How are acne and skin pH linked?
Newborns have a high skin pH compared with adults. Skin pH of a newborn is around 7, which is neutral on the pH scale.
When newborns and infants develop diaper rash and other skin conditions that show up as blisters and fragile skin, they typically respond well to eliminating all soaps because soaps have alkaline pH (above 7), which can further contribute to the problem.
This is also why lotions and ointments containing gluconolactone and lactobionic acid help to treat the condition.
Children also have a more fragile acid mantle compared with people who’ve entered puberty and adults.
For adolescents and adults, skin’s pH is somewhere around 5.5, and here specifically, we’re talking about the pH of the acid mantle, which technically sits on top of the skin’s surface.
Technically, the pH of the acid mantle ranges from about 4.0 to 6.0 depending on a person’s age, the location the skin sample’s taken from (for example, studies show that on average, the pH of the skin on your forehead is a little bit lower than the pH of the skin on your neck), skin color and other genetics.
Sometime around age 50 or so, skin’s pH begins to become slightly more alkaline, and this is commonly associated with dryness in older adults.
How does your skin change throughout the early years of life?
Infants have smaller corneocytes and a thinner stratum corneum than adults. They also have a higher rate of cell turnover compared with adults.
During childhood, while the dermal and epidermal thickness increases in both girls and boys, boys develop a thicker dermal and epidermal layer compared with girls.
Dermal composition begins to change in adolescence with the amount of collagen in skin decreasing at a linear rate in both girls and guys. While this rate of collagen reduction is about the same between girls and guys, because women start with a lower collagen density than men, we appear to age earlier than men.
Before we move on from here, it’s worth noting, babies and children have different skin properties than adults.
The skin of premies and newborns has a higher absorptive capacity than adults, and given their tiny size, the surface area to volume ratio of skin to body in these babies is worth serious consideration.
For this reason, things you wouldn’t think about twice for your skin could cause harm to these little ones.
One of the most frequent questions I’m asked is “can I use this on my child?” My response is “why do you want to use it on your child?”
I’m all for using only what’s necessary, and this applies to skincare as well.
If it weren’t necessary for me to use skincare regularly and have glowing gammes, itch free skin, and a radiant blemish free complexion, I wouldn’t have a daily skincare routine.
As a child, I didn’t have dry, itchy skin, and until I hit puberty, I didn’t have acne. I don’t know of very many children who complain of dry, itchy skin.
Is it safe to use essential oils on infants?
Also, we commonly gloss right over essential oils accepting them as safe because their natural. Essential oils are powerful.
And, it’s one thing for a 125-pound woman to apply body oil containing essential oils all over her body every day. I do this daily without a second thought. It’s another thing to slather an 8-pound baby with body oil containing essential oils.
Sunscreen safety and children
While I’m on my soapbox, let’s cover one more point. What about sunscreens? Ah, you caught me. That is the one skincare product (not counting soap) that I used as a child. And, there’s research that likely none of these sunscreens, the two physical sunscreens now included, are safe.
In case you missed it, we’ve covered sunscreens in a series that’s linked in today’s shownotes. For now, let’s reign this conversation back in to continue figuring out what’s linked w/ breakouts.
Sebum and acne
The sebaceous gland contains sebocytes that are filled with sebum. Sebocytes are holocrine glands, and this means that when they release sebum they’re destroyed, so along with the sebum, which we’ll discuss in more detail in a sec, the cell membrane of the sebaceous gland and all of its cellular components are part of the secretion.
Sebum is composed of about 40% triglycerides, about 25% wax esters, roughly 10 to 15% squalene and about ~15% of free fatty acids.
So, why don’t children get acne?
Children produce less sebum than adults. One study evaluated sebum compared to the number of sebocytes in children. Here, the researchers looked at the unique part of sebum, specifically the wax esters, and the unique part of the sebocyte, specifically cholesterol and cholesterol esters found in the sebocyte’s cellular membrane, and were able to normalize sebum production in children and adults on a wax ester to cholesterol + cholesterol esters.
In this study, sebum was collected and measured for 24 children between the ages of 6 and 8 (four age 6, ten age 7, and ten age 8), and the researchers found a strongly linear relationship between age and sebum levels in the children with the highest sebum levels in the 8 year olds.
