Why the pH of Skin and Products Are Crucially Important (2020 Updated)
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I’ll be honest, the concept of pH is something I neglected and didn’t know about for many many years. Had I been familiar with it I could’ve saved myself from major setbacks, avoided some severe reactionary breakouts, and cured my acne ten times faster.
pH is important for maintaining skin barrier integrity, knowing what products you should never mix, and everything in between. Let’s break down this idea in the simplest way possible so you can start incorporating it to make smarter decisions about your skincare.
Don’t worry, this won’t be like one of those boring chemistry lessons in school or anything. I’ll keep you entertained. 😉
Table of Contents
- 1 What is pH?
- 2 Why Does pH Matter For Skincare?
- 3 What Disrupts Our Skin’s pH and Acid Mantle?
- 4 What’s the pH of that?
- 5 pH Dependent Skincare Products.
- 6 pH and Wait Times. Are They Necessary?
- 7 Order of Skincare Products.
- 8 Want to Subscribe for Updates?
What is pH?
pH stands for the “power of hydrogen” or “potential of hydrogen,” and is the measurement of how concentrated hydrogen ions are in a solution. In simpler terms, it measures how “acidic” or “basic” a substance is in comparison to distilled water which has a “neutral” pH of 7.0. (1)
Anything below a pH of 7.0 is considered an acid, and anything above a pH of 7.0 is considered an alkaline or “basic.” Generally speaking, acids taste sour and bases taste bitter.
Lemon juice, for example, is sour because it contains approximately 5% citric acid which has a pH of 2.2 meaning it’s highly acidic. On the other hand, baking soda taste bitter because it has a pH of 9.0 (highly alkaline). Two things, by the way, that you should NEVER be putting on your face — more about that later.
To further hammer down this point, let’s give some common examples of basic and acidic substances:
- pH 1 = Battery Acid
- pH 1.5 – 3.5 = Gastric (Stomach) Acid
- pH 2 = Lemon Juice
- pH 3 = Soft Drinks
- pH 3.4 = Distilled White Vinegar
- ph 3.5 = Orange Juice
- pH 4.5 = Beer
- pH 5.0 = Tea and Coffee
- pH 5.5 = Rainwater
- pH 6.2 – 7.4 = Saliva
- pH 6.8 = Milk
- *pH 7 = Distilled Water (the focal point of this scale)
- pH 7.4 = Human Blood
- pH 9 = Baking Soda
- pH 9 = Seawater
- pH 9.0-10.0 = Soaps and Detergents
- pH 10.5 = Milk of Magnesia
- pH 11.5 = Household Ammonia
- pH 12.6 = Household Bleach
- pH 14 = Lye (Sodium Hydroxide)
Why Does pH Matter For Skincare?
Because the pH of skin influences several factors contributing to its overall health. It’s been demonstrated that skin with pH values below 5.0 are healthier, more hydrated, and have a stronger barrier function than those above 5.0. (2)
Our skin is protected by something called the “acid mantle.” It is a small film on the surface of the stratum corneum composed of fatty acids, lactic acid, pyrrolidine carboxylic acid, amino acids, and a bunch of other sciencey terms and stuff that can be a little overwhelming. Let me translate that to English for normal people.
We have an acid mantle and it kicks BOOTY. Acid mantle = protective barrier on surface of skin composed of sweat, skin oils, and dead skin cells.
This acid mantle is what gives our skin its pH, and ranges anywhere from 4.0 to 7.0, with the average being 4.7. (3) It protects our skin from bacteria, fungi, viruses, environmental pollutants, makes skin soft and supple — it does everything!
Disrupting this lovely skin protector can have adverse effects and lead to stuff like inflammation, atopic dermatitis, dehydrated skin (skin that is both dry and oily at the same time), dry skin, skin sensitivity, acne, malassezia folliculitis etc. (4)
Of equal importance, is the acid mantle’s ability to maintain the integrity of our skin’s moisture barrier and microbiome (i.e. the healthy bacteria that live on our skin).
