How Often Can You Reapply Deodorant? Derms Weigh In On The Sweaty Situation

'Tis the season of stepping outside and immediately feeling drenched in sweat. It's hot out there, y'all, and if the rising humidity has you reapplying your deodorant (again, and again, and...), you're definitely not alone. Even if the deo doesn't exactly stop the sweat (non-antiperspirants won't, FYI), your damp pits can at least smell nice, no?

Short answer? The exact timing doesn’t really matter. It may be best to apply your deodorant before you notice a funky smell (i.e., first thing in the morning or after rinsing), so the product can control the odor before it arises. But the timing itself doesn’t necessarily make a difference.  

Now, many people believe you should apply deodorant at night when you’re less sweaty, so the formula can penetrate the pores better. This is true for antiperspirants—the sweat glands are less active at night, so the formula can better seep into your skin and stop odor-causing sweat. 

But deodorants don’t necessarily stop you from sweating; their main gig is to neutralize odor (hence the term, deodorant), so it doesn’t matter what time of day you apply. Feel free to swipe on whenever you’d like, just make sure your pits aren’t wet while you apply. Many deodorants also do their best work on clean, dry skin—particularly if the formula works by limiting bacterial growth in the area. 

You can apply as often as you like—assuming the formula doesn't irritate your skin. 

To be clear: You can face irritation from both traditional and natural deodorant options; although, traditional sticks may include more alcohols and formaldehyde-releasing preservatives, which are common irritants. "While any ingredient can irritate the skin, the fewer ingredients someone is exposed to, the less risk there is of an allergic reaction," board-certified dermatologist Lisa Airan, M.D., once told mbg. "Traditional deodorants contain more ingredients, which puts the patient at increased risk for skin irritation." 

Even if you discover a natural deodorant you adore, though, a couple of ingredients can still aggravate sensitive armpits: First, "Many natural deodorants rely on baking soda to absorb moisture and neutralize odor, but too much baking soda can cause skin irritation in some people," notes board-certified dermatologist Hadley King, M.D., (baking soda has a basic pH, while your armpits are more acidic; combining them together can cause a reaction). 

Acid-based formulas (like glycolic-acid-based solutions) are common culprits as well: These effectively lower your skin's pH and make it too acidic for odor-causing bacteria to thrive1, but some people may find AHAs way too harsh for their liking, especially when relying on multiple swipes throughout the day. 

As a general rule, apply your deodorant to clean, dry skin—which we admit is a touch more difficult when you're sweating up a storm, but it's worth taking the time to pat your pits dry before reapplying. Especially if you use an antiperspirant: "Otherwise sweat will dilute the antiperspirant, and it will fail due to insufficient concentration," says King.