How can medications change our body odor?

The body odor is not produced by sweat, which is initially odorless.

It results from the interaction at the surface of the epidermis between the secretions of the sweat glands and the skin microbiome. The eccrine glands, distributed across the entire body, release mainly water and salts, while the apocrine glands, located in hair-bearing areas, secrete denser organic compounds such as lipids and proteins. By metabolizing these substances, the bacteria that reside on our skin release odorous volatile compounds. This process is called bromhidrosis.

Body odors also depend on external factors, particularly on what we ingest through our diet.

Indeed, when we consume a food, it is normally metabolized by the liver before being eliminated. However, if certain residues are not completely broken down, they are carried by the bloodstream to the sweat glands. When excreted through the pores, these metabolites modify the chemical composition of sweat or alter the skin’s bacterial ecosystem, thereby changing—subtly or markedly—the odor emitted by the body.

Most changes in body odor related to taking a medication are not caused by the drug itself, but by its ability to stimulate the production of sweat.

Certain active substances interfere with the autonomic nervous system, which regulates our automatic functions, including body temperature. By sending an incorrect signal to the sweat glands, these medications trigger heavy sweating even when the body does not need to cool down. This increased presence of water and nutrients on the skin’s surface provides a fertile environment for bacteria. The more material bacteria have to break down, the more odorous volatile compounds are released, thereby intensifying the body’s natural smell.

This phenomenon of excessive sweating is frequently observed with antidepressants and anxiolytics. These treatments alter the concentration of neurotransmitters, such as serotonin and norepinephrine, which are involved in thermoregulation in the brain. By disrupting this internal thermostat, they cause night sweats or hot flashes. This effect is also seen with certain hormone therapies or blood pressure medications, such as Captopril or Enalapril, which can dilate blood vessels and indirectly activate the skin’s glands.

This list is not exhaustive: zidovudine, tramadol, pregabalin, tamoxifen, codeine, bupropion hydrochloride, and paroxetine mesylate can also increase perspiration.

Less commonly, certain medications change the “chemical signature” of our secretions. Once ingested, the drug is broken down by the liver into smaller molecules called metabolites. If these breakdown products have a strong odor and are not completely eliminated by the kidneys, they are excreted through the pores. This is the case with certain antibiotics, particularly penicillin, whose sulfur-containing molecules are carried by the blood to the apocrine glands. The sweat then takes on a distinctive smell, often described as acidic or chemical.

Finally, some treatments alter the balance of the skin microbiome. By eliminating certain “good” bacteria in favor of other, more odor‑producing species, medications such as broad‑spectrum antibiotics can durably transform body odor. In this case, the change does not come from inside the body, but from the modification of the living ecosystem on its surface. Although this imbalance is temporary, it often requires special attention to hygiene and to the choice of cleansing products that respect the physiological pH, in order to restore a healthy skin flora.

If you notice a persistent and/or bothersome change in your body odor after starting a new treatment, do not hesitate to seek the advice of your primary care physician.

• LAZAREVIC V. & al. Mapping axillary microbiota responsible for body odours using a culture-independent approach. Microbiome (2015).

• DOTY R. L. & al. Impact of antibiotics on smell dysfunction. World Journal of Otorhinolaryngology - Head and Neck Surgery (2018).

• BAKER L. B. Physiology of sweat gland function: The roles of sweating and sweat composition in human health. Temperature (2019).

• SMEETS M. & al. Intrinsic and extrinsic factors affecting axillary odor variation: A comprehensive review. Physiology and Behavior (2023).