Fuel:One Thermo Stack Review

Thermo Stack is fat-burner by Fuel:One, an Iovate (MuscleTech) brand, which uses similar ingredients and doses as other Iovate weight-loss supplements…

Fuel:One Thermo Stack



Carnitine is an amino acid that is heavily involved with the metabolism of fat for energy. It is required for the proper transport of fatty acids in the mitochondria, where they are oxidized (burned) for energy through the process known as “beta-oxidation”.

Carnitine deficiency has been shown to hinder fat-burning capacity, but studies investigating whether excess Carnitine intake (i.e. supplementation) can burn-fat haven’t been very encouraging thus far.
Although Carnitine supplementation (1g/day) has been shown to increase fatty acid oxidation rates in humans without Carnitine deficiency, it has failed to induce weight-loss in rats, as well as moderately obese women.

Carnitine does have mechanisms by which it may stabilize the fat-burning process in individuals who are Carnitine deficient (unlikely if you eat enough protein), but is unlikely to actually burn fat, especially in Thermo Stack which contains only 500mg per serving.


Caffeine is by far the most common ingredient among stimulant-based fat-burners because it triggers the release of Noradrenaline, a potent activator of lipolysis.

Although Caffeine possesses pro-fat-loss properties, the effects tend to fade with prolonged use, rendering it ineffective as a long-term weight loss solution on its own. However, when paired with other fat-burning stimulants, Caffeine can kick-start the fat-burning process.

Fuel:One lists the amount of Caffeine in Thermo Stack at 270mg per serving (like many other MuscleTech products), more than enough to make most users feel noticeably more alert and focused.


Choline, once inside the body, is converted into the neurotransmitter Acetylcholine which is associated with many functions including (but not limited to) memory, attention, and muscle control.

Choline Bitartrate supplementation has been shown to reduce bodyweight while preserving strength in female Judo athletes but the dose present in Thermo Stack is nowhere near that used in this study.


Green Tea has been shown to inhibit Catechol-O-Methyl Transferase (COMT), thereby extending/amplifying the effects of stimulants such as Caffeine. We discuss the fat-burning implications of Green Tea Extract more in this article.

Fuel:One does not disclose the exact dose of Green Tea Extract present in Thermo Stack, but we know (based on the weight of the proprietary blend) that its nowhere near what has proven effective in a clinical setting.


Longan fruit extract has been implicated in improving memory and cognition, but these effects have only been demonstrated in mice at this time.

Anti-obesity effects have also been noted in mice, with an increase in fecal triglycerides indicating that Longan may reduce fat-absorption via Lipase inhibition.

At this time, Longan is still a highly speculative ingredients, though preliminary research is moderately encouraging. In the context of Thermo Stack we wouldn’t consider it a particularly influential ingredient.


Nelumbo Nucifera (NN), sometimes referred to as Indian Lotus, is a flowering plant which has been shown to have anti-obesity effects in mice. These effects are primarily attributed to the Higenamine, although there are other compounds which may potentiate these effects. Higenamine is a Beta(2) Adrenergic Agonist (same mechanism as Ephedra), meaning it stimulates the Beta(2) Adrenergic Receptors which initiate fat-burning.

Fuel:One does not list the exact dose of Nelumbo Nucifera, but it doesn’t take much to be at least somewhat effective, so Thermo Stack doesn’t appear under-dosed in this regard.


Green Coffee Extract contains Chlorogenic Acid which has been shown to block carbohydrate absorption in humans, thus mimicking the effects of a reduced carb-diet. We discuss Green Coffee Extract in depth in this article, but with 200mg per serving (45% Chlorogenic Acid), two servings of Thermo Stack is needed to obtain a border-line effective dose.


The primary bioactive in Garcinia Cambogia is Hydroxycitric Acid (HCA), which is alleged to reduce body weight via inhibition of ATP Citrate Lysase, an enzyme required for the synthesis of fatty acids from carbohydrates (de novo lipogenisis).

In theory, blocking this enzyme would essentially stop excess carbohydrates from being stored as fat. Unfortunately, while inhibition of ATP Citrate Lysase has resulted in weight-loss in rodents, the implications for humans are less promising, because de novo lipogenesis occurs less in humans than rodents.

