PHA sounds like laughter.<br>.<br>This is the first time I've ever heard about PHA(Polyhydroxy Acid), and it's supposed to be similar to AHA.<br>.<br>The skin surface improving AHA has some side effects like stimulation.<br>.<br>PHA has the same functions as the AHA, but is much milder in the means of stimulation.<br>COSRX PHA Moisture Renewal Power Cream review<br>.<br>A cream that will smooth the skin mildly with the relatively safe PHA ingredient.<br>How To:<br>When using as a mask: As the last step in your nighttime routine, apply a thick layer to your face avoiding the eye area. Leave on for 10 minutes and rinse off. Or leave on overnight, rinsing off in the morning. When using as a moisturizer: After cleansing and toning, apply a thin layer to your face and allow it to completely absorb into the skin. Pat to aid absorption.