The ingredient in Celsius that gets the most attention as “banned” is guarana, a plant-based source of caffeine that appears on the NCAA’s banned substances list. But the full picture is more nuanced than headlines suggest. Guarana isn’t banned on its own. It’s listed as an example of a caffeine source, and the NCAA only flags caffeine when it shows up in an athlete’s urine above 15 micrograms per milliliter. For non-athletes, no ingredient in Celsius is banned by the FDA or prohibited for sale in the United States.
Why Guarana Gets Singled Out
Celsius contains a “thermogenic proprietary blend” that includes guarana seed extract, green tea leaf extract, caffeine anhydrous, taurine, ginger extract, and glucuronolactone. Guarana is a South American plant whose seeds contain about twice the caffeine concentration of coffee beans. When you drink a can of Celsius, the guarana and the added caffeine anhydrous both contribute to the total caffeine load, which hits 200 mg in a standard can and 270 mg in the Celsius Essentials line.
The NCAA lists guarana only as an example of a caffeine source, right alongside green tea extract and yerba mate. NCAA drug testing doesn’t actually screen for guarana itself. It screens for caffeine in urine. If a college athlete’s sample comes back above 15 micrograms per milliliter, that’s a positive test. A standard 200 mg Celsius consumed close to competition could push some athletes past that threshold, depending on body weight, hydration, and how quickly they metabolize caffeine. That’s why athletic compliance offices often tell student-athletes to avoid Celsius and similar energy drinks before competition.
How Celsius Compares to Caffeine Limits
A regular can of Celsius contains 200 mg of caffeine from all sources combined. That’s roughly equivalent to two cups of brewed coffee. Celsius Essentials pushes higher at 270 mg per can. For context, Canada’s food safety standards cap single-serving caffeinated energy drinks at 180 mg. Several brands of caffeinated energy drinks, including products exceeding that limit, have been recalled from the Canadian market for non-compliance with caffeine content and labeling rules.
The World Anti-Doping Agency, which governs drug testing for Olympic and professional sports worldwide, does not ban caffeine. It sits on WADA’s 2025 Monitoring Program, meaning the agency tracks usage patterns but doesn’t penalize athletes for it. So the “ban” is specific to NCAA competition, not professional or international sports.
The Labeling Problem
Part of the confusion around Celsius ingredients stems from how caffeine is disclosed on labels. The FDA does not require any food or beverage to list caffeine content in milligrams. Dietary supplements with added caffeine must name it as an ingredient but don’t have to state the quantity. If caffeine appears inside a proprietary blend, the label only needs to show the total weight of the blend, not how much caffeine is in it.
Celsius’s original formulation listed its thermogenic blend at 1,810 mg total, combining taurine, guarana, green tea, caffeine anhydrous, and other ingredients without breaking out individual amounts. Many consumers don’t realize that guarana is essentially another dose of caffeine, so a product listing both guarana and caffeine can deliver more stimulant than people expect. Celsius now prominently states total caffeine per can on its packaging, but this level of transparency isn’t legally required.
What About Synephrine?
Some older discussions about Celsius mention synephrine, a compound found in bitter orange (citrus aurantium) extract. Synephrine is explicitly listed on the NCAA’s banned stimulants list. Celsius has used citrus flavoring and ingredients in some of its formulations, which has fueled speculation. Synephrine is commonly used in weight management and thermogenic products for its metabolism-boosting effects, and bitter orange extract has a complicated regulatory reputation. However, clinical reviews of published human studies have found that synephrine at commonly ingested oral doses does not appear to produce significant adverse cardiovascular effects, and no adverse events have been directly attributed to it.
Whether a specific Celsius product contains enough synephrine to trigger a positive NCAA test depends on the formulation. The broader point is that the NCAA’s banned list captures entire classes of stimulants and anything “chemically or pharmacologically related,” so even trace amounts of a listed compound create risk for tested athletes.
Caffeine and Heart Health
The health concern behind these regulations is real. A systematic review of energy drink case reports published in the World Journal of Cardiology found that the most common adverse events from energy drinks affect the heart and nervous system. Among cardiac events, arrhythmias (irregular heartbeats) were the most frequently reported, accounting for 35% of cases. Other reported events included coronary vasospasm, cardiac arrest, and dangerous changes in heart rhythm.
In one controlled study, healthy adults who consumed 500 mL of an energy drink daily for five days saw their heart rate increase by 5 to 7 beats per minute and systolic blood pressure rise by 10 mmHg. Notably, the cardiovascular effects were stronger after five days of daily use than after a single dose, suggesting the body doesn’t simply adapt to habitual consumption.
These risks are dose-dependent. A single 200 mg caffeine serving is within the range most healthy adults tolerate without problems. But stacking multiple cans, combining Celsius with coffee, or drinking it on an empty stomach can push total intake into territory where side effects become more likely.
The Bottom Line on “Banned”
No ingredient in Celsius is illegal or banned for the general public in the U.S. The “banned” label comes almost entirely from the NCAA context, where caffeine above a specific urinary concentration triggers a positive drug test. Guarana and green tea extract are flagged because they’re caffeine sources, not because they contain some separate prohibited compound. For college athletes subject to NCAA testing, even one can of Celsius before competition carries real risk of exceeding the 15 microgram-per-milliliter threshold. For everyone else, the relevant concern isn’t regulatory status but total caffeine intake across everything you consume in a day.