Gentle Brighteners: Ingredients like Niacinamide (Vitamin B3) and Tranexamic Acid are generally well-tolerated and effective for fading dark spots.
Soothing Ingredients: Formulas that include ingredients to calm the skin, such as Allantoin, Centella Asiatica, or Squalane, are a good sign.
Fragrance-Free: Avoid products with added fragrance or "parfum," as these are a common trigger for sensitive skin irritation and redness, which can actually worsen dark spots.
Lower Concentration of Actives: If the serum contains Vitamin C, Retinol, or strong acids (like Glycolic Acid), a lower concentration is usually less irritating.