Wait, should I be using antiperspirant or deodorant?

Mass vs. weight. Soda vs. pop. Antiperspirant vs. deodorant. It’s all the same thing, right? Not quite. While we won’t get into the soda or pop debate, we can shed a little light on the antiperspirant vs. deodorant debacle. (Actually, real quick: Mass is a measurement of matter, weight is gravitational force.)

Back to your armpits. There is a difference between antiperspirant and deodorant, but if you’ve ever gotten lost in the drug store aisles, it may not be immediately clear. Simply put: one covers up body odour and the other stops sweating and body odour.

You may think the choice is obvious (better to kill more birds with one stone, right?) but there’s a little more nuance than that. Not all armpits are created equal. That’s why we asked dermatologists to break down the difference between antiperspirant and deodorant, the pros and cons of each, and which you should reach for when things get steamy.

• Jeannette Graf, MD, is a board-certified dermatologist and assistant clinical professor of dermatology at Mount Sinai School of Medicine in New York City.
• Anar Mikailov, MD, is a board-certified dermatologist and founder of Skintensive.
• Corey L. Hartman, MD, is a board-certified dermatologist and founder and medical director of Skin Wellness Dermatology in Birmingham, Alabama.
• Sheila Farhang, MD, is a board certified dermatologist and founder of Avant Dermatology in Tucson and Beverly Hills.

• What is antiperspirant?
• What are the benefits of using antiperspirant?
• Are there any risks to antiperspirants?
• What to look for in an antiperspirant
• What is deodorant?
• What are the benefits of deodorant?
• Are there any risks to deodorant?
• What to look for in a deodorant
• Key differences
• Should I get both deodorant and antiperspirant?

As the name suggests, antiperspirants block that sweat thanks to a trusty active ingredient called aluminum. (Yep, it’s the same stuff your kitchen foil and soda cans are made of.) "Aluminum helps block the ducts that cause sweat, which helps reduce wetness under the arms," says board-certified dermatologist Dr. Corey Hartman. "It can also help reduce bacteria found on the skin that leads to underarm odor."

Your armpits are home to eccrine glands, which activate and secrete sweat when you’re nervous (cortical sweating), eating spicy food (medullary sweating), or are overheated (hypothalamic sweating). Generally, sweating is your body’s way of regulating your temperature, so while it can be annoying, it's a necessary part of life.

Antiperspirant pulls double-duty on sweat glands, making it a popular choice if you’re prone to heavy sweating or live in a super hot climate. Essentially, it comes down to this.

• It blocks the amount of sweat produced. "The primary benefit of using antiperspirant is that you don’t have to worry about excess sweat that can be visible through clothing," says board-certified dermatologist Dr. Jeannette Graf.
• It reduces odour. Damp underarms are ripe for odour-causing bacteria. If your armpits are dry, you’re less likely to create a friendly environment for bacteria to thrive.

Antiperspirants have gotten a bad reputation in recent years, thanks to the health and wellness rumour mill. Some worry that excess exposure to aluminum compounds like aluminum chloride, aluminum chlorohydrate, and aluminum zirconium (all common ingredients in antiperspirants) is tied to an increased risk of Alzheimer’s disease. That particular fear came from a study done on rabbits, which scientists say are not a reliable model for humans. "There is no direct link between aluminum in antiperspirant and Alzheimer’s Disease," affirms Dr. Hartman.

"Another concern is an increased risk of breast cancer – that using a product with aluminum close to breast tissue would increase the risk of cancer," says Dr. Hartman. "There isn’t a direct scientific link on that concern either, so if you use a product with aluminum that works and you use it as directed, I wouldn’t be concerned. I consider aluminum safe and not toxic."

However, antiperspirants do have a few proven (but far less serious) downsides. While serious correlations like cancer and Alzheimer’s have no scientific backing, aluminum might decrease the amount of bacteria on your armpits which, yes, cause odor, but also protect us from pathogens. Without them, you’re more likely to get psoriasis, rosacea, and acne.

"Burning and irritant contact dermatitis are also common side effects, particularly in women who shave," says board-certified dermatologist Dr. Anar Mikailov. "Additionally, aluminum can cause a yellow discolouration on fabric, so some people avoid it for that reason."

