My Sweat Smells Bad All of a Sudden: Why and What to Do?

Why do I have sweat smells bad while other people don’t?

Some people experience more pungent sweat due to genetic, hormonal, or, rarely, medical reasons.

Sweating is a natural process of the human body that helps regulate body temperature. When it occurs in areas with a high concentration of sweat glands, it can lead to unpleasant odors.

There are two main types of factors that can explain why some people (likely including you if you’re reading this article) have sweat that smells stronger or worse:

1. Genetic factors, over which we have no control;
2. Factors that we can take action on.

I will quickly discuss reasons over which, unfortunately, we cannot take action. Even though we can certainly try to mask odors, that’s something I’ll delve into further.

Some people (both men and women) may have a genetic makeup that makes them more prone to excessive sweating (see this article on the genetics of excessive sweating – coming soon in english) or increased sebum production, which can influence body odor. This is partially hormone-related.

Additionally, some people may have a bacterial composition that promotes the breakdown of substances in sweat into odor compounds.

Some diseases can exacerbate bacterial proliferation and, consequently, unpleasant odors (Semkova 2015):

• Obesity
• Diabetes
• Intertrigo: skin inflammation occurring in skin folds where skin rubs against skin, such as in the groin, inguinal, and buttock areas.
• Erythrasma: a superficial skin infection caused by a bacterium called Corynebacterium minutissimum. It typically presents as pink or brown patches on the skin and may be associated with a characteristic odor.

Finally, there is a rare sweating disorder called bromhidrosis. Those affected often describe the smell of their sweat as “nauseating,” resembling that of “rotten fish.”

Thus, strong-smelling sweat is rarely due to poor hygiene, especially in people who are conscious of it. If you’re reading this article and are concerned about this issue, it’s likely that, on the contrary, you maintain very good personal hygiene.

Why can sweat suddenly smells bad?

There are several reasons that can explain why, from one day to the next, your sweat suddenly smells bad:

1. Dietary Factors: What you eat or drink plays a role; certain foods like garlic, onions, strong spices, and specific types of meat can affect sweat odor. See diet and sweating. See also: Food ans sweating problems
2. Reduced Hydration: Drinking less than usual can concentrate odor-producing substances in sweat, intensifying the smell.
3. Stress and Emotions: Stress and emotions can influence the chemical composition of sweat, sometimes increasing its intensity. During stressful periods, people often sweat more, making areas like armpits or other perspiring body parts, including groin, more prone to unpleasant smells.
4. Hormonal Changes: Hormonal fluctuations related to the menstrual cycle, puberty, or menopause can influence sweat odor. Adolescence, during middle or high school, is often when people become self-conscious about their sweat, especially if they have hyperhidrosis (excessive sweating).
5. Skin Infections: Bacterial or fungal infections on the skin can lead to increased production of odor-causing bacteria.
6. Medical Conditions: Certain chronic illnesses indirectly result in increased sweating or more odorous sweat. See this article on diseases causing excessive sweating.
7. Medication: Taking certain medications can impact the odor of sweat, especially cancer treatments (see my article on cancer and sweating).

To identify the cause of sudden malodorous sweat in your case, consider how long the intensified odor has been present: 1 or 2 days? Continuously for several weeks?

The longer the unpleasant odor persists, potentially the more likely a medical cause is at play.

Conversely, if the strong odor only occurs periodically for a few days, it’s more reasonable to attribute it to your diet or lifestyle, perhaps during a more or less stressful period.

Of course, if this concerns you, it’s advisable to discuss it with your primary care physician during your next visit (see: specialist in sweating – coming soon in English).

Does the sweat smells bad last ‘forever’?

No, the sweat doesn’t necessarily smells bad last forever. It largely depends on the underlying cause of the unpleasant smell.

If it’s related to diet, eliminating or reducing the consumption of the responsible food can be effective.

If the bad odor is due to something beyond our control (like genetics), in that case, strong sweating may persist ‘forever,’ but it’s possible to mask it or take action to minimize discomfort.

Let’s explore what can be done to reduce or eliminate the smell of sweat.

What to do to reduce or eliminate sweat odor?

