Conjugated linoleic acid CLA is a slightly altered form of the essential fatty acid linoleic acid.

CLA for weight loss
Some studies, mostly in rodents, have shown that CLA may reduce weight but others have shown conflicting results. It's possible that CLA could be effective as a weight loss supplement but I'm not yet totally convinced. Overall, there does not seem to be convincing evidence that CLA is clearly helpful as a weight loss supplement. However some people do like to use CLA. I personally think Diet Rx, which has a combination of hoodia extract, green tea extract, ginger, cinnamon, garcinia cambogia, choline, carnitine, 5-HTP, guggul, acetylcarnitine, and several other herbs and nutrients is a better option for  appetite suppression than CLA alone. You can find out more about Diet Rx below.

CLA supplement, 750 mg, 50 softgels - Club Natural

CLA (conjugated linoleic acid) is a recently recognized supplement. CLA is found naturally in a variety of foods, including dairy. CLA offers a rich source of conjugated linoleic acid to supplement the diet naturally.

Each capsule provides 750 mg CLA supplement.
Directions: Take 1, 2 or 3  CLA softgels daily or as recommended by your health care provider.

Click here to buy a CLA supplement, get a FREE bottle of Diet Rx, or to sign up to a FREE newsletter

Subscribe to a FREE Supplement Research Update newsletter. Twice a month we email a brief abstract of several studies on various supplements and natural medicine topics, including CLA, and their practical interpretation by Ray Sahelian, M.D.

Diet Rx for appetite suppression
If you would like to eat less, consider a product called Diet Rx. This natural appetite suppressant works without stimulants. Diet Rx does not have CLA and has no added caffeine, ephedra, ephedrine alkaloids, synephrine, hormones, guarana, ginseng, or stimulating amino acids.

Benefits of Diet Rx
All natural appetite suppressant, decreases appetite so you eat less
Helps you maintain healthy blood sugar levels
Helps you maintain healthy cholesterol and lipid levels
Provides a variety of antioxidant from two dozen herbs and nutrients
Provides healthy fiber
Improves energy
Balances mood
Improves mental concentration and focus
Improves will power and choice of food selection

You can buy Diet Rx here and see a list of hundreds of high quality natural supplement products

More about CLA fatty acids
CLA is a family of positional and geometric isomers with 2 conjugated double bonds formed from linoleic acid and linolenic acid. Most dietary CLA in humans is obtained from dairy products, accounting for the cis-9,trans-11 CLA isomer, also known as rumenic acid, for more than 90% of the total CLA intake. Commercial CLA supplements industrially produced, contain trans-10,cis-12 and cis-9,trans-11 CLA isomers in diverse proportions. Different companies making CLA supplements may have slightly or moderately different fatty acid compositions.

CLA and weight loss
A June, 2004 human study showed that a year treatment with CLA reduces body fat in overweight adults. A March, 2006 study in humans indicated a CLA supplement did not prevent weight gain. Therefore, at this time, it is premature to claim that CLA is an effective weight loss supplement.

CLA and cholesterol
An October 2004 study showed that CLA had beneficial effects on cholesterol metabolism, it had unfavorable effects on blood sugar and insulin sensitivity. Dairy products naturally enriched with cis-9,trans-11 CLA and trans-11 18:1 do not appear to have a significant effect on blood lipid profile. There are several good options for cholesterol management.

High Quality products formulated by a medical doctor
These include Mind Power Rx for better mental focus, concentration, and mood; Diet Rx which helps you eat less. It really works to curb appetite; Good Night Rx for better sleep; Eyesight Rx with lots of antioxidants for better vision; MultiVit Rx a daily comprehensive multivitamin for more energy and vitality; Joint Power Rx for healthy joints; Prostate Power Rx for a healthy prostate gland; Passion Rx for sexual enhancement in men and women; and Veg Rx supplies the missing nutrients in a vegetarian diet.

