Is there scientific evidence for CELSIUS?

December 28, 2025 •

4 min read

According to several university-led studies funded by the company, drinking Celsius before exercise can enhance the benefits of a workout, such as improved body composition and increased cardiorespiratory fitness. This article delves into the scientific basis for CELSIUS, examining the ingredients and the studies behind its thermogenic and energy-boosting claims.

Quick Summary

An analysis of the ingredients and clinical studies pertaining to Celsius energy drinks reveals that while research suggests modest metabolic and performance benefits when combined with exercise, these are primarily linked to thermogenic ingredients and a high caffeine content. The evidence, often derived from industry-funded research, indicates effects are not a substitute for a healthy lifestyle, and potential health risks exist, especially with high consumption.

Key Points

Industry-Funded Studies: While Celsius has funded several studies suggesting metabolic benefits, it is important to acknowledge the potential for industry bias in the research.
High Caffeine Content: Celsius contains a high level of caffeine, ranging from 200mg to 270mg, which provides energy but can also lead to side effects like increased heart rate, anxiety, and jitters.
Metabolic Boost via Exercise: Studies indicate that the thermogenic effect of Celsius—its ability to increase metabolism—is most apparent when combined with exercise, not when consumed alone.
Not a Magic Bullet: Experts stress that Celsius is a supplement, not a replacement for a healthy diet, regular exercise, and adequate sleep.
Ingredients Contribute to Stimulant Effect: Ingredients like guarana extract contain additional stimulants that enhance the effects of the primary caffeine content.
Taurine Concerns: Recent research has raised concerns about taurine, an ingredient in Celsius, and its potential role in fueling leukemia cells, prompting calls for more investigation.

Examining the Ingredients and Claims

CELSIUS energy drinks are marketed as a healthy fitness partner, and they contain a proprietary blend of ingredients, including green tea extract, guarana, ginger, chromium, and various B vitamins. The central claim is that this "MetaPlus®" blend triggers thermogenesis, a process that boosts metabolic rate and increases calorie and fat burn when combined with exercise. While some ingredients, particularly caffeine and green tea extract, have documented thermogenic properties, the overall efficacy and safety depend on dosage and individual health.

Caffeine: The Primary Stimulant

Each can of Celsius contains a significant dose of caffeine, ranging from 200 mg to 270 mg depending on the product line. This is substantially higher than a typical cup of coffee, which contains about 95 mg of caffeine. Caffeine is a known central nervous system stimulant that can increase alertness, reduce fatigue, and contribute to an increase in metabolic rate. However, high intake can lead to side effects like jitters, anxiety, and heart palpitations, particularly in sensitive individuals. Health professionals advise against exceeding 400 mg of caffeine per day, a limit two cans of Celsius can easily reach or exceed.

Green Tea Extract and EGCG

The green tea extract in Celsius contains epigallocatechin gallate (EGCG), a compound that has been linked to boosting metabolism. EGCG is a potent antioxidant that may support thermogenesis. However, the amount of EGCG necessary for significant effects and its synergy with other ingredients in the Celsius blend remain areas that require more comprehensive, independent research.

Guarana Seed Extract

Guarana, a plant native to the Amazon, contributes additional caffeine and other stimulants like theobromine and theophylline to the Celsius formula. Studies suggest guarana can provide an additional stimulating effect beyond caffeine alone. However, like caffeine, high doses can lead to side effects, and the precise amount of guarana in Celsius is not disclosed, raising concerns for some experts.

Scientific Studies and Findings

Several university studies have been conducted on Celsius, often funded by the company itself. While some findings appear promising, it is crucial to consider the potential for industry bias.

Metabolism and Fat Loss

Acute Energy-Expenditure Study (Dalbo et al., 2008): A 60-person crossover trial found that resting energy expenditure was 10–12% higher for three hours after consuming Celsius compared to a placebo. Fat mobilization markers also increased. The study was industry-funded and limited to a three-hour window.
10-Week Training Study (Stout et al., 2012): This double-blind study involved 38 sedentary adults who drank Celsius or a placebo for 10 weeks while following an exercise program. The Celsius group saw a 6.6% reduction in fat mass and a 2.0% gain in lean mass, significantly better than the placebo group. Limitations include the small sample size and industry funding.

