Reader-supported: we may earn a commission from links on this page.
Quick answer: Is Celsius bad for you? For most healthy adults, one can a day is unlikely to cause harm, but it isn’t a health drink. Each 12 oz can has 200 mg of caffeine, half of the 400 mg a day the FDA cites for most adults, and it’s sweetened with sucralose. The “burns calories” claim rests on small, short studies Celsius paid for, and in the longest one, the drink alone didn’t change body fat without exercise. Celsius’s own label says it’s not recommended for anyone under 18, during pregnancy or for people sensitive to caffeine.
“Is Celsius bad for you?” gets searched about 22,000 times a month in the US, and the top results are mostly forum posts and store pages. So we did the homework: we read the label, pulled the studies Celsius points to, and went through the lawsuits, recalls and investigations, including a new one in 2026.
Table of Contents
What’s in a Can of Celsius?
Here’s what the label of a regular 12 oz Celsius lists, using the Sparkling Green Apple Cherry flavor as an example: carbonated water, citric acid, taurine, guarana seed extract, caffeine, green tea extract, vegetable juice for color, malic acid, calcium carbonate, vitamin C, glucuronolactone, sucralose, ginger root extract, natural flavor, B vitamins, chromium and biotin.
| Celsius (original) | Celsius Essentials | |
|---|---|---|
| Can size | 12 oz | 16 oz |
| Caffeine | 200 mg | 270 mg |
| Sugar | 0 g | 0 g |
| Label warning | Not recommended for people who are caffeine sensitive, children under 18, or women who are pregnant or nursing | Same warning |
Caffeine amounts are from Celsius’s own fact page. The label also says not to drink more than two cans a day.
Check the current price of Celsius
The original has 10 calories and is sweetened with sucralose. The short version: Celsius is a zero-sugar caffeine drink with a “fitness” blend added. Taurine, guarana, green tea extract and ginger are common energy drink ingredients. None of them change the main fact, which is the caffeine.
Does Celsius Really Burn Calories? We Read the Studies
Celsius calls its formula “clinically proven.” The best-known studies behind that claim were done at the University of Oklahoma between 2008 and 2010. Here’s what three of them actually tested:
| Study | People | How long | What it found |
|---|---|---|---|
| Dalbo et al., 2008 | 60 young adults | One drink, measured for 3 hours | Burned more energy at rest than a placebo for 3 hours. Funded by Celsius. |
| Roberts et al., 2008 | 60 young adults | 28 days | Small drop in body fat vs. placebo, no change in safety blood tests. Funded by Celsius. |
| Lockwood et al., 2010 | 38 previously inactive men | 10 weeks | The drink alone changed nothing. With a workout program, the drink group lost more fat than the placebo-plus-exercise group. |
- The studies are small and short. Between 38 and 60 people each, and from 3 hours to 10 weeks.
- Celsius paid for them. The two 2008 papers state that Celsius funded the research through a grant to the university. We couldn’t see a funding statement for the 10-week study, but Celsius posts it on its own website as one of its clinical studies.
- Two of them seem to describe the same people. The 3-hour study and the 28-day study list identical ages, weights and body-fat numbers for their 60 volunteers.
- The longest study is the most honest one. Its authors concluded that a once-daily drink without diet changes “appears ineffective at improving body composition” in inactive men. The benefits only showed up with exercise.
Our take: caffeine does raise the number of calories you burn a little for a few hours, and that’s most of what these studies show. It won’t do the work of a diet or a workout plan.
How Much Caffeine Is in Celsius?
A regular can of Celsius has 200 mg of caffeine, and Celsius Essentials has 270 mg. Here’s how that compares, using the same 12 oz serving so can sizes don’t hide anything:
| Drink | Caffeine per can | Per 12 oz |
|---|---|---|
| Celsius (12 oz) | 200 mg | 200 mg |
| Celsius Essentials (16 oz) | 270 mg | 203 mg |
| Red Bull (8.4 oz) | 80 mg | 114 mg |
| Monster (16 oz) | 160 mg | 120 mg |
| Brewed coffee (12 oz cup) | About 133 to 200 mg | About 133 to 200 mg |
Coffee range based on the FDA‘s note that 400 mg is about two to three 12 oz cups. See all 19 drinks in our healthy energy drinks scorecard.
Per ounce, Celsius is one of the strongest popular energy drinks. It packs more caffeine into a 12 oz can than Red Bull or Monster do.
How Long Does Celsius Last?
Caffeine levels peak 30 to 120 minutes after you drink it, and your body takes about 3 to 6 hours to clear half of it, according to a review in the Annals of Pharmacotherapy. So a Celsius at 4 p.m. can still leave up to half its caffeine in your system at bedtime. That’s why many people find an afternoon can hurts their sleep.
Is Celsius Bad for Your Heart, Kidneys or Liver?
