9. Ignoring Ingredient Interactions

Not all skincare ingredients play nicely together. Mixing retinol with vitamin C or layering acids like glycolic and salicylic can cause irritation, redness, or even make products less effective. For example, retinol and benzoyl peroxide may neutralize each other, while combining multiple strong actives can overwhelm sensitive skin. Experts recommend reading product labels and researching which ingredients are compatible before layering. When in doubt, space out potent ingredients or use them at different times of day to avoid unwanted reactions.