There is a lot of understandable confusion about the difference between sulfa drugs, sulfites, sulfates and sulfur. Many people are allergic to sulfa drugs and sulfites and thus assume that they have to avoid sulfates and sulfur, also. I will explain the difference between these four substances in this article.

Sulfa Drugs (Sulfonamides)

Allergies to sulfa containing drugs are not unusual. Sulfa drugs actually contain a molecule called sulfonamide. Sulfonamides contain Sulfur, Oxygen, Nitrogen, and Hydrogen. The sulfonamide drugs were the first antimicrobial drugs (antibiotics) These molecules plug up the bacteria’s ability to reproduce. The allergic reactions occur due to the actions of the molecule, not the sulfur. So, Sulfonamides (Sulfa drugs) contain Sulfur but the Sulfur is not the problem.

Sulfites (also Sulfur Dioxide)

Sulfites are naturally occurring sulfur containing molecules that occur in the fermentation process. They are found in red wines. Some wine manufacturers add additional sulfites as preservatives. Sulfites contain one Sulfur atom surrounded by either 2 or 3 Oxygen atoms. Sulfites can cause sensitivity reactions in some people to include possibly headaches and breathing problems. Sulfites are not the same as Sulfa Drugs.

Sulfates

Sulfates contain one sulfur atom surrounded by 4 Oxygen atoms. Sulfates are very important molecules for everyone’s health and do not cause allergic or sensitivity reactions. Sulfates are used as escort molecules for a number of supplements including glucosamine sulfate and vanadyl sulfate. Sulfates are different from Sulfites and Sulfa Drugs. Thus, people who are sensitive to Sulfites and Sulfa Drugs will not be sensitive to Sulfates.

Sulfur

Sulfur is the chemical element that is found in Sulfa Drugs, Sulfites, and Sulfates. Sulfur is an essential element of life and is found in amino acids and other important molecules in the body. It is IMPOSSIBLE to have a sulfur allergy. You cannot survive without sulfur. When people say that they are allergic to sulfur they mean sulfites or sulfonamides, not sulfur or sulfates.

I hope this helps clear up that mess!!

Chemistry would be so much more fun if they did not give things similar names.