CLA and weight loss 2007
Data from 18 previous studies on CLA were analyzed. It was found that, when given at a dose of 3 grams per day, CLA appeared moderately effective at promoting body fat loss. People who took a CLA supplement lost a modest amount of 0.2 pounds of fat per week compared to placebo. Dr. Leah D. Whigham, of the University of Wisconsin at Madison, found the body-fat benefits of CLA accrued for 6 months, then gradually faded. It is not clear how CLA works, but it may affect enzymes responsible for body fat storage. There have been some concerns raised about the side effects of consuming CLA. Some studies, for instance, have suggested that the fat may promote insulin resistance, a precursor to diabetes. But other studies have either failed to show this effect, or found that CLA improves the body's use of insulin. American Journal of Clinical Nutrition, May 2007. For information on weight loss pills.

CLA and weight loss 2006
Conjugated linoleic acid supplementation for 1 y does not prevent weight or body fat regain
American Journal of Clinical Nutrition, Vol. 83, No. 3, 606-612, March 2006
Conjugated linoleic acid ( CLA ) is marketed as a safe, simple, and effective dietary supplement to promote the loss of body fat and weight. However, most previous studies have been of short duration and inconclusive, and some recent studies have questioned the safety of long-term supplementation with CLA. Our aim was to assess the effect of 1 year supplementation with CLA (3.4 grams per day) on body weight and body fat regain in moderately obese people. One hundred twenty-two obese healthy subjects with a body mass index (in kg/m2) > 28 underwent an 8-wk dietary run-in with energy restriction (3300–4200 kJ/d). One hundred one subjects who lost >8% of their initial body weight were subsequently randomly assigned to a 1-y double-blind CLA (3.4 g/d) or placebo (olive oil) supplementation regime in combination with a modest hypocaloric diet of –1250 kJ/d. After 1 year, no significant difference in body weight or body fat regain was observed between the treatments. The CLA group regained a mean 4.0 kg body weight and 2 kg fat mass compared with a regain of 4 kg body weight and 2.7 kg fat mass in the placebo group. No significant differences in reported adverse effects or indexes of insulin resistance were observed, but a significant increase in the number of leukocytes was observed with CLA supplementation. A 3.4-g daily CLA supplementation for 1 year does not prevent weight or fat mass regain in a healthy obese population.

Lack of effect of dietary conjugated linoleic acids naturally incorporated into butter on the lipid profile and body composition of overweight and obese men
American Journal of Clinical Nutrition, Vol. 82, No. 2, 309-319, August 2005
The researchers compared the effects on plasma lipoproteins and body composition of the consumption of a modified butter naturally enriched with CLA (CLA-B: 4.22 g CLA/100 g butter fat) by the addition of sunflower oil to the diet of dairy cows with the consumption of a control butter (CON-B) that was low in CLA (0.38 g CLA/100 g butter fat). The study was a crossover design study including an 8-wk washout period, 16 men were fed each of the 2 experimental isoenergetic diets, providing 15% of energy as protein, 45% as carbohydrates, and 40% as lipids, of which >60% was derived from experimental fats, for 4 wk. Consumption of the CLA-B diet induced a significantly smaller reduction in plasma total cholesterol and in the ratio of total to HDL cholesterol than did consumption of the CON-B diet. Abdominal adipose tissue area showed no difference in accumulation of either visceral or subcutaneous adipose tissue after the 2 experimental diets. These results suggest that a 10-fold CLA enrichment of butter fat does not induce beneficial metabolic effects in overweight or obese men.

