1. High pH Levels Avoid serums with a high pH, as they can render vitamin C ineffective.
2. Lack of Information Avoid products without clear ingredient lists, concentrations, or information about the form of vitamin C used.
3. Artificial Fragrances Fragrances can irritate the skin, so opt for serums without added artificial scents.
4. Harsh Ingredients Steer clear of serums containing harsh or potential irritants, such as alcohol or parabens.
5. Discolouration If a serum has changed colour or turned brown, it indicates vitamin C degradation, & it’s best to avoid using it.