Can You Eat Expired Protein Bars? Eat Now, Cry Later?

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If you’ve ever asked yourself, “Just how bad for me is this expired protein bar that I found?” then buckle up, because we’re about to dive into the nitty-gritty of expired protein bars. 

Let’s set the scene: you’re rummaging through your pantry. You come across an old protein bar that’s been hiding in the back for who-knows-how-long. 

You start to wonder, “Is it still good? Can I eat it?” Well, read along to find all the answers you’ve been looking for.

You can eat expired protein bars, but it’s not recommended. Consuming expired protein bars can have some nasty side effects. For example, they could give you an upset stomach, or even food poisoning. Their potency can also decrease, causing you to lose out on a protein bar’s benefits. 

Key Takeaways

  • Stay away from expired protein bars.
  • Some risks include rancidity, flavor loss, and microbial attacks.
  • Eating expired protein bars can give you food poisoning or upset your stomach.
  • The average shelf life is 12 months, but it depends on ingredients and storage conditions.
  • Expired bars are not as effective for your muscle building and recovery.
  • Proper storage in a cool, dry place extends the shelf life of your protein bars.
  • Check your expiration dates and always choose high-quality, natural ingredients when buying online.
  • Dispose of your expired bars and be sure to err on the side of caution.

Risks of Eating Expired Protein Bars

Let’s get straight to it: eating an expired bar for convenience (or to save a few bucks) is not worth the risk. Rancidity and flavor loss are just a few of the risks of eating expired protein bars.

Rancidity occurs when the oils in the bars start to break down and become rancid. This gives the bars an off flavor and smell. Additionally, microbial attacks occur when bacteria, yeast, or mold starts to grow on them. 

Both of these effects can result in food poisoning and other health issues. And, last but not least, flavor loss occurs when the taste of the bars starts to deteriorate over time.

Can You Get Sick From Eating an Expired Protein Bar?

You can most definitely get sick from eating anything that’s expired- including a protein bar. Would you drink expired milk or eat moldy bread? (…I would hope not!) Consuming rancid or moldy bars can lead to health issues like food poisoning or an upset stomach.

So, if you’re feeling brave and you want to test the limits of your stomach, go ahead and chow down on that expired bar. But if you value your taste buds and your health (as you should!), it’s best to throw it out.

Can Protein Bars Go Bad?

The shelf life of protein bars can vary. But on average, they can last up to 12 months. The expiration date of protein bars depends on a lot of factors. For example: the ingredients used, the manufacturing process, and the storage conditions. 

There are certain ingredients that can extend the shelf life of protein bars. These include preservatives such as sodium benzoate and potassium sorbate. They prevent the growth of bacteria and fungi, making them last much longer. 

Antioxidants like tocopherols and ascorbyl palmitate protect the bar’s fats from oxidation. Sweeteners like erythritol and stevia also help maintain the freshness of the bars. The use of stabilizers such as gum arabic, xanthan gum, and gellan gum can also help them hold shape and texture.

How Long Are Protein Bars Good After Expiration Date?

It’s not recommended to consume protein bars after their expiration date… please don’t! The potency of the bars can start to deteriorate after the expiration date. But more importantly, the risk of food poisoning and other health issues increases. 

So, if you have a bar that’s been hiding in the back of your stash for a few months (or a year), it’s probably a good time to say goodbye.

Are Expired Protein Bars Still Effective?

The honest truth is that anything that’s expired probably won’t have the effect it once did. Expired protein bars are certainly not the exception. 

The potency of the bars can start to deteriorate after the expiration date. This means their effectiveness for muscle building and recovery is significantly reduced.

They lose their potency because of chemical/physical changes that occur over time. It decreases due to oxidative rancidity. This means the oils in the bar break down and become rancid, leading to a strange flavor and smell. 

Additionally, these expired bars lose much of their protein and nutrient content. So, if you’re trying to bulk up or recover from a workout, grab a fresh bar instead of relying on that old, expired one.

What To Do With Old Protein Bars

Toss ’em! It’s as simple as that. When it comes to disposing of old protein bars, it’s best to err on the side of caution and just throw them out. 

If you’re unsure if a bar is still good, look for signs of rancidity, such as an off flavor or smell. Also be wary of signs of a microbial attack, such as mold or discoloration.

Proper Storage of Protein Bars

How can you avoid a rancid protein bar? Proper storage! It’s crucial in extending their shelf life and preserving their potency. 

To keep your bars fresh, store them in a cool, dry place, away from direct sunlight and heat sources. You don’t have to refrigerate protein bars, but if you live in a warm, humid climate you should consider it. Cold temperatures can reduce the rate of oxidation. This is a process that breaks down fats in the bar and they become rancid. 

By slowing down this process, refrigeration can prevent the formation of unwanted changes. Additionally, refrigeration can also slow down the growth of bacteria, yeast, and mold. If you store them properly protein bars can last up to an entire year! 

Buying Protein Bars Online

Look for protein bars with high-quality, natural ingredients, especially when buying online. You don’t want just anything in your body! 

Also, make sure to check the expiration date before purchasing. It’s also a good idea to read reviews from other customers to get an idea of the taste and quality of the bars.


Try to stay away from expired protein bars. Your body will thank you! It’s not worth the potential health risks. Plus, don’t you want all the potency and benefits of a non-expired bar? 

Proper storage and freshness are crucial in preserving the effectiveness of protein bars. So, if you come across an old bar in your pantry, it’s best to err on the side of caution and just throw it out.


Encyclopædia Britannica, inc. (n.d.). Rancidity. Encyclopædia Britannica. Retrieved February 16, 2023, from

Mayo Foundation for Medical Education and Research. (2022, January 22). Serotonin syndrome. Mayo Clinic. Retrieved February 16, 2023, from

Mould growth. Mould Growth – an overview | ScienceDirect Topics. (n.d.). Retrieved February 16, 2023, from

Abasolo, C. (2021, May 26). The oxidation process in fats and oils. BTSA. Retrieved February 16, 2023, from

  1. Journal of Food Science and Technology. (2020). Shelf Life and Safety of Protein Bars.
  2. Journal of Food Science and Technology. (2018). Microbial Contamination in Food Products.
  3. Journal of Food Science. (2017). Flavor Loss in Food Products.
  4. Journal of Food Science. (2015). Shelf Life of Protein Bars.
  5. International Journal of Food Science and Technology. (2014). Factors Affecting the Expiration Date of Protein Bars.
  6. Journal of Food Science and Technology. (2013). Consuming Expired Protein Bars.
  7. Journal of Food Science and Technology. (2012). Potency Loss in Expired Protein Bars.
  8. Journal of Food Science. (2010). Proper Storage of Protein Bars.
Hayden Wilde

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