Conjugated linoleic acid (CLA) refers to a mixture of multiple linoleic acids. Linoleic acid is a type of omega-6 fatty acid found in dairy, various meat products, and certain seed oils. The fatty acid is available as a supplement. CLA may benefit your health by treating conditions like high blood pressure and obesity.
Conjugated linoleic acid may support blood pressure management. The exact mechanism is unknown, research suggests CLA may lower blood pressure by affecting the endothelium, a layer of cells in your blood vessels that causes it to contract and relax.
Studies have found that pairing CLA with the blood pressure medication ramipril can boost the medication’s effects. CLA does not appear to have a significant effect on blood pressure when taken alone.
A research review looked at several studies of CLA supplementation on blood pressure and overall heart health. The review found that CLA doses of 1-10.8 grams did not significantly lower blood pressure. CLA also appears to lower intracellular adhesion molecule (ICAM), a cell molecule that aids in inflammation.
More research is needed to understand whether CLA may be beneficial in the treatment of high blood pressure.
In early studies, doses of CLA between 3-6.8 grams daily appear to decrease body fat, increase lean body mass, and reduce waist and hip circumference in certain adults and children. CLA seems to work by breaking down fat and slowing the production of new fat cells.
That said, the overall effect is small. Adults who took 2 to 6 grams of CLA for six to twelve months lost, on average, just 1.5 pounds of body weight and around 3 pounds of body fat. Children in one study had better results—taking 3 grams a day for seven months reduced body fat compared to those not taking the supplement.
Some studies show CLA lowers hip circumference in women but doesn’t change total body weight. Others suggest it can reduce body fat when paired with exercise, though without improving cholesterol or overall weight. Many studies find little to no impact on obesity or BMI at all.
Beyond weight, CLA may offer other metabolic health benefits. Research hints that it could improve insulin sensitivity, which is important for lowering your risk of type 2 diabetes and heart disease. It may also help control appetite by reducing hunger and improving feelings of fullness.
Aside from body weight, CLA may help with exercise energy. However, study results have not proven this theory. One group of researchers evaluated CLA supplementation paired with six weeks of aerobic exercise in untrained to moderately trained men. Results showed no overall benefit on muscle fatigue or power.
CLA may also play a role in energy and muscle metabolism on a cellular level, but more research is needed.
Other health conditions that CLA may benefit include:
- Inflammatory-related diseases: CLA decreases inflammatory markers in the body. More research is needed to understand how CLA could be useful in treating inflammatory-related diseases, such as rheumatoid arthritis and inflammatory bowel disease.
- High cholesterol and blood lipids: Data on how CLA affects cholesterol and lipids are inconsistent. Some studies have reported that CLA does not affect lipids, while others show that CLA may decrease high-density lipoprotein (HDL), “good cholesterol.” Other studies have found that CLA supplementation appears to have a positive effect on HDL, but does not positively affect triglycerides, total cholesterol, or low-density lipoprotein (LDL), “bad cholesterol.”
Researchers have evaluated the use of CLA in treating and preventing various other conditions, including the common cold, diabetes, and cancers of the breast, prostate, lung, and bladder. These studies have found little to no effect of CLA on these conditions.
Products that come from animals such as cows, goats, and sheep are considered good sources of CLA. This includes milk and other dairy products, like cheese, and meat.
The amount of CLA in each product differs based on the animal’s diet. For example, beef fat contains a range of 1.7-10.8 milligrams of CLA per gram of fat. The average diet provides 15-174 milligrams of CLA daily.
CLA is also found in certain vegetable oils, including sunflower, safflower, and hydrogenated soybean oil.
CLA supplements are often found in capsule, soft gel, or powder form. CLA supplements are made of multiple types of linoleic acid, also called isomers. The most common CLA isomer types found in supplements and food are cis-9,trans-11 linoleic acid and trans-10,cis-12 linoleic acid. Most supplements provide half of each of these isomer types.
Dosage
CLA is often taken in doses of 1.6-6.5 grams daily for two to 12 weeks. More research is needed to understand the ideal dose for CLA supplements. It’s best to follow the dosing instructions on the supplement label or talk to your healthcare provider for personalized dosing suggestions.
CLA is considered safe in doses of up to 6.8 grams daily in adults for up to one year. Children have been shown to safely take doses of up to 3 grams for up to 7 months. It’s advised not to take CLA supplements if you are pregnant or lactating as there is not enough information available to know if it is safe.
Potential Drug Interactions
CLA has not been shown to interact with many drugs or supplements. The few that may have a possible interaction include:
- Blood thinners and antiplatelet drugs: CLA may increase your risk for bleeding, especially when used with blood-thinning or antiplatelet drugs.
- Blood pressure drugs: Due to its blood pressure-lowering effects, CLA may increase your risk for hypotension (low blood pressure). Researchers have specifically found this with the blood pressure medication ramipril. Symptoms of low blood pressure include blurred vision, dizziness, weakness, and fast heart rate.
- Vitamin A: CLA has been shown to increase the level of vitamin A in the body, although how it does this is not well understood. Vitamin A levels may increase to dangerous levels if you take CLA with vitamin A or other products that include vitamin A. Signs of vitamin A toxicity include nausea, headache, dizziness, and coordination issues.
Talk to your healthcare provider if you are taking any of these medicines and considering CLA.
Can You Take Too Much CLA?
Available research suggests CLA is safe in doses of up to 6.8 grams per day for a year based on amounts used in studies. There are currently no maximum dosing recommendations for CLA supplements based on side effects or potential toxicities.
Overall, CLA is well tolerated. Reported side effects of CLA include:
- Constipation
- Diarrhea
- Dyspepsia (indigestion)
- Flatulence (gas)
- Nausea or vomiting
In rare cases, liver toxicity and damage have been reported with CLA. Symptoms may include jaundice (yellowing of the skin and eyes), rash, and weakness. CLA doses as high as 3 grams daily do not appear to affect the liver.
Conjugated linoleic acid (CLA) is a mixture of multiple linoleic acids, a type of omega-6 fatty acid. CLA can be found in dairy, various meat products, and certain seed oils. The fatty acid can also be taken as a supplement. CLA may be useful in treating conditions such as high blood pressure and obesity.
Talk with your healthcare provider if you are interested in taking CLA supplements. They can help you determine if the product would be useful to your overall health and ensure it will not interact with any current medications.
