Deodorants and Antiperspirants: Sweat Science, Aluminum Safety, and Smarter Ingredients

No one wants to smell, as in … stink, or have that dreaded B.O. So, it’s no surprise that deodorants are among the most common personal care products. Antiperspirants are also used, but they’re not technically the same.

Deodorants target odor and may help neutralize the bacteria responsible for the smell. They are classified by the FDA as cosmetics and aren’t regulated as strictly as antiperspirants.

Antiperspirants are classified by the FDA as over-the-counter (OTC) drugs because they affect the body’s function of producing sweat. For this purpose, the FDA allows specific aluminum compounds that clog sweat pores.

Sweat 101: Why Odor Happens (It’s Not the Sweat)

Sweating is the body’s natural cooling response: sweat evaporates and cools you in hot weather, when overdressed, or during exercise. Sweating can also happen with anxiety, which triggers the fight or flight response, preparing the body for action. Regardless of the trigger, sweat itself has no odor. That’s right—sweat doesn’t stink.

Our bodies are covered—inside and out—with many kinds of bacteria. Studies have shown that some skin bacteria interact with the immune system to help fight infection, and that’s a good thing. These good bacteria keep the bad bacteria at bay. What produces body odor are the compounds created by the interaction of our skin bacteria with our sweat.

Let’s look at the way deodorants and antiperspirants work to reduce odor.

Deodorants tackle odor in several ways. They can:

Neutralize odor-causing bacteria with ingredients like triclosan, propylene glycol, quaternary ammonium compounds, octoxyglycerin, 2-ethylhexylglycerin, and ethyl lauryl arginate hydroxychloride.
Mask odor with agents such as limonene, linalool, eugenol, geraniol, and hexylcinnamaldehyde, or with umbrella “fragrance” (a catch-all term for many chemicals).
Absorb moisture with modified starches—sodium bicarbonate (baking soda), cornstarch, or arrowroot. Other absorbers include zinc carbonate and talc.

⭐️ Curious about safer scent options? Check out our Healthiest Fragrance & Essential Oil Brands Guide for fully disclosed, safer fragrance picks.

Antiperspirants often use many of the same chemicals as deodorants to reduce smells, but they also do one more important thing: they reduce the amount of sweat produced in the first place, by clogging pores so sweat can’t reach the skin’s surface.

Aluminum compounds are used as the clogging agent. Common ones include aluminum chlorohydrate (ACH), aluminum sesquichlorohydrate (ASCH), aluminum zirconium tetrachlorohydrex gly, and aluminum chloride. If the label says “Antiperspirant,” there’s an aluminum compound in the product.

Aluminum and Safety: What Research Shows

Years ago, aluminum was vilified for being associated with Alzheimer’s and breast cancer. Years of research have shown no conclusive association, and organizations such as the National Cancer Institute state there are no known links to breast cancer. Even the Environmental Working Group (EWG) ranks these aluminum compounds 1–2 (green).

These compounds are large, and very little (estimated at less than 0.01%) is absorbed through the skin. By far our greatest exposure to aluminum comes from food and other ingested products like antacids. Aluminum is readily excreted, mostly through the kidneys. It should be noted that people with kidney disease or those on dialysis should avoid aluminum.

A Note on Potassium Alum (“Crystal” Sticks)

Aluminum compounds found in antiperspirants should not be confused with the naturally occurring salt crystal called potassium alum. While aluminum is part of this compound, the FDA does not include it among antiperspirant aluminum compounds and has classified it as generally recognized as safe (GRAS). This very large compound, used in deodorants, is not absorbed because of its size, acts as an astringent, and has antibacterial properties. Natural potassium alum crystals have been used for centuries in Asia and continue to be a popular personal care product.