Conjugated linoleic acid supplementation, insulin sensitivity, and lipoprotein metabolism in patients with type 2 diabetes mellitus.
American Journal of Clinical Nutrition, Vol. 80, No. 4, 887-895, October 2004
Some animal studies have suggested that conjugated linoleic acid CLA supplementation may have therapeutic potential with respect to insulin sensitivity and lipid metabolism, which are important cardiovascular disease (CVD) risk factors associated with type 2 diabetes mellitus. We investigated the effect of CLA supplementation on markers of glucose and insulin metabolism, lipoprotein metabolism, and inflammatory markers of CVD in subjects with type 2 diabetes. The study was a randomized, double-blind, placebo-controlled trial. Thirty-two subjects with stable, diet-controlled type 2 diabetes received CLA (3.0 g/d; 50:50 blend of cis-9,trans-11 CLA and trans-10,cis-12 CLA) or control for 8 wk. A 3-h 75-g oral-glucose-tolerance test was performed, and fasting plasma lipid concentrations and inflammatory markers were measured before and after the intervention. CLA supplementation significantly increased fasting glucose concentrations and reduced insulin sensitivity. Total HDL-cholesterol concentrations increased by 8%, which was due to a significant increase in HDL2-cholesterol concentrations. The ratio of LDL to HDL cholesterol was significantly reduced. CLA supplementation reduced fibrinogen concentrations but had no effect on the inflammatory markers of CVD (C-reactive protein and interleukin 6). CLA supplementation had an adverse effect on insulin and glucose metabolism. Whereas CLA had positive effects on HDL metabolism and fibrinogen, a therapeutic nutrient should not be associated with potentially adverse effects on other clinical markers of type 2 diabetes.

Influence of dietary conjugated linoleic acid and fat source on body fat and apoptosis in mice.
Obes Res. 2004 Sep;12(9):1435-44. Related Articles, Links
To determine whether altered dietary essential fatty acid (linoleic and arachidonic acid) concentrations alter sensitivity to conjugated linoleic acid (CLA)-induced body fat loss or DNA fragmentation. Mice were fed diets containing soy oil (control), coconut oil [essential fatty acid deficient (EFAD)], or fish oil (FO) for 42 days, and then diets were supplemented with a mixture of CLA isomers (0.5% of the diet) for 14 days. Body fat index, fat pad and liver weights, DNA fragmentation in adipose tissue, and fatty acid profiles of adipose tissue were determined. The EFAD diet decreased linoleic and arachidonic acid in mouse adipose tissue but did not affect body fat. Dietary CLA caused a reduction in body fat. Mice fed the EFAD diet and then supplemented with CLA exhibited a greater reduction in body fat (20% vs. 7% in EFAD and EFAD + CLA-fed mice, respectively) compared with mice fed soy oil. Dietary FO decreased linoleic acid and increased arachidonic acid in mouse adipose tissue. Mice fed FO or CLA were leaner than control mice. FO + CLA-fed mice did not differ in body fat compared with FO-fed mice. Adipose tissue apoptosis was increased in CLA-supplemented mice and was not affected by fat source. Reductions in linoleic acid concentration made mice more sensitive to CLA induced body fat loss only when arachidonic acid concentrations were also reduced. Dietary essential fatty acids did not affect CLA induced DNA fragmentation.

Effects of cis-9,trans-11 conjugated linoleic acid supplementation on insulin sensitivity, lipid peroxidation, and proinflammatory markers in obese men.
Am J Clin Nutr. 2004 Aug;80(2):279-83.
We recently showed that trans-10,cis-12 (t10,c12) conjugated linoleic acid CLA causes insulin resistance in obese men. However, metabolic effects of the c9,t11 CLA isomer are still unknown in obese men. Because c9,t11 CLA is the predominant CLA isomer in foods and is included in dietary weight-loss products, it is important to conduct randomized controlled studies that use c9,t11 CLA preparations. We investigated the effects of c9,t11 CLA supplementation on insulin sensitivity, body composition, and lipid peroxidation in a group at high risk for cardiovascular disease. In a randomized, double-blind, placebo-controlled study, 25 abdominally obese men received 3 g CLA /d or placebo (olive oil). Before and after 3 mo of supplementation, we assessed insulin sensitivity (hyperinsulinemic euglycemic clamp), lipid metabolism, body composition, and urinary 8-iso-prostaglandin F(2alpha) (a major F(2)-isoprostane) and 15-keto-dihydro-prostaglandin F(2alpha), markers of in vivo oxidative stress and inflammation, respectively. All subjects completed the study. Compared with placebo,  CLA decreased insulin sensitivity by 15% and increased 8-iso-prostaglandin F(2alpha) and 15-keto-dihydro-prostaglandin F(2alpha) excretion by 50% and 15%, respectively. The decreased insulin sensitivity was independent of changes in serum lipids, glycemia, body mass index, and body fat but was abolished after adjustment for changes in 8-iso-prostaglandin F(2alpha) concentrations. There were no differences between groups in body composition. A CLA preparation containing the purified CLA isomer increased insulin resistance and lipid peroxidation compared with placebo in obese men. Because CLA occurs in commercial supplements as well as in the diet, the present results should be confirmed in larger studies that also include women.