Your Heart
There’s no study on Celsius and heart problems specifically. The most cited research is a 2024 Mayo Clinic study of 144 people who survived sudden cardiac arrest: 7 of them (5%) had an energy drink shortly before it happened, and 4 of those 7 had a diagnosed genetic heart rhythm condition. The researchers said larger studies are needed but that an early warning seems wise.
For healthy adults, the FDA’s 400 mg a day figure still applies. The FDA lists a fast heart rate, palpitations and high blood pressure among the signs of too much caffeine. If you have a heart condition, ask your doctor before drinking any energy drink.
Your Kidneys and Liver
Two of the Celsius studies above ran safety blood tests over 28 days and 10 weeks, including liver and kidney markers in the 10-week study, and found no harmful changes. Those were small, Celsius-linked studies in healthy young people, but they’re the best direct evidence there is.
One ingredient worth knowing about is green tea extract. Celsius doesn’t list how much is in a can, and says it’s as safe as a home-brewed cup of green tea. A US Pharmacopeia review found reports of liver injury linked to green tea extract at 140 to about 1,000 mg of EGCG a day, with a higher risk when taken on an empty stomach. If you also take a “fat burner” supplement, check whether it contains green tea extract too.
Celsius Side Effects
Most side effects people report are simply caffeine side effects. The FDA lists these signs of too much caffeine:
- Fast heart rate or palpitations
- High blood pressure
- Trouble sleeping
- Anxiety and jitters
- Upset stomach, nausea or headache
Does Celsius make you poop? It might. Celsius hasn’t been studied for this, but in a small 1998 study, caffeinated coffee stimulated the colon about as much as a full meal and 60% more than water. Caffeine is likely part of the reason.
Is Celsius Good for Weight Loss?
Not on its own. Celsius has just 10 calories, so swapping it for a sugary soda or energy drink does cut calories. But the longest study found the drink alone didn’t change body composition in 10 weeks. Any fat-burning effect beyond caffeine’s small, short boost hasn’t been shown in large or independent studies.
Celsius Lawsuits, Recalls and Investigations
Celsius has faced more legal trouble than most people realize. Some of it involves Alani Nu, a brand Celsius bought in 2025. A lawsuit is a claim, not a finding, and none of these cases has ended with a court ruling that Celsius drinks are unsafe.
| When | What happened | Status |
|---|---|---|
| Dec 2022 | Class action over a “No Preservatives” label: buyers said the citric acid in Celsius works as a preservative. | Settled for 7.8 million dollars, no admission of wrongdoing |
| Jan 2023 | Rapper Flo Rida won an 82.6 million dollar jury verdict in a dispute over his endorsement deal. | Appeals court kept his win but ordered damages recalculated |
| Jan 2025 | The SEC charged Celsius Holdings over how it accounted for stock awards in 2021. | Settled for a 3 million dollar penalty, without admitting or denying |
| Jul 2025 | High Noon recalled vodka seltzer that ended up in cans labeled Celsius Astro Vibe after a packaging supplier mix-up. | Recall; no illnesses reported |
| Apr 2026 | A Texas family sued two Alani Nu distributors over the death of their 17-year-old daughter. | Lawsuit filed |
| Jun 2026 | The Texas Attorney General opened an investigation into Celsius over marketing Alani Nu to minors. | Investigation open |
| Sep 2026 | Investors filed a class action claiming Celsius misled them about Alani Nu’s risks. | Lawsuit filed |
The Texas Case Behind the 2026 Investigation
In April 2026, NBC News reported that the family of Larissa Rodriguez, a 17-year-old cheerleader from Texas, filed a wrongful death lawsuit claiming Alani Nu energy drinks caused her death. According to NBC, the county medical examiner listed the cause as an enlarged heart due to stress and large amounts of caffeine. Celsius told NBC its products comply with federal labeling rules and that the label says the drink is not recommended for children.
In June 2026, Texas Attorney General Ken Paxton announced an investigation into whether Celsius marketed Alani Nu, which has 200 mg of caffeine per 12 oz can, to children and teens. These are allegations, and the investigation is ongoing. But the case is a reminder of what the American Academy of Pediatrics already says: the caffeine and other stimulants in energy drinks have no place in the diet of children and adolescents.
One more thing: if you searched “Celsius lawsuit” and found news about a crypto company, that’s Celsius Network, a different company with no link to the drink.
Who Owns Celsius?
- Celsius Holdings, a public company, makes Celsius.
- PepsiCo took an 8.5% stake for 550 million dollars in 2022 and became its main distributor. In 2025, a new deal raised PepsiCo’s effective stake to about 11%.
- Celsius bought Alani Nu for 1.8 billion dollars in 2025, and took over Rockstar Energy in the US as part of the 2025 PepsiCo deal.
