Beauty Tips For Body Care
There seems to be a lot of interest in ceramides and not a lot of transparency on the part of skincare companies, so I thought I’d make this post. Super long, so bear with me.Full disclosure: I work in the industry.TL;DR - most products that are marketed as having ceramides have a ridiculously low amount and in the wrong ratios when combined with cholesterol and free fatty acids, which they ideally should be combined with. They may still work for you because lotions and creams are generally moisturizing, but the ceramides are likely adding nothing. Hopefully skincare companies will become more transparent and honest as time goes by and more consumers demand it.What are ceramides, and why are they beneficial to skin?Ceramides are waxy substances that, in part, make up the “mortar-like” barrier in between the “brick-like” corneocytes that prevents skin from losing water (transepidermal water loss, or TEWL). The other major components are cholesterol and free fatty acids. Together, these components form a liquid crystal structure that is very efficient at preventing water loss. The application of this would be for skin suffering from atopic dermatitis, skin that is adjusting to retinoid usage, or skin that has been stripped by aggressive treatments or environment factors (aggressive acid treatments, stripping cleansers, very cold or dry weather, etc.).Do ceramides need to be combined with cholesterol and free fatty acids to work?In short, probably. There is research by Mao-Qiang and Feingold (they are experts on this topic and have a number of very good papers on this - google their names and “physiologic lipids” and you can even see some of their full papers as pdf’s) that indicates that when any one of these components is used in isolation of the others, or in the wrong molar ratios, it actually delays repair of the barrier.What ratios are ideal for ceramides, cholesterol and free fatty acids for barrier repair?The research indicates that a 1:1:1 to 3:1:1 molar ratio of any of the components works to repair the barrier. Some research shows different populations benefiting more or less from ceramide, cholesterol or free fatty acid-dominant blends. For example, aged skin benefits more from a cholesterol-dominant ratio, while infants benefit more from a free fatty-acid dominant ratio, and eczematic skin benefits more from a ceramide-dominant ratio. All three work for irritant contact dermatitis (caused by aggressive treatments, weather, friction, etc.), which is good news, since most people in the general population looking for ceramide-laced products would fall into this category.Can I depend on the fatty acids found in plant oils to provide the free fatty acids in a product?You could, but I wouldn’t recommend it. Most of the free fatty acids in plant oils are bound to triglycerides, meaning that it must go through an enzymatic process for the fatty acids to be freed. That process is not especially predictable (microflora on the skin seems to affect this as well, such as those suffering with malassezia overgrowth) and can vary between people. The free fatty acids should ideally be provided in predictable, precise quantities to ensure a proper ratio to the ceramides and cholesterol. Labmuffin has a good post on her blog about this as well, so look there if you want more detail.What % of ceramides is useful to skin?The research by Mao-Qiang and Feingold shows that a total combined concentration of 1% to 1.6% of ceramides, cholesterol and free fatty acids is capable of repairing the barrier. When examining the optimal 3:1:1 molar ratio, researchers they tested a total concentration of 1%-1.2%.That means at an optimal 3:1:1 molar ratio at a concentration of 1-1.2%, with any component being dominant, the ceramide concentration needs to be .3%-.7%.It’s useful to note, at this concentration, the lipid mixture outperformed petrolatum by the 2-hour mark, which is impressive since petrolatum is often considered the gold standard in preventing transepidermal water loss.How does a ceramide/cholesterol/free fatty acid combo differ from an occlusive such as petrolatum?Petrolatum acts as a physical barrier to moisture loss (occlusive), and provides about a 50% recovery from baseline immediately upon application to skin. Over an 8 hour period, this stays pretty consistent, with just a minor drop by the 8 hour mark.A proper blend of ceramides/cholesterol/free fatty acids, however, does not