Skin care products can effect the skin surface pH. Making sure the products you use are formulated to match the pH of healthy skin can help maintain natural barrier function and prevent disruption of the acid mantle.
The pH value of skin/hair care products can directly influence the skin surface pH. If the pH is too high or too low, these formulations could have detrimental effects effects on skin barrier stability and skin hydration.
The issue starts to become more apparent, when you look at the data specifically related to seborrheic dermatitis and dandruff.
Just consider the following facts:
- Inhibition of malassezia is often the focus of most seborrheic dermatitis treatment [1, 2]
- In the lab, a pH of 4.5 was able to inhibit malassezia growth by roughly 95% 
- Out of 26 commercial anti-dandruff shampoos investigates noted that 80.77% of them showed a pH above 5.5 
- Formulations which are not formulated to match the skin’s optimal pH value can cause a lasting increase in skin surface pH, alter the skin microflora and lead to instability of the skin barrier 
Taken together, it is possible that over-exposure to skin care products which raise the skin surface pH may directly unfavorably influence the malassezia presence and fuel seborrheic dermatitis progression.
Though it’s hard to say for sure weather or not skin care products with elevated pH levels may trigger seborrheic dermatitis, using products which are formulated to have a balanced pH value can still play an important role in stabilizing the skin environment and paving the way for long term progress.
Ideas for Integrations
Many skin care products are now marketed to be pH balanced, commonly noting that they have been formulated to match the skin’s natural pH of 5.5.
Shampoos on the other hand are a little different and the majority of commercial shampoo formulations actually have a pH of over 5.5. To make things worse, the trend to carefully balance pH levels and properly advertise this, has not yet caught on.
For example, a paper that investigated a total of 123 commercial shampoos noted the following found that 61.78% of the analyzed shampoos had a pH higher then 5.5 . This means that with random selection most individuals have nearly a 40% chance of finding a shampoo with a pH below 5.5. That’s not bad you may think.
In either case, the medical literature on the subject actually indicates the optimal skin pH is actually lower than 5.5. This makes you wonder how well traditional skin care products are formulated and why such inconsistencies exist.
Nonetheless, choosing products which at-least take into account pH values seems to be a better approach then simply random selection. You could, however, get a little more technical and test the pH values yourself using a simple pH meter.
- Oil only formulations do not actually have a pH value, due to the absence of water
- If the pH of the formulation is too low, it can cause irritation and contact dermatitis
- Even plain water (with an average pH value of 7) can influence the skin surface pH