Conjugated Linoleic Acid

Conjugated linoleic acids · Rumenic acid

Snapshot

Indications	Contraindications
Body composition in overweight/obesity¹ Weight management² Fat loss alongside exercise³ Inflammatory cytokines^4–6 Cancer prevention⁷	Diabetes⁸ Cardiovascular disease⁸ Metabolic syndrome⁸ Insulin resistance⁸

Conjugated linoleic acid (CLA) is a group of linoleic acid isomers found in dairy and ruminant meat⁷. Its antiobesity effect is attributed to the trans-10,cis-12 isomer altering fat metabolism⁷. Supplementation is used for body fat reduction and weight management in overweight and obese adults, and for cancer prevention, where human studies are limited and mixed⁷.

Meta-analyses find small reductions in body weight and fat mass that may not reach clinical importance^{1, 2, 9}. Blood pressure was unchanged, while C-reactive protein rose. In a 2024 mouse study of high-fat-diet insulin resistance, supplementation improved glucose tolerance and insulin signaling; no human trial has replicated it. Products list CLA mainly as softgels and powders; see Form comparison.

The most consequential caution is metabolic: CLA caused insulin resistance in obese men⁷, and a meta-analysis in patients at risk of cardiovascular disease found higher fasting glucose¹⁰. Its labels ask for a practitioner's advice before use for weight loss or in pregnancy⁸.

Last updated October 16, 2026. Read how we make monographs.

In the full monograph

66 sources, 57 studies

When to useThe situations practitioners use it for, each with the reason and the study behind it.
SafetyWho should avoid it, who needs extra care, and the side effects reported in studies.
InteractionsThe medicines and supplements it interacts with, the effect of each, and what labeling says to watch.
Protocol notesThe doses used in studies, how and when they were taken, and how the forms on the market compare.
How it worksWhat it is and how it works in the body, in plain terms.
Published studiesThe studies behind each use, popular claims checked against them, and trials still under way.
Word of mouthWhat patients and practitioners report online, kept separate from the clinical evidence.
Clinical perspectiveA closing read of where the evidence is solid, where it is thin, and what has not been studied.

Snapshot

In the full monograph

Sources