Tuesday, 7 February 2012

Natural oils and their comedogenic properties

The phenomenon of comedogenicity is related to formation of blackheads and whiteheads - some substances cause hyperkeratinization - and they are actually "comedogenic".

The main source of information on comedogenicity amiable in the internet is the table from J. Soc. Cosmet. Chem, 40, 321-333 (1989). The assessment of comedogenicity was performed using laboratory animals - rabbits. In this method (not used anymore!) the compound is applied to the ear of an animal, and after some time biopsy is made, and comedones are assessed using microscope. In 2009 EU nearly fully banned animal testing of beauty products. 

Natural oils are usually mild and they rarely cause any skin irritation. According to the above paper the only (but still mildly!) irritant oils are mink oil, shark liver oil and cotton seed oil.

The most comedogenic oils are cocoa butter and coconut butter (4 per 5 in the comedogenicity scale proposed by authors), followed by hydrogenated vegetable oil, sesame, corn, avocado, evening primrose, mink, soybean and cotton seed oils (3 per 5).
Peanut oil, olive oil, almond and apricot kernel possess medium comedogenic properties (2 per 5), while castor oil, chaulmoogra oil (I have never heard of it!), babassu, squalene, safflower and sunflower oil are practically non-comedogenic.

Comedogenicity may be considered, when we formulate DIY beauty products or choose oil mixes, for example for oil cleansing method.

At the moment, as I have some mild problems with comedones (I haven't unfortunately spotted the reason yet), I use predominantly sweet almond oil mix with castor oil (10% castor oil, rest sweet almond, with around 5% of argan oil, that unfortunately can be comedogenic!) for the oil cleansing method (called sometimes OCM). I don't have much experience with that method, even though I use the muslin cloth cleansing for quite a while already - but the OCM seems to be working very, very well for me.
Previously I have used an excellent mix of glyceryl cocoate and sunflower oil as a hydrophilic cleansing oil - and I also really recommend this kind of products for a fusion of make-up removing and a deep cleanse.

I think I need to start thinking about a rich in antioxidants serum soon also, it is definitely going to be home-made, and I am going to share the recipe and effects here!

(photos from wikipedia - traditional production of argan oil and Liz Earle website - muslin cloths. Those cloths are actually the ones I am using!)

Sunday, 5 February 2012

Mandelic acid peel and AHA treatments

Mandelic acid - fights acne and first signs of ageing (do we want more?)

AHAs are sometimes called fruit acids - the beauty industry uses numerous natural and synthetic fruit acids in the products that are supposed to reduce wrinkles, give skin "youthful glow" or "reduce effects of photo ageing".  Many AHAs have clinically proven effects on epidermis: they cause the formation of a new stratum corneum of the skin, most probably due to change in cellular cohesion between skin cells. Some AHAs, that are able to penetrate the skin easily, have also effects on dermal layer - they remodel the mucopolysaccharides and collagen, what results in increased skin thickness. At the same time AHAs do not cause inflammation.

Mandelic acid name comes from German - "mandel" means "almond". The molecule of mandelic acid is larger than a molecule of very popular glycolic acid, and therefore the acid is less bioaccessible, but also results in less irritation, and redness (erythrema). It means, that we actually look like an average human being after the peel (if we use a simple, oily moisturiser that will minimise the peeled skin appearance).

There are two ways to use mandelic acid: low-concentration, frequent use topical treatments, or high-concentration acid peel. The acid peels are great for fighting acne, while the low-concentration AHA products are probably better for fighting ageing. Mandelic acid is bacteriostatic, this is probably why mandelic acid peels are more effective agains acne than glycolic acid peels. It fights comedonal, pustular and papular acne remarkably, also it can fight bacterial folliculitis. However, the effects of the peel on the 

Side effects - irritation and sun sensitivity

FDA (1997) says, that a product containing any AHA that are sold publicly should have:

  • The AHA concentration is 10% or less
  • The final product has a pH of 3.5 or higher
  • The final product must have an effective sunscreen in the formulation or warn people to use sunscreen products

does it mean that the products are dangerous? Yes, to some extent. They are not toxic, cancerogenic, or anything like that, but they are irritants. Used in a wrong way can cause skin damage - chemical burns. "Wrong way" includes using too high concentration, too low pH etc. So, before you start doing anything with AHA products - read about them, especially if you want to make your own products, lotions or DIY peel. The AHA product formula may contain allantoin or glycyrrhizinic acid to reduce redness and irritation, however mandelic acid peeling properties are the mildest AHA products. If you are too afraid of AHA, you can use aspirin mask or aspirin tonic instead (there is lot of resources about them in the internet), they have even milder, but also real, effects.
Because of the peeling effect, AHA cosmetics make the skin more vulnerable to UV - it is really very important to use the proper SPF (sun protection). There are interesting botanic ingredients showing high SPF properties, I plan to write about them at some point.

