Supplements for Fat Loss

Few nutrition supplements that promise fat loss can actually assist the process. There are some supplements for fat loss, however, that have been proven to be effective.

Supplements for fat loss

Thermogenic aids

Thermogenesis is just a fancy name for raising body temperature. Thermogenic supplements are stimulants, mostly herbal in origin. They actually work pretty well in boosting the metabolic rate and assisting the uncoupling process via beta-agonists.

How They Work

The main ingredients for most of these fat loss or “energy” supplements are stimulants like caffeine and green tea extract. These, frequently combined with other thermogenic substances like cayenne pepper and yohimbine, work by stimulating the body’s output of noradrenaline. This elevates the body’s metabolic rate and causes more calories to be burned. Current NIH guidance notes that caffeine can increase thermogenesis and fat oxidation, but its effect on actual weight loss appears modest; green tea and green tea extract may also produce only small effects on body weight, and concentrated green tea extracts have some safety concerns (18).

Potential Problems

Over-use of stimulants can cause anxiety, irritability, insomnia, and increases in blood pressure and heart rate. Very high stimulant doses can produce serious adverse effects, and combining multiple stimulants can amplify those effects (18). Recommended doses vary from brand to brand, depending on standardization, and you should never exceed the manufacturer’s recommended dosage. It makes sense to cycle stimulant usage on and off, because tolerance and loss of effect can occur with habitual caffeine use (18). If you choose to use stimulants, you should start with half a dose and see how you feel. People who are pregnant, have hypertension, arrhythmia, or other cardiac problems, or take medications that can interact with stimulants should consult a clinician before using stimulant-containing weight-loss supplements.

L-carnitine

L-carnitine plays an important role in fat metabolism because it helps transport long-chain fatty acids into the mitochondria, where they can be burned for energy. That basic physiology has made carnitine a popular fat-loss supplement for decades. The important question, however, is whether taking extra carnitine actually makes you burn more fat.

For healthy people, the body can normally make the carnitine it needs, and simply taking more does not automatically force your muscles to burn more fat. That said, recent research suggests that supplemental L-carnitine may still provide a modest benefit for weight loss, particularly in people who are overweight or obese.

A 2020 meta-analysis of 37 randomized controlled trials involving more than 2,200 people found that L-carnitine supplementation reduced body weight by an average of about 2.7 pounds compared with control groups. The researchers also found reductions in BMI and fat mass, although the better-quality studies confirmed the weight-loss effect more consistently than the changes in body composition. About 2 grams per day appeared to produce the best weight-loss response in their dose-response analysis (21).

That doesn’t make L-carnitine a magic fat burner. Losing a couple of extra pounds over the course of a study is useful, but it is nowhere near the effect you’ll get from controlling calorie intake and exercising consistently. Think of carnitine as a possible assist to a good fat-loss program, not a replacement for one.

Carnitine has also been studied extensively for exercise performance. The results are mixed. Some studies have shown improvements in high-intensity exercise performance, power output, fatigue, and recovery, while others show little or no benefit. A 2021 systematic review found some benefit from L-carnitine during high-intensity exercise, but no significant improvement in moderate-intensity endurance performance (22). So claims that carnitine automatically increases endurance, oxygen utilization, or lactate clearance are overstated.

There may be a recovery benefit as well. Some studies suggest that L-carnitine can reduce muscle soreness and markers of muscle damage following hard exercise. That may be useful for people training frequently, although this is a different benefit from directly increasing fat burning.

Most supplemental studies use somewhere around 1 to 4 grams of L-carnitine per day. For fat-loss purposes, the evidence is strongest around 2 grams daily rather than gigantic doses. There is also no compelling reason to treat carnitine like a stimulant that has to be swallowed immediately before a workout. Many of the studies showing benefits used regular supplementation for weeks or months.

L-carnitine is generally well tolerated, but it is not completely free of side effects. Around 3 grams per day or more can cause nausea, stomach cramps, diarrhea, vomiting, or a fishy body odor in some people (19). More is definitely not better.

So to summarize: L-carnitine is a legitimate nutrient involved in fat metabolism, and modern research suggests that supplementation may produce a small additional weight-loss benefit. It may also help certain aspects of exercise performance and recovery. Just keep your expectations realistic. Carnitine can potentially help a good nutrition and exercise program work a little better – it isn’t going to rescue a bad one.

Hydroxycitric acid

Hydroxycitric acid (HCA) comes from the herb Garcinia cambogia, which is a variant of the English brindleberry. In studies with laboratory animals, HCA showed the ability to inhibit the action of ATP-citrate lyase (17), which is a liver enzyme that is partially responsible for the conversion of dietary carbohydrate to fat. The real kicker with HCA, however, is a lesser known fact — HCA suppresses the body’s l-carnitine rate-limiting enzyme malonyl coenzyme A, which allows the carnitine palmitoyl transferase enzyme (which initiates the fat transport process) to continue unchecked (18).

