Fumaric acid is a chemical compound that is normally found in nature, but scientists have also learned how to make a synthetic version of it to add to all kinds of products including foods, medicines and dyes. Learning more about the properties of fumaric acid can help you understand all the different ways you might interact with it in your everyday life.

Talking about fumaric acid as a chemical compound can sound confusing, but it really just means that it is a mixture of separate elements. In fumaric acid’s case, it is an (E)-2-butenedioic acid. When it is found in nature, it often appears in moderate to chilly climates in the Northern Hemisphere, on plants like lichen, bolete mushrooms and Iceland moss. There, it appears as a fine white or colorless crystalline powder. If you were to taste any of those plants, you might notice a bit of a sour flavor. That’s the taste of fumaric acid, and it’s a taste that scientists have replicated in order to add it to food.

Fumaric acid isn’t only found on plants. Similar to Vitamin D, the human body also produces fumaric acid when skin is exposed to direct sunlight. Scientists still need to learn more about that fumaric acid production, its relation to the sun and why that is an important bodily function. What they do know, though, is that there are some people who don’t form fumaric acid when they are exposed to sunlight. People who have psoriasis, a condition that leads to dry and itchy patches of skin, don’t seem to create fumaric acid when they are in the sun. Medical researchers still don’t know why that happens, or what role it might play in the overall treatment or cure for psoriasis. Still, in some countries, dermatologists recommend that some people with psoriasis take fumaric acid supplements. In addition, some medical practitioners advise taking a bath with some of the herbs that contain fumaric acid in order to treat painful flare-ups of psoriasis.

While fumaric acid is common in nature, scientists have also discovered how to create a synthetic version of it. One of the most common uses for that is as an additive in food. Some additives, like adipic acid in food, are rarely found in nature, making them less appealing as an additive to some people. But fumaric acid is one of the additives naturally found in most human bodies, making it a relatively safe food additive.

Fumaric acid is used in a wide variety of foods, often to add or intensify the sour flavor of a food. In addition, it is also helpful to increase the acidity levels of food, which then helps to prevent mold growth and keep the food safe to eat for longer periods of time. The presence of fumaric acid in a food always depends on the brand that creates that food, but you might find the additive in many popular brands of foods like tortillas, some types of breads, wine, fruit juices, packaged desserts and jellies.

In addition to food, you can find synthetic fumaric acid in some cleaning products, as well as in some varieties of industrial dyes and polyester resins.

In these ways, fumaric acid is often present in the world around you, and understanding more about the compound can help you see the different roles it plays everywhere from your skin to your next meal.