Important Context

It is essential to understand that these benefits are observed when Celsius is combined with exercise and a healthy lifestyle. Many health professionals emphasize that no single drink can substitute for a multi-pronged approach to health. The estimated daily calorie burn attributed solely to Celsius is modest, around 15–20 extra calories over three hours.

Expert Opinions and Warnings

Experts and dietitians offer cautious perspectives on Celsius, emphasizing moderation and awareness of potential risks.

Cardiologists have noted that stimulants like caffeine and guarana can increase blood pressure and adrenaline, which can be problematic, particularly with multiple cans per day.
Warnings exist for individuals with cardiovascular issues, anxiety disorders, and for those who are pregnant or nursing.
The American Academy of Pediatrics discourages energy drink consumption in children and adolescents due to high caffeine levels.

Comparison of Energy-Boosting Methods


Method	Primary Mechanism	Pros	Cons
Celsius	Thermogenesis, high caffeine	Modest metabolic boost with exercise; often zero sugar; convenient	High caffeine content; potential side effects; studies are industry-funded
Coffee (Black)	Caffeine	Natural source of caffeine; lower cost; contains antioxidants; widely available	Potential for jitters or sleep disruption with high intake
Green Tea	Caffeine, EGCG	Contains antioxidants; lower caffeine than Celsius; potential metabolism support	Less significant stimulant effect; metabolic boost is modest
Nutritious Diet & Exercise	Sustained energy from nutrients	Foundation for long-term health; provides vitamins and minerals naturally	Requires consistent effort; results may not be immediate

Conclusion

So, is there scientific evidence for CELSIUS? The answer is yes, but it comes with important caveats. The company's own, industry-funded research indicates that when consumed before exercise, Celsius can provide modest, short-term increases in metabolic rate and help enhance body composition. This effect is primarily driven by its high caffeine content, supplemented by ingredients like green tea extract and guarana. However, experts caution that Celsius is not a magic bullet and its benefits are dependent on being paired with a healthy lifestyle. The high caffeine levels pose risks for certain individuals and can lead to adverse effects, especially with frequent, high-dose consumption. Ultimately, while Celsius can be a component of a fitness routine for healthy adults, it should be consumed in moderation with a full understanding of its stimulant content and limitations. For many, more natural options or prioritizing diet and exercise may provide safer, more sustainable results.

Visit the NIH website for more clinical studies on supplement ingredients.

Frequently Asked Questions

Scientific evidence, primarily from company-funded studies, suggests Celsius can contribute to modest weight loss and fat reduction when used in conjunction with a regular exercise routine. It is not a standalone solution for weight loss and its effects are not a substitute for a healthy diet and consistent exercise.

Celsius boosts metabolism through its blend of thermogenic ingredients, including high-dose caffeine, green tea extract (EGCG), and ginger. This blend is designed to stimulate the body's metabolic rate, which studies show is most effective when paired with physical activity.

Yes, due to its high caffeine content, potential side effects of drinking Celsius include increased heart rate, elevated blood pressure, anxiety, jitteriness, and insomnia. Sensitive individuals or those consuming multiple cans per day are at higher risk.

No, individuals with pre-existing heart conditions, anxiety disorders, or sensitivity to stimulants should consult a healthcare professional before consuming Celsius. The high caffeine content poses potential risks for cardiovascular health.

Green tea extract in Celsius contains EGCG, a compound with antioxidant and potential metabolism-boosting properties. This works alongside caffeine to contribute to the drink's thermogenic effects.

Recent studies have raised concerns about taurine, an amino acid found in Celsius and other energy drinks, suggesting it could act as a fuel source for leukemia cells. While research is ongoing, it has prompted caution, especially for regular, high-dose consumption.

The American Academy of Pediatrics (AAP) and other experts advise against energy drink consumption for children and adolescents. The high stimulant levels can disrupt sleep, increase heart rate, and have other adverse developmental effects.

Celsius typically contains a higher caffeine dose (200-270mg) and fewer calories or sugars compared to many traditional energy drinks like Red Bull or Monster. Its proprietary blend focuses on thermogenesis, but the core energy effect remains primarily due to caffeine.