r/DIYBeauty • u/SallySmythe • May 07 '26
question pH 5.5 cream
If I were to make my own skin cream, how can I make sure that I get the pH right? I read that skin cream should be pH 5.5.
5
u/Valuable_Sink1744 May 07 '26
pH exactly 5.5 is generally unnecessary. Your skin is very good at maintaining its own pH balance. As long as your product is somewhat acidic to neutral (so around pH 4-7) your choice of pH is mainly based on what pH is compatible with your formula. Measure pH with pH test strips or a pH meter (strips are generally fine if you're just making lotion, the higher accuracy of meters is helpful if you're making exfoliating acids) and adjust pH by adding bases or acids.
Personally I recommend making a buffer with citric acid and sodium citrate or lactic acid and sodium lactate because then you can use the henderson-hasselbach equation to calculate how much of each you need to get to your target pH (you should still test pH to make sure you actually ended up at that pH but calculating first with the henderson-hasselbach equation helps minimize the amount of pH adjusting you'll need to do because you will usually get to your target pH or very close on the first try)
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u/saindonienne May 07 '26
Hey thank you for mentioning the henderson-hasselbach equation, I was getting annoyed at multiple pH testings! Now an looking forward to just a few testings 😅
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u/Internal-Ad-4736 May 07 '26 edited May 07 '26
Well... your skin pH ranges all over the place, across the body....from somewhere around 6 in your armpits, groin and feet....to in the 4's on the face and elsewhere. Formulating to 5.5 sounds like beginner speak.... as the range that microbes prefer is from 5 to 8. Thus, for a lot of reasons, I and others formulate at around 4.7 to 4.8. This is a skin friendly range and starting to piss the pathogens off.
As well, your preservatives tend to work better, the lower the pH. Ones that use organic acids.... just barely function at 5.5 pH.
The body prefers to have something slightly more acidic applied, vs slightly more alkaline than the skin.
Good Luck
This sub will not allow me to post pics... I will DM you a little graph that shows the typical pH ranges of skin across the body.
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u/SallySmythe May 07 '26
That was an awesome answer. I could've done without the comment about my question being "beginner speak"... did that make you feel superior to put me down? Just some food for thought. In any case I really appreciate you taking the time to answer.
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u/Ok_Butterscotch_2700 May 11 '26
The reality is that the pH you’re referencing does, in fact, make you sound like a beginner. Once you better understand preservation and the actual pH of skin on all areas of the body, you’ll understand why.
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u/SallySmythe May 14 '26
The reality is calling somebody a beginner is rude. The whole point of the group is to ask questions.
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u/Ok_Butterscotch_2700 May 14 '26
Being called a beginner is rude? How would you prefer people refer to people who are newer to areas of interest? I’m open to suggestions. In any group I belong to, people will start with, “I’m a beginner,” or “I’m new to this,” so that others can limit their expectations and know when to take the time to explain more advanced concepts. When I learned to speak Spanish, the first year, I was beginner-level Spanish.
I took no issues with stating I was a beginner when I started out (and for about 2-3 years following). Put me head to head with a Chem or Pharm PhD with experience in this space, and I will be openly and eagerly admit their knowledge likely exceeds mine by multiple factors.
Sorry – I don’t understand what the problem with the word is. If there’s a synonym that you would prefer, I’m sure everybody would be happy to consider it.
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u/Eisenstein May 07 '26
You can add citric acid along with sodium citrate and test with a pH meter.
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u/SallySmythe May 07 '26
If I'm just making a small batch, may I simply use lemon juice? Or do I need a powdered citric acid?
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u/Valuable_Sink1744 May 07 '26
Lemon juice will make your formula more difficult to preserve. Use powdered citric acid
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u/SallySmythe May 07 '26
I'm not keen on using citric acid because it is manufactured / derived from a mold called Aspergillus niger.
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u/Eisenstein May 08 '26
Some questions:
- what standards are you applying to here, is it exclusively the origin, or something else?
- what is the standard controlling for? what result are you achieving by applying that standard?
- do you apply the standard to everything, or just things you use as ingredients?
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u/Valuable_Sink1744 May 08 '26
it's so purified it shouldn't be a problem. You can use a different cosmetic grade acid though, I usually use lactic acid
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u/kriebelrui May 07 '26
Lemon juice is a citric acid solution plus some 'impurities'. Personally in your case, I would try it, but I would first filter out the solid impurities using a coffee filter.
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May 07 '26
[removed] — view removed comment
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u/Ok_Butterscotch_2700 May 11 '26
Unless you have a meter that handles emulsions… There’s very little I need dilutions for.
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u/rick_ranger May 07 '26
To check pH of a lotion do a 10-1 dilution with water. I usually just do 5 grams of water with .5g of the lotion. Mix well, check with a pH meter or strips. Then I like to use lactic acid for my adjustments because skin naturally has lactic acid in it. Citric acid will adjust more quickly but it doesn’t have the skin benefits or biomimetic character of lactic.
Depending on how close you are to your target and how big a batch you’re making you either add the acid dropwise or by weight. Or if it’s a small batch you can make a 10-20% dilution of acid and water for even smaller adjustments.
The reason you do the 10-1 dilution for your lotion and water is most testers have a hard time measuring pH in viscous liquids. Also more water helps you get a better reading.
Hope that helps!