What Are Mycotoxins?

There are around 3 million species of molds on the planet, but only about two dozen cause health problems in humans. Mold spores are everywhere; in the air, on surfaces, in soil. On their own, they’re dormant and do very little. Mold growing in indoor environments with moisture make spores and these spores carry mycotoxins.

Think of mold spores like seeds in a packet. Without water, nothing happens. Add moisture, and they grow. Attached to those growing spores is a secondary metabolites: the mycotoxins. These toxins serve one purpose for the mold: destroying competing bacteria so the mold can keep its food source to itself.

This is actually the same mechanism that led to one of the most important discoveries in medical history. In 1928, Alexander Fleming noticed that a Penicillium mold had contaminated one of his petri dishes and was killing the bacteria around it. That observation eventually led to the development of penicillin, the first antibiotic, which has saved an estimated 200 million lives. The toxin the mold produced to destroy bacteria turned out to be a lifesaving medicine. Today, the immunosuppressant cyclosporine given to bone marrow transplant patients is also derived from a mycotoxin.

But while some mold byproducts have been harnessed for medicine, the mycotoxins produced by indoor molds are harmful to human health and far more common than most people realize.

Mycotoxins can enter your body in three ways: by breathing them in, by eating contaminated food, or by absorbing them through the skin.

The most common route is inhalation. When mold grows in a water-damaged building – behind walls, under flooring, inside HVAC systems, in ceiling tiles – it releases mycotoxins into the air along with its spores. Research has shown that water-damaged homes can have mycotoxin concentrations in indoor dust that are 1,000 times higher than the indoor air mold spore count. And while mold spores measure 4 to 20 microns, mycotoxins measure just 0.1 microns, about the size of a virus, meaning they can reach deep into the lungs and even cross into the bloodstream.

Low levels of mycotoxins are also found in everyday foods like cereals, coffee, nuts, wine, and beer. The WHO estimates that 25% of the world’s crops are contaminated by mold. But the amounts in food are typically far below the threshold for causing illness. The concern is prolonged indoor environmental exposure, where concentrations are dramatically higher and exposure is continuous day after day, in the place you sleep or work.

Mycotoxins affect nearly every organ system in the body. Published research has linked mycotoxin exposure to immune dysregulation, neurological damage, kidney and liver damage, hormonal disruption, genetic damage, birth defects, and cancer. The International Agency for Research on Cancer has formally classified several mycotoxins as carcinogenic or possibly carcinogenic to humans.

The World Health Organization has called disease caused by mycotoxin exposure “the Great Masquerader” of the 21st century. The reason: mycotoxin illness presents with nonspecific symptoms that affect multiple systems at once, fatigue, brain fog, headaches, gut problems, joint pain, anxiety, hormonal changes, and these symptoms overlap almost completely with conditions like chronic fatigue syndrome, fibromyalgia, Lyme disease, multiple sclerosis, and autoimmune disorders. Patients with mycotoxin illness are frequently misdiagnosed because the symptoms look like something else, and mycotoxins are rarely on the clinician’s list of possible causes.

The adverse health effects range from acute toxicity to long-term consequences including autism, Alzheimer’s disease, Parkinson’s disease, inflammatory bowel disease, mast cell activation syndrome, and cancers.

One of the most challenging things about mycotoxins is that you can’t see, smell, or taste them. The musty odor people associate with mold is actually caused by volatile organic compounds (VOCs) a different category of mold byproduct. Mycotoxins themselves are odorless. You can be exposed without knowing it.

Mycotoxins are also extremely persistent. Even after mold is removed from a building, mycotoxins can remain on dust, furniture, clothing, and building materials. The EPA cautions that approximately 50% of fungal growth can be hidden from view; behind walls, in crawl spaces, inside ventilation systems. And mold-producing toxins are always present in homes and workplaces that have experienced water damage.

Because mycotoxins are invisible and their symptoms mimic so many other conditions, testing is the only way to confirm whether your body is responding to mycotoxin exposure.

Blood serum antibody testing measures your immune system’s actual response.  IgG and IgE antibodies produced when your body recognizes specific mycotoxins as a threat. This is different from urine testing, which detects mycotoxin metabolites that can come from normal food intake. Blood serum testing distinguishes between incidental dietary traces and clinically meaningful immune exposure.

MyMycoLab tests for 14 mycotoxins with both IgG and IgE antibody detection, 28 data points from a single blood draw.

This article is your starting point. If you want the full picture; how exposure happens, why some people get sicker than others, what symptoms to watch for, how testing works, and what recovery looks like, our complete guide covers everything.