Conjugated linoleic acid supplementation for 1 y reduces body fat mass in healthy overweight humans
American Journal of Clinical Nutrition, Vol. 79, No. 6, 1118-1125, June 2004
Background: Short-term trials showed that conjugated linoleic acid CLA may reduce body fat mass (BFM) and increase lean body mass (LBM), but the long-term effect of CLA was not examined. Objective: The objective of the study was to ascertain the 1-y effect of CLA on body composition and safety in healthy overweight adults consuming an ad libitum diet. Design: Male and female volunteers (n = 180) with body mass indexes (in kg/m2) of 25–30 were included in a double-blind, placebo-controlled study. Subjects were randomly assigned to 3 groups: CLA free fatty acid (FFA), CLA triacylglycerol, or placebo (olive oil). Change in BFM, as measured by dual-energy X-ray absorptiometry, was the primary outcome. Secondary outcomes included the effects of CLA on LBM, adverse events, and safety variables. Results: Mean (± SD) BFM in the CLA triacylglycerol and CLA FFA groups was 8.7 ± 9.1% and 6.9 ± 9.1%, respectively, lower than that in the placebo group. Subjects receiving CLA FFA had 1.8 ± 4.3% greater LBM than did subjects receiving placebo. These changes were not associated with diet or exercise. LDL increased in the CLA FFA group, HDL decreased in the CLA triacylglycerol group, and lipoprotein(a) increased in both CLA groups  compared with month 0. Fasting blood glucose concentrations remained unchanged in all 3 groups. Glycated hemoglobin rose in all groups from month 0 concentrations, but there was no significant difference between groups. Adverse events did not differ significantly between groups. Long-term supplementation with CLA FFA or CLA triacylglycerol reduces BFM in healthy overweight adults.

Conjugated linoleic acid inhibits proliferation and modulates protein kinase C isoforms in human prostate cancer cells.
Nutr Cancer. 2004;49(1):100-8.
Prostate cancer is the second most common cancer in men. The disease etiology is poorly understood, but diet and lifestyle are contributory factors. Conjugated linoleic acids CLA, naturally occurring fatty acids in ruminant food products, have antitumor properties in animal models of cancer and antiproliferative effects on cancer cells in vitro. The cellular mechanisms by which CLA elicit these effects are unclear, particularly for prostate cancer cells. We have previously identified protein kinase C (PKC) isoforms, alpha, delta, iota, mu, and zeta in LNCaP prostate cancer cells. The objective of this study was to determine the effects of CLA (individual cis-9, trans-11 and trans-10, cis-12 isoforms and a 50:50 mixture) on PKC isoform abundance in LNCaP cells. Confluent cells were treated with 6, 25, and 50 microM CLA for 0.5, 6, and 24 h. Cytosol and membrane protein fractions were assayed for PKC isoforms (mainly alpha and delta but also iota, mu, and zeta) by Western blot analysis using specific antibodies. CLA clearly modulated the abundance of these PKC isoforms, both positively and negatively, depending on the isoform, concentration of CLA, and period of treatment. Increased PKC-delta and decreased PKC-iota membrane abundance was consistent with CLA eliciting increased apoptosis and, in part, with their antitumor effects.

