17 Totally Not Dumb Questions You’ve Been Too Embarrassed to Ask About Underarms

Updated: Mar. 25, 2021

Got a burning question about your armpits? We've left no stone unturned in our quest to answer all your armpit queries.

armpit embarrassedLana Veshta/Shutterstock
Why do armpits have hair?

The bottom line about armpit hair is that no-one knows for sure why it’s there. Perhaps it’s an evolutionary relic, left over from when all humans had significantly body hair to protect them against the harsh elements when clothing was limited to animal skins? Some scientists believe that it may be there to help wick sweat away from the skin, helping to limit underarm dampness and reduce the bacteria that thrive in those conditions. Having it permanently removed might be a bad idea if you’re worried about body odor, however.

Armpit hair does share genetic code with the hair in other areas of the body. It’s often the same color, so if you’re a natural blonde you’ll probably have blonde hair in your pits. But scientists are also unclear why it’s shorter and coarser than other hair, except that long flowing locks would be totally impractical!

What are the ingredients of sweat?

Because armpits are folds in the body, they’re warmer than most of the rest of your skin. This (plus the fact that there’s hair there), means that we sweat more under our arms, and it hangs around longer because it can’t evaporate easily.

All sweat contains sodium (salt), chloride and potassium, but underarm sweat differs from sweat elsewhere on the body. The apocrine sweat glands (found in folds of the body), create thicker sweat, which also contains urea, ammonia and fatty acids.

Why do our armpits smell?

It’s not the sweat that causes B.O.: It’s the bacteria which live happily in all that warmth and dampness. Scientists from the University of York UK, discovered that the Staphylococcus hominis bacteria were mainly responsible for producing a bad odor.

“Those odorless molecules come out from the underarm, they interact with the active microbiota, and they’re broken down inside the bacteria,” research scientist Daniel Bawdon explained to The Independent. The bacteria excrete an organosulphur compound—thioalcholols—which smell like sulphur, onions, or meat when concentrated. That’s what causes the odor.

Other factors, such as spicy food and some medications, can make the underarm problem of body odor worse.

Why does the smell of sweat vary between people?

There are several factors which can influence the exact smell of our sweat, which accounts for why one person’s sweat differs from someone else’s. The odor can vary because of gender, diet, and even medications. Factors such as obesity can also affect the make-up of the odor.

Some medical conditions produce a distinct smell. For example, diabetes can create a sweeter smell, because of ketones in the body, while liver and kidney problems may cause sweat to smell like bleach.

Where does the bacteria come from?

Billions of bacteria thrive on our skin, but under our arms bacteria multiply more rapidly because of the warm, damp conditions. Good hygiene, including regular baths or showers to wash bacteria away, will help limit the interaction between bacteria and sweat and help us stay sweet-smelling.

Using deodorants and antiperspirants can also help. A study by North Carolina State University found that regular use can even affect the amount of bacteria we produce.

Julie Horvath, PhD, head of the genomics and microbiology research laboratory at the NC Museum of Natural Sciences told Science Daily about this discovery. “Using antiperspirant and deodorant completely rearranges the microbial ecosystem of your skin—what’s living on us, and in what amounts,” she said.

What’s the difference between deodorant and antiperspirant?

Deodorants work by neutralizing the odor that’s produced from the sweat and bacteria, but doesn’t stop us producing that sweat in the first place. Antiperspirants actually stop the body creating sweat by blocking the pores under the arms. Check out these common deodorant mistakes.

But these products contain harsh chemicals, such as parabens which are potentially linked to breast cancer, aluminum compounds which also have health risks, silica (a skin irritant), and triclosan, which kills both good and bad bacteria and is listed as a possible carcinogen.

Are there natural alternatives to deodorants and antiperspirants?

Many household products can be used as a natural and kinder alternative to deodorants and antiperspirants. Try combining baking soda and cornstarch—add your favorite essential oil for added fragrance. Baby powder is also a popular alternative, or consider using lemon juice for a fresher option.

Why do some people sweat copiously, and what can be done about it?

Around 3 percent of people suffer from hyperhidrosis—excess sweating that is so severe it can affect their quality of life. Heavy underarm sweating is usually caused by primary focal hyperhidrosis, a form that produces copious amounts of sweat in one or more specific areas.

Treatments for this underarm problem include special prescription antiperspirants, Botox to prevent sweat glands from over-production, and laser treatment. Medication can some times help, but in severe cases, surgery to remove sweat glands can be undertaken. As a last resort, spinal surgery to cut the nerves to the sweat glands is sometimes done, but it carries significant side effects so isn’t usually recommended unless all other options have failed.

