What Are Mycotoxins and How Can They Affect the Body?

When most people think about mold, they picture the fuzzy spots on a wall or the musty smell in a basement. But mold can also make something you can’t see or smell: tiny chemical compounds called mycotoxins.

Understanding mycotoxins helps explain why mold-related health problems can be so confusing, and why they can affect so many parts of the body.

Mold Spores and Mycotoxins Are Not the Same

It helps to separate two things:

• Mold spores are like seeds. Molds release them to spread and grow in new places.
• Mycotoxins are chemicals that some molds make, often when they are stressed or competing with other microbes for food and space.

Not every mold makes mycotoxins. Even molds that can make them don’t always do so. It depends on the type of mold and the conditions it’s growing in.

Mycotoxins are also very stable. They can cling to dust and tiny mold particles and may remain even after the mold itself has died. This is one reason simply killing mold is not the same as cleaning it up.

Common Mycotoxins

Scientists have identified hundreds of mycotoxins. A few you may hear about include:

• Ochratoxin A, made by some Aspergillus and Penicillium molds
• Trichothecenes, made by several molds, including Stachybotrys, often called “black mold”
• Aflatoxins, made by certain Aspergillus molds
• Gliotoxin, made by some Aspergillus species
• Zearalenone, which can act like the hormone estrogen in the body

How Are People Exposed?

The best-studied way people take in mycotoxins is through food. Grains, corn, peanuts, coffee, and dried fruit can become contaminated when crops are grown or stored in damp conditions. That’s why many countries test foods for certain mycotoxins.

In water-damaged buildings, environmental medicine clinicians are concerned about other routes:

• Breathing in contaminated dust and tiny mold particles
• Swallowing dust that settles on hands, food, or surfaces
• Skin contact with contaminated materials

How much each route matters, and how harmful indoor exposure is compared with food, is still being studied.

How Might Mycotoxins Affect the Body?

Researchers and clinicians have described several ways mycotoxins may affect our cells.

1. Oxidative stress. Mycotoxins can increase oxidative stress, a kind of “wear and tear” inside cells. Your body fights this with antioxidants, especially glutathione, often called the body’s master antioxidant. When the demand is greater than your supply, cell membranes and other parts of the cell can be damaged.

2. Energy production. Inside nearly every cell are tiny power plants called mitochondria. They make the energy your body runs on. Some research suggests mycotoxins can stress mitochondria. One model, called the Cell Danger Response, suggests that cells under threat may slow down energy production to protect themselves. This may help explain the deep fatigue many people describe, though it is still a working theory.

3. The immune system. Mycotoxins can affect immune signaling. In some cases they may weaken certain defenses, and in others they may increase inflammation. Some practitioners check inflammation markers, such as TGF-beta or C4a, in complex cases. These markers can be helpful, but they aren’t specific to mold, so they need to be read alongside the rest of the picture.

4. Hormones. Some mycotoxins, such as zearalenone, can act like estrogen. This is one reason hormone balance is often part of the conversation.

Why Symptoms Can Be So Wide-Ranging

Because mycotoxins may affect basic processes like energy, inflammation, and antioxidant defenses, symptoms can show up almost anywhere. People often report:

• Fatigue
• Brain fog
• Headaches
• Digestive problems
• New sensitivities to foods, smells, or chemicals
• Skin reactions
• Trouble sleeping
• Mood changes

These symptoms can have many other causes too. That’s why a careful look at your exposure history, your environment, and your overall health is so important.

What About Urine Mycotoxin Testing?

Some practitioners use urine tests to look for mycotoxins. These tests show what your body is releasing at the time of the test. They can’t tell you for certain where the exposure came from, such as food or a building, or prove that a particular mycotoxin is causing your symptoms. We cover this in more detail in our article on mold testing.

The Bottom Line

Mycotoxins are real chemical compounds made by some molds, and their harmful effects are well documented in food safety research. Their role in illness linked to water-damaged buildings is still being studied, but they may help explain why mold exposure can affect energy, immunity, the brain, and more.

The best approach looks at the whole person: how much exposure there was, how healthy the body was to begin with, and what other stressors are in the picture.