Overall, sebum production rates between near 0 and 400 micrograms per 10 squared centimeters per 3 hours were observed in the children. Compared to adolescents without acne where wax ester secretions range from 70 to 804 micrograms per 10 squared centimeters per 3 hours and adolescents with acne where sebum secretion levels above 1 milligram per 10 squared centimeters per 3 hours.
The study goes on to suggest that increases in adrenal secretions, specifically DHEA and DHEAS, which begins around age 7, and references another study that found a significant correlation between urine content of several different adrenal androgens and the ratio of wax esters to cholesterol + cholesterol esters in the surface lipid composition of children aged 5 to 10.
Reproductive hormones impact the rate of sebum secretion. Androgens, like testosterone and dihydrotestosterone stimulate secretion. Estrogens inhibit secretion.
Sebaceous glands that house those sebocytes may exist independently on the surface of your skin or lie in the well of a hair follicle, where it’s known as a pilosebaceous unit.
Pathogenesis of acne
The outermost layer of skin, the stratum corneum tracks the topography of the skin’s surface. So, where there’s a sebaceous gland or hair follicle, the stratum corneum (and all the layers of skin below it) follow maintaining that barrier between your body and the environment.
Acne is considered to be a problem with keratinization (aka cornification). In fact, there’s a term for it: follicular hyperkeratinazition (this info comes from multiple references below, and sorry, I didn’t keep track here). Keratinocytes/corneocytes are designed to push each other up and out of the way and eventually (once they reach the skin surface) to slough off.
Well, when things go awry, the keratinocytes stick to each other too well and do NOT shed as they should. When this happens inside the hair follicle or clogs the surface of, the excess keratinocytes can plug the pilosebaceous apparatus causing one of four things:
- Acne pustule
- Acne cyst
So, why won’t the keratinocytes just act normal? Why won’t they migrate like they should, what’s going on?
Several papers demonstrate that lower pH impairs wound healing by reducing keratinocyte viability and keratinocyte/corneocyte migration (see references 5 through 7).
Why is this?
Well, if we look at how desquamation happens, enzymes help promote shedding (aka sloughing aka desquamation) of the corneocytes.
These enzymes perform optimally at neutral pH of 7.0 (Reference 3).
Wait, but skin is acidic, right?
We all know our skin has an acid mantle. This acid mantle is a very thin film composed of free fatty acids, sweat, and normal skin flora and this film is on top of our outermost layer of corneocytes at the very top of the stratum corneum. The pH of this acid mantle is usually reported to be between 4.5 to 5.5. However, just below the surface, the pH of the skin begins to increase pretty rapidly within those first few layers of the stratum corneum itself. The cell layer thickness of the stratum corneum varies depending on where on your body we’re talking about.
Skin cell turnover rates vary depending on which part of the body we’re talking about, so let’s talk about your face. With the exception of the skin around your eyes, the stratum corneum is about 20 to 30 cell layers thick.
Skin’s pH increases from a surface pH between about 4.5 and 5.3 up to about 6.8 in the lower levels of the stratum corneum (one note, the exact location where the pH approaches 6.8 varies between scientific papers, one study cited for this episode states pH 6.8 in the lower levels of the stratum corneum and a second study indicates that pH level isn’t achieved until hitting the stratum granulosum layer).
Either way, this pH gradient is very important and either too shallow or too steep a gradient is observed in a number of skin conditions. And, pH at the skin’s surface is also linked to a number of skin conditions from acne to rosacea. For acne, a higher pH at the skin’s surface is typical, however, this doesn’t mean high surface pH causes acne. It’s likely a result of the pathogenesis of acne.
So, if pH like acne is a result of hyperkeratinization or of keratinocytes being too sticky and not shedding properly, what can you do to help this process?
Skin hydration is important for controlling acne
Those enzymes required for digesting the desmosomes that hold the keratinocytes together require water.
Likewise, the lipid bilayer composing the cellular membrane of your skin’s cells (and your body’s cells) need a sufficient amount of free water, and this may be especially necessary for the cellular membrane of the sebocytes, since the lipid bilayer of the sebocyte becomes part of the cellular debris when the sebocyte breaks open to release sebum.
