Conjugated Linoleic Acid
What is it? Overview Usage Side Effects and Warnings

What is Conjugated Linoleic Acid?

Conjugated linoleic acid (CLA) is a mixture of different isomers, or chemical forms, of linoleic acid. Linoleic acid is an essential fatty acid—a type of fat that your body needs for optimum health.

Based on preliminary evidence, CLA has been promoted as a "fat-burning" supplement and as a treatment for diabetes. However, there is little evidence that it works and growing evidence that CLA might actually worsenblood sugar control in people who are overweight.

While CLA is often recommended for aiding weight loss or improving body composition (ratio of muscle to fat), evidence from studies is conflicting. 1 One meta-analysis (systematic statistical review) of all the data found minimal benefits at most. 2 Another meta-analysis concluded that, when taken at a dose of 3.2 grams per day, CLA slightly reduces body fat levels. 3 Finally, in one study, a combination of CLA and chromium failed to improve body composition. 4

Note: Some, but not all studies have raised concerns that use of CLA by overweight people could raise insulin resistance and therefore increase risk of diabetes. In addition, it might increase cardiovascular risk in other ways, as described in the Safety Issues .

One study failed to find that CLA-enriched...

Safety Issues

CLA appears to be a generally safe nutritional substance. 5 However, there are some concerns with its use.

During the course of investigations into its effect on fat, CLA was found to act somewhat similarly to some oral medications used for diabetes . This led to research into the possible usefulness of CLA as a treatment for diabetes. In one study, CLA reduced blood sugar levels in diabetic rats as effectively as a standard diabetes treatment. 6 The same researchers also performed a small, double-blind, placebo-controlled trial in humans. The results indicated that CLA improved insulin responsiveness in people with type 2 (adult onset) diabetes. However, several subsequent studies found opposite and rather alarming results: Use of CLA by people with diabetes...