Why do some men experience an onion-like body odor when they exercise?

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Last updated: July 6, 2025View editorial policy

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From the Research

Some men experience an onion-like body odor when they exercise due to the breakdown of sulfur compounds in their sweat by skin bacteria, as supported by the study published in 2009 1. This process occurs primarily in the apocrine sweat glands, which are concentrated in areas like the armpits and groin. These glands release a protein-rich sweat that contains compounds like thioalcohols, which have a distinct onion or sulfurous smell when metabolized by skin bacteria. The intensity of this odor can be influenced by genetics, diet, and personal hygiene habits. Foods high in sulfur compounds, such as onions, garlic, and certain spices, can make the odor more pronounced. To reduce this odor, men can:

  • Shower promptly after exercise
  • Use antibacterial soap to reduce bacteria populations
  • Apply antiperspirants containing aluminum salts to reduce sweating
  • Wear breathable fabrics during workouts
  • Maintain good overall hygiene Some may also benefit from clinical-strength antiperspirants or consulting a dermatologist if the odor is particularly strong or bothersome, as suggested by the study published in 2011 2 and 2016 3. Additionally, a study published in 2006 4 found that a non-meat diet can lead to a more attractive and pleasant body odor, which may be relevant for men who experience strong body odor. However, the most recent and highest quality study on this topic is from 2009 1, which provides the most reliable evidence for the causes and potential solutions for onion-like body odor in men.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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