No, it is neither safe nor effective to use baking powder or baking soda for skin lightening. Baking powder contains sodium bicarbonate mixed with acidic agents. Both substances are highly alkaline and can severely disrupt your skin's natural protective barrier. This disruption can lead to dryness, irritation, redness, and even chemical burns, which can ultimately cause post-inflammatory hyperpigmentation (darkening of the skin). For safe skin brightening, I highly recommend using gentle, dermatologically tested ingredients such as Vitamin C, Niacinamide, or Kojic acid. Please consult a dermatologist to find a safe treatment tailored to your skin.