Chromium picolinate

Chromium is essential for the metabolism of glucose, insulin, fatty acids, and protein (19). Chromium is one of the most deficient minerals in America, with an average daily intake of only 25-33 mcg (20). Since chromium is vital to insulin utilization, adequate chromium intake is essential for a fat loss program. There are many studies that show chromium supplements aid in improving body composition. Active folks need more chromium than couch potatoes, because it is used rapidly during exercise (21). Chromium picolinate is the most bioavailable form of chromium (22). Supplement with 200 – 400 mcg per day. Current NIH guidance is more cautious: chromium may play a role in carbohydrate, lipid, and protein metabolism, but supplementation produces at most very small changes in body weight and body fat, with little clinical significance; safety data at high supplemental intakes are also limited (20).

One point of note – in 1996, columnist Jane Brody wrote a story that was picked up by several major newspapers claiming that chromium picolinate causes chromosome damage. For your information, her reference was a single study conducted in 1995 that showed that chromium picolinate caused clastogenic (chromosomal) changes to Chinese hamster cells (23). Cells in a test tube, not in a hamster. Oh, and they also used a dose that was five to ten thousand times the bodily level of chromium achieved with recommended supplemental amounts. This is the kind of crap that gives legitimate nutrition supplementation a bad rap. In a living system, long-term supplementation with chromium picolinate is very safe, even in large doses (24,25,26). Do your best to educate yourself and always evaluate any information that comes screaming down the media pipeline.

References Cited

1. Tendera EW. Int J Obes 1993;17:343-347.
2. Astrup, et al. The effect and safety of an ephedrine/caffeine compound compared with ephedrine, caffeine, and placebo in obese subjects on an energy restricted diet. Int J Obesity 1992;16:269-277.
3. Dullo, Miller. The thermogenic properties of ephedrine/methizanthine mixtures; human studies. Int J Obesity 1986;10:467-481.
4. Tendera EW. Int J Obes 1993;17:343-347.
5. Wooter, et al. Intercerebral hemorrhage and vasculitis related to ephedrine abuse, Ann Neurol 1983;13:337.
6. Colgan, M. The New Nutrition. C.I. Publications, 1994, p.181.
7. Fleury, et al. Uncoupling protein-2: a novel gene linked to obesity and hyperinsulemia. Nat Genetics, 1997; 15:269-272.
8. Ghorbam, et al. Hypertrophy of brown adipocytes in brown and white adipose tissues and reversal of diet induced obesity in rats treated with a beta-3 adrenoceptor agonist. Biochem Pharmacol, 1997;54:121-131.
9. The uncoupling concept has been summarized from the Colgan Chronicles, vol. 2 no. 4 and 5. I do not wish to take credit for Dr. Colgan’s exhaustive research on the subject, and no infringement upon any copyright is intended.
10. Colgan, M. The New Nutrition. C.I. Publications, 1994, p.181.
11. Siliprandi, et al. Metabolic changes induced by maximal exercise in human subjects following l-carnitine administration. Biochem Biophys Acta 1990;1034:17-21.
12. Bremer J. Carnitine metabolism and function. Physiol. Review 1983;63:1420-1480.
13. Stumpf DA. Carnitine deficiency organic acidemias and Reye’s syndrome. Neurology 1985;35:1041-1045.
14. Marconi C, et al. Effects of l-carnitine loading on the aerobic and anaerobic performance of endurance athletes. Eur J Applied Physiol 1985;54:131-135.
15. Angeline C, et al. Clinical study of efficacy of l-carnitine and metabolic observations in exercise physiology. Clinical Aspects of Human Carnitine.
16. Colgan M. Optimum Sports Nutrition. Advanced Research Press, 1993.
17. Groff, et al. Advanced Nutrition and Human Metabolism. West Publishing Co, 1995.
18. Colgan, M. Colgan Chronicles, vol. 2 no. 5. 1998.
19. Colgan, M. The New Nutrition. C.I. Publications, 1994:96.
20. Anderson RA. Trace Elements in Human and Animal Nutrition, 5th ed. Academic Press, 1987:225-244.
21. Anderson RA, et al. Effect of exercise (running) on serum glucose, insulin, glycogen, and chromium excretion. Diabetes, 1982;31:212-216.
22. Broadhurst, et al. Characterization and structure by NMR and FTIR spectroscopy, and molecular modeling of chromium (III) picolinate and nicotinate complexes utilized for nutritional supplementation. J Inorganic Biochem, 1997;66:119-130.
23. Stearns, et al. The dietary supplement chromium picolinate induces chromosome damage in Chinese hamster ovary cells. FASEB J, 1995;9:1643-1648.
24. Saner, G. Chromium in Nutrition and Disease. 1980.
25. Mertz, W. Chromium occurence and function in biological systems. Physiol Rev, 1969;49:163-203.
26. Anderson RA, et al. Lack of toxicity of chromium chloride and chromium picolinate. US Society of Toxicology Annual Meeting, 1996.

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