CLA Supplements Side Effects – How Safe CLA Supplements Compare To Natural CLA?

March 25, 2018

Jelly Bell

CLA Supplements Side Effects – How Safe CLA Supplements Compare To Natural CLA?

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Conjugated Linoleic Acid, or CLA for short, is a fatty acid which has powerful health effects, including burning fat, as has been shown in many research and studies [1].

Beef and dairy are natural sources of CLA, and CLA supplements have been using worldwide as weight loss treatment, and many other health benefits [2].

However, many people concern whether CLA supplements – like many others weight loss supplements – have harmful side effects, and how safe CLA supplements are or WHAT DOSAGE IS RIGHT.

Therefore, many studies have been conducted and have shown that CLA supplements are overall safe and effective, but CLA supplements may have serious adverse effects when using a high dose or used by patients with medical conditions.  

In this article, some common CLA supplements side effects are listed below.

How CLA contributes to losing weight and other health effects?

Obese people are rising in number around the world, and CLA has been found with a possibility to REDUCE BODY FAT levels by cutting down calories in, enhancing fat burn, stimulating fat breakdown and inhibiting the production of it. Click to see WHAT DOES CLA DO to your body [3].

CLA has been found with a possibility to REDUCE BODY FAT levels
CLA has been found with a possibility to REDUCE BODY FAT levels

CLA’s mechanism on losing body fat by speeding up metabolism, which means the food is converted into energy more efficiently. In fact, CLA DOESN’T HELP LOSE YOUR OVERALL BODY WEIGHT, but it keeps fat cells not growing bigger instead.

In one controlled group study, Pariza found that CLA can alter fat-to-muscle ratio in those who stopped their diet and don’t take CLA,  put on weight back after all with a fat-to-muscle ratio of 75-25. In other group, participants also kept using CLA after stopping dieting, also gain weight but with 50-50 fat-to-muscle proportion [1].

It’s essential to remember CLA supplements are not magical medications. Nothing can replace good eating habits and decent daily exercise. Nevertheless,  CLA supplements have significant benefits to participants on a psychological side when they are on special diets.

Pariza and his partners on one study showed that people in CLA supplements used group claimed that their feelings improved compare to the placebo received group. Pariza said CLA supplements mostly help people who on a weight-loss diet less stressful. Seeing better results encourage them to stay on a diet.

Several of these studies have shown that people who get a lot of CLA from foods have a lower risk of various diseases, including type 2 diabetes, heart diseases, and cancer.

In short, CLA found naturally in food is beneficial for your health and CLA supplements are good for your body, including shedding some pounds, make sure to choose THE BEST CLA FOR WEIGHT LOSS.

What are CLA supplements side effects?

Like other oral supplements, CLA supplements are mostly safe orally taken with food amounts and is probably safe when taken in treatment amounts, in which the dose is higher.

Researchers have found some CLA supplements side effects. The question is how safe CLA supplements are, and if there are any precautions and warnings.
Many people have suggested that it is the BEST TIME TO TAKE CLA SUPPLEMENTS BEFORE OR WITH MEALS. CLA supplements side effects are rare but may include fatigue, nausea or stomach discomfort. People who report CLA supplements side effects claim to feel better after two weeks. CLA supplements side effects are explained in details below.

Until now, researchers are still searching for answers to safety in using long-term CLA supplements. It hasn’t been established for CLA supplements safety, and toxicity levels and CLA supplements side effects have not been well scripted and proven.

Negative CLA supplements side effects due to large dosage

Negative CLA supplements side effects due to large dosage
Negative CLA supplements side effects due to large dosage

Some adverse effects of CLA supplements on animal studies have been reported. Nonetheless, in studies on animals, where used dosage is much higher than human trials, these unwanted effects mostly appear, which may imply that there could be a dose-associated issue with CLA supplements.  Positive benefits like weight loss, muscle gain are more likely to happen on a high dosage, but some side effects also appear.

There is no doubt that CLA found naturally in food is beneficial. However, CLA found in supplements is made from vegetable oils, which makes the difference in benefits and side effects.

According to some studies, CLA supplements are beneficial when taken with amounts of real foods but harmful taking in large doses or some with medical conditions. CLA supplements side effects usually don’t happen when taken a recommended dose or they are transient. Some CLA supplements side effects, especially take place when taken overdosed, are quite severe and should be carefully considered.

Some common CLA supplements side effects are:


One study from Norway showed that small doses of CLA could cause a minor decrease in body fat mass. However, fatigue is one of CLA supplements side effects fatigue, even when taken with the recommended dose.

Having constant fatigue may worsen your ability to stay active and focus therefore interrupt your normal daily activities. You may also crave for more time sleeping to feel revived and awake.

Gastrointestinal discomfort: diarrhea, stomach pain, nausea

Using CLA supplements can cause stomach discomfort for some people. There are reports that consumers have a sensation of nausea after using CLA supplements, which may cause a short-term loss of normal appetite. Some also reported loose stools or diarrhea when taking the supplements.