Just like the bacteria and yeast in our gut that keep us safe from stuff like crohn’s, food sensitivities, autoimmune diseases etc., our skin flora keeps us safe from diseases like acne, rosacea, psoriasis, and dermatitis. (5, 6, 7) Research has shown there is a very close relationship between the pH of skin and having healthy skin bacterium. (8, 9)
What Disrupts Our Skin’s pH and Acid Mantle?
Pollutants, pathogens, excessive occlusion, detergents, soaps, cleansers, heck — even water! (10, 11, 12, 13) I can hear you already, “what WATER?!” Now that you’re utterly terrified, let me calm you down and explain.
Here’s a general rule of thumb: the higher the pH of something, the more disrupting it is to the acid mantle and therefore moisture barrier. So while water isn’t bad per se, “hard water” is. Hard water is simply tap water with a high mineral content causing it to have a pH of 8.5 or more.
Fun-fact: this is why micellar water was invented! Back in the 90s, France was notorious for having “hard water,” so an awesome chemist formulated micellar water so poor french women could clean their faces without nuking their acid mantle.
If you have no idea what micellar water is or want to know how it works, check out this awesome article by the lovely LabMuffin. Cute illustrations included! Let’s continue….
The biggest acid mantle overkill you need to be worrying about is cleanser. You know that super squeaky feeling you get after using one? Yeah, that isn’t good! It’s an indication that your acid mantle has been disrupted. You should be avoiding that super squeaky feeling at all costs!
The goal is to cleanse your skin without over-stripping it of its natural oils. This is a reason the “oil cleansing method” is so popular. It removes debris and gunk, but leaves your face oils alone. Best of all, oils don’t have pH so you don’t gotta worry about alkalinity when choosing which one to use.
The comedogenicity of oils however… well, that’s another story. ~*Insert OCM horror stories here*~
All this is not to say we should stop cleansing altogether for fear of disrupting our acid mantle. In fact, cleansing is important. However, the trick is to use a gentle pH balanced cleanser to maintain our skin barrier’s integrity. A cleanser that is “pH balanced” simply means it has a pH similar to that of skin (4.5-5.5).
Generally speaking, 5.5 is a good number to aim for and doesn’t interfere with skin microflora like alkaline soaps do. (14) Personally, any cleanser higher than pH 6 is a no-go for me. Which brings me to why you should never be putting baking soda on your face….
Baking soda has a pH of 9! Far too alkalizing. Contrary to popular belief, it is often the extremely alkaline substances that cause “chemical burns.” Remember that scene in fight club when Tyler Durden burns the protagonist’s hand? Great film, btw!
Well, that wasn’t an acid: it’s lye (a.k.a. sodium hydroxide). Lye has a pH of 14! It isn’t an acid at all, but a compound on the highest end of the alkalinity scale.
Hold up, wait…. OMG!
YOU. The person reading this right now. WHAT’S THAT THING BEHIND YOU???? Is that lye about to be poured on your face???? QUICK! RUN!
Kidding. Just trying to grab your attention. Like I said, this wasn’t going to be a boring chemistry lesson.
Anyway, alkaline substances (like baking soda) need to be avoided in all skincare routines. Research has shown that using them is very damaging. (15) In fact, there was even this messed up study that tested alkaline products on babies.
They used 2 to 16 week old “infants without skin disease” to see the effect detergents had on them. Those scientist, I tell yuh….
They ended up finding that alkaline soap (9.5 pH) significantly increased the pH of skin (go figure) and concluded that,
“The increase of the skin pH irritates the physiological protective ‘acid mantle’, changes the composition of the cutaneous bacterial flora and the activity of enzymes in the upper epidermis.” (16)
In laymen terms, it f*cks you up. Just kidding. No, but really it does…. To summarize everything we’ve discussed thus far, here’s a quote from a couple dermatologist researchers:
“Skin pH [is] a key factor in barrier homeostasis, stratum corneum integrity, and antimicrobial defense… Recognizing factors that alter skin pH and selecting products that preserve the acid mantle is of prime importance in treating dermatologic patients.” (17)
If baking soda is so bad, then why is it in my awesome acne-fighting cleanser that beauty guru recommended?
