How much fat does CLA take off?

According to the meta-analysis of 18 studies and adjusted to the median dose of 3.2 g a day, about 0.09 kg of fat per week versus placebo. A little over a kilo in three months, with consistency. It is a real, small effect, not a fat burner.

Does CLA have side effects?

In a 12-week trial in 60 men with metabolic syndrome, the t10c12 isomer increased a marker of oxidative stress by 578% and C-reactive protein by 110% versus placebo, and the rise in the former was related to worsening insulin resistance. It is the same isomer credited with the effect on fat.

How long does CLA take to show results?

The meta-analysis describes a linear effect up to about six months. Given its size, in four weeks there is nothing visible on the scale or in the mirror.

How many CLA capsules do you need?

It depends on the CLA percentage of the oil in each tub, which you need to read on the label. Reaching the 3.2 g of CLA from the meta-analysis usually takes quite a few more capsules than the recommended serving on the pack, which changes the real price per day.

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CLA · Weak evidence

What CLA is for and what the evidence says

The short answer. CLA is a fatty acid that worked very well in animals and much less well in people. The meta-analysis used to sell it is real and so is its figure: at 3.2 g a day, fat loss versus placebo is about 0.09 kg per week. That is, a little over a kilo in three months, at best and with consistency. And there is a trade-off that does not appear on labels: in men with metabolic syndrome, the t10c12 isomer multiplied a marker of oxidative stress almost sixfold and doubled C-reactive protein.

Reviews find no consistent effect. It is listed because it sells, not because it works. No figure on this page is attributed to a specific product: the effect belongs to the ingredient and every number carries its source next to it.

01 What it does and how much

Each row is a measured effect, with the figure the study gives and the source number. Where the evidence gives no figure, the column says so instead of making up a percentage.

Effects of CLA with their source
Effect	How much	Detail
Fat loss versus placebo	0.09 kg per week	Adjusted to the median dose of 3.2 g a day. That is about 1.2 kg of fat in three months, on top of whatever the diet was already doing. [1]
Effect per gram per week	-0.024 kg	The dose-effect relationship from the meta-analysis. It is what allows the figure above to be calculated and shows the magnitudes involved. [1]
Duration of the effect	linear up to 6 months	After that it slowly approaches a plateau towards two years. It is not an effect that speeds up over time. [1]
Oxidative stress	+578%	With the t10c12 isomer in men with metabolic syndrome over 12 weeks, measured as urinary F2-isoprostanes. The increase was independently related to worsening insulin resistance. [2]
C-reactive protein	+110%	Same trial, same isomer, versus placebo. That isomer is precisely the one identified as responsible for the effect on fat. [2]

02 How to take it

Dose. 3.2 g a day is the median dose from the meta-analysis.
When. With meals, because it is a fat.
How long before you notice it. The effect is linear up to about six months. In four weeks there is nothing to see.

Details that change the result

The contradiction is uncomfortable: the isomer credited with the effect on fat is the same one that worsened markers in the metabolic syndrome trial.
Capsules usually contain 1000 mg of oil with a percentage of CLA. Reaching 3.2 g of CLA takes quite a few more capsules than the tub suggests.
With excess weight, metabolic syndrome or insulin resistance, that is precisely the profile of the trial where markers worsened.
The same fat loss can be achieved with a small dietary adjustment, free and without inflammatory markers involved.

03 When it makes sense and when it does not

Worth it if

With diet, training and sleep already sorted, accepting that the measured effect is roughly one kilo of fat in three months.

Not worth it if

With metabolic syndrome, insulin resistance or diabetes, the profile of the trial where markers worsened.
Expecting it to replace a calorie deficit, which is what actually moves body fat.
At one or two capsules a day, which comes nowhere near the 3.2 g of the meta-analysis.

04 Sources

Every figure above comes from here. They are position stands from scientific societies, meta-analyses and peer-reviewed reviews: if a claim cannot hang from one of these lines, it is not on the page. References are cited in their original form.

Whigham LD, Watras AC, Schoeller DA. Efficacy of conjugated linoleic acid for reducing fat mass: a meta-analysis in humans. Am J Clin Nutr. 2007;85(5):1203-1211. Dieciocho estudios: perdida de grasa frente a placebo de -0,024 kg por gramo de CLA y semana; ajustado a la dosis mediana de 3,2 g/dia, 0,09 kg por semana frente a placebo; efecto lineal hasta 6 meses. doi:10.1093/ajcn/85.5.1203
Riserus U et al. Supplementation with conjugated linoleic acid causes isomer-dependent oxidative stress and elevated C-reactive protein: a potential link to fatty acid-induced insulin resistance. Circulation. 2002;106(15):1925-1929. Sesenta hombres con sindrome metabolico, 12 semanas: el isomero t10c12 aumento los isoprostanos 8-iso-PGF2alfa un 578 % y la proteina C reactiva un 110 % frente a placebo, con el aumento de isoprostanos relacionado de forma independiente con el agravamiento de la resistencia a la insulina. doi:10.1161/01.CIR.0000033589.15413.48

This is not medical advice. It is what some studies say about an ingredient, not a protocol for you. With an illness, medication or pregnancy involved, the decision belongs to a healthcare professional who knows you.

Questions about CLA

Answered with the data on this page

How much fat does CLA take off?: According to the meta-analysis of 18 studies and adjusted to the median dose of 3.2 g a day, about 0.09 kg of fat per week versus placebo. A little over a kilo in three months, with consistency. It is a real, small effect, not a fat burner.
Does CLA have side effects?: In a 12-week trial in 60 men with metabolic syndrome, the t10c12 isomer increased a marker of oxidative stress by 578% and C-reactive protein by 110% versus placebo, and the rise in the former was related to worsening insulin resistance. It is the same isomer credited with the effect on fat.
How long does CLA take to show results?: The meta-analysis describes a linear effect up to about six months. Given its size, in four weeks there is nothing visible on the scale or in the mirror.
How many CLA capsules do you need?: It depends on the CLA percentage of the oil in each tub, which you need to read on the label. Reaching the 3.2 g of CLA from the meta-analysis usually takes quite a few more capsules than the recommended serving on the pack, which changes the real price per day.

And now, which to buy

Prices, kept apart from the evidence

This page explains what CLA does and deliberately names no brand. The comparison is the other half: 29 products from 6 stores from €0.038 per capsule, sorted by price and by how verifiable their certification is.

See the cla comparison

Other guides

What each supplement does, with its sources