Research

Hormonal

Supplementation with the trans10cis12 (t10c12) isomer of conjugated linoleic acid (CLA) causes significant insulin resistance and worsens lipid profiles in obese men with the metabolic syndrome.

If you are obese and have signs of metabolic syndrome (like high blood pressure or high triglycerides), avoid supplements containing the trans10cis12 isomer of conjugated linoleic acid (CLA). While marketed for weight loss, this specific isomer has been shown to worsen insulin resistance and lower 'good' HDL cholesterol, potentially increasing your risk for type 2 diabetes and heart disease. Standard CLA mixtures also failed to improve body composition in this group.

GoodRefutesHIGH confidence
Unexpectedly, t10c12 CLA increased insulin resistance (19%; P < 0.01) and glycemia (4%; P < 0.001) and reduced HDL cholesterol (-4%; P < 0.01) compared with placebo
Ulf Risérus et al. · Diabetes Care · 2002

Why this rating

Randomized, double-blind, placebo-controlled trial with a clear mechanism and statistically significant results, though limited to a specific male demographic.

Source

Treatment With Dietary <i>trans</i>10<i>cis</i>12 Conjugated Linoleic Acid Causes Isomer-Specific Insulin Resistance in Obese Men With the Metabolic Syndrome

Ulf Risérus et al. · Diabetes Care · 2002

DOI 10.2337/diacare.25.9.1516

rct · n=60Cited 436×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

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