Good question. Same reason there are so many drugstore products that do diddly squat or damage skin: skincare companies and websites are either stupid, or trying to give people skin problems so they keep buying more stuff. A perfect example is a newly created website called “thankyourskin .com” (Yes, I’m totally throwing shade at it).
The guy running it is only interested in monetary gain, so while he sometimes gives decent advice like “use vitamin C serums” he clearly doesn’t know what he’s talking. Case in point, his stupid article “13 Wonderful Reasons Why You Should Be Using Lemon in Your Beauty Routine.” (More about why lemon is bad in a bit.)
Need more proof he’s a moron? The guy’s blogging about the whole website’s purpose being a $10,000 monthly project: http://www.cloudliving .com/10k-challenge/ — Can you tell I have no respect for these kinds of people?
I’ve said it before: don’t fall prey to the marketing BS out there. There’s a ton of it. Take the time to learn about skincare science, and this stuff becomes blatantly obvious. One pair of skincare researches said it best:
“Most products recommended for sensitive skin have a considerable irritation effect, which is related to the pH of the product. Better regulation of advertisement specifications including the pH level and type of cleanser contained is necessary for the majority of soaps and cleansers.” (18)
Wait, so do I need a toner?
It depends. Toners were originally intended to minimize the harsh effects of high pH detergents by dropping the skin pH back down to a healthy equilibrium. However, since the discovery of the ill effects harsh alkaline cleansers have, companies have been formulating their cleansers with lower pHs to do the work a toner is supposed to.
If you’re following the guidelines outlined here and get a pH balanced cleanser (as you should), toner isn’t necessary.
However, there is a whole step in Asian skincare involving the addition of an “acid toner” after cleanser, but that’s a topic for another time. We’re interested in keeping this pH talk at newbie 101 level.
If all this has been confusing, don’t worry. I gotcho back. Here’s a list of my favorite cleansers, all of which are pH balanced and gentle. If you’d like a longer list, go here.
|Acne.org Cleanser||pH 5.5||Good for normal skin.|
|CeraVe Foaming||pH 5.5.||Good for normal to oily skin.|
|La Roche Posay Toleriane Hydrating Gentle Facial Cleanser||pH 5.5||Good for dry, normal, or sensitive skin.|
|Vanicream Gentle Facial Cleanser||pH 6-7||Good for normal to oily skin.|
Now it’s time to have some fun and do a little experiment by going on a pH testing rampage to see where certain items are ranking. It’ll be like a pH jeopardy game! We’ll call it….
What’s the pH of that?
- Contestant #1
Dr Bronner’s, a.k.a that totally “all natural” stuff those holistic vegan chicks on youtube say you should wash your face with because it’s, you know… “natural” and “free of chemicals.” What does our litmus test have to say about this?
Ooooooo. Fail. Look at that delicious pH! Completely incompatible with our poor acid mantle. I can hear it crying already, “please! please! get that stuff away from me!” (It does make a good microfiber cloth cleanser though.)
- Contestant #2
Random hand soap in mother’s kitchen.
Verdict: pH 6. Not bad. Not bad. You raised us well woman!
- Contestant #3
Atrocious. Absolutely atrocious.
- Contestant #4
Paula’s Choice Skin Perfecting 8% AHA Gel.
Verdict: pH 4. Solid.
See what I did there? I purposely tested the last product to prove a point and make a slick transition into the last topic of this article.
pH Dependent Skincare Products.
There are certain ingredients in the skincare world that require specific pHs to work their magic. This is known as pH-dependency. Which products need to be calibrated to a proper pH, you ask? Various active ingredients like chemical exfoliates and serums. Let’s go over a few.
Chemical exfoliates like BHAs (salicylic acid) and AHAs (glycolic, lactic, mandelic) have something called a “Free Acid Value” (FAV), which tells you the true strength of its exfoliating prowess.
