In 30 seconds
- Look at the milligrams of CLA a day, not of oil: 3 softgels of 1,000 mg at 80% provide 2,400 mg of CLA. The key meta-analysis used 3.2 g a day.
- The CLA-rich oils assessed by EFSA are made from safflower oil and contain around 80% CLA, with its two main forms in equal parts.
- Tonalin is the brand name of a CLA raw material. What counts are its figures: source, concentration and milligrams a day.
- The chemical form matters less: in a one-year trial, CLA as triglycerides reduced fat mass by 8.7% compared with placebo, and as free fatty acids, by 6.9%.
To choose a CLA supplement, check three things on the label: the milligrams of CLA a day, not of oil; a concentration of around 80%, like that of the oils assessed by EFSA; and that it is made from safflower oil 1 2. Tonalin is the brand name of one of these raw materials: it tells you where the CLA comes from, but the figures you need to check are the same. If you first want to know what it does, see what CLA is good for.
What to look for on the label
| What it says | What it means | What to look for |
|---|---|---|
| “1,000 mg” per softgel | Almost always the weight of oil in the softgel | Multiply it by the percentage of CLA |
| “CLA 80%” | In every 1,000 mg of oil, 800 mg is CLA | Around 80%, like the oils assessed by EFSA |
| Daily dose | The softgels you take each day | Between 2.4 and 3.5 g of CLA a day, adding them all up |
| “Safflower oil” | The starting oil, rich in linoleic acid | Safflower and GMO-free |
| “c9,t11 and t10,c12” | The two main forms of CLA | In equal parts, as in most trials |
| “Tonalin®” | The brand name of a CLA raw material | The same figures: percentage and milligrams a day |
| Gelatine softgel | What the shell is made of | If you avoid animal products, choose a plant-based shell |
Our own compilation based on EFSA (2010 and 2012), the FSAI (2008), Whigham et al. (2007) and the NIH Office of Dietary Supplements.
We explain each point below, one by one, with what the studies say.
1. Milligrams of CLA, not of oil
The big number on the pack is usually the weight of oil in each softgel. To find out how much CLA you are taking, multiply it by the concentration:
- 1,000 mg softgel at 80%: 800 mg of CLA.
- 3 softgels a day: 2,400 mg of CLA.
How much do you need? The key meta-analysis, covering 18 trials, adjusted its results to 3.2 g of CLA a day, the median dose across the trials. At that dose, people lost 0.09 kg more fat per week than with placebo 5. Trials lasting 6 months or more used between 2.4 and 6 g a day 4.
The ceiling is set by safety: EFSA considers 3-3.5 g of CLA a day safe for 6 months 1. Look for a product that gives you between 2.4 and 3.5 g when you add up the softgels in the daily dose, and do not go above it.
Oil is not CLA
What is in a 1,000 mg softgel at 80%
2. Concentration: around 80%
The CLA-rich oils assessed by the European Food Safety Authority (EFSA), Tonalin TG 80 and Clarinol, contain around 80% CLA 1:
- Tonalin TG 80: its specification requires at least 700 mg of CLA per gram, and the batches analysed came out at 77-78% 2.
- Clarinol: at least 78% CLA 3.
With a lower concentration, you need more softgels for the same dose. That is why the percentage has to be on the label: without it, you cannot do the maths.
3. Where it comes from: safflower oil
CLA occurs naturally in dairy products and beef 4, but in small amounts. The CLA in supplements is made from an oil rich in linoleic acid, the omega-6 it is derived from.
Classic safflower oil contains between 67 and 83% linoleic acid 6. Both oils assessed by EFSA start from it 2 3. An isomerisation process shifts the double bonds in linoleic acid to a new position and turns it into CLA 2 3.
In the case of Clarinol, the assessment specifies that it starts from a non-genetically modified variety of safflower 3. Look for “GMO-free” on your CLA. There is more about this oil in safflower oil: properties and its link to CLA.
4. What is Tonalin?
Tonalin® is the trade name of a CLA-rich oil sold as a raw material to supplement manufacturers. It is not a different type of CLA: it is a brand, just like Clarinol.
Its Tonalin TG 80 version was assessed by EFSA in 2010 2:
- Source: safflower oil high in linoleic acid.
- Concentration: around 80% CLA.
- Forms: c9,t11 and t10,c12, in a 1:1 ratio.
- Chemical form: mainly triglycerides.
- Dose assessed: 4.5 g of oil a day, equivalent to 3.5 g of CLA, for up to 6 months.