Several factors can contribute to intensifying these unpleasant sweat odors, even if they are partly due to causes we can’t control. Here’s what you can do to maximize your chances of smelling less bad under your arms or in other parts of your body where your sweat is malodorous:

• Avoid wearing tight clothes that promote heat and moisture retention.
• Choose undergarments that allow for better heat and moisture dissipation (fabric, shape) (see my article: how to hide underarm stains).
• Limit the presence of hair that can retain sweat.
• Avoid prolonged sitting in a static position; different parts of the body breathe and dry less, leading to the accumulation of bad odor.
• Change clothes frequently to allow them time to dry.
• Ensure thorough cleaning of the body parts that smell bad with a mild and non-irritating soap. Some individuals may need to wash (sometimes with just a washcloth) several times a day.
• After a shower, dry yourself completely, especially in skin folds. Moisture promotes the growth of bacteria responsible for odors. The same applies if you exercise or sweat a lot at once: you can use the restroom to wipe yourself, making sure to always have a suitable towel or fabric on hand.

I wash myself but still smell bad: what to do?

It’s common to wash properly but still experience a lingering unpleasant odor—you’re not alone!

If regular washing isn’t enough to reduce the bad smell of your sweat, you can try implementing other tips I’ve provided:

• Choose breathable underwear and clothing.
• Avoid positions or places that prevent well-ventilated, aired-out areas of the body (as air helps dry the skin, limits sweating, and thus reduces bad odors).
• Limit the presence of hair.
• Use antiperspirants that are more effective in reducing the amount of sweat produced or deodorants that truly mask odors.

Regarding deodorants and antiperspirants, effectiveness can vary from person to person, so try several until you find the right one! There are substances and concentrations that may be more effective than others, as discussed in my article on supposedly the most effective antiperspirants.

Personally, the two antiperspirants for which I’ve observed the most positive effects on me (after trying dozens, and still testing) to reduce bad odors are:

• For women: Nivea Fresh Natural 48H (see on Amazon)
• For men (I find it even more effective, although I don’t like the smell): Nivea Men Dry Impact (see on Amazon).

Although I would have loved for alum stone, known for masking odors, to have an effect, it has never been the case. And this is the feedback I’ve received from everyone with hyperhidrosis (excessive sweating) I’ve discussed it with.

I regularly conduct surveys among subscribers to my newsletter (800+ subscribers in 2024: hyperhidrosis’sufferer). Here is the most recommended antiperspirant:

The bad smell of sweat persists despite deodorant: what to do?

Here’s what you can do if the smell of sweat persists despite using deodorant:

• Try different deodorants: Make sure to use an antibacterial deodorant or antiperspirant, depending on your needs.
• Clean highly sweaty areas like armpits before applying deodorant. Use an antibacterial soap (see on Amazon) to eliminate bacteria on the skin.
• Exfoliate the skin: This can help remove dead skin cells, reducing bacterial proliferation that contributes to odors. Exfoliation can be done with specific products such as scrubs or exfoliants containing abrasive particles or gentle chemical ingredients.
• Ensure you apply deodorant according to the instructions on the packaging. It’s often recommended to apply it to dry skin (use a hairdryer if necessary).
• Use different fabrics for your clothes, and choose looser, more breathable clothing.
• Opt for well-ventilated spaces (open window, fan) that can help dry the skin, reduce sweating, and consequently, cause fewer bad odors.

Is there a home remedy for underarm odors?

I’ve already dedicated a full article to home remedies for sweating (and indirectly against bad odors; coming soon in english).

Even though many are suggested, I’m very skeptical about their usefulness and effectiveness for individuals for whom regular antiperspirants or deodorants, designed to be more effective, do not work.

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Do you have any comments or questions? Your comments are welcome 🙂 !

You may also like:

• Smelly Crotch Area in Men: 10 Practical Tips
• Cause of Sweating From Only One Armpit
• My blog on hyperhidrosis

 📚 SOURCES

Malik AS, Porter CL, Feldman SR. Bromhidrosis treatment modalities: A literature review. J Am Acad Dermatol. 2023 Jul;89(1):81-89. doi: 10.1016/j.jaad.2021.01.030. Epub 2021 Jan 20. PMID: 33482257.

Semkova K, Gergovska M, Kazandjieva J, Tsankov N. Hyperhidrosis, bromhidrosis, and chromhidrosis: Fold (intertriginous) dermatoses. Clin Dermatol. 2015 Jul-Aug;33(4):483-91. doi: 10.1016/j.clindermatol.2015.04.013. Epub 2015 Apr 8. PMID: 26051066.