Hello, from the formula that members mentioned. If members add ingredients that are
สารกันแดด to be more proportional, it will increase the SPF of the formula. Not sure how much the rate is. to achieve the desired SPF 50 You can try to adjust the formula and send the formula to test the SPF value at the company lab. (If using company ingredients The company provides free measurement services. and issue reports that can be used to inform the FDA)