This past week I have seen a number of blogs and videos encouraging the use of baking soda to exfoliate the skin and felt the need to create a response refuting this advice. This is a popular home remedy that needs to be put to rest – do NOT put baking soda on your face. Not only is it ineffective, but it is actually damaging to your skin.
Beauty Chemistry Lesson
Let’s start with the Bronsted-Lowry Concept which states that acids are proton donors that give up a proton (the hydrogen cation or H+), and bases are proton acceptors that are able to receive a proton (H+). Bases neutralize acids by bonding with the acid’s hydrogen ion. But there are also amphoteric molecules that have the ability to react with both acids and bases and are capable of accepting and donating hydrogen ions. Baking soda (sodium bicarbonate) is one such molecule and can give or receive a hydrogen ion…meaning that baking soda has the potential to react with both acids and bases (but it tends to be a stronger base than acid).
Baking soda as an exfoliant is typically mixed with water:
HCO3- + H2O → H2CO3 + OH-
What this means is that when you mix baking soda with water it tends to become even more alkaline (pH ~ 8) than it was originally on its own.
But why is something that is alkaline bad for the skin?
The pH of the products you use is very important to the health of the skin. The pH scale runs from 0-14 with 7 being neutral. Anything greater than 7 is alkaline or a base and those things less than 7 are acidic. Your skin naturally falls somewhere between a pH of 4.5-6 – this acid mantle is maintained by you sebaceous glands, sweat glands, and normal skin flora, among others and is critical for healthy resilient skin.
When you apply a product with an alkaline pH to the skin you negatively disrupt the skin barrier. A study on skin products found that using an alkaline cleanser, even once, can damage the skin barrier. An alkaline product disrupts the skin’s acid mantle (affecting the integrity of the skin barrier), and changes the natural microbiome on the skin and the activity of the enzymes in the upper layers of skin. This damage is cumulative; the more you use alkaline products the greater the degree of damage.
Key indicators of an impaired acid mantle:
- Limited sebaceous gland excretions, skin may be lipid dry or essential fatty acid deficient, this is when your skin is literally stripped of the much needed oils and sebum through use of incorrect skincare products and treatments
- Skin has a reactive/rosacea appearance (there is a direct link between an impaired acid mantle and rosacea)
- It can appear hot/burning
- Possibly itchy skin
- Prone to acne and other infections
- Shows signs of excess keratinisation
- Indicates loss of structural integrity
- Marks and scars easily
- Chronic alkalization can knock the acid mantle out of balance leading to atopic skin diseases (ie. dermatitis, eczema, etc)
With baking soda and water, not only are you disrupting the acid mantle, but you’re also manually exfoliating the skin, making it even more damaging and drying.
Skip the baking soda skin exfoliating, reserve your baking soda to scrub your sink or deodorize your fridge and stick to something gentler with a lower, more acidic pH for your skin. This is why I highly recommend sticking to professionally formulated products for your beauty routine (and make sure you avoid common acne triggers – see list here). It’s not that I don’t love a good DIY home remedy, but I think it’s easy to become misinformed and misuse products like baking soda in ways that do more harm than good in the long run.
Have a beautiful day!
Gfatter R, Hackl P, Braun F, Effects of Soap and Detergents on Skin Surface pH, Stratum corneum Hydration and Fat Content in Infants. Dermatology 1997;195:258-262