How to choose the right ready product?

You need a high enough concentration of the AHA in the product, if you want it to actually work. It is not required to state the concentration of the ingredient on the INCI list, but lots of companies actually state the AHA content of the product in an "advertising" way. Start from 5-10% AHA, and remember, that those are not the most pleasant beauty products: they sting, they make your skin peel in an unpleasant way, but the final results are actually quite amazing (even though you have to wait few weeks). I recommend DIY products, as you can customise them, but lots of companies have interesting formulations.

Why do I perform an acid peel? Are they effective agains acne?

In US the products sold to the consumers cannot have, as stated above, the concentration of AHA above 10%. Trained beauticians can apply peels containing up to 30%, and doctors apply higher concentrations.
Mandelic peels are called superficial peels, because the risk of necrosis of skin is minimal ( the peeling works only on a stratum corneum). EU allows for products with up to 2.5% lactic acid (and pH above 5.0), or up to 4% glycolic acid (and up to pH 3.5).

The main benefit of mandelic acid over other acid peels is that it doesn't cause erythrema (redness!) and massive irritation. Also, according to medical authors mandelic acid peel can be performed with success in all ethnic skin types without hyperpigmentation after the peel (note, that it is still necessary to use a sunscreen). Quite often it is said that mandelic acid does not require usage of SPFs and that it can be done even in the summer - I am unfortunately not convinced.

Concentration of AHA below 5% is not really efficient (doesn't show much effect in clinical studies). The pH of an AHA solution should be 3.0-4.0 for the products used regularly (low pH - more acidic - without using of some buffering may results in too deep peeling effect). It is worthy to consider buying some pH strips (remember, you need at least 1-7 pH range if you are playing with acidic products).

I regularly (twice a week if necessary) use a 10% mandelic acid solution alkalised by sodium lactate in the presence of butylene glycol and hyaluronic acid.

How to perform a DIY acid peel?

If you decide to perform a home acid peel you definitely need to make sure you understand, that it is quite an invasive procedure. If you don't feel confident or you don't understand something, I think it is better not to try. Numerous professionals (beauticians and doctors) perform acid peels, including the ones with much higher does of mandelic acid - if you trust professionals more - arrange a consultation.

First, you have to decide, if you want to add alcohol to the peeling. Use clean alcohol, it is a good vehicle (makes penetration of the acid into your skin easier), however if your skin is particularly sensitive, you may want to omit that ingredient. Alcohol improves solubility of mandelic acid, if it doesn't solubilize well - heat the solution a little bit.
Mandelic acid comes in a tightly closed box in a form of white crystal flakes. I mix my solutions in a little vodka glass, there is no need to shake vigorously or so - the ingredients just dissolve after some time. Just before applying the solution, cleanse your face with something. You can use alcohol for that, or you can use 2% mandelic acid buffered solution (it means that you should use baking soda or something to neutralise the acid in the mix).
I apply the solution to my face with a cotton pad - but you can use also a face-mask brush or something like that. Try not to get it into your eyes, so be careful! I do it in front of the mirror, carefully, as the peel mixture is just watery - it can drip. Now, find yourself something to do. Because the acid stings. It is unpleasant. It can cause some temporary redness etc. I usually browse the internet or watch tv, it is hard to cope without it. You probably need to wait 5-10 minutes. HOWEVER if something bad happens - for example you can't cope with the feeling - just wash it off. 10-15% sodium bicarbonate solution can be used for neutralisation - just wash your face first with the baking soda solution, and than with a large amount of water. I recommend cold water - it soothes the skin nicely. After the peel moisturise your skin with something simple - I recommend some natural oils, for example a mixture of sweet almond oil and argan oil. You will probably start peeling in the third day after the procedure - avoid picking the peeling skin, and moisturise well. Your "new skin" is going to be exposed now, take care of it.

So, once again:
1. Start from low-concentration serum/tonic/product for 2-4 weeks, before you attempt the peel. You may even decide you don't want to go further! If you are hypersensitive to the ingredient, that will save you possible problems.
2. Remember: it stings. And it peels afterwards. If you don't like it - don't do the procedure.
3. Have everything prepared: container for mixing, measuring spoons, alcohol and clean water (boiled or deionized water), brush or cotton pads, mirror, neutralising solution: one teaspoon of baking soda (not powder) per 200 ml water or traditional soap (not a liquid soap, not a face gel - traditional soaps are mildly alkaline, so they will neutralise the acid).
4. Remember, that you need a sunscreen after the peel. Never use sun beds and don't suntan when you use any AHA products.
And of course, you should not use any peel in the case of viral diseases

Read more:
Internet fora, articles, blogs and so:
Summary of Mandelic Acid for the Improvement of Skin Conditions Skin. Mark B. Taylor M.D, Cosmetic Dermatology, 1999 June