Lower-Caffeine Alternatives to Celsius
If you like Celsius but want less caffeine, these zero-sugar drinks scored best in our energy drink scorecard:
| Drink | Caffeine | Sweetener | vs. Celsius |
|---|---|---|---|
| Zevia Energy | 120 mg (12 oz) | Stevia | 40% less caffeine |
| Juno Energy | 125 mg (12 oz) | Organic stevia | About 38% less |
| Aspire | 80 mg (12 oz) | Sucralose | 60% less |
Check the current price of Zevia Energy
Check the current price of Juno Energy
Check the current price of Aspire
The PrimeDigger Verdict
Celsius isn’t poison, and one can a day is within the FDA’s caffeine guidance for most healthy adults. But it’s a strong caffeine drink, not a health drink: 200 mg in a 12 oz can, more per ounce than Red Bull or Monster. Its “clinically proven” fat-burning claim rests on small, short studies Celsius paid for, and the drink did nothing for body composition on its own. Keep it to one can, skip it in the afternoon if you sleep badly, and keep it away from kids and teens. If you want the same lift with less caffeine, try Zevia Energy.
More PrimeDigger investigations: our healthy energy drinks scorecard and is Prime healthy?
This article is for general information, not medical advice. If you’re pregnant, have a heart condition, take medication or are sensitive to caffeine, talk to your doctor before drinking energy drinks.
Want the full picture? Our ebook The Energy Drink Bible covers Celsius, Alani Nu, Prime and 16 more cans in one scorecard, how much caffeine is safe for you, the heart and sleep research, what parents of teens should know, and a 14-day plan to cut back without headaches, with 5 printable tools. Get the ebook ($19) → See all our ebooks →
Frequently Asked Questions
Is Celsius bad for you?
For most healthy adults, one can a day is unlikely to be harmful. But each 12 oz can has 200 mg of caffeine, half the 400 mg a day the FDA cites for most adults, so it is a strong caffeine drink. It is not recommended for anyone under 18, during pregnancy or for people sensitive to caffeine.
Is Celsius an energy drink?
Yes. Celsius markets itself as a fitness or essential energy drink, but with 200 mg of caffeine per 12 oz can, it is a high-caffeine energy drink.
How much caffeine is in Celsius?
A regular 12 oz Celsius has 200 mg of caffeine. Celsius Essentials has 270 mg per 16 oz can. That is more caffeine per ounce than Red Bull or Monster.
Does Celsius have alcohol?
No. Celsius drinks do not contain alcohol. In July 2025, High Noon recalled some vodka seltzer that was filled into cans labeled Celsius Astro Vibe by mistake, after a packaging supplier mix-up. Those cans were not made by Celsius.
Is Celsius good for weight loss?
Not on its own. In the longest study, a 10-week trial, the drink alone did not change body composition. Benefits only appeared when it was combined with exercise.
How long does Celsius last?
Caffeine peaks 30 to 120 minutes after drinking it, and the body takes about 3 to 6 hours to clear half of it. An afternoon can may still affect your sleep.
Is Celsius safe for teenagers?
No. Celsius’s label says it is not recommended for children under 18, and the American Academy of Pediatrics says energy drinks have no place in the diet of children and teens.
Who owns Celsius?
Celsius is made by Celsius Holdings, a public company. PepsiCo owns about 11% and distributes the drinks. Celsius also owns Alani Nu.
Sources
- Celsius: Essential Facts (caffeine per can)
- Dalbo et al. (2008), Journal of the International Society of Sports Nutrition: Acute effects of a commercial thermogenic drink
- Roberts et al. (2008), Journal of the International Society of Sports Nutrition: Efficacy and safety after 28 days
- Lockwood et al. (2010), Journal of Strength and Conditioning Research: Low-calorie energy drink in previously sedentary men
- FDA: Spilling the Beans, How Much Caffeine Is Too Much?
- Annals of Pharmacotherapy (2008): Timing of blood pressure measurement related to caffeine consumption
- Martinez et al. (2024), Heart Rhythm: Sudden cardiac arrest near energy drink consumption
- Oketch-Rabah et al. (2020), Toxicology Reports: USP review of green tea extract liver safety
- Rao et al. (1998), European Journal of Gastroenterology and Hepatology: Is coffee a colonic stimulant?
- American Academy of Pediatrics (2011), Pediatrics: Sports drinks and energy drinks for children and adolescents
- MediaPost: Celsius agrees to pay 7.8 million dollars over “No Preservatives” claims
- Fortune: Flo Rida wins 82 million dollar lawsuit against Celsius (2023)
- NBC Miami: Appeals court upholds Flo Rida win, challenges award
- SEC: Administrative proceeding against Celsius Holdings (January 2025)
- FDA: High Noon recall of vodka seltzer in Celsius-labeled cans (July 2025)
- NBC News: Family says Alani Nu energy drink played role in cheerleader’s death (April 2026)
- CBS Texas: Texas AG investigates Celsius over Alani Nu marketing (June 2026)
- National Law Review: Investor class action against Celsius Holdings (September 2026)
- CNBC: PepsiCo takes 550 million dollar stake in Celsius (2022)
- Yahoo Finance: PepsiCo increases stake in Celsius (2025)
- Celsius Holdings: Celsius to acquire Alani Nu (2025)
