Do B Vitamins Cause Body Odor? Causes and Solutions

Why Do I Smell After Taking B Vitamins?

Why Do I Smell After Taking B Vitamins?
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Updated on August 6, 2025
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Vitamins can help make up for any nutritional deficiencies in your diet. For example, vegetarians may need to take B12 supplements because plant foods do not naturally contain vitamin B12.

But taking too many B vitamins that include choline may cause a fishy body odor.

 This is especially true for folks who have a condition called trimethylaminuria.

Read on to learn more about trimethylaminuria, which B vitamins might change your body odor, and ways to address it.

What Is Trimethylaminuria?

People who have trimethylaminuria experience a buildup of trimethylamine, a fishy-smelling compound the body produces when foods like fish, beans, and eggs are consumed. This buildup is due to irregular functioning of the enzyme FMO3, which is responsible for breaking down trimethylamine in the body.

Once trimethylamine builds up, the fishy scent may make its way into your sweat, breath, saliva, and urine. While some folks may experience body odor related to trimethylaminuria only when sweating or stressed, others might notice the fishy scent more often.

Trimethylaminuria is rare. It occurs in only 1 out of every 200,000 to 1 million individuals worldwide.

If you notice body odor that smells different than usual and think you may have this condition, it’s best to check with a doctor.

Which B Vitamins May Cause a Smell?

Some vitamin B complex supplements may include choline, an essential nutrient for your body.

But choline also plays a role in producing trimethylamine in your body. So if you have trimethylaminuria, frequently taking choline-containing vitamins could lead to a buildup of trimethylamine and result in a fishy body odor.

What Else Could Cause a Smell?

If you have trimethylaminuria, any foods or supplements that cause a buildup of trimethylamine could lead to fish-scented body odor. These foods could include:

Even if you don’t have trimethylaminuria, your diet could affect the scent of your sweat.

For example, eating foods rich in sulfur — like onions, garlic, cabbage, broccoli, cauliflower, and even red meat — could lead your sweat to have a sulfur smell.

 And alcohol may metabolize into acetic acid, which could be released through your skin and in your breath.

Hormone changes could also lead your sweat to smell differently. Several health conditions can alter the scent of your body odor, too. If you have diabetes-related ketoacidosis, for example, high ketone levels may result in a body odor with a fruity scent.

Plus, even everyday factors like stress, hot weather, exercise, and your genetics can affect the way your body odor smells.

How to Address It

If you have trimethylaminuria, your doctor might advise you to avoid foods and supplements that could lead to a buildup of trimethylamine in your body. These may include B vitamins that contain choline. Your doctor may also suggest using certain lotions or soaps that can help remove the fishy scent from your skin.

If you don’t have trimethylaminuria but still notice that your sweat has an unusual smell, a healthcare professional can perform a physical exam and any necessary lab tests to determine the cause. Depending on their diagnosis, they can work with you to create a treatment plan that’s best for you.

You can also try removing sulfur-containing foods from your diet to see whether that changes or eliminates your body odor.

A few personal hygiene strategies may also help reduce body odor:

  • Wipe the areas where you sweat the most, like your armpits and groin, with antibacterial soap daily. Consider shaving in those areas, too, to help sweat evaporate more quickly.
  • Wear loose-fitting clothes made of cotton, and be sure to wash them regularly.
  • Use a topical antiperspirant, which can help decrease your sweat production.

The Takeaway

  • If you notice an unusual fishy body odor after taking vitamin B supplements, it may relate to trimethylaminuria, a rare condition. A healthcare professional can diagnose and help you manage this condition if you think you may have it.
  • Dietary choices, including sulfur-containing foods, and health conditions can also influence how your body smells.
  • Personal hygiene strategies, like washing often and using antiperspirants, can help manage any body odor you experience. But if the odor is different than usual and doesn’t go away, it’s best to check with a doctor.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Niklewicz A et al. The Importance of Vitamin B12 for Individuals Choosing Plant-Based Diets. European Journal of Nutrition. December 5, 2022.
  2. Vitamin B. National Institute of Diabetes and Digestive and Kidney Diseases. May 27, 2021.
  3. Trimethylaminuria (Fish Odor Syndrome). Cleveland Clinic. April 5, 2024.
  4. Body Odor. Cleveland Clinic. March 4, 2022.
  5. How 7 Different Foods Affect Your Body Odor. Cleveland Clinic. April 1, 2024.
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Michelle Seguin, MD

Medical Reviewer
Member of American College of Lifestyle Medicine

Michelle Seguin, MD, is a board-certified family medicine, lifestyle medicine, and certified functional medicine physician (IFMCP). She is a practicing physician at Root Functional Medicine, a leading telemedicine practice specializing in personalized, root-cause care.

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Andrea Boldt

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Andrea Boldt has been in the fitness industry for more than 20 years. A personal trainer, run coach, group fitness instructor and master yoga teacher, she also holds certifications in holistic and fitness nutrition.

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