Those CLA supplements side effects are usually lessened when taken with milk and tend to subside around two weeks later.  
Consult your physician if you continuously feel nausea, vomit, pain in stomach.

Patients with medical conditions listed below may suffer from CLA supplements side effects.

Cardiovascular disease

Another unwanted effects studies have shown in research of CLA supplements side effects in human beings is an escalation of triglycerides and LDL – bad cholesterol and reduction of the HDL levels, which means altering negatively in the serum lipids profile. Nonetheless, the findings on serum lipids or effects on blood pressure are not consistent in human studies. So it’s best to consult your physician if you have dyslipidemia.

Medical Center of Pittsburgh University claims that CLA could suppress the function of blood vessels, which might increase C – reactive protein (CRP) levels, an inflammatory marker substance. CRP with a high concentration in blood links with cardiovascular disease as a risk factor. If you have heart conditions or have risk factors that might worsen it,  ask your doctor before using CLA supplements.


Another undesirable CLA supplements side effect is that triggering insulin resistance which leads to high blood sugar, therefore increasing the possibility of worsening diabetes and an increased risk of developing cardiovascular and inflammatory diseases.

Irish researchers studied on effects of CLA supplements on blood sugar in type 2 diabetes patients. One group took 3 grams of CLA every day for eight weeks, and a group received a placebo. The result was CLA supplement seemed to increase fasting glucose levels and insulin resistance noticeably.

However, one study published in  2007, in which they use more reliable measuring method, stated there were no convincing differences in insulin resistance and fasting glucose between treatment group and placebo group.

It is still argued that if CLA increases blood sugar concentration and declines sensitivity of insulin, or affects the response of insulin, which leads to abnormal regulation of sugar in or out human body’s tissues. Since there is mixed evidence, it is probably a good idea to consult with your physician before using CLA supplements if you are suffering from pre-diabetes or diabetes.

Liver fat storage

The liver has a crucial part of energy internally balance, as it converts excessive dietary glucose into free fatty acid which is exported as Triglycerides. Several studies have shown that too much dosage of CLA supplements can cause increased liver fat, which leads to diabetes metabolic syndrome eventually [4].

Hospital of Covilha University – Portugal reported the first case of CLA supplements side effect in human in 2008. The patient was a female, 46 years old, presented symptoms onset of strength lacking, yellowish pigmentation of the skin and eyes and itchy skin, with zero proof of hemochromatosis, hepatitis, or autoimmune disease.

She said that she had started to use CLA supplements for 14 days to lose body fat. Doctors suspected her liver was damaged by CLA supplements and her liver biopsy eventually proved it. After quitting using CLA supplements, her biomarkers for liver health return to normal [5].

Breast Milk

CLA’s effect on reducing fat might lower healthy fat percentage in your milk without affecting the total milk output. This CLA supplement side effect affects your children consume insufficient calories from fat, leads to lack of proper growth. 

CLA's effect on reducing fat might lower healthy fat percentage in your milk
CLA’s effect on reducing fat might lower healthy fat percentage in your milk

Therefore, you should be careful in using CLA supplements. It’s best for pregnant or breastfeeding women to refrain from using CLA after all.

Precautions and Warnings to avoid CLA supplement side effects


CLA is likely safe for children orally taken with medical amounts for less than seven months. Long-term use has yet to be known since there isn’t enough evidence of safety.

Pregnant and breastfeeding women

CLA supplements are possibly safe when taken orally with amounts found in food. It is best to stay safe and avoid using large quantities while in pregnant and breastfeeding periods.

Bleeding disorders

CLA can make blood clotting process slow down. Theoretically, it might increase the risk of bleeding and bruising in people who have bleeding disorders. Stop using CLA supplements at least two weeks before scheduled surgery to avoid extra bleeding.


One of CLA supplements side effects are worsening diabetes by enhancing insulin resistance. Avoid using CLA supplements if you are diagnosed diabetes or prediabetes [6].

Dosage and Safety

Fairly speaking, studies on animals in which harmful effects are shown, used much higher doses than human daily supplementation.

However, as in some case reports and some of the studies on humans with usual dose, some concerning CLA supplements side effects are still shown.

It’s important to remember that CLA supplement side effects increase with dosage.

It is advised that it’s best to use 3.2 to 6.4 grams of CLA per day. Find out HOW TO TAKE CLA correctly.

The FDA considered CLA as Generally Regarded as Safe and can be added to the diet.   

Should You Take CLA Supplements?

Natural CLA is sure good for your health, and CLA supplements also offer many benefits as has been scientifically proven its ability to burn fat. Since CLA supplements side effects are reported and concerned, many scientific trials are going on to test its safety, so it’s the best to ask your doctors for advice before taking CLA supplement.

It’s also recommended that you check liver function tests, metabolic markers and blood tests to make sure that you’re not doing any harm to your body.

Remember to choose BEST CLA SUPPLEMENTS on the market to help you with weight loss and minimize CLA supplements side effects. Still, keep in mind that CLA supplements are not a magical pill, you might need a decent weight loss plan which includes a healthy, low-calorie diet and EXERCISE REGULARLY to lose and continue to maintain your weights.

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