Does CLA reduce body fat?

Short answer

Barely. Across 70 studies, CLA cut only 0.44 kg more body fat than a placebo on average, and in the high-quality studies alone there was no difference.

Does CLA reduce body fat?
'Just take it and the fat comes off' — does this ad hold up?
CLA (conjugated linoleic acid) reduced fat in animal studies and is sold as a diet supplement. We checked whether it cut body fat in humans, and if so, by how much.
It did cut fat, about 0.09 kg a week
After 6 months, the effect stopped growing
An analysis that pooled 18 studies found that 3.2 g a day cut about 0.09 kg more fat per week than a placebo. The effect kept building for 6 months, then barely grew after that.
Over half a year: 1.33 kg
The body weight difference was 0.70 kg
An analysis of 7 studies lasting more than 6 months found 1.33 kg more fat loss and 0.70 kg more weight loss than a placebo. 4 of the 7 had serious flaws in how they reported their methods. Side effects included constipation, diarrhea and loose stools.
In well-designed studies, there was no difference
The average across 70 studies was 0.44 kg
A 2024 analysis of 70 studies (4,159 people) found an average fat loss of 0.44 kg and a drop of 0.77 percentage points in body fat. But looking only at high-quality studies, body fat and body fat percentage did not go down.
What about taking it with exercise?
Body weight was no different from exercise alone
An analysis of 20 studies combining exercise and CLA found no difference in body weight or exercise performance compared with exercise alone. Body fat dropped a little more, but only in studies lasting longer than 4 weeks. In a study of 76 people taking CLA during 7 weeks of strength training, the fat difference was 1.2 kg.
The 'fat-burning' form actually backfired
Insulin resistance rose by 19%
In a 12-week study of 60 people with a lot of belly fat, a standard CLA mix did not lower body fat or weight compared with a placebo and only lowered good cholesterol by 2%. The group taking the 'fat-burning' form alone (t10c12) saw insulin resistance rise by 19%.
Bottom line: at most about 1 kg
The formula fails at 'take it and lose fat'
Pooling all the studies, CLA cut 0.44 to 1.33 kg more body fat, but high-quality studies alone showed no difference. The body weight difference was under 1 kg. CLA does not noticeably reduce body fat.