Those lipid bilayers can crystallize when there’s not enough water around, and this leads to that uneven appearance even in the absence of acne.
How do you get more water into your skin? A few ways are:
- Absorb more water. If you feel like you drink plenty of water and your skin is still dry, you’re not alone. I’m right there with you. Encourage your body’s tissues to absorb more of the water you drink by:
- Warm it up. Drink lukewarm or even hot water instead of cold to absorb more of it.
- Add lemon to it. Ginger and a little pinch of salt are two more ingredients to reach for when you don’t have lemon.
- Sip throughout the day. Don’t focus on drinking a set amount of water. Instead, drink when you’re thirsty, sit down when you drink, and sip throughout the day. Your body loses water steadily throughout the day through sweat, urine, and transepidermal water loss (TEWL), so drinking water at a slow and steady pace throughout the day encourages infusion of that water into your tissues rather than encouraging your body to eliminate it as it comes in all at once.
- Get your daily dose of PUFAs. There’s so much controversy over polyunsaturated fatty acids right now. Here’s the deal. These oils are not safe to cook with.
Safflower oil, canola oil, and soybean oil, the common fryer oils and vegetable oils sold as safe cooking oils shouldn’t be used for frying or cooking your foods. The reason for this is that these oils are fragile containing multiple unsaturation points within their fatty acid chain, and when heated to temperatures not even all that high (like 150 to 300 Fahrenheit) very quickly (like 40 minutes or less). When they degrade due to heat exposure, they form oxidative species generating oxidative stress in the body once they’re eaten.
However, your body needs PUFAs. These are the essential fatty acids, omega-3 and omega-6. Chances are, you’re getting your daily omega-6 without even thinking much about it as nuts and seeds are rich in this fatty acid.
Omega-3 is trickier. Aside from fish, good sources of omega-3 are flaxseed and chia seed. Pistachios, brazil nuts, and brussel sprouts are 3 more good sources of omega-3. And, these seeds go rancid quickly because of their high oil content.
Now, there’s all sorts of fear floating around right now about how flaxseeds aren’t stable and are by and large rancid when you buy them. You can taste rancidity. And, you can smell it. It will taste and smell like it’s “gone off”. This is the time to toss it.
Over the years, I’ve spent quite a bit of time evaluating essential fatty acids, and you’ll find links to two in-depth blog posts are linked below:
- Apply ingredients to reduce transepidermal water loss.
Occlusives: Ingredients like high molecular weight hyaluronic acid and certain oils and butters form a film on the surface of your skin to prevent TEWL.
These ingredients are known as occlusives, and we’ve talked about occlusives as one way to increase your skin’s moisturization factor in a previous episode.
Olive oil is an exceptional oil in that it offers both occlusive and restorative properties. Shea butter and cocoa butter are also excellent occlusives, and argan oil is one more oil based occlusive.
Water binding ingredients: Aloe, panthenol, low molecular weight hyaluronic acid all bind to water and help retain it within your skin.
- Oils: Yes, an oil can help moisturize or hydrate your skin 😊 This goes back to PUFAs. A lack of EFAs is linked to eczema and other skin conditions. The cellular membrane of your body’s cells and also your skin’s cells incorporate oils, specifically free fatty acids, into the lipid bilayer, and those essential fatty acids, both omega-3 and omega-6 are necessary for healthy cellular membranes.
- Occlusives: Ingredients like high molecular weight hyaluronic acid and certain oils and butters form a film on the surface of your skin to prevent TEWL.
- Exfoliate from within
So often, we think of exfoliation as something that happens at the surface. And, yes, that’s how physical exfoliation happens, and it’s where chemical exfoliation starts.
The problem with too much exfoliation, specifically chemical exfoliation, is that it feeds into a vicious cycle.
