Hey there, fitness fanatics! Do you wonder, “is it bad to drink expired liquid protein shake?” Then, you've come to the right place!

As a fitness coach and nutritionist, I've encountered this question quite a few times, and I'm happy to shed some light on the matter.

While it's not ideal to drink an expired protein shake, it's not necessarily a death sentence.

So, let's deep dive into this topic and find out what is safe to do and what's not.

Well, it depends. The product's expiration date on a protein shake is more of a guideline than a hard and fast rule.

It's actually not an expiration date, but it is meant to indicate the date by which the manufacturer can guarantee the product's quality. The use by date doesn't necessarily mean the expired protein powder has gone bad after that date.

That's why I want first to address the elephant in the room - the word "expired." It has a negative connotation, and understandably so.

When we hear expired protein powder or expired protein shake, we often assume it's no longer safe for consumption.

Still, think of it like this - if you have a bottle of milk in your fridge that's a day or two past its expiration date, you might still drink it if it smells fine and tastes okay.

The same goes for protein shakes and other protein products, especially those which contain whey protein.

If it's only been a few days or even a week past the expiration date, and the shake looks, smells, and tastes okay, it's probably safe to drink an expired protein powder.

The worst that could happen is that the protein might start to break down, making it less effective for muscle building, but it's unlikely to make you sick.

What About For Vegan Protein Drinks?

The vegan diet and, thus, vegan protein supplements have been conquering the market unstoppably for years now.[1]

So, I guess many of you want to hear more about vegan protein spoilage and not just expired whey protein, the main muscle-building protein product.

Vegan protein powder has a longer shelf life and can be used for quite a while longer past its expiry date compared to whey protein or casein protein. 

Bacteria multiply quickly in dairy ingredients, much faster than in vegan protein sources, which are also less likely to trigger allergic reactions.

Having said that, it does not mean you should use expired protein powders a year later. 

Also, if you are about to drink a pre-made protein shake, check other ingredients because they may be more susceptible to spoilage, compromising safety.

Woman Adding A Scoop Of Gnarly Vegan Plant Protein To Tumbler

6 Signs That A Protein Shake May Not Be Safe to Drink

Several warning signs indicate a protein shake may not be safe to drink.[2]

Those signs are usually very obvious, so you shouldn't have any problems noticing them.

1. Foul Or Off-putting Odor

While it may not smell exactly like chocolate milk or a milkshake from a fast-food chain, a protein shake should still smell quite pleasant. Any occurrence of an off-putting odor is a red flag.

Such odor is a direct consequence of bacteria growth. If the nerves in your nose recognize an unpleasant smell, don't risk it but throw it away immediately.

2. Unusual Texture Or Appearance

Detecting unusual textures or appearances can be trickier than detecting odor, particularly if you are new to using protein powders and shakes. It can be lumpy and gritty for other reasons than being bad.

Nevertheless, pay special attention to whether it is discolored, muddy, and different than before.

The cause can be bacteria growth or a simple breakdown of the protein in the shake, which does not automatically mean that it is spoiled, but it shows that the expired protein shake's effectiveness is reduced.

3. Visible Mold Or Other Growths

It can't get any more evident than this. If you can see mold or other growth in your protein shake, it's definitely not safe to consume. Consuming such a shake would expose you to toxins that can cause illness.[3]

4. Unpleasant Taste

Determining which taste is a consequence of spoilage and which one simply does not suit our taste can be problematic.

Yet, you should be able to distinguish sour and bitter or otherwise unpleasant tastes, a common sign that food products may have gone bad, from not-so-tasty but generally safe protein powder.

5. Damaged Packaging

If the packaging of your protein shake is damaged, air and moisture exposure has occurred, which is detrimental to its safety and quality.

Check for cracks, leaks, or other signs of damage before consuming the properly stored shake.

6. Long Stay At Room Temperature

Another potential reason a protein shake may be unsafe to drink is if it has been left at room temperature (warm environment) for a few hours or more.

Protein powders, like other perishable foods, can grow bacteria when left at room temperature, and that's the answer to the question, "why does protein powder expire?"

This is especially true if the shake contains dairy or other ingredients prone to spoiling.

How Should Protein Shakes Be Stored To Prevent Spoilage?