"In general, I recommend avoiding antiperspirants that contain common skin irritants like perfume, synthetic fragrance, and propylene glycol," says Dr. Mikailov, specifically if you have sensitive skin. Your next decision will be the format. Antiperspirant comes in sprays, gels, lotions, powders, and roll-on liquids. Sprays are great if you have a hard time reaching your armpits for any reason while gels leave less of a white cast on dark clothing. It really all comes down to personal preference and lifestyle.

Most antiperspirants can be found over the counter, including those marketed as "clinical strength." But conditions like hyperhidrosis (excessive sweating) might require a prescription antiperspirant with a higher concentration of aluminum to stop the heavy perspiration, says Dr. Mikailov.

"This is my choice for anyone who has sensitive skin, but still experiences sweating under the arms and wants to minimise that," says Dr. Hartman. “I recommend it to patients with skin conditions like eczema and contact dermatitis.”

If you need a little extra sweat protection, Dr. Mikailov recommends the clinical-strength Certain Dri Everyday Strength Clinical Antiperspirant. "It’s meant to be applied at night, which is actually an ideal time to apply antiperspirant," he says. "A nighttime application gives the aluminum salts enough time to plug up the sweat glands and reduce sweating in the daytime."

Most antiperspirants are deodorants, but all deodorants are not antiperspirants. Instead, deodorant refers to an aluminum-free product that doesn’t block sweat ducts, and targets smell instead.

"Some people just don't sweat very much," says board-certified dermatologist Dr. Sheila Farhang, so they may opt for deodorant only. She explains that many deodorants are formulated with alcohol, "which helps decrease body odour by targeting bacteria."

You may also find deodorants formulated with "magnesium hydroxide and essential oils such as sage, eucalyptus, and tea tree oil," to mask odour, says Dr. Mikailov. “Some deodorants incorporate baking soda, which can create an alkaline microbiome,” which means it would create a PH environment too high for odour-causing bacteria to thrive in.

Aluminum is the only FDA-approved antiperspirant, but if sweating isn’t top of mind for you, deodorant offers a few benefits of its own.

• It controls body odour. By neutralising bacteria with ingredients like alcohol or baking soda, deodorant can help curb dreaded B.O.
• It can help reduce friction. Some deodorants are formulated with nourishing skincare ingredients like coconut oil, shea butter, and aloe, which can help reduce underarm friction.

The main risks with deodorants are tied to irritating ingredients. "The biggest problem I've seen with deodorants is an allergic contact dermatitis due to an ingredient," says Dr. Farhang. Essential oils and perfume are common culprits, so those may be ingredients you’ll want to avoid.

Alcohol can also be harsh on skin. "Deodorants are often alcohol-based," adds Dr. Graf, so if you have extra sensitive skin that is prone to irritation or dryness, you may want to skim the ingredients and find something alcohol-free.

"Deodorants can contain potentially sensitising ingredients like baking soda and synthetic fragrances," says Dr. Mikailov. "Instead, consider deodorants formulated with natural antimicrobial ingredients like coconut oil. If you are looking to reduce underarm wetness as well without blocking the sweat glands, look for ingredients such as clay, rice powder, corn starch, and arrowroot powder, which absorb moisture."

"Ultimately, you’re looking for a deodorant that works well with your skin and that you enjoy the scent of and the way it works," adds Dr. Graf.

"This is an accessible and effective deodorant that is great for sensitive skin," says Dr. Graf about the Dove 0% Aluminum Sensitive Skin Deodorant. The formula is alcohol-free and “includes moisturizers to keep underarms soft and smooth, as well.”

Dr. Hartman recommends the Megababe Rosy Pits Daily Deodorant, which also features antifungal coconut oil, colloidal oatmeal to hydrate and soothe sensitive pits, and cornstarch to absorb some underarm wetness.

Generally speaking, one is not better (or safer) than the other. It totally depends on what issues you’re trying to address and what your skin will tolerate. "It really depends on personal preference," says Dr. Graf.

If you’re trying to stay dry and control sweat, you’ll need an antiperspirant with aluminum salts to target your sweat glands. If odour is your only concern, deodorant will offer odour protection. Deodorant is also more likely to meet retailers’ clean beauty standards, so it may be the best pick if that’s a priority for you.

We won’t stop you, but it’s probably not necessary to buy both. "Most antiperspirants are deodorants as well, so you don't need to double up," says Dr. Farhang.

This article originally appeared on Allure.