperly. Considering all these caveats, how should one use retinol / retinyl palmitate products (if at all)? As of the time of this writing, research indicates that the most reliable way to get all the skin rejuvenation benefits of retinoic acid is to actually use retinoic acid a.k.a. tretinoin (or other directly acting retinoids at optimal concentration. However, this may not be a viable option for some people. Retinoic acid and other directly acting retinoids require a prescription (at least in some countries) and are relatively expensive. They also tend to cause skin irritation, especially in sensitive individual or if used imprudently. The closest alternative is to use either topical retinaldehyde or retinyl retinoate (each of these agents is only one step away from retinoic acid). However, even though retinaldehyde creams do not require a prescription, they tend to be expensive and may still cause skin irritation whereas retinyl retinoate is a novel agent that is relatively untested and not easily available. If for any of the above reasons retinoic acid (tretinoin, Retin A), retinaldehyde or retinyl retinoate are not suitable for you, a product with retinol and/or retinyl palmitate may be worth a try. When looking for such a product, it is important to find a stable, sufficiently concentrated formulation that does not irritate your skin. If commercial retinol/retinyl palmitate products prove too expensive or otherwise unsuitable for you, a do-it-yourself approach may help. It allows to easily customize retinol concentration to fit your skin physiology, i.e. you can adjust the concentration high enough to produce benefits but not so high as to cause irritation. Furthermore, if the DIY cream is used up soon after is has been prepared, retinol does not have time to degrade too much. For more on making your own retinol cream see DIY Anti-Aging Skin Care Infopack
Bottom lineDespite the increasing availability of products containing various forms of vitamin A (retinoids precursors), retinoic acid a.k.a. tretinoin still offers a better chance of anti-wrinkle effects because its activity does not depend on conversion rates and other variables. Among retinoids precursors, retinaldehyde is the nearest (on metabolic pathway) to retinoic acid and is likely to match its benefits more closely. However, well-designed products containing retinol and/or retinyl palmitate provide an additional alternative that may be cheaper and, at least for some people, less irritating. A retinoic acid (tretinoin) user who has developed side-effects, such as skin irritation and/or chronic peeling, may first try to reduce the concentration or frequency of application. Then she might try a retinaldehyde product. If that fails, a well-selected retinol/retinyl palmitate product may be worth a try. (Caution: neither directly-acting retinoids nor any forms of vitamin A should be used in the event of continuing chronic side-effects.) For more on pros, cons and practical use of retinoids and various forms of vitamin A, see Skin Rejuvenation Infopack.
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