Monday, April 27, 2009

Better crafting through chemistry: Hydrovance

Hydrovance by National Starch (INCI: hydroxyethyl urea) is a moisturizing agent that can be added to your lotions and water based products at 1 to 20%. It's hygroscopic, meaning it draws water from the atmosphere (to your skin), so we treat it as a humectant. (In studies conducted by the company, Hydrovance absorbed 82% of its weight in water, compared to glycerin at 24%. As this was a study conducted by the company, always take the results with a grain of salt.)

Having said this, urea is a very effective humectant. It is actually found in our skin, where it takes in water, creates a solution, then acts as a humectant in the strateum corneum of our skin! (Learn more about skin chemistry in this post!)

Water soluble with a ph of 6.5 to 8.5, it comes in a liquid you can add to the cool down phase of your creation or integrate it cold to things like surfactant systems. Hydrovance can experience some pH drift (the pH of your creation changes), so if you are using this regularly, you might want to invest in some pH strips or a pH tester (if you're itching to buy me a wedding present, I would love one of these!) to check that your products aren't getting out of the pH range you want in a product. (This is a great link from Lotioncrafter about preventing pH drift by Hydrovance!) 

So what does this all mean to us? It means we can substitute Hydrovance for any product containing a humectant like glycerin, propylene glycol, honey, and the like (I wouldn't substitute it for olive oil in a recipe as the oil is both your emollient and your humectant, and you want it in a lotion). Why would we use Hydrovance over those other products? It could be a better humectant than the others, it is thinner and more spreadable than glycerin, and doesn't leave behind a sticky residue.

I like to use hydrovance in body sprays and very light lotions to keep the stickiness of glycerin out. I would normally use sodium lactate in this capacity, but sodium lactate can be sun sensitizing, which is the last thing you want for a summer cooling spray or an apres sun spray! So let's do some substituting!

From my post "Create a toner!"

Lavender & Chamomile Toner
30% witch hazel hydrosol
25% lavender hydrosol (or another hydrosol of your choice)
25% water
10% aloe vera liquid
2% hydrovance (was sodium lactate)
3% honeyquat
2% panthenol
2% cromoist (or another hydrolyzed protein like soy or wheat...I just like oat protein!)
0.5% extract (I use chamomile)
0.5% preservative (I use Germall Plus)

Please visit the post "Create your own toner" for the instructions!


Jelena said...

Hi! Do you know what is the difference between Hydrovance (INCI:Hydroxyethyl Urea) and Urea (INCI: Urea)?

Which one is more moisturizing?

Susan Barclay-Nichols said...

Hi Jelena. I created a post this morning on this topic - Hydrovance vs. urea. The summary? I really don't know, but I'd probably go with Hydrovance.

Jelena said...

Thanks a lot!

Anonymous said...

Can you use hydrovance in a lotion bar?

Susan Barclay-Nichols said...

No, it's water soluble and lotion bars are oil soluble.

Nina said...

Can one use hydrovance and sodium lactate in a lotion?
How to make a lotion extra moisturising?
Could you give a recpie please?

Susan Barclay-Nichols said...

HI Nina! I have many many recipes with a combination of humectants. I don't use Hydrovance much as it can cause pH drift, which can destabilize preservatives. But you use it as you wish.

As a note, moisturizing is generally about oils, while hydrating is about humectants. If you look up "hydrating" on the blog, you'll see a lot of comments about that.