The effect of conjugated linoleic acid CLA supplementation after weight loss on body weight regain, body composition, and resting metabolic rate in overweight subjects.
 Int J Obes Relat Metab Disord. 2003 Jul;27(7):840-7.
To study the effects of 13 weeks conjugated linoleic acid CLA supplementation in overweight subjects after weight loss on weight regain, body composition, resting metabolic rate, substrate oxidation, and blood plasma parameters. Subjects either received 1.8 g CLA or placebo per day (low dosage, LD) or 3.6 g CLA or placebo per day (high dosage, HD).  Multiple regression analysis showed that at the end of the 13-week intervention, CLA did not affect % body weight regain. In conclusion, the regain of fat-free mass was favorably, dose-independently affected by a 13-week consumption of 1.8 or 3.6 g CLA per day and consequently increased the resting metabolic rate. However, it did not result in improved body weight maintenance after weight loss.

Effect of conjugated linoleic acid on body composition and plasma lipids in humans: an overview of the literature.
Antonius HM, Utrecht University, Utrecht, Netherlands.
Studies in mice have indicated that feeding diets containing 0.5-1% conjugated linoleic acid (CLA) considerably reduces body fat. These findings have attracted much interest because of the potential use of CLA as a tool to promote weight loss in humans. Several CLA studies in humans have now been published, and the objective of the present review was to give an overview of these experiments. Most of the studies were done in free-living subjects and were not strictly controlled for nutrient and energy intakes. None of the studies found a significant reduction in body weight, and only 2 studies showed a significant but relatively small body fat-lowering effect. Some studies suggested that CLA may have a tendency to increase lean body mass. Furthermore, there are indications from animal studies that CLA may have effects on plasma lipids. However, only one study in humans showed a significant HDL-cholesterol-lowering effect of CLA; in all the other studies, there were no significant effects on plasma total, LDL-, and HDL-cholesterol concentrations or on plasma triacylglycerol concentrations. Thus, the results of the studies in humans indicate that the effect of CLA on body fat is considerably less than that anticipated from mice studies and that CLA has no major effect on plasma lipids.

Supplementation with conjugated linoleic acid causes isomer-dependent oxidative stress and elevated C-reactive protein: a potential link to fatty acid-induced insulin resistance.
Riserus U, Basu S, Circulation 2002 Oct 8;106(15):1925-9
Department of Public Health and Caring Sciences/Geriatrics, Uppsala University, Uppsala, Sweden.
Conjugated linoleic acids CLAs, a group of fatty acids shown to have beneficial effects in animals, are also used as weight loss supplements. Recently, we reported that the t10c12 CLA-isomer caused insulin resistance in abdominally obese men via unknown mechanisms. The aim of the present study was to examine whether CLA has isomer-specific effects on oxidative stress or inflammatory biomarkers and to investigate the relationship between these factors and induced insulin resistance. In a double-blind placebo-controlled trial, 60 men with metabolic syndrome were randomized to one of 3 groups receiving t10c12 CLA, a CLA mixture, or placebo for 12 weeks. Insulin sensitivity (euglycemic clamp), serum lipids, in vivo lipid peroxidation (determined as urinary 8-iso-PGF(2alpha) [F2-isoprostanes]), 15-ketodihydro PGF(2alpha), plasma vitamin E, plasma C-reactive protein, tumor necrosis factor-alpha, and interleukin-6 were assessed before and after treatment. Supplementation with t10c12 CLA markedly increased 8-iso-PGF(2alpha) and C-reactive protein compared with placebo and independent of changes in hyperglycemia or dyslipidemia. t10c12 CLA supplementation increases oxidative stress and inflammatory biomarkers in obese men. The oxidative stress seems closely related to induced insulin resistance, suggesting a link between the fatty acid-induced lipid peroxidation seen in the present study and insulin resistance. These unfavorable effects of t10c12 CLA might be of clinical importance with regard to cardiovascular disease, in consideration of the widespread use of dietary supplements containing this fatty acid.

