Written by Ben Carlisle
Last updated on: Sep 25, 2022
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If you're a fitness enthusiast, you've probably heard that whey protein is a fast and efficient way to help your body recover after a workout. But are you concerned whether or not whey protein expires? And if it does, how long will it stay fresh?
If you're like most people, you probably don't think much about the expiration date on your whey protein powder. After all, it's just a supplement, right? Wrong. Just like any other food product, whey protein powder can go bad.
In fact, it's one of the few supplements that can actually expire.
The first thing to understand is that whey protein powder is a dairy product. That means it's made from milk, which is a highly perishable food. As such, whey protein powder can spoil just like any other dairy product.
The main difference is that whey protein powder has a much longer shelf life than most dairy products. That's because the whey is dried and concentrated, which makes it much less susceptible to spoilage.
According to research, under normal conditions, the shelf life of whey protein ranges between 12 months to 19 months (1).
However, even though whey protein powder has a longer shelf life than most dairy products, it can still go bad earlier than the expiry date. The main way that whey protein powder goes bad is through oxidation.
Oxidation is a chemical reaction that occurs when oxygen is exposed to the powder. This causes the whey proteins to break down, which reduces the powder's potency and effectiveness. According to research, for every 10°C or 50°F, oxidation increases by 10-fold (2).
Whey protein powder usually comes with an expiration date on the label. However, this date is not always accurate. The reason for this is that oxidation can occur way before the expiration date. That's why it's important to check the powder regularly, even if the expiration date hasn't passed yet.
Therefore, when using whey protein powder, you don’t just need to know its expiry date, but also ensure that it stays fit for consumption by not exposing it to the air. More importantly, you need to be aware of the signs the powder has gone bad, so that you don’t keep on consuming a perished powder.
Oxidation, however, is not the only aspect that determines the “best before” window for your whey protein powder. There are several other factors that impact its shelf life, including:
There are four types of whey protein – whey protein concentrate (WPC), whey protein isolate (WPI), whey protein hydrolysate (WPH), and native whey protein. WPC is the least processed form of whey, and thus has the shortest shelf life.
WPI and WPH are more processed, and thus have a longer shelf life. Native whey protein is the most minimally processed form of whey, and thus has the longest shelf life.
The moisture content of whey protein powder also plays a role in its shelf life. Whey protein powder with a higher moisture content will have a shorter shelf life than whey protein powder with a lower moisture content. To learn more about the effects of temperature and humidity on whey protein, go this insightful study (3).
The storage conditions of your whey protein powder also play a role in its shelf life. Powder that is stored in a cool, dry place will last longer than powder that is stored in a warm, humid environment.
The type of container that your whey protein powder is stored in also impacts its shelf life. Powder that is stored in a glass container will last longer than powder that is stored in a plastic container.
The presence of additives in your whey protein powder will also impact its shelf life. Powder that contains antioxidants will last longer than powder that does not contain antioxidants. Some of the additives used include maltodextrin, salt, and lecithin (4).
So, how can you tell if your whey protein powder has gone bad? The first thing you'll notice is that the powder will change color. It may turn a yellowish-brown color, or it may even turn black. The powder may also start to clump together, and it may have an off odor. Other signs the powder has gone bad include bitter taste and clumping (5).
If you notice any of these changes, it's important to throw the powder away and get a new one.
To keep your whey protein in its optimal usable condition, be sure to store it properly. Whey protein powder should be stored in a cool, dry place. If you're going to be storing it for more than a few months, it's best to keep it in the refrigerator. However, if you're only going to be using it for a short period of time, you can store it at room temperature.
Here are some of the issues you can face when you keep consuming a whey protein powder that has gone bad:
One of the most common consequences of consuming expired whey protein powder is it loses its effectiveness at supporting lean muscle growth and strength development. Even in the best whey protein powder supplements, the protein will begin to break down, and become less effective.
Another problem with consuming expired whey protein powder is the potential for food poisoning. The protein in the powder can start to break down and form bacteria, which can cause nausea, vomiting, and diarrhea.
A final consequence of consuming expired whey protein powder is that it can weaken your immune system. When the protein in the powder breaks down, it releases toxins into your body that can make you sick and more susceptible to infection.
Whey protein certainly proves useful for muscle function (6). But does it expire? The answer is a clear yes. Your whey protein won’t last forever, and it may not taste or perform as well after a certain amount of time. You shouldn’t rely on the expiry date. How long your whey protein lasts will depend on how you store it and how often you open the container.
If you want to get the most out of your whey protein, try to buy in bulk and store it in a cool, dry place. And if you’re not going to use all of it right away, put it in the freezer so that it will stay fresh for longer.