Deodorants & Antiperspirants: Ingredients to Be Wary Of

Several ingredients widely used in deodorants and antiperspirants have health concerns:

Triclosan – A commonly used antibacterial; considered an endocrine disruptor and can promote antibacterial resistance.
Phthalates – A group of chemicals, some of which are known carcinogens and serious endocrine disruptors, typically used for fragrance.
Parabens – Preservatives used in personal care products. While many deodorants have stopped using them, they remain in some formulas. Several parabens are endocrine disruptors.
BHT (butylated hydroxytoluene) & BHA (butylated hydroxyanisole) – Preservatives/antioxidants with health concerns, including cancer.
Fragrance (parfum) – A combination of unknown chemicals that give a product its scent. Many of these chemicals are endocrine disruptors and carcinogens.
Talc – Hydrated magnesium silicate used to absorb moisture and reduce friction. Concern: asbestos contamination and association with cancers.
Hydrofluorocarbon 152a (HFC-152a) – A flammable gas used as a propellant. It is a greenhouse gas and harmful to the environment.

⭐️ Looking for safer scent alternatives? Download our free guide to the healthiest fragrance & essential oil brands vetted by our Green Living Expert.

Resources to Help You Shop Safer

There are thousands of possible ingredients in deodorants and antiperspirants, and memorizing them isn’t realistic. These tools can help you scan labels and spot concerns quickly:

EWG Skin Deep® database – Search products or ingredients and see hazard profiles; includes an Antiperspirant/Deodorant category and explains how ratings are calculated. Good for quick ingredient lookups and seeing if a product is EWG VERIFIED™.
MADE SAFE® – Certification program that screens ingredients against human-health and ecosystem criteria; browse the Personal Care catalog for pre-vetted products. Helpful if you prefer third-party certification over scores.
Detox Me by Silent Spring Institute (free mobile app) – Research-based tips for lowering everyday exposures, with practical checklists across home and personal care. Also available on iOS and Android.
Clearya (browser extension + mobile app) – Flags ingredients that appear on authoritative hazard lists while you shop online and suggests alternatives.. Great for real-time shopping.
Yuka (mobile app) – Scan barcodes and get a product score with an ingredient breakdown; offers alternatives when something rates poorly. Handy for in-store checks.
Think Dirty (mobile app) – Barcode scanner that surfaces ingredient info and “cleaner” options; known for simple, at-a-glance summaries.
INCI Beauty (mobile app) – Analyzes a product’s INCI (ingredient) list and explains each component; large international database. Good for cross-checking European labels.

Use these tools wisely: each platform has its own scoring method and focus. Treat scores as starting points, not final verdicts. Always read the full ingredient list, consider your sensitivities, and patch-test when trying something new.

⭐️ Healthiest Deodorants & Antiperspirants Brand Guide – ACLP’s free resource recommending trusted deodorant brands that meet high safety and transparency standards.

Everyday Habits to Reduce B.O.

Shower daily to reduce bacteria. Use regular soap or shower gel and a washcloth. Avoid antibacterial soaps (many use triclosan). Wash the entire armpit area (bigger than you think) and allow enough dwell time for the soap to encapsulate bacteria before rinsing.
Shower immediately after exercise or sweating to avoid the bacteria party.
Try mixing a small amount of water with either apple cider vinegar or lemon juice in a spray bottle. Spray on armpits (before shaving, not after). The acid will help to kill bacteria. Rinse off.
Shave or trim; hair increases temperature and creates a warm environment that bacteria love.
Try not to overdress. Wear loose-fitting, breathable fabrics like cotton, wool, or linen. Avoid synthetics.
Avoid spicy foods if they make you sweat.
Wash your clothes regularly. If clothing still smells after washing, soak in white vinegar for several hours to kill any leftover bacteria and neutralize smells.
Reduce stress overall, or anticipate stressful situations using meditation techniques.

The Bottom Line

Sweat itself doesn’t smell—odor comes from bacteria breaking it down. Deodorants help by neutralizing or masking odor, while antiperspirants reduce wetness with aluminum compounds that research shows are safe for most people, with minimal absorption.

Some ingredients (like triclosan, phthalates, parabens, BHA/BHT, talc, and undisclosed fragrance) raise health or environmental concerns, so it’s worth checking labels. Tools such as EWG Skin Deep, MADE SAFE, Detox Me, Clearya, Yuka, Think Dirty, and INCI Beauty can make that easier.

Smart picks and simple habits—showers, breathable fabrics, quick post-workout rinses, a bit of stress management—keep you fresh without the health trade-offs.