Tonalin CLA can cause potentially serious side effects including high blood sugar levels, low HDL cholesterol, hyperglycemia, nausea and allergic reactions, according to eMedTV. Symptoms of an allergic reaction to Tonalin CLA can also include difficulty breathing or swallowing.
Conjugated linoleic acid refers to a number of chemicals found in the fatty acid called linoleic acid, according to WebMD. Dairy products and beef are the major dietary sources of CLA. When taken as a supplement, CLA is often used for bodybuilding as well as for conditions including cancer, hardening of the arteries, obesity and weight loss resulting from chronic disease.
CLA consumed through dietary sources is not likely to cause significant side effects, states eMedTV. Dietary supplements such as Tonalin CLA can cause negative reactions, however, including nausea, diarrhea and fatigue. More serious reactions can include hyperglycemia as a result of one of the isomers in Tonalin CLA that causes the body to become more resistant to insulin,
CLA occurs in different forms called isomers, according to eMedTV. When compared to dietary sources of CLA, synthetic CLA usually contains more of the particular isomer that is linked to harmful side effects, such as high levels of C-reactive protein, which may indicate inflammatory problems, and an allergic reaction that may cause wheezing and other respiratory problems.