Finding the right deodorant can be a tricky task: Aluminum or no aluminum? Gel or cream? Normal or clinical strength? Just when we think we’ve nailed the perfect formula for our picky underarms, a heatwave comes along to disprove everything. Is your deodorant not working for you anymore? Here are 12 common reasons why it probably isn’t doing the job it should.

You Might Not Be Using the Right Formula

New York plastic surgeon Melissa A. Doft, MD says deodorant usually falls into two categories: deodorants and antiperspirants. Mary Further, founder of Kaia Naturals, a brand specializing in all-natural deodorants, says this difference is critical to understand: “Deodorants work to keep you from smelling, while the role of antiperspirants is to stop you from sweating.”

As for which works “better,” Dr. Doft states that antiperspirants are usually recommended for those who sweat more, while deodorants are more helpful in neutralizing underarm bacteria and odor.

Dove dermatologist Dr. Alicia Barba adds, “If you’re looking for both odor and wetness protection, I recommend an antiperspirant with aluminum salts [her favorite is a tie between Dove Dry Spray ($6) or Dove Advanced Care ($5)] that help control the flow of seat under the arms, along with deodorant to mask the smell,” she says. “If you’re looking for odor protection, Dove 0% Aluminum Deodorant ($6) is for you.”

You Might Have Hyperhidrosis

Sweating is a normal part of life. But if you find yourself perspiring more than others, and your deodorant doesn’t seem to be working, you may have a genetic condition called hyperhidrosis. Some warning signs include an excessive amount of sweat, which can affect the hands, feet and armpits. “For hyperhidrosis, deodorant alone is not going to help,” explains Nanuet, NY dermatologist Heidi Waldorf, MD, who usually recommends patients with the condition start with an over-the-counter formula containing a high concentration of aluminum zirconium, plus moisturizing ingredients. The doctor’s favorites: Dove Clinical Strength Aluminum Zirconium Tetrachlorohydrex Gly (20 percent) or Secret Clinical Strength (also 20 percent). “Ideally the product is used at night before bed. In the morning, the patient can use a regular antiperspirant or non-antiperspirant deodorant,” says Dr. Waldorf.

If you find that you sweat more than the average person, it’s wise to have a conversation with your doctor about treatment options, as conditions like this usually aren’t treated with antiperspirants and deodorant. “You may need to take internal medication for your sweating,” adds New York dermatologist Debra Jaliman, MD. “For some people, the sweating is so intense that they need to take a pill every day, called anticholinergics, to decrease the swelling.”

You Might Need an Acid-Infused Deodorant

Deodorant brands are increasingly adding acids, particular alphahydroxy acids, into their formulas for one specific reason: “When these fruit- and plant-derived acids are added to deodorants, it’s meant to lower the pH balance of the skin, and thus limit odor-producing bacteria from growing,” explains Bay Harbor Islands dermatologist Stacy Chimento, MD. In other words, odor isn’t being masked, it’s being eliminated.

Beauty brand Kosas jumped onto the acid-spiked deo bandwagon with their Chemistry Deodorant ($16), which is also infused with hyaluronic acid, aloe and peptides. “Our end goal was to create a clean deodorant that not only keeps you from smelling, but also treats the skin with nourishing ingredients so it’s smoother, more evenly toned and bump-free,” says founder Sheena Yaitanes. “It’s a completely different approach to deodorant.”

While Dr. Chimento contends that the AHA levels in these types of products are typically low and safe to use, she does flag that if you are someone who is highly sensitive to hydroxy acids, a conversation with your dermatologist or a patch test is the best option.

You Aren’t Applying Deodorant at Night

Most of us habitually apply our deodorant onto our underarms before heading out for the day, but experts like Drs. Jaliman and Waldorf find that the best time for antiperspirant application is at night, right before bed. “Antiperspirants work best at night when the skin is dry,” says Dr. Jaliman. “The aluminum-based ingredient can easily get to the sweat gland to effectively plug the pore. It then can reduce sweating for up to 24 hours.”

Dr. Waldorf agrees, explaining a clinical-strength antiperspirant should be applied before bed to reduce overall sweat, and an antiperspirant-deodorant or deodorant should be applied alone in the morning.

Secret Deodorant launched a Night Time Treatment version (it’s lavender-scented!) of their coveted Clinical Strength deo for this very reason. “We learned from clinical testing that while Secret Clinical Strength works great when applied in the morning, it works even better when applied at night,” says Dr. Maiysha D. Jones, P&G Personal Care scientific communications manager. “Secret Clinical Strength Night Treatment ($8) was created to make the benefit of night time application clear to the consumer. At night, your body temperature is naturally lower, and your sweat rate is too. This allows your antiperspirant to provide a stronger barrier against sweat.”

