Thursday, January 10, 2013

Facial scrubs: Which exfoliants to choose? Chemical exfoliants

As much as we love our physical exfoliants (part 1 and part 2), don't forget about the awesome power of the chemical exfoliants we can add to products that include water or alcohol. And since I've already written huge posts on each of these ingredients, I'll encourage you to click on the link if you want to read more than my quick synopsis here.

Physical exfoliants work by abrading our skin and remove the dead skin cells. Chemical exfoliants work through chemical reactions that generally happen on top or under skin. There are three main types of chemical exfoliants we use - alpha hydroxy acids, B-hydroxy acids or salicylic acid, and fruit enzymes.

AHAs work by penetrating our skin through the stratum corneum to the stratum granulosum. It acts as an exfoliant on the top layer of our skin by disrupting the bonding between the cells and allowing them to slough off, revealing those new and lovely cells. (I really encourage you to check out this post on the chemistry and biology of our skin for more information on the different layers.)

This lovely exfoliation this can work against us if too much of the stratum corneum is exposed. This can increase transepidermal water loss, so you will want to add extra humectants and occlusive ingredients to any products including AHA. This can also lead to thinning of the stratum corneum, so you will want to make sure if you are using AHA products, you're keeping your skin well protected. Always use a sunscreen if you are using AHAs in your products because AHAs can make you sun sensitive (even if you're using it in night cream, as taking the moisturizer off won't necessarily make you less sun sensitive!). And note that because AHAs actually penetrate our skin, they will bring other active ingredients with them, which means some extracts and other wonderful things will be more effective as they penetrate the skin.

Suggested usage rate: It is considered safe to use them at up to 10% of your product in the heated water phase, but you will need to adjust the pH with a pH adjuster to a reasonable level if you're using that much! The ideal pH for AHA products is 3.5 to 4.0, so you really do want to make sure you have a pH meter or good pH testing strips nearby! I'd start low - say 1% or 2% - and work up if your skin doesn't mind it.

MULTIFRUIT BSC (aka Fruit Acid Complex)
INCI Water & Vaccinium Myrtillus (Bilberry) Extract & Saccharum Officinarum (Sugar Cane) Extract & Acer Saccharinum (Sugar Maple) Extract & Citrus Aurantium Dulcis (Orange) Fruit Extract & Citrus Medica Limonum (Lemon) Extract
This extract contains a number of different extracts that behave as AHAs in our products. Add at 5% to 15% in the cool down phase of a water based product. You cannot use this in an oil based product.

Click here to see the toner in which I used this complex. I used 3% to see how my bestie's skin would react. She did just fine! (That's the picture to the left!) 

Salicylic acid is a keratolytic (exfoliant), anti-fungal, anti-inflammatory, analgesic, and anti-itching ingredient we can add as a powder or as part of an extract like willow bark. It works by getting inside the sebaceous unit or pore of our skin and solubilizes the oils and other things inside it, so it's great for blackhead prone skin. It reduces the adhesion between the cells and encourages them to slough off, revealing nice, new skin cells. It works from the stratum corneum of our skin and works its way down to the lower layers.

Salicylic acid is a powerful anti-inflammatory, so it is great for any water based creation you might be making to help with inflammation, such as post sun exposure or wind chapping. It helps our skin shed more readily, open clogged pores, and neutralize bacteria. It is used at 0.5 to 3% in acne related products, like cleansers, toners, and moisturizers. It can help with photodamaged skin thanks to its exfoliating qualities. It is a great inclusion in hair care products intended for dandruff prone hair. And it's a fantastic addition to something like an after shave lotion or tonic to reduce redness and inflammation, and prevent ingrown hairs.

Finally, salicylic acid helps with oil control, so it is good for products for people with really oily skin - hair care, facial care, and skin cleansers and moisturizers.

Suggested usage rate: Up to 2% in the heated water phase of your product, although you might want to start at 1% to see how your skin tolerates it. You will have to dissolve it in alcohol or a polyol like propylene glycol, glycerin, butylene glycol, as it is only barely soluble in hot water. (Click here to see the chart).

This study showed a salicylic acid peel at 30% in polyethylene glycol had a great effect on Japanese sufferers of acne. I'm not suggesting you make something like this, but I think it shows that salicylic acid can have a great impact on acne prone skin.

It can be found as a powder or a water soluble extract with a shelf life of up to 2 years (ask your supplier for more information). It contains salicylic acid and tannins, and is recommended for oily and acne prone skin.

Suggested usage rate: For the powder, use at up to 1% in the cool down phase of your water based product. For the liquid, use at 2.5% to 5% in the cool down phase of your water based product.

