Can Illness Change Your Body Odor?What Studies Found

If your usual smell has changed and nothing in your routine has, it’s reasonable to wonder whether something inside has changed.

Why illness can change your smell

The body releases hundreds of chemicals into the air through skin, breath and urine, and their mix reflects how the body is working. So an infection or a metabolic illness often changes body odor.¹ Researchers are studying these chemicals as possible ways to diagnose disease.¹

Smelling sick within hours

In a Swedish lab study, healthy volunteers were injected with endotoxin, a substance that switches on the immune system, or with a placebo.²

• Within a few hours, their body odor was rated less pleasant after endotoxin than after placebo.²
• The stronger a person’s immune response, the bigger the change.²

This was a short, induced immune reaction in a lab, not an everyday cold, but it shows how fast body chemistry can shift.

A smell linked to Parkinson’s

Researchers worked with a person with an unusually keen sense of smell who could detect Parkinson’s disease by odor.³ They analyzed skin oil swabbed from the upper backs of 64 people, 43 with Parkinson’s, and found a distinct chemical pattern, confirmed in a second group of 31.³ It’s research, not a test you can get.

Causes doctors look for

A dermatology reference lists causes of unusually strong body odor:⁴

Type	Examples
Illnesses	Diabetes, liver disease, kidney failure, obesity4
Medicines	Penicillin, bromides, dupilumab4
Inherited conditions	Trimethylaminuria (fish odor syndrome) and others4

UK guidance adds that some antidepressants can make body odor worse.⁵ The person with the odor may not notice it themselves.⁴

When to get checked

Don’t wait if

1. Emergency

   Get emergency care for a fruity or nail-polish smell on your breath with intense thirst, peeing a lot, deep breathing, vomiting or confusion; see fruity breath and ketoacidosis.

See a doctor if your body odor has changed from how it usually smells, or you suddenly sweat much more than usual, and self-care hasn’t helped.⁵

Related: musty or ammonia breath, trimethylaminuria testing and smell changes after a new medicine.

Try: “My body odor has changed over the past few months and nothing in my routine has. I also started a new medicine in the spring. Could either be behind it?”

Arms Up covers this in Chapter 8, “Still Smell After a Shower?,” in sections called “Hormones, Age, and Your Usual Smell” and “When a Smell Is a Signal.” Its Fresh Log keeps a medicine column beside the smell notes, so a change can be matched to its timing. See the book.