Not medical advice. I am a software engineer, not a physician. This page documents my own protocol and the research I read while building it. Talk to a qualified clinician before changing your supplementation, diet or any treatment. Lab reference ranges quoted here vary by laboratory and by individual.
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Conjugated Linoleic Acid (CLA) is a naturally occurring family of fatty acids found primarily in grass-fed beef and dairy products. The two biologically active isomers — cis-9, trans-11 (c9,t11) and trans-10, cis-12 (t10,c12) — each exert different physiological effects. The t10,c12 isomer is primarily responsible for the body composition effects, while c9,t11 has modest anti-inflammatory properties. Modern diets provide far less CLA than ancestral diets due to grain-fed livestock practices, making supplementation relevant for those seeking body composition optimization.
CLA is not a fat burner in the stimulant sense. It works through metabolic pathway modulation: reducing fat storage, enhancing fatty acid oxidation, and modestly shifting body composition toward lean mass over time. The effects are real but moderate — expect 0.05 kg/week of additional fat loss over placebo when combined with proper training and nutrition. CLA is a long-term metabolic optimization tool, not a quick fix.
The t10,c12 isomer of CLA inhibits lipoprotein lipase (LPL) activity in adipose tissue. LPL is the enzyme that breaks down circulating triglycerides into free fatty acids for uptake and storage in fat cells. By reducing LPL activity, CLA decreases the rate at which dietary and circulating fats are deposited into adipose tissue. This is a storage-reduction mechanism, not a fat-burning mechanism — an important distinction.
CLA upregulates carnitine palmitoyltransferase I (CPT-1), the rate-limiting enzyme for fatty acid entry into mitochondria for beta-oxidation. It also activates PPARalpha, a nuclear receptor that drives expression of fat oxidation genes in liver and skeletal muscle. The combined effect is a modest increase in the rate at which stored and circulating fatty acids are burned for energy rather than stored.
Realistic expectations: Meta-analyses show CLA produces approximately 0.05 kg/week of additional fat loss over placebo. This is meaningful over 6-12 months but will not produce dramatic changes in weeks. CLA works best as part of a comprehensive body composition strategy including caloric deficit, resistance training, and adequate protein.
| Parameter | Detail |
|---|---|
| Product | NOW Foods — CLA 800 mg |
| Dose | 800 mg x 3 softgels = 2,400 mg CLA |
| Timing | With breakfast (all 3 softgels together) |
| Isomers | 50:50 blend of c9,t11 and t10,c12 isomers |
| Notes | Minimum effective dose in meta-analyses is 3.2 g/day of CLA mixture. Take consistently for 12+ weeks to observe effects. |
CLA has been the subject of several meta-analyses and randomized controlled trials examining body composition effects. The evidence consistently shows modest but statistically significant fat mass reduction.
Whigham, L. D., et al. (2007). Efficacy of conjugated linoleic acid for reducing fat mass: a meta-analysis in humans. Am J Clin Nutr, 85(5), 1203-1211. PubMed 17490954
Pariza, M. W., et al. (2001). The biologically active isomers of conjugated linoleic acid. Prog Lipid Res, 40(4), 283-298. PubMed 10867045
Blankson, H., et al. (2000). Conjugated linoleic acid reduces body fat mass in overweight and obese humans. J Nutr, 130(12), 2943-2948. PubMed 15213024
| Test | What It Measures | Link |
|---|---|---|
| Lipid Panel | Total cholesterol, LDL, HDL, triglycerides; monitor for any lipid changes during CLA supplementation | Lab Tests |
NOW Foods — CLA 800 mg (90 softgels) — $13.80 on iHerb.
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A 2025 comprehensive review in Food Science & Nutrition examined CLA's dual role in obesity and metabolic disorders, finding that while preclinical and clinical studies confirm CLA promotes fat oxidation and modulates adipocyte function, results remain dose-dependent with significant individual variability. A separate 2025 double-blind, randomized, placebo-controlled trial published in Molecular Nutrition & Food Research demonstrated that CLA supplementation suppresses de novo lipogenesis in adults with high body fat, identifying a new mechanistic pathway beyond its known effects on lipolysis. The meta-analytic consensus remains that 3.2 g/day of CLA produces a modest but statistically significant loss in body fat (approximately 0.09 kg/week), and future research should focus on personalized approaches considering genetic and lifestyle factors.