The pH balance of your skin helps control how well it functions as an active defensive barrier against the world. Research now shows that the ideal “natural” pH is around 4.7 (Lambers et al., 2006). Skincare products formulated at this more acidic pH of about 4.5-5 can help preserve skin’s protective acid mantle and allows the skin’s good bacteria to thrive. The skin’s Microbiome is referred to as the Skins Bacteria layer on the skin and everyone has it. This is where our good bacteria ensures that we are able to fight off pathogens, viruses, fungus and bad bacteria. On the other hand, alkaline products, like harsh cleansers with pH 8-10, can be disruptive over time (Lukic et al., 2021) and help create a higher pH environment that is conducive from the propagation of bad bacteria on the skin’s surface. Checking a product’s pH helps pick ones to benefit skin. Dr Thanni Skin Clinic takes formulations that prioritise pH seriously as we have observed the successful changes it can bring about. A pH change of 1 + or – brings about a logarithmic 10x change in a formulation’s concentration and efficacy. pH is the negative logarithm (ten base) of the H+ concentration that refers to the concentration of free hydrogen ions.

Your skin barrier relies on certain enzymes needing an acidic pH around 5. If pH rises above 5-5.5, these enzymes lose efficiency making ceramides and other essential lipids (Hachem et al., 2005). It’s harder for skin cells to mature and shed properly at higher pH too. This opens up cracks allowing allergens, germs, and chemicals to penetrate deeper and trigger reactions. Proper pH acts like an invisible shield protecting you!

Healthy Skin Bacteria requires a low pH environment to thrive in. These are the 3 main types of bacteria found on every person’s skin. Please keep in mind that these bacteria’s have sub-versions (or categories) of themselves that are slightly different in structure and they would behave differently against the skin (think aggressive) and could be pathogenic.

The strain of skin bacteria that is most common is Staphylococcus epidermidis. However, Staphylococcus aureus, a close relative of the “Staph” bacteria, is not so kind. Cellulitis and skin abscesses, or boils, are bacterial infections caused by S. aureus. Additionally, it is thought to play a MAJOR role in skin conditions like rosacea, psoriasis and eczema. This specific bacteria is very harmful because it can penetrate the skin, get into the bloodstream, and lead to life-threatening lung and bloodstream infections.

The second most common type of bacteria found on skin is Corynebacterium. Skin is home to a wide variety of Corynebacterium strains, most of which are found under moist or sebaceous (oily) conditions. They can grow in high-salt concentrations and use the lipids in sebaceous conditions as a source of nutrition. They also rely on the vitamins in sweat to survive! (source: Fischbach and Scharschmidt, 2013)

The most well-known bacterium on skin is called Cutibacterium. A particular kind of bacteria called Cutibacterium acnes, or simply C. acnes, is most common on the face and back; in fact, 100% of people have varying levels of C. Acne bacteria on their skin. Its name implies that it is related to acne, as it grows most happily in sebum-filled follicles (pores) (ref: Marinelli, Fitz-Gibbons, et al, 2012). Skin issues like redness, inflammation, and uneven skin tone and texture are also linked to C. acnes.

pH tracks acidity versus alkalinity on a 0-14 scale, with 7 as neutral. Lower numbers signal greater acid content from hydrogen ions, while higher numbers indicate increasingly alkaline solutions lacking hydrogen ions. Think lemon juice with acidic pH of 2, versus oven cleaner solution with highly alkaline pH over 13. The skin surface has a pH of 4.7. The internal body systems and blood have a pH of above 7.4. Every increase or decrease by 1, will exponentially influence the concentration of Hydrogen. The difference in pH by 1 up or down increases or decreases concentrations from 10 to 100 to 1000 or vice versa. It is an exponential increase and not one that is linear.

Skin generates microscopic acid molecules internally during renewal processes transforming old cells into fresh ones. Certain intact skin barrier proteins additionally break down into helpful amino acid products that lower pH (Lukic et al., 2021). Skin also has resident populations of “good” bacteria needing surrounding acidic conditions to thrive, which keeps bad germs or bacteria away.

Washing, especially with harsher alkaline soaps and dirtied water or even normal water, can temporarily spike pH and strip acidic barriers (Lambers et al., 2006). Skin disorders like eczema or conditions causing dryness equally disrupt acid balance. And ingredients in certain skincare items themselves shift pH up or down too. Routinely using higher pH products ages skin quicker over time.

Look for cleansers and moisturisers specifically labelled pH 4-6 because these formulations aim to align with skin’s naturally acidic setpoint. However, evidence now shows that pH 4.5 is ideal for optimal barrier function and microflora health (Lambers et al., 2006; Lukic et al., 2021). So products tailored to this more acidic pH help skin even more. Alternate higher pH washes (if you prefer their properties) with pH 4.5 restores. Importantly, wait times between layering variable pH products lets them work best.

Try a regimen for sensitive skin where you apply products from lowest to highest pH values as you apply the various products in steps during your routine.

Since our products and other well made products are formulated to prioritise pH we don’t see a need to include a toner as a step in your skincare routine. Be aware that the pH of water is around 7 and the skin thrives at pH 4.5-5.

Research reveals that the natural pH of healthy skin is around 4.7 once stabilised and free from product interference (Lambers et al., 2006). Skincare products formulated at pH 4.5-5, like cleansers and moisturisers, help maintain this ideal acidity shown to optimise skin barrier function and resident microflora balance (Lukic et al., 2021). Enzymes vital in lipid synthesis have a pH optimum around 5, and good bacteria thrive at lower pH while harmful bacteria are restricted. Using an acidic skincare routine preserves skin’s protective acid mantle and keeps your natural defences strong. So be aware of the pH of your skincare – you and your skin will benefit from products crafted around pH 4.5-5.