Proper storage is key to preventing spoilage and ensuring your protein shake remains 100% efficient and safe. Here are some tips to protect your muscle building power shakes.

Refrigerate The Protein Shake

The best storage method is to refrigerate at 40 °F or below. This will significantly slow down the growth of microorganisms.

Make sure to drink it within the recommended timeframe. A refrigerated liquid protein shake won't last a few months, but you will have days to drink it.

You can also freeze protein shakes, but that will have a more significant impact on the taste (negative; Maillard browning.)

To minimize these effects, it's best to shake the protein well before freezing and thawing. Consume it as soon as possible after thawing.

Use A Clean And Dry Container

The best option is to use the original container and follow storage instructions. If water gets into it, wash the container with hot water and let it dry completely before using it.

The same goes if you transfer the protein shake from the original packaging to another due to damage.

Keep The Container Sealed

After each use, close it as tightly as possible to prevent air and moisture from getting in. Otherwise, moisture and air may penetrate or even bugs. When buying, check whether it is sealed.

Avoid Exposure To Light

You are probably wondering how light can affect it.

Exposure to light can cause a chemical reaction - protein (mainly amino acid lysine) will break down, affecting the flavor, protein content, and other nutrients - thus, muscle growth. Store it in non-transparent containers.

What Could Be The Side Effects Of Consuming Expired Shakes?

Consuming expired shakes can lead to many unpleasant side effects, but don’t mistake them for allergic reaction. Some of the most common ones are:

  • Diarrhea
    Diarrhea signifies the body is trying to expel growing bacteria and other harmful substances. Diarrhea usually goes away on its own, but severe symptoms indicate that you need urgent medical help.
  • Vomiting
    This is another way the body tries to cleanse itself. If you vomit for more than 12 hours, life-treating dehydration may occur.
  • Nausea
    Nausea is the most common symptom of food poisoning. Other symptoms, such as stomach pain, often accompany it. Sometimes it can result from lactose intolerance and not an expired shake.
  • Fever
    Fever is the most serious side effect because it shows that the body is trying to deal with severe food poisoning. It is necessary to contact the doctor right away.[4]
Getting The Body Temperature Of A Sick Person Using Thermometer

Expired Protein Shakes Common Questions

How long does the protein shake last in the fridge?

Protein shakes, both homemade and when opened, typically last 3-5 days in the fridge. However, I would use it for a maximum of 3 days since individual ingredients and other factors affect food spoilage.

Can I freeze liquid protein shakes to extend their shelf life?

Yes, you can freeze liquid protein shakes to extend their shelf life. Freezing in shake form can help preserve the nutrients in the shake and prevent it from getting a rancid smell and taste. You have to keep in mind that the texture and taste will be affected after freezing and thawing.

How do manufacturers determine expiration dates for protein shakes?

Manufacturers generally determine expiration dates for protein powders based on different aspects, including the ingredients used, the packaging, and the processing methods. They also conduct stability testing to determine how long the product will remain safe and effective under normal storage conditions.

Do Premier protein shakes expire?

Premier Protein Shakes may be the most popular on the market, but they expire like all protein shakes and protein powders. The expiration date is printed on the bottle. It's essential to check the expiration date before buying and consuming the shake to ensure it is safe and nutritious.


The answer is not a simple yes or no. It depends on various factors, such as how long ago it expired and how it looks, smells, and tastes. Also, whether it has been stored properly.

Use your common and other senses to determine whether the shake is still safe to consume, and don't make a habit of using expired products.

And remember, when in doubt, it's always better to be safe than sorry! If you're concerned at all, just buy new drinks to replace the old ones.


  1. https://link.springer.com/article/10.1007/s40279-021-01434-9
  2. https://www.usda.gov/media/blog/2016/03/25/protecting-your-family-food-spoilage
  3. https://pubmed.ncbi.nlm.nih.gov/23462093/
  4. https://www.cdc.gov/foodsafety/symptoms.html
Miloš Lepotic

Miloš Lepotic

Meet Miloš, a certified sports nutritionist and self-taught supplement expert whose pharmacological background and nearly a decade of gym experience make him the perfect guide for optimizing your health and athletic performance through supplement reviews and practical advice rooted in factual, science-backed information.