The pH of the skin surface is between pH 4.5 – 5.0 (i.e., lower than the pH inside the body, pH 7.4). This ‘acid-mantle’ is essential for maintaining healthy skin and a healthy skin microbiome. Indeed, many inflammatory skin conditions are associated with an increase in skin pH. For example, atopic dermatitis, ichthyosis (dry skin), and diaper dermatitis (nappy rash). A flat-tip pH electrode can be used to measure skin pH across many different body sites, including the scalp. Equipment of this type usually has a thin glass membrane at the tip of the instrument and relies on the diffusion of ions through this membrane from the skin surface into the buffer solution sitting between the electrodes in the device. So, in effect, you wet the skin surface slightly by placing the instrument on the skin to create a thin film of water. H+ ions in this water film then diffuse into the detector and give you a quick reading. The portable pH meter and flat-tip electrode used at TRI can be used for preclinical and clinical testing. Contact us to investigate how this measurement can be incorporated into your protocol.