If a label says “Tonalin”, it is telling you where the raw material comes from. What you need to check is still the same: the source, the percentage of CLA and the milligrams a day.
5. The two forms of CLA, in equal parts
CLA is not a single molecule. Its two main forms are called c9,t11 and t10,c12 4. Supplements usually contain it as an equal mix of the two, and that mix is the one used in most human trials 5.
It is also the ratio in the oils assessed by EFSA 1. If the label lists the forms, look for 50:50 or 1:1.
6. Triglyceride or free fatty acid
The CLA in supplements comes either as a triglyceride or as a free fatty acid 4. The two forms were compared in a one-year trial with 180 overweight adults eating normally 7:
- Triglyceride, 3.4 g of CLA a day: 8.7% less fat mass than with placebo 4 7.
- Free fatty acid, 3.6 g of CLA a day: 6.9% less fat mass 4 7.
Both worked, and the authors checked that the changes could not be explained by diet or exercise 7. It is not the factor that should weigh most in your choice: before the form, look at the milligrams of CLA a day.
7. The softgel, stimulants and price
- The softgel. Many are made of gelatine. If it is bovine, the product is not suitable for vegans, even though the oil comes from a plant.
- No stimulants. CLA contains no caffeine or synephrine, and you take it with meals. We compare it with the rest in fat burners: which ones work, according to the studies.
- The price per day. Divide the price by the number of days the bottle lasts. It is the fair way to compare.
Who should check with their doctor first
In the Clarinol assessment, the proposed labelling advised that it should not be taken by pregnant or breastfeeding women or by children under 5, and that anyone taking medication should consult their doctor 3. EFSA has also not established its safety in people with type 2 diabetes 2.
If this applies to you, check with your doctor first. You will find the details in CLA: side effects and who should not take it.
You will find the routine, softgel by softgel, in how to take CLA and all the trials in CLA: what the studies say.
Frequently asked questions
What is Tonalin?
It is the brand name of a CLA-rich oil that supplement manufacturers use as a raw material. Its Tonalin TG 80 version, assessed by EFSA, is made from safflower oil and contains around 80% CLA, with its two main forms in equal parts.
What does 80% CLA mean?
That 80% of the oil in each softgel is CLA. A 1,000 mg softgel contains 800 mg of CLA, and 3 softgels, 2,400 mg.
How many mg of CLA should you take a day?
The key meta-analysis adjusted its results to 3.2 g a day, and trials lasting 6 months or more used between 2.4 and 6 g. EFSA considers 3-3.5 g a day safe for 6 months. Always follow the dose on your label.
Is CLA better as triglycerides or as free fatty acids?
Both forms worked in a one-year trial with 180 overweight adults: fat mass ended up 8.7% below placebo with triglycerides and 6.9% below with free fatty acids. Before the form, look at the milligrams of CLA a day.
Is CLA suitable for vegans?
It depends on the softgel. Safflower oil comes from a plant, but many softgels are made of gelatine.
Sources
- EFSA Panel on Dietetic Products, Nutrition and Allergies. Statement on the safety of the «conjugated linoleic acid (CLA)-rich oils» Clarinol® and Tonalin® TG 80 as novel food ingredients. EFSA Journal. 2012;10(5):2700. View publication
- EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on the safety of «conjugated linoleic acid (CLA)-rich oil» (Tonalin® TG 80) as a novel food ingredient. EFSA Journal. 2010;8(5):1600. View publication
- Food Safety Authority of Ireland. Initial assessment: Clarinol™ CLA-rich oil. 1 May 2008. View publication
- Office of Dietary Supplements, National Institutes of Health. Dietary supplements for weight loss: fact sheet for health professionals. View publication
- 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. View publication
- Oyen LPA, Umali BE. Carthamus tinctorius L. In: van der Vossen HAM, Mkamilo GS, editors. PROTA (Plant Resources of Tropical Africa). Wageningen: PROTA; 2007. View publication
- Gaullier JM, Halse J, Høye K, Kristiansen K, Fagertun H, Vik H, Gudmundsen O. Conjugated linoleic acid supplementation for 1 y reduces body fat mass in healthy overweight humans. Am J Clin Nutr. 2004;79(6):1118-1125. View publication
Information based on published studies. It does not replace the advice of a doctor or registered dietitian. The results describe what was measured in each study, not the properties of any specific product. A varied and balanced diet and a healthy lifestyle are important.