We discuss Garcinia Cambogia in depth in this article. Thermo Stack contains 200mg of Garcinia Cambogia providing 60% HCA.


Most of the weight-loss potential of Thermo Stack comes from the stimulants present as the non-stimulant ingredients are either under-dosed or just ineffective in general. Two servings daily may encourage some weight-loss but there just isn’t anything particular special about the Thermo Stack formula compared to other fat-burners.

Still not sure which fat-burner is right for you? Check out our Top 10 Fat-Burners List!

Supplement Facts

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  10. Elsawy, Gehan, Osama Abdelrahman, and Amr Hamza. “Effect of choline supplementation on rapid weight loss and biochemical variables among female Taekwondo and Judo athletes.” Journal of human kinetics 40.1 (2014): 77-82.
  11. Thielecke, Frank, et al. “Epigallocatechin-3-gallate and postprandial fat oxidation in overweight/obese male volunteers: a pilot study.” European journal of clinical nutrition 64.7 (2010): 704-713.
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  15. Park, Se Jin, et al. “The memory-enhancing effects of Euphoria longan fruit extract in mice.” Journal of ethnopharmacology 128.1 (2010): 160-165.
  16. Yang, Deng-Jye, et al. “Antiobesity and hypolipidemic effects of polyphenol-rich longan (Dimocarpus longans Lour.) flower water extract in hypercaloric-dietary rats.” Journal of agricultural and food chemistry 58.3 (2010): 2020-2027.
  17. Ono, Yuka, et al. “Anti-obesity effect of< i> Nelumbo nucifera leaves extract in mice and rats.” Journal of Ethnopharmacology 106.2 (2006): 238-244.
  18. Nojima, Hiroshi, Mari Okazaki, and Ikuko Kimura. “Counter effects of higenamine and coryneine, components of aconite root, on acetylcholine release from motor nerve terminal in mice.” Journal of Asian natural products research 2.3 (2000): 195-203.
  19. Bai, Gang, et al. “Identification of higenamine in Radix Aconiti Lateralis Preparata as a beta2‐adrenergic receptor agonist1.” Acta Pharmacologica Sinica 29.10 (2008): 1187-1194.
  20. Vinson, Joe A., Bryan R. Burnham, and Mysore V. Nagendran. “Randomized, double-blind, placebo-controlled, linear dose, crossover study to evaluate the efficacy and safety of a green coffee bean extract in overweight subjects.”Diabetes, metabolic syndrome and obesity: targets and therapy 5 (2012): 21.
  21. Thom, E. “The effect of chlorogenic acid enriched coffee on glucose absorption in healthy volunteers and its effect on body mass when used long-term in overweight and obese people.” Journal of International Medical Research 35.6 (2007): 900-908.
  22. Watson, John A., and John M. Lowenstein. “Citrate and the Conversion of Carbohydrate into Fat FATTY ACID SYNTHESIS BY A COMBINATION OF CYTOPLASM AND MITOCHONDRIA.” Journal of Biological Chemistry 245.22 (1970): 5993-6002.
  23. Mattes, Richard D., and Leslie Bormann. “Effects of (−)-hydroxycitric acid on appetitive variables.” Physiology & behavior 71.1 (2000): 87-94.
  24. Watanabe, Takuya, et al. “The blood pressure-lowering effect and safety of chlorogenic acid from green coffee bean extract in essential hypertension.”Clinical and experimental hypertension 28.5 (2006): 439-449.
  25. Egras, Amy M., et al. “An evidence-based review of fat modifying supplemental weight loss products.” Journal of obesity 2011 (2010).
  26. Heymsfield, Steven B., et al. “Garcinia cambogia (hydroxycitric acid) as a potential antiobesity agent: a randomized controlled trial.” Jama 280.18 (1998): 1596-1600.
  27. Kim, Ji-Eun, et al. “Does Glycine max leaves or Garcinia Cambogia promote weight-loss or lower plasma cholesterol in overweight individuals: a randomized control trial.” Nutrition journal 10.1 (2011): 94. exists to educate the supplement community and seperate the science from the hype.

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