CLA Side Effects

Conjugated linolenic acid -- or CLA for short -- is a naturally-occurring derivative of the essential fatty acid called linoleic acid 23. This fatty acid is found in dietary sources, such as beef and dairy products, as well as supplements. Though additional research is necessary to support the purported health benefits of CLA, this supplement may help reduce high cholesterol, decrease body fat and prevent certain forms of cancer. Before taking CLA supplements, discuss the side effects of this natural treatment with your doctor.


You may feel unusually fatigued as a side effect following treatment with CLA. Increased fatigue may negatively affect your ability to remain active and attentive during your normal daily activities. You may also find that you need to sleep for longer periods of time than usual to feel refreshed.


Intestinal irritation may occur after you take a dose of CLA. Consequently, you may experience frequent, urgent bowel movements that produce loose stools -- a side effect more commonly known as diarrhea. Episodes of diarrhea may also be accompanied by stomach pain, cramping or bloating. If diarrhea persists, you may be at risk of becoming dehydrated. Dehydration may result in symptoms of dizziness, headache, dry skin or increased thirst. Seek additional care from your primary medical provider if you experience recurrent episodes of diarrhea or if you exhibit symptoms of dehydration.

Stomach Discomfort

Treatment with CLA supplements may cause stomach discomfort in certain people. Sensations of nausea may lead to a temporary loss of your normal appetite. Contact your doctor if nausea doesn't subside or if you develop additional stomach-related effects, such as vomiting.

Additional Health Concerns

If you have a personal or family history of heart disease or diabetes, consult your physician before taking CLA supplements. Health professionals with the University of Michigan Health System report that treatment with CLA supplements may negatively affect the function of your blood vessels, which may elevate your risk of developing heart disease 2. Additionally, CLA supplements may also increase your blood sugar levels and may exacerbate diabetes symptoms in affected people.