Why do underarms get dark?
Underarms can get darker than the surrounding skin for various reasons. Some of these factors are tied to lifestyle while others may be tied to your genetics. There’s no one answer for everyone and there may even be multiple reasons causing your dark underarms. It's important to talk with a healthcare professional if you are concerned your dark underarms are due to an underlying medical condition. We can’t replace a visit to your healthcare provider and the below information is not meant to treat or diagnose a disease or condition.
Hormones can cause changes in the production of melanin in your skin. Melanin is responsible for giving your skin its pigment so if you have more melanin than you are more likely to experience hyperpigmentation. If you are pregnant, you may experience hormonal shifts which can trigger excess melanin production. This is common on your inner thighs, areolas, underarms, and even your face-- known as “pregnancy mask.” Coloration may go back to normal after you’ve given birth.
It's especially important to consider the skincare products you are using while pregnant or breastfeeding as some ingredients may not be recommended as safe to use. Please consult your doctor about the skincare products you are using. Taking birth control also affects your hormone levels which can cause the overproduction of melanin in your skin in similar areas as when you are pregnant.
Friction from shaving or waxing
Shaving without the proper lubrication may increase friction against your skin and the blade. A dull blade can also cause friction and pull hair. And while waxing is an alternative, it too can cause inflammation of the hair follicle. This is called post inflammatory hyperpigmentation or PIH for short.
Natural deodorants containing baking soda
A lot of natural deodorants include sodium bicarbonate also known as baking soda. But with a pH of about 9, it is highly alkaline which does not always agree with your body’s skin pH of around 4-5.5. By applying a deodorant with baking soda in it, your skin may react to the change in pH by getting irritated and therefore becoming darker.
If you are using many products, including DIY, on your underarms for your darkness, consider taking a break and giving your underarms time to heal and breathe. Keep this in mind while you are determining your underlying cause and be patient and gentle with your skin.