Thursday, April 1, 2010

Formulating anhydrous scrub bars for different skin types

I love love love scrub bars for my body and my feet. Like sugar scrubs, they offer moisturizing by trapping in water from your shower or bath after exfoliating all that non-desquamated skin from your stratum corneum. (Okay, I don't really say this in real life. I usually say, "Pretty" or "Nice"!)

So how can we adapt this product for different skin types?

Note: Original post with all the information on the various ingredients can be found here, with modifications for using mango butter here, modifications for itchy skin here, and modifications for your feet here. I'm not modifying the foot scrub bar because I think the oils and butters I've chosen would work for pretty much anyone's feet because it's not like we have really oily feet at any given time! And if you have perfect feet, then I choose to glare at you from afar rather than re-formulating this recipe!

SOLID SCRUB BAR FOR THE BODY
50% cocoa butter
20% mango, shea or other butter
3% cetyl alcohol
4% Incroquat BTMS
2% wax of choice - beeswax, soy wax, etc. For candellia wax, please use 1% as it is very hard.
3% sodium lactate (as a bar hardener, not a humectant)
12% oils - sunflower, rice bran, olive oil at 4% each
2% cyclomethicone
2% dimethicone
1% fragrance oil
1% Vitamin E (if you are using oils with less than 6 months' shelf life)

FOR ALL SKIN TYPES

Cocoa butter: (Click here for the post.) This is a great occlusive and moisturizing ingredient that gives shape to the bar. I have tried other butters in its place, but I have found nothing really compares to cocoa butter. If you want, you can try illipe, sal, or kokum in its place.

BTMS: (Click here for the post.) This is an emulsifier and conditioning agent. This will adsorb to your skin and make it feel smooth and moisturized. (The BTMS will emulsify anything that isn't oil soluble, like the sodium lactate.)

Cetyl alcohol: (Click here for the post.) This offers oil free moisturizing and glide. It also works well with BTMS to create more substantivity to your skin.

Wax: I got this idea from CathyMB's legendary Apres Glow bars on the Dish. It creates a light barrier so the good stuff can stay on your skin. If you don't want to use it, add 2% to your butters or oils.

Cyclomethicone: (Click here for the post.) This offers slip and glide with detackification of the oils and butters (in other words, it makes things feel less sticky, but I really do love the word detackification!) If you don't want to use this, add 2% to your butter or oils or find a silicone replacement you like.

Dimethicone: (Click here for the post.) This is a barrier ingredient to help keep our skin moisturized and protected from the outside world by forming a light film. If you don't want to use this, add 2% to your butter or oils or find a silicone replacement you like.

Sodium lactate: Because sodium lactate rinses off in water, this is included as a bar hardener, not a humectant.

Vitamin E: (Click here for the post.) This is a great anti-oxidant for our oils and butters, as well as a lovely moisturizer for our skin.

If you want to try adding some humectants to this recipe, the BTMS will help emulsify small amounts of glycerin or honeyquat or other cationic polymers. Don't include sodium PCA as it will rinse off.

ADAPTING THIS TO YOUR SKIN TYPE - THE OILS AND BUTTERS

All skin types can benefit from exfoliation (desquamation), and the sugar performs that role well in this recipe. We don't need to add more desquamation, so we can concentrate on the specific needs of each skin type.

Dry skin, normal: (Click here for the post.) Reduction of trans-epidermal water loss and occlusion are the key words for dry skin products. We're occluding through dimethicone and cocoa butter, so we can focus on the moisturizing qualities. We want to choose oils high in linoleic acid - like soy bean, sunflower, sesame, or rice bran oils. As for the butters, shea butter is the dry skinned girl's friend - lots of stearic acid to offer serious moisturizing! And you can add some olive oil as both a humectant and a very good moisturizing ingredient.

Dry skin, sensitive: Your skin barrier may be damaged, so our focus is on repairing that barrier, reducing TEWL, and occluding the skin. We have dimethicone and cocoa butter to occlude, so we can focus on the skin barrier repair and reduction of TEWL. Oils high in linoleic acid, GLA, and phytosterols will reduce itching and inflammation and help repair skin's barrier protection. Borage oil is always a good choice, as is soy bean oil - high in linoleic acid, Vitamin E, and phytosterols. Olive oil will act as a humectant and moisturizer. You can also choose rice bran or sesame oil - both are well balanced between linoleic and oleic acid, and both offer good levels of phytosterols.

Oily skin, normal: If you're planning to try this recipe, consider if you really want more oils on your body. Odds are pretty good you want some moisturizing as no one is really super oily on their arms or legs, so you might want to consider more astringent ingredients. Mango butter is a dry butter, so that might be a good choice (personally, I found it too dry and so I usually use shea butter, but it doesn't hurt to try it!) And consider using more astringent oils like hazelnut, grapeseed (short life span), or borage oil.

Oily skin, sensitive: The key is to reduce inflammation and moisturize, so choose oils like soy bean oil (lots of Vitamin E and phytosterols, as well as linoleic acid) or macadamia nut oil (astringent, great levels of ß-sitosterols). Shea butter is a very good anti-inflammatory ingredient, so consider using that instead of the more astringent mango butter.

Wrinkled skin: The key for wrinkled skin is increase moisturization - which we've done - and to include some skin smoothing ingredients like hydrolyzed proteins, silicones, and quaternary polymers. We've done that, so now you need to choose whether you're following the dry or oily skin type.

For the oils and butters, all skin types should consider the not-really butters like green tea butter (high in lovely polyphenols and anti-oxidants) or aloe butter (all the goodness of aloe in an anhydrous format). I like aloe butter in my scrub bars, but I've been testing out the green tea butter and quite enjoy that also!

So our recipe pretty much looks the same - the key difference in formulating for a different skin type is to include different oils and butters. But is there a huge difference in each formulation? All skin types can find something to love in soy bean oil - Vitamin E, phytosterols, linoleic acid - and olive oil - squalene, oleic acid, and phytosterols, as well as behaving like a humectant. I think if you made this recipe with shea butter, soy bean oil, and olive oil everyone would enjoy it!

Join me tomorrow for fun formulating an emulsified sugar scrub!

3 comments:

Stacey Dee said...

Hello Susan!
Just wondering if I could substitute poly 80 or poly 20 for the Incroquat BTMS?
Thank you! very excited to try these.

Susan Barclay-Nichols said...

No, you can't. The BTMS adds conditioning, emulsifying, moisturizing, and hardening to the bar, while the polysorbates would offer some solubilizing of oils. They are completely different ingredients and you can't substitute one for the other. You could substitute another emulsifying wax, though.

Stacey Dee said...

Thank you so much! I do have emulsifying wax :)