How to lighten dark underarms

What is causing the darkening?

Shaving irritation, tight clothing and reactions to deodorant can leave dark marks. This is called postinflammatory hyperpigmentation: extra pigment left after skin inflammation or injury. It can affect anyone, but tends to be darker and last longer in darker skin tones. Treating the irritation matters because another lightening product cannot fix an ongoing trigger.134

Thick, dry, velvety patches can be acanthosis nigricans, a skin change that often affects the armpits, neck or groin. It can be linked to diabetes, hormone conditions or certain medicines, and can also occur in otherwise healthy people. Washing will not remove it. A doctor can usually recognise the pattern by examining your skin and arrange tests if needed.256

What should you do first?

1. 1Reduce the products you apply to the area, because underarms do not need their own cosmetics department.
2. 2Replace irritating products with gentler options labelled for sensitive skin or fragrance free. If deodorant causes a rash, changing it is a reasonable first step.
3. 3Reduce friction from tight clothes and avoid repeatedly injuring the area through shaving. Pigment left after injury can fade when the skin is no longer being injured.
4. 4Stop using a product if it burns or stings. If inflammation or itching continues after changing deodorant, see a doctor.
5. 5Protect exposed underarms from sunlight before going outside. General dark spot guidance favours tinted sunscreen containing iron oxide, with SPF 30 or higher, broad spectrum protection and water resistance; apply it to skin clothing will not cover.

Which treatments can help?

After the cause is addressed, a dermatologist can choose a cream to improve the colour or thickness. Options for dark underarms include niacinamide, retinol, kojic acid and hydroquinone. For acanthosis nigricans, ammonium lactate, tretinoin or hydroquinone can help improve appearance, but treating an underlying medical problem takes priority. Do not stop prescribed medicine yourself if you suspect it is contributing; ask the prescriber about alternatives.146

Chemical peels and laser treatments can help some surface pigmentation, but injury from these procedures can also worsen postinflammatory pigmentation. They do not treat pigment lying deeper in the skin. Discuss procedures with a dermatologist rather than treating them as the automatic next step.3

How can you lighten dark underarms naturally?

Reducing irritation and friction gives marks a chance to fade without adding a lightening treatment. An armpit detox is not an established lightening treatment, despite the impressive job title. Potato juice and egg yolk oil are also unproven options. Lemon's citric acid exfoliates, but excessive exfoliation can irritate skin; discuss home remedies with a doctor before trying them. Never apply liquid bleach to skin.14

How quickly can you lighten dark underarms?

For pigmentation left by irritation, general fading times are 6 to 12 months for marks a few shades darker than your usual skin colour, once the trigger stops. Deeper pigment can take years. Treatment can speed fading. Acanthosis nigricans should fade over time when its cause is treated, although the patches do not always disappear completely.245

When should you see a doctor?

Arrange an appointment for new dark patches or skin changes you cannot explain. Seek prompt assessment if thick, velvety darkening develops suddenly or spreads widely. Mention weight changes, a family history of diabetes, irregular periods or unusual hair growth. These details help a doctor decide whether blood sugar testing or investigation of a hormone condition is needed.126