Warming Sensation from Whitening Serum Actives
Question
In my formula, I have the following active ingredients: Tranexamic Acid 2.5%, Activated Resorcinol™ 0.5%, MSH White 1%, and White Cumin 2.5%. When applied to the skin, there is a slight warming sensation. What is the cause of this?
Answer
The warming sensation you are experiencing after applying the formula is most likely due to the Activated Resorcinol (4-Butyl Resorcinol) in the formulation. The description for Activated Resorcinol notes that while highly effective, high doses can cause skin irritation. Although your formula uses it at 0.5%, which is within the recommended usage rate of up to 1% for leave-on products, it is still a potent active ingredient. Some individuals, especially those with sensitive skin, may experience a warming or tingling sensation as a form of mild irritation.
Tranexamic Acid at 2.5% is also present at a relatively high concentration (though within the allowed cosmetic limit of 3%) and could potentially contribute to skin sensitivity or a warming feeling in some cases, particularly when combined with other strong actives.
The combination of multiple potent active ingredients like Activated Resorcinol and Tranexamic Acid, even at recommended individual concentrations, can sometimes increase the overall potential for skin reaction or sensitivity, leading to sensations like warming.
Related Products Mentioned
