Fatty Acid

CLA

Conjugated linoleic acid (mixture of c9,t11-CLA and t10,c12-CLA isomers)

Evidence TierCWADA NOT PROHIBITED

tuneTypical Dose

3-6 g per day

watchEffect Window

12-24 weeks for minor body composition shifts.

check_circleCompliance

WADA NOT PROHIBITED

Overview

Clinical Summary

Conjugated linoleic acid is a group of linoleic acid isomers found in meat and dairy. It is used for small body fat reduction effects in body composition protocols.

Meta-analyses show small reductions in body fat with little change in total body weight, and results vary by isomer and duration. Some studies report small lean mass changes, but findings are inconsistent. Minority effects include immune modulation and lipid changes, often mixed. In some people, insulin sensitivity markers may worsen, limiting net benefit.

Interacts with PPAR-alpha to modulate lipid metabolism. May inhibit lipoprotein lipase and upregulate carnitine palmitoyltransferase. The t10,c12 isomer paradoxically worsens insulin resistance.

Outcomes

What This Is Expected To Influence

Primary Outcomes

  • Modest body fat reduction (clinically insignificant ~0.09 kg/week)

Secondary Outcomes

  • Minor lean body mass preservation during weight loss

Safety

Contraindications and Interactions

Contraindications

  • Diabetes
  • Metabolic syndrome
  • Fatty liver disease

Side effects

  • GI upset
  • Bloating
  • Diarrhea
  • May worsen insulin resistance (t10,c12 isomer)

Interactions

  • Diabetes medications (paradoxical worsening of insulin sensitivity)

Avoid if

  • Type 2 diabetes
  • Metabolic syndrome
  • Non-alcoholic fatty liver disease

Evidence

Study-level References

cla-SRC-001Meta-analysis of RCTs
Sourceopen_in_new

Whigham LD, et al. "Efficacy of conjugated linoleic acid for reducing fat mass: a meta-analysis in humans." Am J Clin Nutr. 2007.

Population: Healthy and overweight adults

Dose protocol: Source-listed

Key findings: CLA given at a dose of 3.2 g/d produces a modest loss in body fat in humans (average 0.05 kg per week).

Paper content

CLA given at a dose of 3.2 g/d produces a modest loss in body fat in humans (average 0.05 kg per week).

cla-SRC-002Double-blind, randomized, placebo-controlled trial.
Sourceopen_in_new

Jia K, She Y, He Y, He J, et al. Conjugated linoleic acid supplementation suppresses the de novo lipogenesis in adults with high body fat. Mol Nutr Food Res. 2025;69(23-24):e70306. doi:10.1002/mnfr.70306. PMID:41169023.

Population: Adults with elevated body fat percentage.

Dose protocol: 12-week CLA supplementation versus placebo in 65 adults with high body fat.

Key findings: CLA supplementation decreased erythrocyte C16:1n7 and C18:1n9, increased C18:3n3, and suppressed de novo lipogenesis markers correlated with improved plasma and liver lipid profiles.

Notes: Provides a mechanistic link between CLA intake and lipid metabolism changes in humans with elevated body fat.

Paper content

This double-blind RCT randomized 65 adults with elevated body fat to CLA or placebo for 12 weeks. CLA supplementation decreased erythrocyte C16:1n7 and C18:1n9 (markers of desaturase activity related to de novo lipogenesis) while increasing C18:3n3. These fatty acid shifts correlated with improvements in plasma and liver lipid profiles, suggesting that CLA suppresses de novo lipogenesis in humans with high body fat. The study provides a mechanistic link between CLA intake and lipid metabolism changes, supporting the small body composition effects seen in meta-analyses.

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