Omega/Fatty Acid ·Moderate evidence ·Reviewed May 2026
Naturally occurring trans fat found in grass-fed meat and dairy with body composition benefits.
The bottom line
Evidence rating moderate. Most-documented uses: body composition, fat loss support, immune modulation. 18 sources indexed (2000–2024), with 5 interaction records on file.
Core mechanism
Activates PPARgamma in adipose tissue, reducing lipogenesis. Inhibits stearoyl-CoA desaturase (SCD-1) and lipoprotein lipase, modulating fat storage and oxidation.12,16
Ranked by evidence and value.
Real-world pricing across three quality tiers. Assumes Mixed Isomer CLA Softgels.
Assumes 3-6 g/day. Vendor basis: NOW Sports/iHerb, Vitacost, BulkSupplements softgels, and Amazon marketplace; multi-softgel dosing raises daily cost. Updated 2026-05-28.
How much you'd eat to match a supplemental dose.
Whole foods contain CLA in small amounts; typical diet portions do not match common supplemental doses.
What to test, the optimal window inside the conventional range, and how long a response takes.
CLA supplementation raises plasma CLA isomers; the trans-10, cis-12 isomer is associated with body fat reduction but also with adverse lipid and insulin resistance signals in some studies.16
Specialty fatty acid panel. Track lipid panel and fasting insulin because of mixed metabolic signals.
CLA and green tea extract are often combined for body composition support and may have complementary effects on fat oxidation and energy expenditure.
Recommendation: Acceptable to combine for weight management goals. Because green tea extract carries a dose-dependent hepatotoxicity risk, avoid high-dose extracts and prefer taking with food.
L-carnitine supports transport of fatty acids into mitochondria for oxidation, which is mechanistically complementary to CLA's role in fat metabolism.
Recommendation: Reasonable to combine for body composition goals. No timing precautions; both are generally well tolerated.
Combining CLA with fish oil may offset CLA's tendency to worsen some lipid and inflammatory markers, since omega-3s improve triglycerides and have anti-inflammatory effects.
Recommendation: A sensible pairing; fish oil can counterbalance potential unfavorable lipid or insulin-sensitivity effects sometimes seen with CLA. No special timing needed.
CLA (specifically the t10,c12 isomer in standard 50:50 supplements) has documented potential to reduce insulin sensitivity, while chromium is taken to improve it. Because both are commonly bundled in weight-management and fat-loss stacks, this opposition is clinically relevant rather than theoretical. The interaction matters most for people with prediabetes, type 2 diabetes, or metabolic syndrome, where unexpected swings in glycemic control carry real consequences.
Recommendation: If you are using chromium to support glucose control, be cautious stacking it with high-dose mixed CLA (3 to 6 g/day). They can be taken in the same day, but monitor fasting glucose or use a glucometer or CGM during the first few weeks of combining them. People with insulin resistance, prediabetes, or diabetes should consult a clinician before pairing them. Consider an isomer-specific CLA (predominantly c9,t11), which has not shown the same insulin-impairing signal, or prioritize chromium and drop CLA if glycemic control is the goal.
CLA can increase lipid peroxidation and oxidative-stress markers, which raises the body's vitamin E (antioxidant) requirement. Pairing CLA with vitamin E is a protective, complementary combination: the vitamin E helps counter CLA-driven oxidation, and because both are fat-soluble they are absorbed efficiently when taken together with food containing fat. This is a favorable pairing rather than a risk, with the main caveat being to keep vitamin E at sensible doses.
Recommendation: Take CLA and vitamin E together with a fat-containing meal for best absorption of both. A standard vitamin E intake (roughly 15 mg or 22 IU natural d-alpha-tocopherol, up to about 100 to 200 IU) is reasonable alongside CLA and may help offset CLA-related oxidative stress. Avoid very high-dose vitamin E (above roughly 400 IU long-term), which carries its own risks, and do not assume vitamin E fully neutralizes the metabolic concerns of the t10,c12 CLA isomer.
Numbered references. Citations throughout the page link here.
Meta-analysis of 14 RCTs found CLA significantly reduced body weight (-0.72 kg), BMI (-0.22 kg/m2), and body fat percentage (-1.32%) in CVD-risk patients. No effect on lipid profile or blood pressure.
Akhgarjand C, Tavakoli A, Samavat S et al.. The effect of conjugated linoleic acid supplementation in comparison with omega-6 and omega-9 on lipid profile: a graded, dose-response systematic review and meta-analysis of randomized controlled trials. Frontiers in nutrition. 2024
CLA supplementation significantly reduced body mass, BMI, waist circumference, fat mass, and body fat percentage, though high-quality subgroup showed CLA failed to change fat mass and body fat percentage.
Rastgoo S, Shimi G, Shiraseb F et al.. The effects of conjugated linoleic acid supplementation on inflammatory cytokines and adipokines in adults: A GRADE-assessed systematic review and dose-response meta-analysis. Frontiers in immunology. 2023
Ghodoosi N, Rasaei N, Goudarzi K et al.. The effects of conjugated linoleic acid supplementation on glycemic control, adipokines, cytokines, malondialdehyde and liver function enzymes in patients at risk of cardiovascular disease: a GRADE-assessed systematic review and dose-response meta-analysis. Nutrition journal. 2023
CLA combined with exercise is generally safe and can lower body fat and insulin resistance but does not reduce body weight or enhance exercise performance.
Meta-analysis of 11 RCTs found CLA significantly decreased MDA concentrations and increased 8-iso-PGF2alpha levels. No significant change in GPx concentrations.
Morvaridzadeh M, Estêvão MD, Morvaridi M et al.. The effect of Conjugated Linoleic Acid intake on oxidative stress parameters and antioxidant enzymes: A systematic review and meta-analysis of randomized clinical trials. Prostaglandins & other lipid mediators. 2022
Meta-analysis of 67 RCTs found CLA produced statistically significant weight difference of -1.08 kg vs placebo (p<0.01), but this did not meet the threshold for clinical significance (>=2.5 kg).
Meta-analysis of 13 trials found CLA significantly reduced body weight (-0.52 kg), BMI (-0.23 kg/m2), fat mass (-0.61 kg) and increased lean body mass (+0.19 kg), but effects were small and may not be clinically significant.
Mohammadi-Sartang M, Sohrabi Z, Esmaeilinezhad Z et al.. Effect of Conjugated Linoleic Acid on Leptin Level: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et metabolisme. 2018
CLA at a dose of 3.2 g/day produced a modest loss in body fat in humans.
CLA supplementation had an adverse effect on insulin and glucose metabolism in patients with type 2 diabetes.
Systematic review of CLA's effects in humans covering body composition, glucose metabolism, and lipid profiles with mixed results on metabolic safety.
The trans-10,cis-12 isomer of CLA decreased glucose and lipid uptake and preadipocyte differentiation due in part to decreased PPARgamma expression.
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