How to brighten dark underarms

Why are your underarms darker?

Shaving irritation, tight clothing and reactions to deodorant or shaving products can contribute to dark underarms. Postinflammatory hyperpigmentation means extra pigment left after inflammation or injury; irritating products can trigger it, particularly in medium to dark skin tones. Thick, dark, velvety patches can instead be acanthosis nigricans, a skin condition linked to insulin resistance, hormonal conditions or certain medicines. Dark underarms alone do not mean you have diabetes. Acanthosis nigricans also occurs in otherwise healthy people, and washing will not remove it.1345

What should you do first?

1. 1Have new or unexplained patches assessed before trying to lighten them. A doctor can examine the skin and arrange tests, including blood sugar tests, if needed.
2. 2Cut back on products applied to the area. An underarm routine can use fewer products, even if the bathroom shelf would prefer a promotion.
3. 3Switch irritating deodorant or shaving products for options intended for sensitive skin, without fragrance or dyes. Address shaving irritation and friction from tight clothes rather than treating pigment while those triggers continue.
4. 4Stop any cosmetic product that burns or stings. If inflammation or itching continues after changing deodorant, see a doctor.
5. 5Once the cause is addressed, consider a pigment treatment. If your underarms will be exposed outdoors, apply tinted sunscreen containing iron oxide with SPF 30 or higher, broad spectrum protection and water resistance before going outside.

Should you scrub or use exfoliating acids?

Strong scrubs and aggressive chemical exfoliation can increase pigmentation, particularly in darker skin tones. Exfoliation is optional, not a required brightening step. If you choose it, the method and frequency should suit your skin; stronger exfoliation needs less frequent use. Never exfoliate open cuts or wounds, and apply moisturizer immediately afterwards. Retinol, prescription retinoids and benzoyl peroxide can make skin more sensitive or prone to peeling, so adding exfoliation can worsen dryness.6

Home remedies such as potato juice, egg yolk oil and armpit detoxes have uncertain benefits. Lemon contains an exfoliating acid, but repeated exfoliation can irritate skin; discuss home remedies with a doctor before trying them. Never apply liquid bleach to skin.13

Which treatments can help?

For irritation related pigment, azelaic acid, kojic acid, glycolic acid, retinoids and vitamin C are options used for dark spots generally. Underarm treatment should match the cause rather than treating that list as a shopping checklist. A doctor can consider creams containing niacinamide, retinol, kojic acid or hydroquinone. For acanthosis nigricans, ammonium lactate, tretinoin or hydroquinone can help improve appearance, but treating an underlying medical problem comes first. Chemical peels and dermabrasion are other clinical options; laser treatment is not common for dark underarms.134

How long does brightening take?

For postinflammatory pigment, a patch a few shades darker than your usual skin color generally takes 6 to 12 months to fade after the trigger stops. Deeper pigment can take years, although treatment can speed fading. Acanthosis nigricans should fade over time when its cause is treated, but the patches do not always disappear completely.235

When should you see a doctor?

Seek prompt assessment if thick, dark patches appear suddenly or spread rapidly. Rarely, rapidly developing, widespread acanthosis nigricans can be associated with cancer. Mention weight gain, a family history of diabetes, irregular periods or unusual hair growth at your appointment. Certain medicines can cause pigmentation or acanthosis nigricans, but do not stop prescribed medication yourself; ask the prescriber whether a change is appropriate.1345