Wednesday, March 9, 2011

An aside: pH and lotions

I know I'm all excited about testing the pH of various products now that I have my lovely pH meter (click here for more information on my lovely pH meter) and I've written a bit about how to adjust pH in surfactant based products in the past, but I thought I'd address the issues of pH and lotions.

For the most part, we don't need to adjust the pH of our lotions as most of our ingredients have a neutral or slightly acidic pH, like our water, hydrosols, oils, and butters. If you want to make a lovely body butter or foot cream, don't worry about the pH as it's likely to be around 6, which is a good level for our skin. Just make the lotion and enjoy the moisturizing goodness.

But if you're using cosmeceuticals, you will need to adjust the pH for some of the ingredients to work properly. We can do this by adding 0.2% citric acid during the cool down phase and testing the pH. If you need to lower it further, add another 0.2% citric acid until you reach the optimal amount.

As well, some of our cosmeceuticals have acidic pH levels and you'll have to increase the pH level to get it to a good level. You can do this by adding sodium hydroxide (also known as lye), which is very alkaline. Dissolve 10% sodium hydroxide in 90% water and add this at 0.1% at a time in the cool down phase, testing after every addition.

You can use apple cider or other vinegars to reduce the pH, but the smell is a bit much for some people (like me!). I can't offer any suggestions about how much vinegar to use as I only tried it the once and I didn't have a pH meter then. As with most things in lotion making, it'll be trial and error to figure out how much you need in your product.

It's hard to predict how much of an ingredient will affect the pH of your lotion (you could work on a formula for it, but it's easier just to test the pH as we add various ingredients). Will adding 1% AHA or 5% Multifruit BSC reduce the pH of your moisturizer to 3.5? Probably not, but it's hard to tell as most of our ingredients aren't as standardized as we think. The only real way to tell what an ingredient will do to the pH of a product is to include said ingredient, then test! And the only way to know how much citric acid or lye to add to the product is to test the pH, decide whether the pH must go higher or lower, then add the acid or alkaline at 0.2% in the cool down phase and test again.

Join me tomorrow as I catch up from my week of exciting illness with more on cosmeceutical ingredients! (I have a good list going, but if you have other ideas, please comment below!)

13 comments:

Nancy Liedel said...

Forget the DMAE idea, I understand it does not smell good and your nose is more sensitive than mine. :)

There are times I have to use a charcoal filter mask and move quick.

Aesthete said...

Hi Susan, I don't have sodium hydroxide, is there something else i can use to increase ph?

Thank you again!

CCrafters on Etsy and Karess Krafters said...

@Aesthete. I am not sure if this works or not but I have read on forums that some use baking soda to increase the pH. I have not tried this so I cannot say if it works or not.

CCrafters on Etsy and Karess Krafters said...

Susan, I wanted to ask, does the lye solution have to be made fresh each time one may need to increase the pH. Or can you make up a solution and use when needed?

Aljonor said...

Hi Susan: I know that this is an older post on PH meters, but I need your to ask a question. I am checking on some PH meters and wanted to know if I should be looking for one that is specifically for water? I've seen some that say it can be used for plants and other objects. The price is right, but I don't know if it is the right thing to purchase.
Thanks for any help.
Aljonor

Erin said...

Aljonor,
I bought a Bluelab pH pen from a hydroponics store last year, and it works really well. Here is the same pH meter on Amazon: http://www.amazon.com/Bluelab-BLU2210-pH-Pen/dp/B005HKRPZG/ref=sr_1_1?ie=UTF8&qid=1365120962&sr=8-1&keywords=bluelab+ph+meter

I use it to check the pH of my face serum, shampoo, and other formulations, and it rarely requires recalibration. Just be sure that you don't let the sensor dry out.

Buy local...eat fresh! said...

Hi Susan - I had a question regarding PH testing on lotions as well. I bought your ebook through Lotioncrafters and I have been following them exactly. I do notice that the lotions seem to burn when applied to the face. I tested some recent lotions and they were coming in around 4. I know lotions should be around 5-7. I got water on my PH meter and it shorted out so I have to buy a new one. It is confusing on which type is appropriate for lotions and do they need to be calibrated to get accurate readings. I am still rather new to lotion making but not to soap making so excuse some of my questions. Thanks, Shelley

Susan Barclay-Nichols said...

Hi Shelley. I'm not sure which question to answer first, so I turned this into a Long Weekend Wondering, which will be up on Monday, October 14th.

Anonymous said...

I was wondering if it would be a good idea to lower the ph of a homemade hair conditioner to use in conjunction with shampoo bars instead of using an apple cider vinegar or citric acid rinse. Do you think this would work? If so what do you think the ph should be?

Susan Barclay-Nichols said...

Hi Anonymous! Please put your name on your question - you'll have to re-write it - because I don't allow anonymous comments.

Why do you want to lower the pH of a conditioner? If you make one of my recipes, it's already pH balanced to be on the acidic side. Why would you want to take it down lower? There is no value in having a very low pH for a conditioner.

Chelsey Luehr said...

Thanks this is just what I was looking for...I ran a cross a lotion recipe that included ammonia and I wondered why. Now I know it was probably to adjust the PH, and I found some alternatives to try.

Sandy said...

Hello Susan My name is Sandy I am making a face cream contains AHA alpha Hydroxy acid face cream but i want to test the ph before. I want to purchase 1 ph meter. can you prefer me one which one i should buy

Susan Barclay-Nichols said...

Hi Sandy. I really like the one I'm using, the Jenco Vision Plus. I'm afraid I don't know the quality of any others.