“Let’s make it clean, gentle, and effective.”
That’s a great starting point! But one of the most overlooked factors in achieving all three of those goals is pH.
As an R&D team working with emerging and established beauty brands, we’re here to walk you through what pH really means, why it matters in skincare formulations, and how it affects your product’s performance, stability, and compatibility with the skin.
What Is pH? A Simple Explanation
pH stands for ‘potential of hydrogen’ and measures how acidic or alkaline (basic) a solution is using a scale from 0 to 14:
Think of it like a ruler for acidity. The lower the number, the more acidic; the higher the number, the more alkaline.
Analogy:
If skincare products were beverages, then:
• Lemon juice (pH ~2) is very acidic — like a strong exfoliating toner • Water (pH 7) is neutral — like a balanced mist or toner
• Soapy water (pH ~9) is alkaline — like a body soap
What’s the Natural pH of Skin?
Healthy skin has a slightly acidic surface, often referred to as the ‘acid mantle’. This delicate acidic layer helps:
- Protect against harmful bacteria
- Maintain the skin barrier
- Regulate oil production
- Support the microbiome
When a product’s pH strays too far from this natural range, it can throw off that balance, leading to issues like:
- Irritation and redness
- Dryness and flaking
- Increased oiliness or breakouts
- Compromised skin barrier function
- Sensitivity to other actives or environmental triggers
This is especially true for sensitive, acne-prone, or post-procedure skin (think after microneedling, laser, or retinoid use).
Why pH Matters in Formulation?
Choosing the right pH isn’t just about avoiding irritation, it’s about enhancing performance and product stability. Here’s how:
Ingredient Efficacy
Many active ingredients are pH-dependent, meaning they only work effectively within a certain pH range. For example:
- Niacinamide is more stable around pH 5–7
- AHAs (like glycolic or lactic acid) need a lower pH to exfoliate properly
Formulation Stability
Incorrect pH can cause formulas to separate, degrade, or become microbiologically unstable. Preservatives may stop working properly, and actives may oxidize or become inactive over time.
Skin Compatibility
Especially for leave-on products, pH should align closely with the skin’s natural range to maintain barrier health and avoid unnecessary irritation. Wash-off products like cleansers can afford to deviate slightly more, but even they should be carefully balanced.
Why Does Skin’s pH Differ Across the Body?
The skin’s pH varies across different areas of the body. As formulators, understanding this variation helps us develop products tailored to specific zones, especially when creating skin care, body care, scalp care, or intimate care lines.
Underarms
pH 5.5–6.5 (This area is more alkaline due to sweat, moisture, and bacterial activity)
Intimate Areas
pH 3.5 – 4.5 (more acidic than other body parts to avoid disrupting the protective flora)
Scalp
around pH 5.5 (A healthy scalp microbiome thrives at this acidity, protecting against dandruff-causing fungi and bacteria)
Hands & Feet
pH 4.5 – 5.5 (These areas are exposed to more environmental stress (washing, friction, etc)
Final Thoughts: Don’t Overlook the Power of pH
In the race to launch the next best skincare product, pH can easily get overshadowed by trendy actives or aesthetic packaging. But behind the scenes, it’s one of the most critical factors in creating a formula that is effective, stable, and skin-friendly.
At the end of the day, respecting pH is part of respecting the skin itself and that’s something we take seriously at every step of formulation.
Want to Launch a Product?‘
We’d love to collaborate with you. Whether you’re looking to enhance an existing line or launch something entirely new, our R&D and production teams are ready to help develop a custom formulation that meets your goals.
Contact us today for samples and formulation consultations!
