Celsius is another product in the line of fitness energy drinks that have become popular over the last 10 years. It claims to provide “healthy energy”, accelerate metabolism and burn body fat. These are common claims in the supplement industry, and Celsius provides 3 basic product lines: originals, naturals and HEAT. Ultimately, these 3 strike us as being near-identical: whilst the dosages in the 3 products differ, they all aim to provide the same benefits and are equally situated in the market. Originals, naturals and HEAT are all marketed as pre-workout energy drinks as a “refreshing alternative to coffee”, without HFCS, artificial preservatives or flavours and is low in sodium.
In this article we’re going to try and unpack the ingredients and effects of Celsius’ main products (originals and HEAT) and evaluate them based on effectiveness, value and how they stack up as a dietary aid. This will mean looking at the ingredients individually, as well as reviewing the effectiveness of the product in the context of a balanced diet.
3 out of 5: doesn’t really burn fat, but it’s okay
Does it burn fat?
The problem that we have with Celsius is that they are incredibly resistant to review. They claim that the effects of their product are due to the ‘MetaPlus’ proprietary blend (“MetaPlus” just means beyond-more), a mixture of taurine, Guarana extract, Green tea extract, Caffeine, Glucuronolactone and ginger extract. These are not particularly ground-breaking ingredients – they are all present in other, similar products. The problem is that Celsius does not have to declare the dosages of each of these compounds in their proprietary blend – this may seem reasonable but it is also interesting to note that the minimum doses of these ingredients is a huge factor in whether they are effective. This means that we can only give a cursory discussion of the product.
The only ingredient we can talk about definitively is caffeine, which is included at around 200mg per can. Caffeine has been proven to improve perception of energy, as well as modest improvements in the resting metabolic rate . However, studies demonstrating these effects at statistically-significant levels were generally dosed above this – with caffeine intake being generally 300-500mg. This means that it may be necessary to consume a 50-150% more caffeine than we Celsius provides, for the purpose of significant weight loss. This dose of caffeine will have different effects on different individuals (considerable variability has been shown in clinical studies), with those who are already used to consuming caffeine being less affected in terms of perceptions of energy and focus.
Green tea extract is an incredibly popular ingredient in supplements – primarily those aimed at “fat-burning”, and has been studied extensively. What these studies have shown is that it does assist in the metabolism of fat, but only to an incredibly modest degree. The clinical research has suggested that 50mg of EGCG (the active ingredient in green tea) can increase fat metabolism by 5.7g  – given that we don’t know the doses present in Celsius, it is impossible to determine what amount of effect we can expect from the product. The other, obvious concern, is that there isn’t much reason to consume Celsius over a regular cup of green tea: the EGCG content of green tea consumed throughout the day can easily equal a supplementary dose. Additionally, the GABA content of green tea counteracts the effects of caffeine (making us MORE tired), making green tea extract a poor choice for an energy drink!
The rest of the ingredients strike us as rather innocuous: taurine, ginger and glucuronolactone have very small effects on the metabolism and do not provide a sufficient effect for us to consider them “fat burners”. This is not to say that they are not beneficial: ginger has a whole host of health benefits and glucuronolactone is a genuine detoxifying agent, as it converts to acids in the body which are associated with the increased excretion of harmful compounds from the body. Overall, these ingredients definitely add some value to Celsius, but they are not the effects that the product is marketed on.
Speaking of beneficial ingredients that don’t do what they say on the label, one of our favourite things about Celsius’ product is the inclusion of an extensive vitamin and mineral matrix. These are fantastic for health – with 100% of the RDA of a number of vitamins such as C and B12 – but they are not specifically beneficial to fat burning. For those who are not deficient in any of these vitamins, they will not find much benefit in consuming supplementary doses. Additionally, there is no discussion of the source of these supplementary doses – something that is a large concern with B12. This vitamin is notoriously poor to absorb and many supplementary sources (primarily those from plant sources or algae) do not absorb at high enough levels for 100% RDA to be an effective dose. 100% of RDA is only enough when we are able to absorb everything we consume. The first microgram of B12 is absorbed at approximately 56%, after which the absorption rate drops off rapidly. Thus, depending on the source of B12 in Celsius, it may be an effective supplement or a totally inert ingredient.