When an acid is formulated at a pH below 2.0 the entire percentage of that acid in solution is considered “free” — in other words, completely unrestrained to do everything it’s gonna do like unclog pores, treat acne, slough off dead skin, upregulate collagen production, increase cell turnover etc.
For example, if we have a 20% salicylic acid product at a pH of 2.0, than that entire 20% is “free” to work its magic. However, the closer the pH of that product is raised to 7.0, the less of that total 20% will actually work.
With that said, other than chemical peels you won’t find BHAs and AHAs at drugstores formulated at that low of a pH. While yes, a lower pH means a chemical exfoliant will penetrate more deeply, work more effectively, and have a greater concentrated effect — it’s also more irritating and simply too powerful and dangerous for most newbie skincare purposes.
Could you imagine the horror of teenagers buying chemical peels at drugstores and nonchalantly slathering them on their face, then not knowing what to do next? Gives me anxiety just thinking about it.
So what skincare companies have done (at least the good ones), is decrease the overall acid percentage and slightly raise the pH of products to maintain the acid’s beneficial effects without compromising user safety.
By the way, remember how I said you should never put lemon on your face? Well, the low pH is a reason why. Lemon juice has a pH of 2.0, meaning a free acid value of 5% citric acid which is highly irritating. Oh yeah, and there’s the fact that lemon oil is phototoxic! (19)
If all of this pH talk has been confusing, overwhelming, or you just want someone to point you in the direction of products that work damn it. Then here’s a cheat sheet with recommended products from amazon to use next time you buy chemical exfoliates or pH-sensitive ingredients. All the products listed here have the proper pH for their respective active ingredients.
Note: included are ingredients like niacinamide that aren’t chemical exfoliates but similarly require a specific pH to work.
pH and Wait Times. Are They Necessary?
Because acids work at a specific pH, it’s important that we don’t mix them with other products so they cancel each other out or cause reactionary breakouts.
A general rule of thumb is to wait 20-30 minutes between acids or low pH dependent ingredients before moving on to the next step in your skincare routine. By then, the acid’s pH (below 4.0) has been effectively neutralized by your skin (4.5-5.5).
There’s a bit of disagreement on whether wait times are needed between products. Some skincare companies like Paula’s choice say they are unnecessary altogether, prompting the juicy discussion here.
The video referenced in that post has since been removed removed by Paula’s Choice, which I think is a pretty good indication they might have been wrong on the subject. As cosmetic chemist Stephen Alain Ko said,
[Not using wait times] shows that the acidic solution ‘defeats’ (…obviously) the buffering solution of the moisturizer – if it has one, which means that if you’re using a moisturizer with pH sensitive ingredients a low acidity exfoliator might disrupt the product – IF this interaction occurs on the skin as well.
In other words, using something acidic like a BHA (pH below 4) would neutralize the antioxidant effects of something like Niacinamide (pH 5-7) because an acid trumps the buffering effect a moisturizer would have.
Newbie translation = acids kick more ass than moisturizers. Therefore, acids influence the pH of moisturizers more than moisturizers influence the pH of acids. Don’t mix the two if you want your moisturizer’s ingredients to work.
Order of Skincare Products.
This is the order of a skincare routine with all the things we’ve mentioned being considered. Depending on what products you incorporate, some of these steps won’t apply. Disclaimer: Asian routines include additional steps not included here.
- Oil cleansing method, or oil cleanser.
- Gentle pH-balanced cleanser (5.5 or below)
- Vitamin C (ascorbic acid). Wait 20-30 minutes.
- BHA. Wait 20-30 minutes.
- AHA (glycolic, lactic, mandelic). Wait 20-30 minutes.
- Retinoids (Tretinoin [Retin-A], Retinol)
- Spot treatments or other actives (e.g. Benzoyl Peroxide, Azelaic Acid).
- Occlusives (Vaseline, Aquaphor)
And that does it for pH talk! Hopefully you left this article a more informed skincare-addict citizen.
