What's the Difference Between a Deodorant and an Antiperspirant?

If you are like most people, you probably use an antiperspirant or a deodorant every day.

It’s something you were probably encouraged to get into the habit of using as a teenager. This is because of something we all have in common: sweating.

Sweating is just about as natural and normal as breathing. There are millions of sweat glands located throughout the human body. But sweating is something we often want to hide or minimize.

Why?

Well, sweating is usually associated with body odor. And most people don’t want the people around them to be put off by the way they smell. Thus, we opt to combat the sweat and body odor with antiperspirants and deodorants.

But have you ever paid attention to the difference between these two products? You may have been under the impression that deodorants and antiperspirants are the same things, but they’re not.

So what is the difference?

Deodorant

Most of us have a product sitting at home—on top of the dresser, in the medicine cabinet, in our gym bags—that we refer to as deodorant.

It could look or smell any number of different ways, but we all reach for this product with one purpose in mind: to keep body odor from embarrassing us and ruining our day.

You probably have a pretty good idea of what deodorant is, but before we can get to the differences between antiperspirants and deodorants, we need a clear definition of what a deodorant is. So let’s get a little technical and give it a proper definition, shall we?

A deodorant is a personal care product that you apply topically. Usually, it is used just on the underarms, and it is designed with this part of the body in mind. It may come as a solid stick that you roll up and wipe across the skin of your armpit. It can also come in a liquid form and may be housed in a bottle with a roller ball on top, to help you dispense the right amount of product. Aerosols are another common type of deodorant formulation and are easily sprayed into the armpit. There may be other types of deodorant formulations on the market, but these are the types most commonly found in your local drugstore or grocery store.

Woman applying deodorant on underarm

But no matter the form—solid, liquid, or aerosol— the goal of the product is to prevent the odor that often occurs with underarm sweat. Although many of us probably think of our daily swipe of deodorant as a necessity, the US Food and Drug Administration (FDA) classifies deodorant as a cosmetic. Deodorants contain ingredients intended to mask or combat odors but provide no health benefits.

Antiperspirant

On the other hand, you have probably noticed that your deodorant of choice may also be labeled an antiperspirant. You may even call you deodorant an antiperspirant, or vice-versa. While we may think of these two terms as interchangeable synonyms, they are actually very distinct products.

Unlike deodorants, antiperspirants function to actually prevent you from sweating at all. Instead of just masking the smell of sweat, you will have no smell because there will be no perspiration if an antiperspirant does its job.

This is especially desirable for preventing the visible signs of sweating, such as pit stains on your shirt or blouse.

An antiperspirant is also different from a deodorant due to the way it is classified. Because of its function to prevent perspiration, it is not considered merely a cosmetic in the way that deodorants are. The FDA actually considers antiperspirants a drug available over-the-counter. This is due to the fact that antiperspirants interfere with a natural body function (sweating). An antiperspirant may come in the same forms as a deodorant—liquid, solid, and aerosol—but will contain certain active ingredients such as aluminum derived compounds.

So how exactly do the ingredients used in antiperspirants stop you from sweating in the first place?

Before we can answer that, we will need to understand how and why you sweat, particularly in the area that most antiperspirants and deodorants are designed to target: underarms.

Underarms

The underarms are a part of the human body that we don’t usually give much thought to unless we are sweating a lot. Then we definitely become hyper-aware of what’s going on in this unique part of our anatomy.

Although we usually call them armpits or simply underarms, this hollow space underneath the shoulder joint is technically called the axilla.

While it seems like a pretty unimportant body part, the armpit actually has a lot going on beneath the surface. The blood vessels of your arms run through it, and there are also over 20 lymph nodes in the armpit.

What exactly are lymph nodes, you ask?

Lymph nodes are an important part of the lymphatic system, a network of tissues in the form of little lumps under the surface of the skin. You can’t see them and you usually can’t feel them, either. As part of the lymphatic system, they help prevent infection.

In addition to these lymph nodes and blood vessels, there are also sweat glands and hair follicles. The sweat glands are usually what armpits are known for, and rightfully so. There are a lot of sweat glands to be found under your arms, and this, of course, is the reason that antiperspirants and deodorants are used there.

Now let’s take a closer look at the sweat glands.

Sweat Glands

Sweat glands are another important part of the body that don’t get much credit for what they do. While we sometimes find sweating to be a nuisance or even embarrassing, sweating provides an important function for our health. Sweat glands are triggered to produce sweat in order to keep us from overheating.

There are actually two types of sweat glands found throughout the human body. There are eccrine glands and apocrine glands. While both are responsible for producing sweat in order to cool the body down, these two types of sweat glands have some major differences.

Eccrine Glands

The first type of sweat gland to know about is the eccrine glands. This type of sweat gland makes up the vast majority of sweat glands in the human body. You have eccrine sweat glands everywhere, but they are very concentrated on the face, bottoms of the feet, palms of the hands, and armpits.

