Treatment for dark underarms

Why are your underarms darker?

Shaving, plucking, friction and deodorants can cause inflammation that leaves extra pigment behind. This is called post inflammatory hyperpigmentation. Underarm skin has a weaker barrier than skin in some other areas, so aggressive lightening treatments can create more irritation instead of solving the problem. Genetics can also contribute to darker underarms.13

Dark, thick, dry patches with a velvety feel can be acanthosis nigricans, a condition that commonly affects the underarms, neck and groin. Skin tags sometimes appear on the patches. The changes often develop gradually, and itching is possible. Acanthosis nigricans can be associated with obesity, diabetes, hormonal conditions or certain medicines, but healthy people can have it too. Dark underarms alone do not diagnose diabetes.24

A doctor can often recognise acanthosis nigricans by examining the skin. Your medical history, family history and medicines help determine whether further tests are needed. Pigmentation following a rash or shaving irritation points toward a different cause; infections and other skin conditions also need their own treatment rather than a lightening cream.234

What should you do first?

1. 1Arrange an assessment for new dark patches or skin changes you cannot explain, especially thickening.
2. 2Reduce the number of products you apply to your underarms. If deodorant causes a rash or irritation, change it.
3. 3Look for products intended for sensitive skin, without fragrance or dyes. A 'natural' label does not make a product less irritating.
4. 4Review whether shaving or tight clothing is irritating the area, and reduce those triggers before adding a lightening treatment.
5. 5If pigmentation persists, discuss a targeted cream or procedure with a doctor rather than adding several treatments at once.

Reducing the number of products you apply is a useful first step, even if the beauty aisle would prefer a longer shopping list.1

Which creams can help?

Expect gradual improvement, not an immediate colour change. In the nine week trial, a good to excellent response occurred in 24% of niacinamide cases and 30% of desonide cases. There is no single standard treatment for underarm pigmentation. The nightly schedule describes that trial, not a universal instruction for every cream; follow the directions for the treatment you choose.3

What if the skin is thick and velvety?

For acanthosis nigricans, treating the underlying cause comes first. Depending on the cause, a doctor can recommend weight management, treatment for insulin or hormone problems, or changing a medicine that contributes to the patches. The patches should fade over time once the cause is treated; there is no fixed timetable.2

A dermatologist can also consider treatments for the appearance and thickness of the skin. Options include acids that loosen the outer skin layer, such as salicylic or glycolic acid, and topical retinoids such as adapalene or tretinoin. These are options for diagnosed acanthosis nigricans, not a reason to apply a facial acid routine to unexplained underarm patches.4

Vigorous scrubbing does not remove acanthosis nigricans. The darkening is a skin change, not something sitting on the surface that needs washing off. A dermatologist can distinguish patches linked to a health problem or medicine from patches with no medical connection.5

Should you try home remedies?

Potato juice, egg yolk oil and armpit detoxes are not established solutions for dark underarms, despite the internet's determination to turn groceries into skincare. Lemon contains an exfoliating acid, but frequent exfoliation can irritate the area. Discuss home acid treatments with a doctor before trying them, rather than assuming kitchen ingredients are automatically gentle.1

Can laser treatment help dark underarms?

Yes. Q switched Nd:YAG laser improved underarm pigmentation in several small studies. Intense pulsed light, or IPL, also improved pigmentation; IPL is a light treatment rather than a laser. Reported adverse effects were generally limited, although pain was reported more often with laser. Laser is not a common first treatment for dark underarms, so discuss whether it fits the cause of your pigmentation.13

When should you see a doctor?

Get persistent inflammation or itching checked, especially if changing deodorant has not helped. Mention irregular periods, unusual hair growth, weight gain or a family history of diabetes. Sudden onset of thick, dark patches also needs assessment. Rarely, abruptly developing acanthosis nigricans can signal a serious underlying illness, particularly without the usual risk factors.14