Tell your friends to stop using lemon juice! When they ask “why?” Share this!
This was incredibly informative and well-written! I love the format of your site — it makes it easy to read, easy to process the content, and aesthetically pleasing. You have certainly made a fan out of me!
So, so extremely helpful. Thank you!
Hey f.c.! Love your website, finally feel like I’m getting an understanding of skincare after years (um decades) of living with terrible skin. My mind is blown and I finally feel excited about my skincare routine! Question about vanicream gentle face wash: did you test the ph yourself to get that number of 5.5? The company claims the ph is 6-7. I want to try it but if it’s the higher ph I may stay away. Thanks!!!
Just for some clarification, so I can figure out where to put products in my routine on my own, after cleansing my face, do I go from lowest pH to highest pH? For example, I want to use vitamin C (SAP), hyaluronic acid, and salicylic acid. Would the correct order be to use the salicylic acid, then the hyaluronic acid, and then the vitamin C (SAP)?
Thank for your great posts!
Hi thanks for the useful information, I have recently come across all these ph thing and one shouldn’t be mixing with another and it could be confusing, but your blog definitely clearing out some doubts. But here I got one which I couldn’t seems to find answer anywhere. I’m using the Crosx BHA blackhead which has a PH of around 4, but when I look at the ingredient list, it says niacinamide is the active ingredient. But niacinamide works better at ph 5-7 so I’m really confused. Thanks in advance!
Thank you so much for this post, it was extremely helpful! I did have a question regarding the order of products. I see that absorbic acid would be used right after cleansing and before moisturizers, but I was thinking of purchasing Mad Hippie Vitamin C Serum and I was wondering if that would change the order due to its more basic pH? Could I still use my moisturizer after the vitamin c serum even though my moisturizer has a lower pH (cerave daily moisturizing lotion)? Thanks again!
Hello there, I’m very new to your site and am very impressed by the quality of your blogs and the scientific basis. I know many others get very science-y, but sometimes it truly gets overwhelming and I enjoyed the clarity of the few posts I’ve read on your posts. Maybe you’ve said it somewhere, but I’m curious if your working in scientific career, and if not, how you became so knowledgable in the science of skincare. Cheers, and thank you! -Mel
Thank you for such a wonderful guide, I was completely lost about pH products and didn’t realize how terrible baking soda and lemon is for your skin! I had thought that lemon was a great brightening agent, but I suppose it’s effective because it’s such a strong pH. I’ll be sure to steer clear from those!
I just bought the CosRx BHA blackhead power liquid, and am not sure when to use it. I usually cleanse with the CosRx Goodmorning low pH cleanser, and then use Benton’s Aloe BHA toner (pH of 6?) after. With the BHA blackhead power liquid, should I be using this right after I cleanse? And then using the BHA aloe toner after waiting 20 minutes? I just want to make sure i’m not screwing something up.
Hi f.c, thanks again for another great article. Such a quality blog. The best I’ve found!
I think my shampoo gets in the skin on my back and sometimes face and messes up the pH (among other things) and although it’s not the harshest shampoo (Sukin nourishing shamooo and conditioner) I’m looking for something gentler for my skin’s sake. I know this is kinda a hair question, but really all for the sake if my acne prone skin . Do you know of any hair products which won’t disrupt the skin it touches too much? So many could destroy my slightly obsessive careful skin routine as they’re so harsh, foamy, fragranced, yuk!! What about a skin Cleanser in the hair? Too crazy? I’d do it!
Hello f.c., Thanks for this post. The city I live in has water with a pH of 9. Will this affect my skin and if so, how would you recommend preventing the effects?
So a BHA exfoliant needs a PH of 4.. and Sodium Ascorbyl Phosphate works best at 6 or 7, does that mean I can’t use them at the same time? I was thinking of trying a vitamin C serum so I ordered Mad Hippie with Sodium Ascorbyl Phosphate, and I also wanted to try a leave on BHA exfoliant for my pores and blackheads. How could use these together? on alternate days? or one for day use and one for night?
