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Everything to know about PH for Homemade Cosmetics

Updated: Nov 30, 2023


I'm sure most of us are familiar with the ph scale. We all learned about it in school. If you need a refresher, the scale goes from 1 - 14.

1 - being the most acidic

14 - being the most alkaline

7 - is neutral, which is the ph of water.

Our skins natural ph level is somewhere around 5.5


What is ph?

PH is a measurement of how acidic/basic water is. 0 is the most acid, 7 is neutral and 14 is the most alkaline. Water has a neutral ph of 7. Only water has a ph, oil does not. So anhydrous products like body butter, facial oils, massages oils, etc don't have a ph. Only aqueous products do. So you don't have to worry about checking and balancing the ph when you make anhydrous products.


Why ph is important?

There are two main reasons why ph is so important when it comes to formulating cosmetics

1. Our skins natural ph level is 5.5, so it's important that we use products that reflects our skins natural ph level so we don't dry or irritated our skin

2. Lots of ingredients we use in cosmetics are ph sensitive. So they have to be in a specific ph level in order to work properly.


So for the most part, most of the products you formulate you want to have a ph between 4.5-5.5, but there are some exceptions to this rule.


There are certain ingredients that are only active in a specific ph level. For example the niacinamide I purchase from lotion crafter and FSS has to be in a formulation with a ph of 6. AHA and BHA have to be in a formulation with a ph around 4.0 (you can go as low as 3.5 and as high as 4.5, but I recommend balancing the ph to 4 incase the ph drifts.) These are just a few examples. When you go to purchase an ingredient from a supplier read the formulating guidelines and it will mention if the ingredient has to be formulated in a specific ph level.

As you can see, ph is really important because if you don't check and balance the ph the product could irritate your skin, or your ingredients you have in your product may not even work.


What tool do you use to measure ph?

There are two different ways you can measure the ph of your products. You could use ph strips or a ph meter. I personally recommend always using a ph meter, since ph strips can be hard to read and they don't give an actual ph number, just a range. PH meters will give you the exact reading of the ph that way you know you are accurately balancing the ph of your products. This is really important when you are working with those ph sensitive ingredients like AHA, BHA, and niacinamide.


If you are on a budget and you are only making simple formulations you can get by using ph strips, but I highly recommend investing in a ph meter. Formulating will be much easier.


What pH meter to buy

I personally recommend buying this ph meter here. This ph meter can take the ph of liquid solutions and solid solutions like creams and lotions. That way you don't have to dilute your cream. This will call for a much more accurate ph reading since diluting your thicker products can actually make the ph a bit higher than it really is. The ph will be roughly 0.30 off, but this could vary product to product. So if you plan on making creams and lotions and want to get an accurate ph reading purchase that ph meter. You can watch my video to see me compare it to my old ph meter and see how to set it up and calibrate it. I also show how I care for and store my ph meter.


How to measure pH

To measure the ph you want to take a small sample of your product and put it in a separate beaker. I use a small 25 ml beaker that way I only need to take a small amount of my product so I'm not wasting a lot of it. I personally don't like dipping my ph meter directly into my product for sanitary purposes. Once you have the sample of your product in a separate beaker you can turn on your ph meter and dip it into the sample. Let the ph meter sit in your sample for about a minute or until the numbers balance. Then take you ph meter out and rinse it in your rinsing solution. I create a rinsing solution by filling a 50 ml or 100 ml beaker with distilled water. This way you can rinse off your ph meter with clean water in between ph readings. Don’t use tap water, only distilled water.


How to create pH buffing solutions

In order to adjust the pH of your products you need a buffer solution. You need one buffer solution that can raise the ph and another that can lower the ph. Honestly the only time I have to use a buffing solution to raise the ph is when I work with AHA and BHA, so most likely you will only be using a buffing solution to lower the pH.


Buffing solution to lower pH

Directions; Dilute 50% citric acid in 50% distilled water. I like to take 50 grams of citric acid and 50 grams of distilled water and add it into a 4 oz plastic bottle. I just shake it up until the citric acid fully dissolves. You can keep this for about a month and use it whenever you need to adjust the ph of your products. You don't need to worry about preserving it since it has such a low ph, just be sure to keep it out of light. I store mine in a dark cabinet. Make sure you add a label on it so you know what it is and when you made it. Create a new buffing solution each month.


You could also use lactic acid to lower the ph. To use lactic acid you need to create a 10% lactic acid dilution with 90% distilled water. I personally don't like this method because lactic acid is rather expensive. I just wanted to let you know there is another method out there besides using citric acid.


Buffing solution to raise pH

Directions; weigh out the distilled water in a plastic container. Look for a container that is PP#5 as this is a hard plastic that can withstand heat. I use this one. Next weight out the sodium hydroxide in an other container. I use a little glass bowl. Go into a well ventilated room or preferably outside and pour the sodium hydroxide into the water, NOT the other way around. Make sure you pour the sodium hydroxide into the water. You also want to make sure you have gloves, a mask, and protective eye wear on when working with sodium hydroxide. After you pour the sodium hydroxide into the water mix it up. You will notice the solution will become foggy, it may sizzle and it will heat up. This is totally normal. Let it sit until the water runs clear and it returns to room temperature. You can then store the 10% sodium hydroxide solution in a thick plastic container. You want to look for HDPE #2. Add a label onto your container so you know what it is and when you made it.


important note; wear protective clothing like long sleeves, goggles, and gloves when working with sodium hydroxide. Also work in a well ventilated room or outside.


You can also raise the ph using triethanolamine, I've personally never used it, but it does seem to be popular. You can purchase it here. I don't know how to use it, since I have never tried it, I just wanted to share this method with you as well.


How to raise and lower pH of your products

I like to start by taking the ph of my product so I know what the starting ph is. I then will begin by adding about 5 drops of my ph buffing solution into my product. I mix it in and let my product sit for about a minute before taking the ph again. Take the ph again and if you need to add more ph buffing solution add more.


When you first make a new product you may have to go back and forth a lot when adjusting the ph, but once you make the product again, you will have a better idea of how much buffer solution you need.


Typically when I use the citric acid buffing solution I may need anywhere between 5 drops - 100 drops, just depends on the starting ph of my product and how big of a batch I made. As for the sodium hydroxide buffing solution I normally factor this into my formula because I use so much. Like I said, the only time I have to raise the ph of my products is when I work with AHA's and usually I use a lot of buffing solution. For example, if I make a toner with 5% glycolic acid I know I will need about 20% sodium hydroxide buffing solution. So I factor in the 20% buffing solution into my formula for the glycolic acid toner. The first time you formulate with an AHA it may take a while until you figure out how much buffing solution you need, but I promise with practice you will learn exactly how much buffing solution to use in each product. AHA's & BHA's are tricky to work with, so I only recommend it if you have been formulating for a while and are comfortable with it.




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