It’s probably safe to say that most of the sweat you see and feel when you get hot is produced by the eccrine glands. The sweat that comes from eccrine glands is clear and fluid and actually has no smell. The goal of the eccrine glands is to get this liquid quickly to the surface of the skin. Once the liquid is there, it can evaporate into the air. This action of liquid evaporating from the surface of the skin helps to promote heat loss and produces a cooling effect.

Apocrine Glands

On the other hand, there are the apocrine glands. These sweat glands differ from the eccrine glands in that they are not located as numerously in the body. In fact, they are limited to just certain areas like the armpits and the area around the genital region. The areas where apocrine glands develop are areas where there are a lot of hair follicles. This is because the apocrine glands release sweat into the hair follicle, whereas the eccrine glands secrete directly to the surface of the skin.

Infographic on sweat glands

And unlike the eccrine glands, the fluid that apocrine glands produce is thicker. This fluid also contains proteins and fats, whereas eccrine excretions are just water and salt. When this apocrine sweat is secreted, it eventually interacts with bacteria located on top of the skin. The bacteria on the skin actually feed on the fats and proteins contained in apocrine sweat. It is this contact between the skin bacteria and apocrine fluid that creates the unpleasant smell that we know as body odor.

As mentioned above, there are quite a few apocrine glands located in your underarms. It is the main reason that we consider armpits to be stinky and worry about using deodorant or antiperspirant in this particular area. In fact, the body odor that often develops in underarms even has its own name: axillary body odor.

What Sweat Is (and What It Isn’t)

There are a lot of myths and false information about sweat and why we sweat. The reality is that all sweat, whether produced from the eccrine or apocrine glands, is the result of nerve activity.

When our body’s nerves receive certain stimuli, they trigger the eccrine and apocrine glands to produce sweat. Some common situations that cause the nerves to initiate sweat include indications in the brain that the body is getting too hot, the activity of emotions and hormones in the body, and of course physical activity such as exercise.

Sweating may be an unwanted reaction to certain situations or circumstances, but sweating is actually perfectly normal in most cases. It is simply the body’s way of regulating temperature and responding to stimuli.

Some people are interested in forcing themselves to sweat in order to release toxins or produce some kind of cleansing or detox of the body. But this is based on a misunderstanding of what sweat is.

Sweat—whether the odorless variety produced by the eccrine glands or the odorous kind of the apocrine glands—is actually made up of mostly water. In fact, sweat is about 99 percent water. The other one percent is just a tiny amount of carbohydrates, protein, salt, and urea. There are no “toxins” in sweat, and therefore you absolutely cannot detox by sweating.

How Deodorants Work

You may be tempted to think that because deodorants don’t actually stop you from sweating and are labeled a cosmetic product, that they are nothing more than perfumes or fragranced balms meant to cover up any bad smells. But this not really true.

While many deodorants have fragrances added to enhance your scent, they actually function to reduce body odor itself.  Deodorants can reduce body odor by killing or preventing the growth of bacteria on the skin. As you may recall, body odor is caused by the interaction of bacteria that lives on the skin with the protein and fat contained in sweat produced by the apocrine glands.

Usually, deodorants are formulated with ingredients such as alcohol, sodium chloride, and other acidic compounds. They work by making the area they are applied to salty or acidic, in order to make the skin uninviting to bacteria. Some deodorants may even contain powerful antimicrobial ingredients such as triclosan. These ingredients can successfully keep bacteria away so that when you perspire there is nothing to cause a foul odor.

How Antiperspirants Work

We mentioned that antiperspirants contain an active ingredient that when applied can stop the  sweat glands in that area from producing sweat. One of the more common ingredients used in antiperspirants is aluminum salts or other aluminum compounds.

When the aluminum salts in an antiperspirant are applied on the armpit, they dissolve into the skin and form a gel. This gel essentially acts as a plug at the opening of the sweat gland. With the sweat glands blocked by the plug, sweat cannot reach the skin’s surface. This, of course, is a temporary blockage, and this plug is removed when you shower and wash away the antiperspirant.

Keep in mind that, although antiperspirants are not designed to combat odor like deodorants are, they are still effective at keeping you smelling fresh. This is because they stop sweat from reaching the skin’s surface, which is where it interacts with bacteria that creates the unwanted smell. Without sweat for the bacteria to feed on, no smell is produced.

Which Should You Use?

Choosing between two deodorants

So now that you know the difference between an antiperspirant and a deodorant, you may be left wondering, “Which one should I be using?”

That’s a good question and one that depends entirely on your body and your particular preferences.

If you tend to produce a lot of sweat—enough to regularly be visible on your clothing—you will probably want the benefits of sweat-reducing antiperspirants.

If body odor is all you’re worried about, then you will probably be fine with just a deodorant.

The truth is, that a lot of people would probably prefer a combination of antiperspirant and deodorant. And luckily, a lot of products you find are formulated to include both. Just look for “antiperspirant and deodorant” on the label.