Conjugated linoleic acid supplementation in humans--metabolic effects.
Smedman A, Vessby B. Lipids 2001 Aug;36(8):773-81
Department of Public Health and Caring Sciences/Geriatrics, Uppsala University, Sweden
Supplementation with conjugated linoleic acid CLA induces a number of physiological effects in experimental animals, including reduced body fat content, decreased aortic lipid deposition, and improved serum lipid profile. Controlled trials on the effects of CLA in humans have hitherto been scarce. The aim of this study was to evaluate the effects of supplementation with CLA in healthy humans on anthropometric and metabolic variables and on the fatty acid composition of serum lipids and thrombocytes. Fifty-three healthy men and women, aged 23-63 yr, were randomly assigned to supplementation with CLA (4.2 g/d) or the same amount of olive oil during 12 wk in a double-blind fashion. The proportion of body fat decreased (-3.8%) in the CLA-treated group, with a significant difference from the control group. Body weight, body mass index, and sagittal abdominal diameter were unchanged. There were no major differences between the groups in serum lipoproteins, nonesterified fatty acids, plasma insulin, blood glucose, or plasminogen activator inhibitor 1. In the CLA group the proportions of stearic, docosatetraenoic, and docosapentaenoic acids increased in serum lipids and thrombocytes, while proportions of palmitic, oleic, and dihomo-gamma-linolenic acids decreased, causing a decrease of the estimated delta-6 and delta-9 and an increase in the delta-5 desaturase activities. These results suggest that supplementation with CLA may reduce the proportion of body fat in humans and that CLA affects fatty acid metabolism.

Riserus, U, et al. Supplementation with conjugated linoleic acid (cla) causes isomer-dependent oxidative stress and elevated C-reactive protein: a potential link to fatty acid-induced insulin resistance. Circulation. 2002 Oct 8;106(15):1925-9.

Inconsistent results
Human studies are evenly split between finding CLA helpful and showing no effect. A study of 180 overweight adults gave some CLA supplements and others placebos. All of the participants were free to eat and exercise as they chose. After one year, people who had been taking CLA supplements lost an average of two to four pounds of body fat, while those receiving placebos lost nothing. The supplements even appeared to boost lean muscle mass among some of the adults. The exercise level between the two groups failed to explain the small changes in body composition. CLA may interrupt several different stages of cancer development. Studies show that CLA can affect the metabolism of carcinogens, protect DNA, slow the growth of cancer cells, promote their destruction, and possibly block the spread of established tumors. In humans, some observational evidence links CLA with breast cancer protection. But controlled studies that could justify a stronger conclusion have only been done in animals. These studies have also produced inconsistent results.

More human studies needed
CLA could improve a person’s immunity. But there are two other areas of possible concern. First, although animal studies show that CLA helps insulin work more effectively, other studies suggest insulin resistance and blood sugar control may be worsened. Second, in some animal studies, CLA seems to decrease fat buildup in blood vessels, but other animal and human studies suggest cholesterol levels and other aspects of heart health become worse. Most researchers say it is too soon to recommend CLA supplements. More human studies must verify the benefits, as well as the risks. The best chemical forms and dose amounts must also be determined. Our normal eating habits provide less than one gram of CLA per day, but studies use doses of three to four grams. Some people have advocated eating higher-fat dairy products to get more CLA. However, CLA is less than one percent of the fat content of these foods. Saturated fat will add up faster than the CLA in these foods. The best plan may be to wait. One recent review of CLA and its anti-cancer effects notes that CLA can accumulate in the body. Studies may now find out whether small amounts of CLA from limited servings of reduced-fat dairy products might add up over time to offer enough cancer and health protection.

CLA emails
Q. Why not eat more foods that have CLA rather than taking a CLA supplement?
   A. A liter of full-fat milk contains about 1 gram of CLA. This is not practical in terms of weight loss.

Q. Would taking a CLA supplement along with hoodia help with weight loss more effectively?
   A. It's hard to say, but the combination could work. See hoodia diet weight loss information.

Q. Can a CLA supplement be taken along with Diet Rx?
   A. Probably, but since Diet Rx works so well to reduce appetite, there may not be a need to take a CLA supplement.

This CLA page was last updated in February 2008.