Skin Reaction to Serum

It's concerning that your mother developed dark patches on her cheeks after using the serum. While the formula contains ingredients like Alpha-Arbutin and Vitamin B3 (Niacinamide) which are known for their brightening properties, skin reactions can sometimes lead to unexpected results like hyperpigmentation.

Here's a possible explanation:

• Irritation or Allergic Reaction: The dark patches could be a form of post-inflammatory hyperpigmentation (PIH) triggered by irritation or an allergic reaction to one or more ingredients in the serum. Even beneficial ingredients can cause sensitivity in some individuals, especially when used in combination or at certain concentrations.
• Combination of Actives: The serum contains several potent active ingredients aimed at whitening, anti-aging, and tightening (Alpha-Arbutin, Niacinamide, Argireline, Leuphasyl, Pepha®-Tight, Glucosamine). While each ingredient has its benefits, the combined effect might be too stimulating or irritating for your mother's skin, leading to inflammation and subsequent darkening.
• Individual Sensitivity: As the staff mentioned, skin responses vary greatly from person to person. Her skin might be particularly sensitive to one or more components in this specific formulation.
• Sun Exposure: Irritated skin is more vulnerable to sun damage, which can worsen or cause hyperpigmentation. Ensuring strict sun protection is crucial when using active ingredients.

It is important to stop using the product immediately if a negative reaction occurs, as advised by the staff. To identify the specific ingredient causing the issue, patch testing each component individually would be necessary, although this is a complex process.

Focusing on gentle, soothing, and barrier-repairing products temporarily might help the skin recover. Always incorporate good sun protection into her routine, especially when using products with active ingredients.