Why do armpits often itch?

The folded skin under the arms is loaded with blood vessels, lymph glands and sweat glands, all of which can suffer from infections. The moist, warm conditions also make an ideal breeding ground for bacteria and fungal infections, causing itchy armpits and sometimes an armpit rash.

What are the most common armpit rashes?

An armpit rash can be caused by a wide range of factors—hot weather being primary among them. Good hygiene can help—prevent rashes during steamy summer months by showering daily. Existing skin conditions such as psoriasis and eczema can be especially problematic in the armpit. Allergic reactions are also a common cause of rashes, often to products such as laundry detergent, cosmetics or deodorants.

Why do we sometimes get armpit pain?

Armpit pain can be caused by a number of things, though a couple of common ones are an infected skin rash or inflammation in the pores or glands under the skin. Lymph glands will often swell when we have an infection elsewhere in the body, such as the flu, which can cause painful armpits.

Sometimes pain under the arms has a physical cause, perhaps because we’ve strained a muscle at the gym or overdone our yard chores.

Why do we get lumps in our armpits?

Lumps in the armpits can be caused by an infection in the hair follicles or in the sweat glands. These lumps are often relatively small, and it’s common to have a series of visible lumps as the infection spreads. Sometimes a shaving rash can lead to an underarm infection; some people find using an antiseptic ointment after shaving can cut down on armpit infections.

Underarm cysts don’t always show up in the armpit, but they can be felt as small lumps. Cysts aren’t usually painful, but if you’re unsure, see your doctor in case it’s something more serious.

Swollen lymph glands are generally larger, and not so easily visible. Although painful, they usually settle down once the underlying infection has been treated. But if the problem persists, or occurs frequently, you should always consult a doctor, as breast cancer can also affect the lymph glands. Swollen lymph nodes can also be one of the symptoms of chronic fatigue syndrome.

What’s the best way to manage ingrown hair in the armpit area?

Occasionally the hair follicles can become blocked, perhaps through shaving or a build-up of secretions from our skin. This can prevent the hair from growing outwards normally, so it curls back and continues to grow under the skin.

This can lead to a painful spot or abscess, which can become infected. In some cases, multiple follicles are affected, causing a painful rash.

Serious cases of ingrown hairs should be treated professionally, but it is possible to tackle ingrown hairs yourself.

Why do we get skin tags by the armpits and what’s the best way to treat them?

Skin tags are benign tumors which often grow in the folds of our skin which are vulnerable to rubbing from surrounding skin or clothing. A skin tag is basically made from collagen and blood vessels enfolded in skin. Genetics sometimes plays a part, with skin tags often running in families.

Skin tags can be removed by cauterizing, freezing, ligation (using a ligature to cut off the blood supply), or surgical removal with a scalpel. However, with care, it’s possible to remove some skin tags at home.

Armpit fat—is it a thing?

If you’ve spotted a little extra bulk between your armpit and your chest area, that’s armpit fat. This is the latest body area to attract weight loss attention, but it’s important to remember that some additional tissue in this area is completely normal, due to the underlying pectoral muscles.

As with most other target areas, spot-fixing armpit fat through exercise is not straight forward and is best done as part of an overall strength and fitness routine. Armpit liposuction is an option, but it’s not without risk. Side effects can include bruising, fluid loss, soreness, numbness and skin irritation in the short term, with horrors such as changes to your skin’s color and texture, and nerve damage as potential longer term consequences.

Should I try armpit lightening?

As with all other body areas, there’s an immense variety in the color of the underarm area, but some people are bothered by the fact that their armpits appear dark. This can be caused by shaving rather than using other exfoliation methods like waxing or electrolysis, as the underlying hair or stubble makes skin seem darker. It can also be due to natural skin pigmentation.

It is possible to use cosmetics to lighten the skin in the armpit. Bleaching products can be effective, but be sure to buy from a reputable source, as unregulated products can contain dangerous chemicals such as mercury which are toxic. Lightening creams can also cause permanent skin damage if overused.

Exfoliating or waxing rather than shaving is also an option, or perhaps try more natural solutions like lemon juice, potato or cucumber.

Can armpit odor be a positive thing?

Sweat contains pheromones which are an important aspect of human attraction. The natural sweaty smell can be a powerful aphrodisiac: Napoleon reputedly wrote to his lover Josephine while he was traveling home, instructing her not to wash until he returned three days later!

More recently, one speed dating trend included potential partners sniffing each other’s armpits to determine attraction. Eww!