Find us on Social Media:

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

Conjugated Linoleic Acid Side Effects and Warnings

Written by FoundHealth.

Safety Issues

CLA appears to be a generally safe nutritional substance. 1 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. 2 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 may worsenblood sugar control; in overweight people without diabetes, CLA might decrease insulin sensitivity, creating a prediabetic state. 3 In contrast, a study using the most precise method of measuring insulin sensitivity failed to find any harmful effect. 4 Nonetheless, at present, individuals with diabetes or who are at risk for it should not use CLA except under physician supervision.

One study found that CLA impairs endothelial function and another that it increases levels of C-reactive protein; both of these effects suggest a possible increase in cardiovascular risk. 5 Concerns have also been raised regarding use of CLA by nursing mothers. A double-blind, placebo-controlled study indicates that use of CLA reduces the fat content of human breast milk. 6 Since infants depend on the fat in breast milk to provide adequate calories and on certain fats to aid proper growth and development, it is probably prudent for nursing mothers to avoid CLA supplements.

Maximum safe dosages of CLA for young children, pregnant women, or those with severe liver or kidney disease have not been determined.


  1. Whigham LD, O'Shea M, Mohede IC, Walaski HP, Atkinson RL. Safety profile of conjugated linoleic acid in a 12-month trial in obese humans. Food Chem Toxicol. 42(10):1701-9.
  2. Belury MA, Mahon A, Shi L. Role of conjugated linoleic acid (CLA) in the management of type 2 diabetes: evidence from Zucker diabetic (fa/fa) rats and human subjects. Paper presented at: 220th ACS National Meeting; August 20-24, 2000; Washington, DC. Abstract AGFD 26.
  3. Risérus U, Arner P, Brismar K, Vessby B. Treatment with dietary trans10cis12 conjugated linoleic acid causes isomer-specific insulin resistance in obese men with the metabolic syndrome. Diabetes Care. 25(9):1516-21.
  4. Syvertsen C, Halse J, Høivik HO, Gaullier JM, Nurminiemi M, Kristiansen K, Einerhand A, O'Shea M, Gudmundsen O. The effect of 6 months supplementation with conjugated linoleic acid on insulin resistance in overweight and obese. Int J Obes (Lond). 31(7):1148-54.
  5. Taylor JS, Williams SR, Rhys R, James P, Frenneaux MP. Conjugated linoleic acid impairs endothelial function. Arterioscler Thromb Vasc Biol. 26(2):307-12.
  6. Masters N, McGuire MA, Beerman KA, Dasgupta N, McGuire MK. Maternal supplementation with CLA decreases milk fat in humans. Lipids. 37(2):133-8.


No one has made any comments yet. Be the first!

Your Comment