Does Celsius Energy Drink Go Bad? Shelf Life, Spoilage & Safety Explained

November 27, 2025 •

4 min read

According to Celsius customer care, their sparkling drinks have a 15-month shelf life from the manufactured date. This raises the question: does Celsius energy drink go bad, and if so, how can you tell? While the drink doesn't spoil in the traditional sense, its quality and potency diminish over time.

Quick Summary

Celsius energy drinks feature a "best by" date that indicates peak quality, not a hard expiration. The beverage will gradually lose its carbonation and flavor past this date, but remains generally safe if unopened and stored correctly. The caffeine potency also decreases slowly over time.

Key Points

Best By vs. Expiration: The date on a Celsius can is for optimal quality, not a strict expiration. It will lose quality over time but not immediately become unsafe.
Check for Can Damage: Never consume from a bulging, rusted, or leaking can, as the drink's contents may be contaminated.
Store Properly: Keep Celsius cans in a cool, dark place away from extreme heat and direct sunlight to maximize shelf life and potency.
Opened Cans Spoil Faster: An opened can of Celsius will quickly lose carbonation and can attract bacteria if left unrefrigerated. Consume within a day for best quality.
Potency Diminishes: Over time, the nutritional components and caffeine potency of an expired Celsius will decrease, meaning you will get less of an "energy boost".
Trust Your Senses: If a drink smells or tastes off, or is completely flat, it has degraded beyond enjoyment. When in doubt, discard it.

The Meaning Behind the "Best By" Date

Unlike perishable foods like milk or meat, Celsius energy drinks do not have a strict expiration date. The date printed on the can is a "Best By" or "Best Before" date, a voluntary measure by manufacturers to indicate the period of peak quality. This date marks when the product is expected to be at its best in terms of flavor, carbonation, and nutrient potency. Consuming a Celsius after this date is not inherently dangerous, provided it has been stored correctly and the can is undamaged. The primary difference will be a noticeably less potent flavor and less fizziness.

Factors That Influence Celsius's Shelf Life

Several environmental factors can significantly impact the shelf life and quality of an unopened Celsius energy drink. Proper storage is crucial for maintaining its freshness and effectiveness.

Temperature: Storing Celsius in extreme temperatures, especially heat, will accelerate the degradation of its ingredients. The active ingredients, including green tea extract and vitamins, are sensitive to heat and will lose their efficacy more quickly. Heat can also build pressure inside the can, potentially causing it to burst. Always store cans in a cool, dry place.
Sunlight: Direct sunlight exposes the can to both heat and UV rays, which can break down the ingredients and potentially affect the flavor. A dark pantry or refrigerator is an ideal storage location.
Packaging: While cans offer a good airtight seal that protects against oxygen and light, the integrity of the packaging is vital. Dented, rusted, or leaking cans should always be discarded, as they may have been compromised and could pose a health risk.

How to Tell If a Celsius Has Gone Bad

Even with a "best by" date, paying attention to the physical characteristics of the drink is important. Your senses are the best tool for identifying if a Celsius is past its prime. Here are the key indicators of spoilage:

Loss of Carbonation: The first and most obvious sign of an older or compromised drink is a lack of fizz. The carbonation is one of the first things to go, resulting in a flat-tasting beverage.
Unusual Smell: Before drinking, give the can a whiff. If it has an off, sour, or metallic smell that is different from its normal scent, do not drink it. One user reported an "unusual smell" and later felt ill after consuming a two-month-expired can, though the taste seemed normal.
Altered Flavor: Even if the smell seems fine, take a small sip to test the flavor. If the taste is strange, dull, or unpleasantly acidic, the quality has degraded. The "Best By" date is a promise of flavor, and once passed, that promise is off the table.
Compromised Can: A bulging, rusted, or leaking can is a major red flag. This indicates that the seal has been compromised, allowing bacteria or other contaminants to enter the drink. Discard any can with physical damage immediately.

Comparison: Unopened vs. Opened Celsius


Feature	Unopened Celsius Can	Opened Celsius Can
Shelf Life	Can last several months past "Best By" date, typically up to 15 months from manufacture.	Should be consumed within 24 hours for best taste. Generally safe for 5-7 days if refrigerated.
Carbonation	Retains its fizz for an extended period if stored correctly.	Rapidly loses fizziness upon opening.
Flavor	Maintains peak flavor quality until the "Best By" date.	Begins to lose flavor immediately after opening due to oxidation and carbonation loss.
Safety	Very low risk of bacterial contamination if can is intact.	Increases risk of contamination from the environment after being exposed to air.
Active Ingredient Potency	Caffeine and other nutrients slowly degrade over time, with a noticeable decrease well past the "Best By" date.	Potency degradation is not a concern for an opened can as it should be consumed quickly.

What to Do If You've Consumed Expired Celsius

Most of the time, consuming an expired but otherwise untainted Celsius drink will result in a less-than-pleasant taste and a weaker energy boost. The risk of serious illness from a properly sealed, unopened can is minimal. However, if the can was bulging, rusted, or you notice any signs of contamination, or if you feel unwell after drinking, it's best to consult a medical professional. The primary issue with expired drinks is a loss of quality, not a sudden toxic conversion. In general, if in doubt, throw it out.

Conclusion

In conclusion, Celsius energy drinks do not truly "go bad" in the way that dairy or fresh food does, but they do have a finite shelf life for quality. An unopened, properly stored can will likely be safe to consume well past its "Best By" date, though with diminished flavor and potency. Once opened, however, the drink's freshness is significantly reduced, and it should be consumed or discarded quickly. Always check the can for any signs of damage and use your senses to determine the quality of the beverage before consuming it. Prioritizing safety and a good taste experience means adhering to the recommended timelines and storage conditions as much as possible.

For more information on the safety of dietary supplements and their ingredients, the National Institutes of Health provides a helpful resource.

Frequently Asked Questions

If an unopened can has been stored properly, it can often be safe to drink for several months to a year past the 'best by' date, although the taste and fizz will decline. Some experts recommend discarding after two years for maximum safety.

Key signs of spoilage include a significant loss of carbonation, a sour or otherwise 'off' smell, a strange or unpleasant taste, and any physical damage to the can, such as bulging or rust.

It is unlikely to cause serious illness if the can was unopened and undamaged. However, consuming a degraded drink could lead to minor digestive issues. If the can was compromised, it could introduce bacteria and pose a risk.

For optimal shelf life, store Celsius in a cool, dry place like a pantry or refrigerator, away from direct sunlight and extreme temperatures.

Yes, over time, the potency of ingredients like caffeine and vitamins will gradually diminish. The energy boost will not be as strong as a fresh can.

An opened can of Celsius should be consumed within 24 hours for the best taste and fizz. While it may be safe for up to a week if refrigerated, it will quickly lose its carbonation and flavor.

Based on manufacturer information, Celsius powder stick packs generally have a longer shelf life than the canned drinks, sometimes up to 720 days (approx. 2 years) if stored correctly.