provide an immediate physical barrier to water loss. Instead, these lipids get incorporated into the skin’s natural pool of lipids, where it then is incorporated into the liquid crystal structure that forms skin’s natural barrier. This takes time, which means that the benefit is delayed. However, by the 2-hour mark, an optimal 3:1:1 blend outperforms petrolatum, providing a 55% recovery (vs 50% for petrolatum), and by the 8-hour mark, the difference is even more dramatic (90% recovery vs 40% recovery for petrolatum). It’s notable that combining the two strategies provides the benefits of both immediate partial relief and long-term recovery for a damaged barrier.Okay, so what products follow the research?Unfortunately, not many. Most companies use a raw material blend called SK-Influx, which is a combination of an emulsifier (sodium lauroyl lactylate) along with 1.5% ceramides, .5% cholesterol, and 3.5% free fatty acids and .5% phytosphingosine, per the manufacturer’s own document (https://personal-care.evonik.com/product/personal-care/downloads/downloads/sk-influx.pdf). They sometimes, more vaguely, say that it has “2.5% active matter”, but they are adding .5% cholesterol and .5% phytosphingosine in addition to the 1.5% ceramides to get to that number.The maximum recommended usage for SK-Influx is 15%, which would result in a .2% final ceramide content. This gets close to the .3% ceramide content supported by the research mentioned above. However, SK-Influx is more typically used in concentrations of 1-5%, which would yield .015%-.075%. That is approximately 10x less than what researchers showed to be effective.How does SK-Influx fare in terms of the molar ratio of cholesterol, ceramides and fatty acids? Simply calculating the ratio between the weights % of the components to calculate ratios is different from molar ratios, which factor in the molar mass of each material. Using the specific molar mass of cholesterol (386.65g/mol), an average molar mass of ceramides (700g/mol), and a typical molar mass of fatty acids commonly used in skincare, such as linoleic, linolenic and stearic acids (280g/mol), we can calculate the molar ratios of the lipids in SK-Influx. This results in 6 parts cholesterol; 1 part ceramides; and 58 parts fatty acids, or a 6:1:58 molar ratio. This is quite far from the 1:1:1-3:1:1 ratio recommended by research!Does this mean that all the products containing SK-Influx on the market will damage your barrier? Probably not - the concentrations of the lipids are too low, and most products will contain a number of occlusives, humectants and emollients that will act act as a partial barrier to water loss. However, it does mean that the dusting of ceramides in those products are mostly for marketing purposes and provide little to no functional benefit.Popular products that use SK-Influx:Cerave (most of their ingredients lists suggest they’re using SK-Influx at a 1% concentration or less, meaning .015% ceramides or less)Drunk Elephant (Lala Retro Whipped Cream with Ceramides, C-Tango Eye Cream - both ingredient lists suggest they’re using SK-Influx at a 1% concentration or less, meaning .015% ceramides or less)Stratia Liquid Gold (especially concerning because the product is often marketed as having the ideal 3:1:1 ratio which SK-Influx is ridiculously far from; the test version on the founder’s blog originally used 10% SK-Influx, resulting in .15% ceramides, but the current ingredient list suggests they’re using it at a 1% concentration or less, meaning .015% ceramides or less)Paula’s Choice (Omega+ serum and all of the other products touting ceramide content; most of the ingredient lists suggest they’re using SK-Influx at a 1% concentration or less, meaning .015% ceramides or less)Chemist Confessions Mr. Reliable (props to them for telling you straight up it’s 3% SK-Influx, meaning it has .045% ceramides so still low but better)Again, you may use and love some of these products. Just saying you’d probably love them just as much without the ceramides. One of the few exceptions that is commonly available is Skinceuticals’ Triple Lipid Restore moisturizer, which at 2% ceramides, 4% cholesterol, and 2% free fatty acids gives a 1:4:3 molar ratio, which is not perfect but not bad. However, the total lipid concentration (8% vs ~1% shown to be effective in the research) and price ($128 for 1.6 oz) are overkill for most.
Girls Blog 2015
Submitted by nocloudstoday
No comments:
Post a Comment