You’re Going Through a “Detox” Phase

If you recently made the popular swap from a traditional antiperspirant to an all-natural, aluminum-free deodorant, Miami dermatologist Heather Woolery-Lloyd, MD says you need to give your body some time to adjust. “Deodorant may not work if you are at the beginning of transitioning from antiperspirant to a deodorant. It can take up to 4 weeks for your body to adjust so it is important to be patient.” She recommends Dove 0% Aluminum Deodorant Spray ($9) which keeps odor at bay for 48 hours.

If you’re transitioning into an AHA-infused deodorant, Yaitanes says you might also go through a similar detox. “Everyone is different, so some will see results right away and some pits need a bit time to detox and adapt to the new environment,” she explains, recommending about five days or so to see full benefits.

You’re Not Treating Bacteria

Believe it or not, sweat isn’t what smells—it’s the bacteria forming in our underarms that does. “If you manage the bacteria, you’ll manage the odor,” says Further. One way to combat this smell: using an antibacterial soap before applying deodorant, “paying close attention to scrubbing the area to eliminate any bacteria,” she says. 

“To reduce foul-smelling odor, try cleansing the underarms and groin areas twice daily and after exercise/sweating with Lasercyn Spray, aka stabilized hypochlorous, which is a very safe, effective and nonirritating anti-microbial,” adds Dr. Waldorf. “We routinely use it to prepare the skin for injectables and to clean wounds. If that is not effective, see your dermatologist.”

Your Clothes Might Be Working Against You

Enter another odor-inducing issue we never gave a second thought: our clothing. Further contends that synthetic fibers hold onto odor due to the nature of the weave, but “natural fibers like cotton, linen and bamboo are woven differently and allow odor to move through the fibers instead of trapping it.” Long story short: Your clothes might be working against you.

Another thing to keep in mind? The fit. “If you’re wearing a close-cut rayon blouse on a hot day with natural deodorant on, it’s very likely you’re going to begin to smell for two reasons,” she says. “One, the tight fit will create friction in the underarm and grab onto the moisture, and two, the odor will be trapped in the fabric.”

You’re Applying on a Damp Underarm

According to Dr. Barba, before applying an antiperspirant or deodorant, we should make sure the underarm is clean and dry. If the area is wet, the moisture can fail to allow your formula to be properly absorbed.

Skin-care expert Xiomi Frans-Cuber agrees, adding that sweat and moisture usually prohibit odor and sweat-fighting ingredients from effectively penetrating the skin. “The moisture and sweat on your underarms can completely wash away your formula.”

Stress May Be to Blame

Stress can also be a surprising cause of your deodorant fails. Frans-Cuber explains that stress produces hormonal changes, which can ultimately cause an increase in odor-causing bacteria. So, while your deodorant may not exactly be to blame in this case, it’s helpful to be aware of how stress hormones can affect the performance of your deodorant.“

Hormonal changes can lead to an increase in sweat output and create a worse odor than you are probably accustomed to,” says Frans-Cuber. “So in this situation, it may not be the deodorant, but rather just a case of stress hormones.” 

Your Deodorant Might Not Be Strong Enough

While it probably makes sense to find the strongest-smelling deodorant possible, sometimes even the most pleasant-scented products can lack the necessary antibacterial properties to neutralize any existing bacteria. If you find that that your deodorant fades too fast, try talking to doctor about treatments, which can help alleviate the problem.“

If your deodorant does not have any or the necessary antibacterial properties, it could be difficult to kill the odor-producing bacteria and minimize body odor,” explains Beverly Hills, CA, dermatologist Tsippora Shainhouse, MD. “If the odor persists after switching deodorants, see your dermatologist about prescription anti-bacterial treatments that can help reduce the bacterial load.”

You Might Need Prescription Deodorants

Another one of your options includes switching to prescription formulas, which are often stronger than over-the-counter products. These formulas often contain higher concentrations of sweat-busting ingredients and work better for those who sweat a lot.“

For some people, over-the-counter antiperspirants are not strong enough and they require prescriptions,” adds Dr. Jaliman. “These are stronger antiperspirants that work better, as they have higher concentrations of the active ingredient.”

You May Want to Consider Botox

If you are looking for stronger underarm relief, Botox Cosmetic can be valid solution to excessive perspiration. Injected into the sweat glands, Newton, MA, plastic surgeon Joseph A. Russo, MD says that Botox Cosmetic effectively reduces excessive sweating by deactivating the glands responsible for perspiration. This leaves your underarms drier and free of bacteria.“

Botox can be injected into the sweat glands, which block chemical signals from key nerve endings to effectively deactivate the glands and reduce excessive sweating,” adds Dr. Russo. “It is most commonly used to control perspiration in the underarms.”