Use a gentle, fragrance-free cleanser
Avoid harsh scrubbing or exfoliating too often
Moisturize the area regularly
Stop using deodorants or antiperspirants that irritate your skin
Shave carefully or switch to waxing, trimming, or laser hair removal
Wear loose, breathable clothing
Reduce friction from repetitive rubbing
Use topical ingredients such as niacinamide, azelaic acid, glycolic acid, lactic acid, or vitamin C
Consider prescription treatments from a dermatologist if needed
Treat underlying causes such as obesity, insulin resistance, eczema, or fungal infections
Avoid home remedies that can irritate the skin, such as lemon juice or baking soda
Use sunscreen on exposed underarm areas
See a dermatologist if the darkening is sudden, severe, or persistent