Products that are patch tested are better, but they still may not mean much. Many brands accept reactions of 5-15% of patients tested.With rare exceptions (which the VH-Rating clearly indicates to alert customers) VMV ingredients, applicators and formulations are approved only if they elicit 0% reactions.Due to this practice and VH-Ratings, we've averaged less than 0.1% (about 0.008%) of reactions reported to our products in over 30 years, and those were mostly to ingredients not considered to be allergens or due to incorrect product usage.A little known fact: many allergens are also photo-allergens - chemicals that can react with light (from the sun but also computer screens and office or house lights) to cause darkening. At VMV we use ingredients that are photo-patch tested and proven not to cause photo-allergic reactions (if you are photosensitive, avoid our makeup colors with dyes).If you are highly allergic, it's best to get a patch test. This painless procedure shows you exactly which ingredients you need to avoid, even if they're not yet well-known allergens. It significantly reduces the expense, frustration and irritations that come with random trial and error. If your doctor is also a member of the American Contact Dermatitis Society (contactderm.org), your results can be entered into CAMP (the Contact Allergen Management Program), which can give you a list of ingredients to avoid, as well as specific brands and products that you can use.If you are very prone to hyperpigmentations (dark spots, blotches or scars), ask your doctor for a photo-patch test. Simple avoidance of the things that trigger your pigmentation can enhance your active lightening therapy or even help clear up existing pigmentations.