New Delhi, Jan 18 (IANS): Some recent soap advertisements caught the eye and raised a few questions. Is there a perfect pH product for human skin? What characteristics define a good soap?

Let's start at the beginning. pH (Potential Hydrogen) is defined as the concentration of hydrogen ions in a solution. PH value ranges between 0 and 14. 7 is the neutral point, 0 being the most acidic and 14 being the most alkaline.

More importantly, your skin isn't exactly pH 5.5! It falls in a range between 4.0 to 7.0 depending on factors as diverse as the body part, age, genetics, ethnicity, environment conditions, to list a few.

So, are products formulated at PH 5.5 perfect for the skin? The short answer: not really! In fact, firstly parameters like surfactants, texture and other ingredients indicate a cleanser's quality, much better than pH alone.

Secondly, though the skin pH rises slightly immediately after cleaning even with plain water, it reverts to its mild acidic pH in an hour. Healthy skin quickly rebalances the ‘acid mantle' - a protective layer over the skin - and is unaffected in the long term by the cleanser's pH. Skin modulates pH, making skin products function optimally not just at various pH levels, but in combination with the overall formula. So why market pH 5.5 products as ‘perfect'? Well, for certain skin types (e.g. oily skin) and certain skin conditions (like acne), an increase in pH can aggravate these skin situations. This might lead to an interpretation of a product needing to be at a 5.5 pH for optimum cleansing.

The Bureau of Indian Standards' mandatory guidelines for soap also exclude pH, demonstrating that composition is more relevant to safety and mildness. BIS even approves the use of such soaps for a baby's skin, underscoring their safety under normal usage conditions.

Commenting on the issue, Dr Aparna Santhanam (MD, DNB) Consulting Dermatologist, Consultant & Author, said, "Recent scientific advances have brought to the fore the importance of the acid mantle in skin health. However, a product's pH is merely one of the important factors that impact the skin. There are many other factors, both endogenous and exogenous, including pre-existing skin conditions, water quality, correct usage and contact time which contribute to the acid mantle after using a product. The skin also performs repair and restorative mechanisms to bring the pH to physiological levels after contact with all or any of these factors. Thus, it is important to understand all of these factors in conjunction, rather than just one of them standalone."

Skincare experts around the country have expressed reservations about the issue of Ph being the sole judge of product safety and acid mantle preservation when multiple factors, including but not limited, to plain water may be contributing to the same. Hence, an ideal product is almost impossible to define. So, can we look at this ‘ideal pH as the only ideal measure of a cleansing product? The answer: look well beyond pH alone!