Thursday, August 31, 2017

Questions from Patreon: Retin A, retinols, and retinoids (part one)

In the August Q&A on Patreon, Mildred asked: Question pls: Can I use a glycolic toner followed by a Retin A cream? I read a blog that these two needs to be used on alternate days but I can't seem to find that writing any more. 

And Mercedes asked: I would like to know more about using Vitamin A and its derivatives in different products. I know some things are medical grade, but I mean things like retinols and learning which suits which skin types the best.

Vitamin A is an oil soluble molecule that can improve skin barrier function, increase cell proliferation, increase thickening of the skin, and increase collagen production. It can also help increase skin's water retention, and it may be effective in preventing, retarding, or restoring changes associated with the aging process. It is also effective in wound healing. It is the most abundant vitamin in our skin (in the form of ester retinyl palmitate), which is hydrolyzed to form Vitamin A, which is then oxidized to produce retinoic acid (the active form).

There are several forms of Vitamin A - the retinoids - we can use in bath and body products - retinol, retinyl esters (retinyl propionate, retinyl acetate, retinyl palmitate), and retinaldehyde. Each of these is ultimately converted into trans-retinoic acid, the active form of Vitamin A in our skin, but the retinyl esters are less effective than retinol, and are less stable in our products. We can find retinoic acid (tretinoin) in some of our oils.

Vitamin A is measured in International Units or IU. An IU of Vitamin A equals 0.3 µg retinol, 0.34 µg Vitamin A acetate, or 0.55 µg Vitamin A palmitate. It is classified as a drug by the FDA, so please don't make any claims about including Vitamin A in your products!

Retinyl palmitate specifically has been found to help maintain skin's barrier properties by stimulating the epidermal cells to produce glycolipids, which are important for the formation of the intercellular lipid lamellar structure in skin.

In a study on hairless mice, a cream with 0.1% Vitamin A administered over 14 days increased collagen content of the mice's skins by 88%. 0.5% Vitamin A palmitate uncreased the collagen content by 10%. And in a study on rats, 10 µg Vitamin A acetate suspended in 0.2 ml water lead to an increase in cell proliferation four hours after usage. In a study on human volunteers, aged 40 to 60, the application of Vitamin A palmitate to the temples showed an increase in skin thickness of 14% in two weeks and 22% over 6 weeks. Unfortunately, once you stop using products with Vitamin A, you return to your previous pre-Vitamin A skin condition. (But this is the case for most things - stop using it, you don't get the benefits!)

Retinol is the most effective form of Vitamin A in bath and body products. The effects of retinol usage can be very quick - epidermal thickening can in a matter of a few hours, take place in days, reduction of fine lines in a couple of weeks, and reduction of wrinkles in weeks to months. And you only need to use 1%!

Vitamin A is touted as a great ingredient for after sun exposure. Our blood levels of Vitamin A decrease when we are exposed to the sun for a short period of time, and the levels keep dropping the longer we stay in the sun. (Isn't that fascinating? No, seriously. Why have I never heard of this before?) A similar effect is noticed in our skin. So by adding Vitamin A to our products (or using oils high in the retinoids or ß-carotene) we can increase the Vitamin A content of our skin. Interestingly enough, scienticians still aren't sure of the exact mechanism by which Vitamin A actually works on sun exposed or photo-aged skin!

Why do we care about how much Vitamin A is in our skin? Vitamin A diminishes the appearance of fine lines due to increased skin cell production, which leads to increased epidermal thickness. The thicker our skin, the less likely we are to see fine lines!

It increases the production of epidermal ground substance (glycosaminoglycans or GAGs), which bind water in the skin. (You might recognize hyaluron or chondroitin sulfate as GAGs.) This results in increased hydration of skin and moisture retention. But we don't want too much GAGs in our skin, and Vitamin A inhibits production of too much ground substance! (Did that make sense? It increases the production but inhibits the production, both of which are good things?) The GAGs are required in our skin for normal collagen structure and function, but too much can lead to wrinkling in photo-damaged skin. (Shar pei dogs have too many GAGs, hence the wrinkled look!) Water retention is a great thing for skin - we want maximum moisturization!

I'll be writing more about glycosaminoglycans shortly. There are just too many topics about which I can write!!! 

It helps with wound healing by increasing the rate of cell proliferation so new cells can come to the surface of our skin quicker. And it helps with skin thickening in this way as well.

An increase in collagen production is a mighty fine thing indeed. As we age, we lose about 1% of our collage per year, which leads to reduced elasticity of our skin. With the reduction in the GAGs in our skin, we will appear less wrinkled.

Vitamin A is a good treatment for acne - it acts on the primary pre-acne lesion - and offers anti-inflammatory benefits, which is why you'll see Retin A prescribed for it.

Retinoids can be irritating to the skin! (Just ask someone like me who used Retinol prescription cream for years! When I cried or my eyes watered, it actually stung my cheeks!) Retinol and retinyl acetate are less irritating than retinoic acid, and retinyl palmitate is the least irritating. Use retinol at less than 1%. Retinaldehyde at 0.05% up to 1% - it's as irritating as retinol - but use retinyl palmitate at up to 2% in your products!

We can find Vitamin A in our oils in the form of carotenoids, pre-cursors to Vitamin A. There are three major groups of carotenes - lycopene, lutein, and ß-carotene - but we find ß-carotene mostly in the oils and other ingredients we use. ß-carotene is oil soluble, and is the pre-cursor to Vitamin A. The body will convert ß-carotene into Vitamin A if it needs it: If it doesn't need it, then it just roams around as an anti-oxidant, free radical scavenging and preventing lipid peroxidation in our bodies and on our skin.

Carotenes are strong anti-oxidants. They either quench the anti-oxidizing process or chemically react with free radicals to form a carotenoid radical.

Carotenes have been shown to have photo-protective effects when we're exposed to the sun. Studies have shown a reduction in thiobarbituric acid (which shows up when we're in the sun!) if our skin is pre-treated with creams including ß-carotene! Lycopene is the strongest in the carotenoid photo-protective sweepstakes, with lutein and ß-carotene less effective.

So what do carotenes offer to bath and body products? The pre-Vitamin A stuff is pretty awesome, considering Vitamin A has such a great effect on our skin, and this is one of the main reasons to seek out carotenes!

It also helps protect from UVB damage and behaves as an anti-oxidant to retard rancidity! The one down side? The strong colour from ß-carotene containing oils might your products a little on the yellow or orange side.

Where can we find these wonderful tetraterpenoids? You can find it in cranberry oilrosehip oilwheat germ oil (which also contains xanthophylls, which have many of the same qualities as the carotenes), calendula oil, and sea buckthorn oil.

This new rosehip seed oil I've been using a lot of lately contains a lot of beta-carotene, which is obvious from the bright orange colour! 

To summarize all of this: Vitamin A and the retinoids improve skin barrier function, increase cell proliferation, increase thickening of the skin, and increase collagen production. It can also help increase skin's water retention, and it may be effective in preventing, retarding, or restoring changes associated with the aging process. It is also effective in wound healing.

We can add it to our products in a few different ways - as Vitamin A, retinol, retinyl esters, and retinaldehyde. Or we can add some oils that contain a lot of carotenoids, like cranberry, rosehip, rosehip seed, wheat germ, calendula, or sea buckthorn oil.

Retinyl esters, like retinyl palmitate or retinyl acetate, are less effective and less stable than retinol.

Wow, this grew very long very quickly, so join me tomorrow as we look at more about the retinoids and our products! 

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1 comment:

Leslie Dimond said...

Woo! so much info, I will need to read through again, thanks so much, the info is so helpful.