Papaya is an interesting extract. The main feature is papain which is a keratolytic (exfoliant) so powerful it can clean wounds of dead tissue and help skin shed quickly so we can see the new cells underneath. It is used as a freckle or age spot treatment, and can help reduce the look of hyptertrophic scars (the red raised lumps on our skin). Papain is very good at breaking down proteins, which is why it is recommended for use for very oily skin cleansers. The main protein in dirt on our skin surface is keratin, followed by sweat protein. Papain breaks up the protein and cleans it away.

Papain can penetrate the stratum corneum, which means it can be a penetration enhancer for other active ingredients.

Suggested usage rate: Use it at a maximum of 0.5% in the cool down phase of your water based product. 


The main attraction in pineapple extract is bromelain, which is (to quote the University of Maryland website) "a mixture of protein-digesting (proteolytic) enzymes found in pineapples". This mixture has been shown to be good at debriding (removing dead skin) from third degree burns and can be used topically to reduce swelling from insect stings and bites. Like the papain in papaya, bromelain can be used as an exfoliant in cosmetic products, which is why I suggest not using it with another exfoliant. It has some anti-bacterial benefits.

In theory, bromelain would work reduce the adhesion between the dead skin cells on the surface of our skin and encourage them to slough off to reveal nice new skin cells, much like salicylic acid does.

Suggested usage rate: Use it at a maximum of 0.5% in the cool down phase of your water based product.

Apigenin is another fantastic feature of honeysuckle extract. It is a very very powerful anti-oxidant that offers anti-inflammatory and exfoliating features to our products.

Suggested usage rate: Use the powdered extract at 0.5% in your cool down phase after dissolving or add the liquid extract at 2 to 10% (or the suggested suppliers' usage rate) in the cool down phase. (The liquid extract appears to be a hydrosol mixed with the extract, but check your supplier for information).

When formulating with these extracts, please be sure not to combine them at maximum usage rates as too much exfoliating is not a good thing! If you really want to use pineapple and papaya together, think about using them at 0.2% each to see if you can handle it. (I suggest 0.2% because our scales aren't as accurate as we like and you could be adding 0.22%, 0.25%, or 0.28%!)

Also remember solubility. You can't use these in anhydrous products as they need water or alcohol to dissolve. And you don't want to use more than the suggested rate as it might not suspend in your product. I've messed up many a foamer bottle by using a ton of extracts in my facial cleansers because the powders sink to the bottom and create a gooey mess!

Join me tomorrow and we'll take a look at making a surfactant based facial scrub with some of these exfoliants!


melian1 said...

i was wondering if using willow bark infused oil would confer some of the properties that using the extract does? i infuse oils for various things, and have the willow bark on hand and was wondering if infusing the oil i make the scrub with would have the same or a similar or a somewhat the same but weaker or none at all effect?

Mychelle said...

Salicylic acid and my skin really get along. I understand its also only efficacious as an exfoliant at a ph of 3-4 and it prefers opaque packaging. I also mix in an AHAgel once a week. I do love these ingredients, though I still buy my facial exfoliants. I know me - once I get into extracts and extracts there's no turning back and the husband is already overrun by my ingredients!

Christopher said...

In my experience Salicylic Acid does nothing for my acne/oily skin. I've been using a 10 % peel now every Sunday for 4 weeks and I have seen no improvement. Previous to that I used a 2% BHA Gel from a certain woman whos name shall not be mentioned (I now hate all of her products :P) and then too I saw no improvements. In fact since I used that product daily, my skin became worse. The 10 % peel I'm using now hasn't made my acne worse, but it's not doing anything to help it. So I'm considering either increasing the percentage of SA or adding an AHA to my regimen.

Robert said...

I have seen several sources report that White Willow Bark is a natural source of salicylic acid. However, I don’t believe this to be correct. White Willow Bark contains salicin which is structurally related to salicylic acid but it is definitely not salicylic acid and likely does not have its exfoliating effects.

I discovered this many years ago when I purchased White Willow Bark extract (which, according to the spec sheet contained salicylic acid) and covered my face with the extract and felt nothing. Had there been some salicylic acid there certainly would be a sting to the ingredient, especially if applied to the face neat (without dilution).

Michele said...

Salicylic acid can be dissolved in oil. I use it in an oil cleansing balm, of course the PH in oil is not an issue, but it definitely keeps my oily acne prone skin in check.

Mychelle said...

Christopher, I use Paula Begouns' products with fantastic results. Just fantastic. Funny how everyone's skin is different, huh? I would advise not going any higher with the SA and instead switching to an AHA. Also, look to your whole routine, diet, and lifestyle. Great skin isn't about one ingredient but a whole combination of factors. Hth! :)

Mandy said...

A bit of a random question...will lemon myrtle extract used in a lotion increase sun sensitivity like an essential oil does?

KMY said...

Susan - I'm trying to view the salicylic acid solubility chart, but keep getting 404 error.