protein powder in black plastic tub

How Long Does Protein Powder Last? What the Science Says

Here’s what the research says about consuming expired protein powder.

10-Second Takeaway

The short answer is yes—you can consume protein powder after the expiration or “best by” date. But be aware that there are some downsides to using expired protein powders, including an off-putting taste, digestive problems, and less protein. 

Let’s be real—we’ve all consumed expired foods and drinks at least once. Maybe it’s just a day or two after the expiration date, or maybe it’s been a few weeks or months—we’re not judging. Sometimes, you don’t notice any off-putting flavors or smells, but other times, the product is so expired that you gag after its first whiff or taste (apologies for the visual).

Protein powder is a popular supplement many people use for various reasons, but typically for muscle growth and recovery. Because it comes in powder form, many question whether or not it’s safe to consume after the expiration date. 

To figure this out, we reviewed the research to give you all of the facts. 

Does Protein Powder Expire? 

The short answer is yes—but it might last longer than you think. 

As with any product you consume, you’d typically have an expiration date on the packaging to tell you when something will go bad. 

But, when it comes to supplement manufacturers, the Food and Drug Administration (FDA) does not require them to include an expiration date if they don’t want to (1).

Fortunately, some manufacturers still provide consumers with a “best by” date and a manufactured date. As you may or may not already know, a “best by” date can indicate when a product will be of the highest quality based on taste, freshness, etc (2). 

But we can’t always trust manufacturers, can we? So, let’s look at the research to confirm protein powder’s true shelf life. 

Protein Powder Shelf Life

According to research, the shelf life varies depending on your protein type, but they tend to stay fresh between 9 and 18 months (3). 

A 2016 study found that the powder had a shelf life of 9 months when stored at 95 degrees Fahrenheit, while others stored at room temperature (70 degrees Fahrenheit) could last up to 18 months with 45 to 65 percent humidity (3).

The same study revealed that over time, the whey protein powder:

  • Became yellow
  • Had a foul odor
  • Decreased in lysine
  • Increased water activity
  • Began to clump up
  • Developed bacteria, coliforms, yeast, and mold

Another study revealed that whey protein powder lasted at least 12 months and upwards to 19 months when stored in normal conditions, which researchers defined as 70 degrees Fahrenheit and 35 percent humidity (

So, in simpler terms, protein powder can last for quite a long time before expiring. Still, that period can be significantly shorter based on the temperature and humidity you store it in. 

If you’ve been keeping your protein powder in your car during the hot summer months for easy access, you’re probably speeding up its expiry.

Can You Eat Expired Protein Powder?

We recommend that you don’t use it past the expiration date, but there doesn’t seem to be much harm in consuming it. 

While “best by” dates are helpful, it’s important to mention that they have more to do with decrease in quality within a product, but there are not really any safety concerns (2). 

Using protein powder safely stored a few days after the date posted on the package may not cause any significant problems, but you may not get the same quality supplement you had before expiration. 

In the same 2016 study mentioned above, researchers discovered that the amino acid lysine in the whey protein decreased from 5.5 to 4.2 percent over 12 months at 70 degrees Fahrenheit with 45 to 65 percent humidity (3). 

Lysine is an essential amino acid (EAA) that may help improve bone growth and healing, prevent fatigue, and increase tolerance to stress (5).

The taste of protein powder may change over time as well. An older study found that whey protein stored at 113 degrees Fahrenheit for 15 weeks increased oxidation in the powder, leading to an increase in volatile compounds that caused an off-putting taste (6).

Oxidation is a chemical reaction that occurs when certain elements (fats, in this case) interact with oxygen. Research has found that whey protein isolate is susceptible to oxidation—especially in heated conditions—thus impacting the quality of protein powders (7). 

So, what can happen if you knowingly or unknowingly consume expired protein powder? Unless you have a stomach of steel, you may get sick, along with other problems. 

Risks of consuming expired protein powder (8, 9, 10)

  • Digestive problems, including gas, bloating, or an upset stomach.
  • Bacterial infections, like salmonella and bacillus cereus.
  • Protein degradation from Maillard browning, as the powder can lose nutritional value when expired.

How to Tell If Protein Powder Has Gone Bad

In most instances, simply looking at the expiration or “best by” date is the best way to figure out when your protein powder may begin degrading. 

If you’re still not convinced, use this checklist before adding the powder to your favorite shaker bottle:

  • Get a nice whiff of the protein powder to see if there are any unusual or foul-smelling odors.
  • Look for any clumps or discoloration within the powder, indicating moisture has entered the powder.
  • If all else fails, tasting the powder will let you know if it’s expired.

If you notice anything that seems questionable about your protein powder—it’s time to chuck it in the trash. 

How to Store Your Protein Powder 

Heat, humidity, and light are the main factors that work to degrade the quality of your protein powder and potentially spoil it. This is especially true if you have a milk-based protein powder (11).

If you want to extend the shelf life, you must provide the best environment. You can do this by storing your protein powder in a cool, dry, and dark place to prolong use and maximize fresh quality. Research suggests your room temperature for protein powder storage should be below 85 degrees Fahrenheit (11).

And lastly, be sure the lid fits snugly on the container to prevent moisture and light from entering your supplement powder.

The Bottom Line

For the most part, you’ll likely be okay if you consume some expired protein powder, as some can last up to 18 months. That said, protein powder stored in a not-so-accommodating place (hot and humid) will have a shortened shelf life, which can lead to unpleasant smells, taste, and potential health problems. 

1. U.S. Food & Drug Administration (2005). Dietary Supplement Labeling Guide: Chapter I. General Dietary Supplement Labeling.
2. U.S. Department of Agriculture Food Safety and Inspection Service (2023). Food Product Dating.
3. Tunick, Michael H. (2016). Physical and chemical changes in whey protein concentrate stored at elevated temperature and humidity.
4. Sithole, R. et al (2005). Rate of maillard browning in sweet whey powder.
5. University of Rochester Medical Center. Lysine.
6. Javidipour, Issa et al (2008). Volatile component change in whey protein concentrate during storage investigated by headspace solid-phase microextraction gas chromatography.
7. Bordignon, Juliany Cristiny Sonda et al (2023). Oxidation of whey protein isolate after thermal convection and microwave heating and freeze-drying: Correlation among physicochemical and NIR spectroscopy analyses.
8. Feng, Xianchao et al (2015). Susceptibility of whey protein isolate to oxidation and changes in physicochemical, structural, and digestibility characteristics.
9. Farakos, Sofia Santillana et al (2014). Relative survival of four serotypes of Salmonella enterica in low-water activity whey protein powder held at 36 and 70°C at various water activity levels.
10. H. Nursten (2002). Maillard Reaction.
11. Ryabova, A.E. et al (2023). Effects of storage conditions on milk powder properties.