Conjugated Linoleic Acid (CLA)
A naturally occurring fatty acid found in dairy products and meat, taken in supplement form at much higher doses than found in food. Despite heavy marketing for fat loss, the evidence shows only very modest effects on body fat — and some studies suggest possible unfavourable metabolic effects.
Quick read · 3 min
- •Evidence: Weak — limited or inconsistent trial data
- •A systematic review found a statistically significant but very small reduction in body fat of approximately 0.
- •GI upset, nausea, and diarrhoea are common at higher doses.
- •Prescription weight loss drugs produce 7–21% weight loss in trials. Most supplements in this category produce less than 2 kg.
Based on clinical trials · No rankings · Every claim linked to source
Last reviewed: March 2026
How it works
CLA is proposed to reduce fat storage by altering fat cell metabolism and increasing fat burning. The exact mechanism is not fully established. In animal models, CLA shows clear anti-obesity effects — but human trials consistently show much smaller effects.
What the evidence shows
A systematic review found a statistically significant but very small reduction in body fat of approximately 0.05 kg per week vs. placebo. Over 6 months this equates to roughly 1.3 kg of fat mass reduction — very modest. Results are inconsistent across trials, and many studies have industry funding. The effect is on body fat specifically, not necessarily total body weight.
Safety
GI upset, nausea, and diarrhoea are common at higher doses. More concerning: some studies have found possible increases in insulin resistance and liver fat markers in people taking CLA supplements. These potential negative metabolic effects — particularly counterproductive in people with obesity — add caution to its use. Not recommended during pregnancy.
Community insights
These are personal experiences shared in public online communities — not medical advice.
“The insulin resistance signal in some studies is a red flag — if you're taking CLA specifically for metabolic improvement, you may be counteracting yourself.”
“You'd need to eat huge amounts of grass-fed beef and dairy to get supplement-level CLA from food. Whether that's worth considering is another question.”
Common questions
After reading this page, most people compare this with other supplements, look at prescription options, or check what they can do today without a prescription.