Exog Dermatol 2002;1:163–175
(DOI:10.1159/000066140) Stratum corneum pH: Formation and Function of the ‘Acid Mantle’. Fluhr J.W. · Elias P.M. https://www.karger.com/Article/Pdf/66140#
Zlotogorski, A. Distribution of skin surface pH on the forehead and cheek of adults. Arch Dermatol Res 279, 398–401 (1987). https://doi.org/10.1007/BF00412626
Overview of Dermatologic Care in Children. https://link.springer.com/chapter/10.1007%2F978-3-319-43630-2_1 Therapy in Pediatric Dermatology pp. 1-5
Takigawa H, Nakagawa H, Kuzukawa M, Mori H, Imokawa G: Deficient Production of Hexadecenoic Acid in the Skin Is Associated in Part with the Vulnerability of Atopic Dermatitis Patients to Colonization by Staphylococcus aureus. Dermatology 2005;211:240-248. doi: 10.1159/000087018
3. K. Kabashima (Editor). Immunology of the Skin: Basic and Clinical Sciences in Skin Immune Responses. Chapter 2. First Edition, 2016, IX, ISBN: 978-4-431-55853-8. https://www.springer.com/gp/book/9784431558538
5. Lönnqvist S1, Emanuelsson P2, Kratz G1,3. Influence of acidic pH on keratinocyte function and re-epithelialisation of human in vitro wounds. J Plast Surg Hand Surg. 2015;49(6):346-52. doi: 10.3109/2000656X.2015.1053397. Epub 2015 Jun 7. https://www.ncbi.nlm.nih.gov/pubmed/26051107
6. Fluhr J, W, Elias P, M: Stratum corneum pH: Formation and Function of the ‘Acid Mantle’. Exog Dermatol 2002;1:163-175. doi: 10.1159/000066140. https://www.karger.com/Article/Abstract/66140
7. Kruse CR1,2, Singh M1, Targosinski S1, Sinha I1, Sørensen JA2, Eriksson E3, Nuutila K1. The effect of pH on cell viability, cell migration, cell proliferation, wound closure, and wound reepithelialization: In vitro and in vivo study. Wound Repair Regen. 2017 Apr;25(2):260-269. doi: 10.1111/wrr.12526. Epub 2017 Apr 24. https://www.ncbi.nlm.nih.gov/pubmed/28370923
8. Prakash, Chaitra et al. “Skin Surface pH in Acne Vulgaris: Insights from an Observational Study and Review of the Literature” Journal of clinical and aesthetic dermatology vol. 10,7 (2017): 33-39. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5605222/
5. M. Thiboutot (2000) The role of follicular hyperkeratinization in acne, Journal of Dermatological Treatment, 11:2, 5-8, DOI: 10.1080/095466300750163645
6. HeikeWagneraKarl-HeinzKostkabClaus-MichaelLehraUlrich F.Schaefera. European Journal of Pharmaceutics and Biopharmaceutics. Volume 55, Issue 1, January 2003, Pages 57-65. pH profiles in human skin: influence of two in vitro test systems for drug delivery testing. https://doi.org/10.1016/S0939-6411(02)00125-XGet rights and content
7. Frank Rippke, Volker Schreiner, Hans-Joachim Schwanitz. The Acidic Milieu of the Horny Layer. American Journal of Clinical Dermatology, 2002, Volume 3, Number 4, Page 261. https://link.springer.com/article/10.2165/00128071-200203040-00004
8. Chan, Aegean and Theodora Mauro. “Acidification in the epidermis and the role of secretory phospholipases” Dermato-endocrinology vol. 3,2 (2011): 84-90. doi: 10.4161/derm.3.2.15140 https://www.ncbi.nlm.nih.gov/pubmed/22891649
11. Öhman, HansVahlquist, Anders et al. The pH Gradient over the Stratum Corneum Differs in X-Linked Recessive and Autosomal Dominant Ichthyosis: A Clue to the Molecular Origin of the “Acid Skin Mantle”? Journal of Investigative Dermatology , Volume 111 , Issue 4 , 674 – 677. 12. https://www.sciencedirect.com/science/article/pii/S0022202X15402441#bb0080
About the Author
Brandy's a formulation scientist and self-proclaimed health geek who loves hiking, gardening, bird-watching, and body boarding.
Her struggle with acne during her teens and 20s led to a holistic and healthy approach to skincare, embracing skin as an organ to be loved and cared for rather than a canvas to wage war on.
Since 2008, she's been developing all-in-one products for a simple routine at home, & Rain Organica started when her backpacking friends asked for a portable skincare routine to keep their skin healthy & happy on and off the trails.
You can try Rain Organica for yourself with The Essentials Kit, a complete skincare routine in just 3 steps.
Subscribe to our newsletter: