PNI Thermadex Review

Thermadex is a fat-burner by PNI which dervies most of its potential from the stimulants contained within but does also contain some effective non-stimulant ingredients (such as Fucoxanthin)…

PNI Thermadex



Caffeine causes an increase in catecholamines, resulting in increased alertness, focus, and perceived energy. These neurotransmitters tend to be pro-lipolytic, so it is commonly assumed that caffeine is a fat-burner. While the mechanisms of caffeine are certainly pro-fat-burner, the effects tend to fade with prolonged use, rendering caffeine ineffective as a long-term weight loss solution by itself.

However, caffeine may potentiate the effects of other stimulant fat-burners as well as increases energy and focus, resulting in longer, more intense workouts. So, while caffeine itself is by no means an effective weight-loss solution, within the context of a stimulant-based fat-burner it can actually be quite effective. Thermadex contains an undisclosed quantity of Caffeine, though we’d estimate it contains in between 200-300mg.


Theobroma Cacao is generally standardized for caffeine, theobromine, or theophylline, which are collectively known as methylxanthines. While each of these compounds possess slightly different chemical characteristics, they all produce similar central nervous system effects. The Theobroma Cacao present in the Thermadex formula is standardized specifically for Theophylline which, combined with Caffeine, may potentiate the effects of the other stimulant compounds present in the formula. Ultimately, while methylxanthines tend to be relatively ineffective for fat-loss by themselves, they can certainly enhance the overall fat-loss capacity of the formula.


Dendrobium has become a popular addition to pre-workout/fat-burner supplements in the past few years, especially after DMAA was banned by the U.S. FDA, but the claims surrounding its use tend to differ from company to company. Dendrobium is alleged to contain several alkaloids, including Phenylethylamines, a class of compounds which cause an increase in the catecholamine neurotransmitters and therefore may induce lipolysis to a relatively potent (though short-lived) degree. However, no analysis of the constituents of Dendrobium has ever found PEA as one of the alkaloids naturally present in the plant. Unfortunately, until more studies on Dendrobium and its constituents are better understood, the weight-loss implications of this mysterious plant will remain unclear.


Bitter Orange Extract is generally standardized for Synephrine, but also contains Octopamine, Tyramine, and Hordenine in smaller amounts. Syneprhine became popular after the FDA banned Ephedra as a dietary supplement for weight loss, because they share a similar mechanism of action. While Synephrine has been touted as a replacement for Ephedra, it is important to understand that it is significantly less potent (which is why it is not banned).

However, this does not mean it is ineffective. A 2011 study, published in the “International Journal of Medicinal Sciences”, found that supplementation of 50mg Synephrine increased the metabolic rate in human subjects without affecting blood pressure or heart rate. So, not only does Synephrine have clear implications for weight-loss, but it is also remarkably safe compared to its predecessor. Similarly to Ephedrine, Synephrine is a beta-receptor agonist and an alpha-receptor antagonist, the net effect of which is an increase in lipolysis.


Capsaicin is the active ingredient in Red Pepper (Capsicum), and has been shown to increase lipolysis in rats as well as humans. In particular, a 2007 study noted an increase in fat oxidation (relative to placebo) during low intensity exercise in healthy adult males who consumed 150mg of capsaicin one hour before exercise. These findings make capsaicin of interest to those looking to decrease fat without the use of stimulants and, while some supplement companies certainly overstate the efficacy of Capsaicin as it pertains to weight loss, all studies certainly indicate fat burning potential. Whether Capsaicin can work synergistically with stimulants such as caffeine and synephrine to further increase fat oxidation remains to be tested in humans, but the implications thus far are certainly in favor of that hypothesis.


Fucoxanthin is a carotenoid found in certain types of seaweed which has several health implications, including some related to weight-loss. Fucoxanthin has demonstrated the ability to raise the metabolic rates of mice via increasing the activity of Uncoupling Proteins in white adipose tissue which essentially removes a step from mitochondrial respiration (energy production). A 2010 study, published in “Diabetes, Obesity, and Metabolism”, found that Fucoxanthin significantly increased the metabolic rate of human subjects, but took 16 weeks for effects to become apparent. These findings are roughly in-line with the animal studies that have been conducted and indicate that Fucoxanthin can indeed result in fat-loss over a sustained period of time at relatively low doses.


