3–6 g/day. In practice, its usefulness for weight loss is marginal.
The effect on fat is small and of doubtful clinical relevance.
View the study (meta-analysis) →In real life the change is usually minimal.
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CLA, or conjugated linoleic acid, is a family of isomers of linoleic acid (omega-6) found naturally in small amounts in dairy and ruminant meat, where it is produced by bacterial fermentation in the rumen before being absorbed and deposited in animal tissues; commercial supplements contain concentrated mixtures (typically cis-9, trans-11 and trans-10, cis-12, in a 50:50 ratio) obtained by catalytic isomerization of safflower or sunflower oil, with amounts per capsule far higher than could be achieved through the diet.
Clinical interest in CLA began in the 1990s with animal studies showing drastic reductions in body fat and increases in lean mass with supplementation, a promise that generated enormous commercial popularity as a "natural fat burner"; the following decades of human research have considerably tempered those initial expectations: the effects on body composition in humans are real but very modest, and there are worrying signals regarding markers of insulin resistance and inflammation with prolonged use at high doses that call for caution.
The strongest evidence for CLA is a modest but replicable reduction in body fat mass with supplementation at 3-6 grams per day for 12-24 weeks: several meta-analyses put the average fat loss at around 0.5-1 kilogram more than placebo over 6 months, a clinically marginal magnitude that hardly justifies supplementation as a main weight-loss strategy.
A meta-analysis published in 2007 in the American Journal of Clinical Nutrition with 18 trials concluded that CLA produces small but statistically significant reductions in fat mass, with effects that tend to plateau after 6 months and do not translate into substantial changes in body weight because they are usually accompanied by small compensatory increases in lean mass.
Unlike most supplements with a benign profile, CLA has metabolic signals that require attention: several studies have documented modest worsening of insulin sensitivity with prolonged use, especially in people with overweight or obesity; increases in inflammatory markers (C-reactive protein); and, in some cases, hepatic steatosis induced by the supplementation itself, an effect attributed mainly to the trans-10, cis-12 isomer.
This duality (a small reduction in fat with possible unfavorable metabolic effects) is the reason most clinical guidelines do not recommend CLA as a strategy for weight loss or metabolic improvement, and the reason many endocrinologists prefer not to include it in their supplementation plans, a position that contrasts with its sustained commercial popularity.
The doses studied range from 3 to 6 grams per day, divided into two or three doses with meals (CLA is a fatty acid and its absorption improves with dietary fat); typical commercial products contain 800-1,000 milligrams per capsule, which translates into 3-6 capsules per day; the effect on body composition appears gradually and requires at least 12 weeks of continuous use for clinical evaluation.
The adverse effects described are mild digestive discomfort (nausea, diarrhea, dyspepsia), especially with high doses and at the start of treatment; the metabolic signals (insulin resistance, inflammation, possible steatosis) argue for limiting use to relatively short periods (3-6 months) and monitoring metabolic markers in people with cardiometabolic risk factors; people with type 2 diabetes, preexisting fatty liver, or insulin resistance should avoid CLA or use it under medical follow-up; in pregnancy and breastfeeding the data are limited, but avoiding high doses is recommended.
Information, not medical advice. Scientific evidence reflects the quality of the studies.