Like other parts of the body, the skin under the armpits can darken or whiten.

Causes of darker skin:

- chemical irritants in deodorants and antiperspirants
- irritation caused by shaving
- shrinkage of dead skin cells due to infrequent exfoliation
- friction caused by tight clothing
- hyperpigmentation, such as increased melanin
- melasma, or dark spots on skin
- acanthosis nigricans, a skin pigmentation disorder associated with diabetes, obesity and abnormal hormone levels
- other skin disorders that can cause darkening
- erythrasma, a bacterial skin infection
- Addison's disease, which can occur when you have a damaged adrenal gland
- smoking, which increases hyperpigmentation

Your first steps towards lighter colored armpits

1. Change deodorant or antiperspirant.
2. Stop shaving. Instead, try waxing or laser hair removal.
3. Exfoliation. Use a light scrub in the armpit area two to three times a week.
4. Wear loose clothing.
5. Try to quit smoking.

Some natural treatments

Potatoes: Grate a potato, squeeze the juice from the mashed potatoes and apply the juice to the armpits. After 10 minutes, rinse armpits with cold water.

Lemon: Cut thick lemon slices and rub into the armpits. After 10 minutes, rinse the armpits with fresh water, pat dry and apply a moisturizer.

Turmeric + lemon: In a small bowl, mix 2 tablespoons of fresh lemon juice with turmeric to make a paste. Apply the paste evenly on your armpits. After 30 minutes, wash the paste.

Coconut oil: Massage a few drops of coconut oil into the armpits. After 15 minutes, rinse with lukewarm water and a mild soap. Repeat these steps two to three times a week.

Source: Healthline