The Thermadex formula is not unlike most other stimulant-based fat-burners, except for the inclusion of Fucoxanthin. Fucoxanthin is a seriously under-utilized fat-burning ingredient, requiring a very low dose to convey its effects. The addition of Fucoxanthin to the Thermadex formula helps separate this simple, yet highly effective fat-burner from most other stimulant-based fat-burners out there. At about 50 cents per serving, Thermadex is quite appropriately priced, making it a worthy candidate for those considering fat-burners.

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

Supplement Facts

  1. Maeda, Hayato, et al. “Seaweed carotenoid, fucoxanthin, as a multi-functional nutrient.” Asia Pacific journal of clinical nutrition 17 (2008).
  2. Abidov, M., et al. “The effects of Xanthigen™ in the weight management of obese premenopausal women with non‐alcoholic fatty liver disease and normal liver fat.” Diabetes, obesity and metabolism 12.1 (2010): 72-81.
  3. Maeda, Hayato, et al. “Fucoxanthin from edible seaweed,< i> Undaria pinnatifida, shows antiobesity effect through UCP1 expression in white adipose tissues.” Biochemical and biophysical research communications 332.2 (2005): 392-397.
  4. Kang, Seong-Il, et al. “Petalonia binghamiae extract and its constituent fucoxanthin ameliorate high-fat diet-induced obesity by activating AMP-activated protein kinase.” Journal of agricultural and food chemistry 60.13 (2012): 3389-3395.
  5. Hu, Xiaojie, et al. “Combination of fucoxanthin and conjugated linoleic acid attenuates body weight gain and improves lipid metabolism in high-fat diet-induced obese rats.” Archives of biochemistry and biophysics 519.1 (2012): 59-65.
  6. Ballinger Shin, Ki Ok, and Toshio Moritani. “Alterations of autonomic nervous activity and energy metabolism by capsaicin ingestion during aerobic exercise in healthy men.” Journal of nutritional science and vitaminology 53.2 (2007): 124-132.
  7. Haaz, S., et al. “Citrus aurantium and synephrine alkaloids in the treatment of overweight and obesity: an update.” Obesity reviews 7.1 (2006): 79-88.
  8. Graham, Terry E., Danielle S. Battram, Flemming Dela, Ahmed El-Sohemy, and Farah S.L. Thong. “Does Caffeine Alter Muscle Carbohydrate and Fat Metabolism during Exercise?” Applied Physiology, Nutrition, and Metabolism 33.6 (2008): 1311-318.
  9. Graham, Terry E., Jorn W. Helge, David A. MacLean, Bente Kiens, and Erik A. Richter. “Caffeine Ingestion Does Not Alter Carbohydrate or Fat Metabolism in Human Skeletal Muscle during Exercise.” The Journal of Physiology 529.3 (2000): 837-47.
  10. Whiting, S., E. Derbyshire, and BK Tiwari. “Capsaicinoids and Capsinoids. A Potential Role for Weight Management? A Systematic Review of the Evidence.” Manchester Food Research Centre, Manchester Metropolitan University, Hollings Faculty, Old Hall Lane, Manchester M14 6HR, UK (n.d.): n. pag.
  11. Joo, Jeong In, Dong Hyun Kim, Jung-Won Choi, and Jong Won Yun. “Proteomic Analysis for Antiobesity Potential of Capsaicin on White Adipose Tissue in Rats Fed with a High Fat Diet.” Journal of Proteome Research 9.6 (2010): 2977-987.
  12. Lejeune, Manuela P. G. M., Eva M. R. Kovacs, and Margriet S. Westerterp-Plantenga. “Effect of Capsaicin on Substrate Oxidation and Weight Maintenance after Modest Body-weight Loss in Human Subjects.” British Journal of Nutrition 90.03 (2003): 651. exists to educate the supplement community and seperate the science from the hype.

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