Thanks :/ xoxo
I love it when I stumble across gems on the Internet. Your blog is definitely one of them. Thank you for all your work. Several years back I first encountered Beautypedia and am thankful for the knowledge I gained there, but some of their information doesn’t go far enough or may even be wrong (regarding acid mantle and when to apply products). After reading your post on the acid mantle, I switched up the order of my skincare and the results were immediate. Now I know that the products I have invested in are reaching their maximum potential!
What would your opinion be on using a facial steamer weekly? Does that disturb the skin or help? I look forward to your thoughts!
I have a pH question regarding my own diy serums:
If I am making a NAG / B3 / B5 / DMAE serum, and I know I want to have the final product to have a pH around 5.0, when I mix the actives together the serum is around pH5 until I add the DMAE bitartrate (which is pH3.5), so the serum drops to a pH of around 3.75 with it added.
Two questions then –
1. If the serum is pH5 and then DMAE is added which drops it below pH4, does this instantly nullify any benefits from the other actives even if I add something to raise the pH back up, meaning if you make a neutral pH serum and put something acidic in it you have instantly ruined the neutral actives?
Or as long as the final product is around pH5 when applied to the face, it does not matter if a serum is acidic while still mixing ingredients?
2. To the above serum which is acidic because of the DMAE, if I add sodium lactate it takes alot just to raise it up a quarter pH point (0.25+), so that sodium lactate does not seem reasonable to raise 3.75 up to 5.0, I would have to add many grams worth to a 1 ounce serum.
So is it better to make a sodium hydroxide solution (1:10 sh/water ratio) with its pH13 and then add a little to the serum until it reaches 5.0?
I am thinking if someone needs small pH increases then sodium lactate is a nice beneficial extra, but for big jumps then sodium hydroxide (although not beneficial) is the right choice?
Thanks for any info on this, I have wondered this but never found the anwer online, gg in fla
Hi, thanks for another absolutely brilliant and helpful article.
Just a couple if questions; when should sunscreen be applied? Just before/instead of moisturiser? Or after? Do you know if the efficacy of sunscreen is affected by the pH? I wonder sometimes if my serums applied beforehand are causing it not to work as well.
Hey! I’ve been using ph balancing toner from Obagi. It has witch hazel in it. I’m trying to fix my dehydrated skin.. how do u feel about witch hazel and do u have any recommendations for a toner? I’ve been looking on ur blog can’t find any. Thank you! PS you are amazing, your blogs are saving my skin and changing my life !
Just found your website. Completely blown away by your work. Stopped a recent order I was about to place until I have had a read of your content.
Quick question – there are a lot of natural deodorants in market these days. Aluminium free they say. I had switched to these because I always broke into rash with regular brands i.e nivea, dove etc. However many of these natural ones have baking soda in them…. What you have an opinion of the use of bi-carb in these products?
Hi! First of all, thank you for taking the time to write your experiences and share your researches! We love you!
Quick question, the acid mantle is made up of ceramides, cholesterol and fatty acids right? So i’m just curious, if i had damaged my acid mantle, would simply using a pH5 cleanser help to restore those 3 elements? Or does it just restores the pH of the skin and do nothing else? Sorry i’m really confused here how these correlate >.<
What about using ACV tonic ? Is it ok? Do I still need to wait 20 min to apply mosturizer? What about carrirer oils, is it ok to apply them on the wet face with the ACV tonic? Please advise.
So if i wash with a ph-balanced cleanser but rinse it off with hard water, this throw the whole purpose of ph-balancing??? Wthhh
Any thoughts on very acidic well water? Ours is around 4.7, which my dentist thinks is the cause of some recent (and uncharacteristic for me) cavities, and my doctor thinks it’s a possibility that the low pH of the water has caused my rosacea to flare out of control. There’s not much out there (that I’ve seen) on problems caused by acidic well water, other than damage to pipes and leaching of metals. (Our plumbing is PEX, so not an issue.)