3 out of 5: there are better choices
HEAT is a similar product to original. The only differences consist in the amount of caffeine (though this is linked to the fact that the product itself is 1/3 larger) and the inclusion of 2g of citrulline. Increased caffeine dosages are welcomed by us, as the positive effects of caffeine are associated with higher intakes (though, of course, this is traded off against slightly higher rates of side-effects).
The citrulline is something we could take or leave: despite some positive effects, the main reason to supplement citrulline is because it converts to L-arginine. L-arginine is an important amino acid for the improvement of blood flow and muscle synthesis, with Citrulline malate being the most efficient delivery system (because Arginine breaks down rapidly in the body). This means that, in the right contexts, citrulline can improve the severity of “the pump” – but HEAT doesn’t necessarily do this – and there are no real benefits to supplementary dosages of Arginine among healthy individuals .
Celsius does offer some research to support their claims, but it generally falls short of the standard of research necessary to confirm these claims . The fundamental problem with this evidence is that it suggests that Citrulline is ineffective without the addition of supplementary glutathione – something that does not appear to be present in HEAT. This is also met with an equally-numerous literature suggesting that increased plasma arginine (from arginine or citrulline supplementation) is not sufficient to improve nitric oxide or performance markers associated with it [4, 6].
Overall, there are no real benefits to supplementary doses in those who are within healthy ranges. Theoretically, there may be some positive effects to HEAT’s ingredients but these are not borne out by enough rigorous, scientific evidence and has too many confounding factors for us to consider it a reliable or effective supplement.
Overall, we’re on the fence with Celsius. We enjoy the inclusion of a diverse vitamin matrix, even if some of these are unreliable or dosed in mildly-effective doses. We dislike the proprietary blend status as it makes customer awareness almost impossible: if we don’t know what is in your product, we’re skeptical about the effects from the start. In the supplement market, there are so many alternatives that practices like this are enough for us to avoid your product!
On balance, we’d say that there’s very little reason to choose Celsius. Given that there are minimal benefits above a conventional energy drink or cup of coffee, but a considerably higher cost at almost $2, we can’t see what the impetus for buying Celsius. The majority of the effects are derived from caffeine – one of the most widely-available drugs in the universe – and the majority of other ingredients are either totally innocuous or associated with health more than fat loss.
The main problem we have with Celsius’ range is that there are almost no real benefits to consuming this product over and above those associated with a proper diet. Even with the vitamin matrix, the only real benefits are caffeine and the small amount of EGCG that come with the product. The interesting part of this is, of course, the fact that a diet including pre-workout coffee and the occasional cup of green tea will have similar effect. Considering the effectiveness of other market alternatives and dietary aids that have similar (or better) effects, we can only give Celsius’ range a 3 overall. It is simply ‘one among many’ within the market space!
 Yoshida et al (1994): ‘relationship between basal metabolic rate, thermogenic response to caffeine, and body weight loss following combined low calorie and exercise treatment in obese women’. International journal of obesity and related metabolic disorders, 18(5), pp.345-350
 Hursel et al (2011): ‘The effects of catechins rich teas and caffeine on energy expenditure and fat oxidation: a meta-analysis’. Obesity reviews, 12(7), pp.573-581
 Ferre, S (2008): ‘An update on the mechanisms of the psychostimulant effects of caffeine’. Journal of neurochemistry, 105(4), pp.1067-1079
 Liu et al (2009): ‘No effect of short-term arginine supplementation in nitric oxide production, metabolism and performance in intermittent exercise in athletes’. Journal of nutritional biochemistry, 20(6), pp.462-468
 McKinley-Barnard et al (2015): ‘Combined L-citrulline and glutathione supplementation increases the concentration of markers indicative of nitric oxide synthesis’. Journal of the international society of sports nutrition 12(1), pp.1-8
 Willoughby et al (2011): ‘Effects of 7 days of arginine-alpha-ketoglutarate supplementation on blood flow, plasma L-arginine, nitric oxide metabolites, and asymmetric dimethyl arginine after resistance exercise’. International journal of sports nutrition and exercise metabolism, 21(4), pp.291-299
John has been a fitness enthusiast for over 10 years, starting out while struggling with obesity as a teenager. Over the years he has advised numerous clients on how to transform their physiques and their lives. As a writer on Nutrition Inspector he aims to help others achieve real results by staying clear of the common hype and false claims in the supplement industry!