Lately the phrase “litmus test” has popped up in the news nearly every day — and it almost always applies to how a Supreme Court appointee might rule on controversial issues. But, if you think back to high school chemistry, you may remember the origin of the phrase. A litmus test is when you dip a little piece of paper into a solution to determine something’s pH, or how acidic or alkaline (basic) it is: 7 is neutral, below 7 is acidic, and above 7 is alkaline.
But “neutral” isn’t always best for you: “Your body likes to keep the pH at a steady 7.4, which is very mildly alkaline,” says Jacob Teitelbaum, MD, an internist and author of the smartphone app Cures A-Z. “Your body will do pretty much whatever it needs to keep it right on that mark throughout your interiors…except where our body meets the outside world.” Your skin, scalp, and vagina, for example, like to be slightly acidic. Here’s how to find the happy pH place for your parts.
Ideal Skin pH: 5.5
On the surface of your skin is a thin, protective layer called the acid mantle, made up of sebum, sweat, and microflora, the bacteria that reside there. (Kinda gross if you think about it for too long.) “If the acid mantle isn’t balanced, it will no longer be able to fight off infection or environmental stress factors like cold, wind, and UV,” explains Dendy Engelman, MD, an associate at Manhattan Dermatology & Cosmetic Surgery.
“If the pH balance is too alkaline,” she explains, “the skin will become dry, which can lead to irritation and minimized protection against bacteria growth, so acne and breakouts may occur.” Another risk you run: wrinkles may appear more rapidly. Crap!
Traditional, soap-based cleansers are the biggest culprit for raising skin’s pH level. To best maintain epidermal equilibrium (which is where both dryness and acne stay at bay), use a non-soap cleanser specifically created for washing your face, like Sebamed® Fragrance Free Gentle Hydrating Cleanser ($15). If you just can’t seem to stay away from the soapy stuff, then you want to immediately restore your skin’s balance with a toner, applied after you cleanse. One we love: Tula Pro-Glycolic PH Resurfacing Gel, ($34) which contains probiotics to help repopulate your skin’s microbiome with good bacteria.
Alternatively, you could end up making your skin’s surface too acidic — by using too many peels or clarifying masks, for example — putting it at risk for “a loss of natural oils and a compromised lipid barrier,” says Engelman. Back off the exfoliants for a bit and calm your skin with a colloidal oatmeal-based cream or mask, like Skinfix Extra Strength Eczema Sheer Face Ointment ($19).
Your body skin’s pH can get thrown out of whack as well, with the same irritating effects. Engelman is a big proponent of apple cider vinegar (or ACV) to rebalance your bod: “ACV is a potent antibacterial, antifungal, and antiviral substance capable of minimizing bacterial levels, so it keeps odors and pimples from forming.” Try pouring a cup or two of ACV into warm bath water and soaking for 20 minutes, once or twice a week. Another option: Using a pH buffered body wash like Eucerin Advanced Cleansing Body & Face Wash ($13) to maintain your bod’s balance.
Ideal Scalp pH: 5.5; Ideal Hair pH: N/A
It shouldn’t come as a shocker that your scalp wants to be at a slightly acidic 5.5 since your scalp is, after all, skin. But why doesn’t your hair have a pH? Get ready to geek out with us here, as Pantene Scientific Communications Expert Jeni Thomas explains: “Hair does not have a pH, it has a pI. A pI is an isoelectric point, which is the point at which hair’s charges are balanced. When hair’s environment [the liquid it’s immersed in] is more acidic than its pI, hair takes on a positive charge and when it is more alkaline than its pI, hair takes on a negative charge.”
So here’s how that works outside the lab: When hair is exposed to something with a very low pH, like lemon juice or a vinegar rinse you’d use to remove mineral buildup, the bonds between the hair fiber and the protective oils can break. That will damage your strands and could also sting your scalp. On the flip side, the hair color process — which uses alkaline solutions to swell the hair fiber and allow color molecules in — will also damage hair fibers and irritate your scalp. So just as with the skin on your face, you want to try to keep the products you use on your scalp and hair as close to 5.5 as possible.
When that’s not in the cards (it’s not as if I’m going to stop coloring my hair!), follow up with products that restore your hair and scalp’s pH. If you’ve over-stripped with acids, restore your lipid barrier with the nourishing formula of Pantene 3 Minute Miracle Repair & Protect Conditioner ($5). After a color service, re-seal the cuticle and prevent breakage with Wella Professionals Wellaplex No. 3 Hair Stabilizer ($21). And for regular pl maintenance, try the Harry Josh Pro Tools Pro Dryer 2000 ($187). This nifty hot tool allows you to choose between infusing your hair with negative (smoothing) ions and positive (volumizing) ones with just a flick of a switch.
Ideal Vagina pH: 3.8 – 4.5
An acidic vagina is a happy vagina! “It’s actually quite rare for the vagina to be too acidic,” says Anuja Vyas, MD, Houston Methodist OB-GYN. “But if this happens, it’s most likely to occur during the second half of the menstrual cycle due to an increase in progesterone levels, and cause symptoms that are similar to a yeast infection, such as burning and itching.”
When your vaginal pH increases, you could be in for common but still highly irritating issues: “If the pH becomes more alkaline, unhealthy bacteria and yeast grow uncontrollably, causing unwanted symptoms,” says Sherry Ross, OB-GYN, author of Sheology and Summers Eve brand advocate. “The vagina can be sensitive and temperamental, often affected by everyday routines,” she adds.
Some women won’t even notice the fluctuations of their pH; others aren’t so lucky. But for everyone, diet is key to keeping things in balance: “What you put in your mouth can either promote or inhibit a healthy microbiome in your genital tract,” says Vyas. “A healthy, nutritious diet that limits processed foods and simple carbohydrates is important. And probiotics specifically formulated for women’s health— for example, those containing lactobacillus crispatus or rhamnosus—taken a few times per week may help restore ideal vaginal pH,” she says, reminding us that we should consult with our doctor before beginning a probiotic regimen.
As for “feminine hygiene,” how many teen magazine articles back in the day told us that, “the vagina is a self-cleansing organ,” and that we don’t need anything but water to keep it clean? As much as we’ve tried to internalize that, sometimes a girl just wants to feel extra fresh.
And while douching is a pH disaster waiting to happen, Dr. Ross has given us the green-light to use external, pH balanced products made especially for the vag. Worth a try: Simply Summer’s Eve® Cucumber Lily Cleansing Wash, ($5) (We kid you not, it’ll make your private lawn smell like fresh-cut grass); The Perfect V VVTM; Beauty Sheets ($24), for a personal pick-me-up on the go.
Dr. Dendy Engelman is a paid Allergan consultant.
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