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Protein powders are a popular supplement to support muscle building, exercise recovery, and weight loss, among other uses.
However, depending on how long that tub of protein powder has been tucked away in your cabinet, you may wonder whether it’s still safe to use.
This article explains whether protein powder expires and if it’s safe to take it after its expiration date.
What is protein powder?
Taking a protein powder is a relatively convenient and inexpensive way to increase your protein intake.
They usually contain 20–30 grams of protein and 120–200 calories per serving.
Protein powders are different from weight gainer supplements, which are loaded with calories from both protein and carbs.
The most popular and common type of protein powder is whey, one of the two main proteins in milk, the other being casein.
However, protein powder supplements may contain protein from other sources, including:
- egg whites
Protein powders may contain protein from one source or several.
They are created through various processing methods and come in different forms, including concentrations, isolates, and hydrolysates.
Concentrates are the least processed and usually contain 70–80% protein by weight, whereas isolates are more processed but contain at least 90% protein by weight.
Protein hydrolysates undergo further processing to break protein into its component amino acids and peptides.
Generally, the more processed a protein powder is, the more expensive it is. So concentrates tend to be the least expensive and hydrolysates the most expensive.
Whey protein usually contains a blend of concentrate, isolate, and hydrolysates.
The cost also depends on whether the protein powder is animal- or plant-based and if it contains other ingredients like probiotics or creatine.
Does protein powder expire?
Protein powders generally have a shelf-life of two years from their manufactured date if they are stored properly.
Shelf life refers to how long a product retains its optimal appearance, flavor, smell, texture, and nutrition.
You can find the manufactured date stamped — usually around the bottom — on most products.
Within two years of this date is when you should consume the product for the best quality.
Although the United States Food and Drug Administration (FDA) does not require an expiration date on supplements like protein powder, some manufacturers list it, saving you from having to do the math (1).
Protein powder supplements with an expiration or best-by date have undergone stability testing, a process that manufacturers use to determine how long — through storage at defined conditions and testing specifics — their product retains optimal quality and nutrition.
In either case, your protein powder can go bad before the stamped expiration date or two years after the manufactured date if it’s improperly stored.
Signs of improperly stored protein powder include (2):
- clumping or caking powder
- poor mixability
- yellowing or browning of color
- an ether- or garlic-like smell
It’s best to throw your protein powder out if you notice any of these signs.
Even if your protein powder is unopened, there is still a chance for spoilage to occur, so you should check for these signs.
Can expired protein powder make you sick?
Except for infant formula, expiration or best-by dates are indicators of quality, not safety (3).
Therefore, it can be safe to take protein powder after the expiration date or two years after the manufactured date if you know it has been stored properly and notice no signs of spoilage.
Humidity and storage temperature are the primary factors involved in the spoilage of protein powder.
Protein powder that has been exposed to warm temperatures or humid conditions becomes sticky and forms lumps or masses, known as caking.
This is because protein powder is highly hygroscopic, meaning it absorbs moisture from the air.
Consequently, this moisture can encourage the growth of harmful bacteria, which cannot be seen by the naked eye.
Protein powders may also turn yellow or brown due to oxidation and a chemical reaction that occurs between the sugar and proteins known as the Maillard reaction (2).
The Maillard reaction also decreases the quality of protein by reducing its digestibility (4).
Signs of oxidation or the Maillard reaction may be difficult to detect if your protein powder was originally yellow or brown due to the type of protein or additives.
Additionally, improperly stored protein powder can encourage the formation of volatile compounds or gases that have an ether- or garlic-like odor.
Hydrolyzed protein powders are especially susceptible to these chemical and physical changes since they have stronger water-absorbing properties (5).
Temperature is another factor that can decrease the shelf life of protein powder.
One study concluded that the shelf life of whey protein held at 95ºF (35ºC) was nine months at most due to the clumping and color changes that occurred (6).
However, this doesn’t mean that you need to or should refrigerate your protein powder.
But, you should store your protein powder in a cool environment under 77ºF (25ºC) with low relative humidity (less than 65%) to maintain the best quality and prevent spoilage (2).
The relative humidity is the measure of water vapor or moisture relative to the temperature of the air.
The ideal relative humidity for health and comfort is 40%–60%.
If you’re concerned that the relative humidity in your home may be higher than this range — or you’re just curious — you can purchase a hygrometer for around $10.
The bottom line
Protein powders are best used by their expiration date or within two years of the manufacture date.
Taking protein powder past these dates likely won’t harm you if it has been stored properly and you don’t notice any signs of spoilage, such as clumping or caking powder, poor mixability, yellowing or browning of color, or ether- or garlic-like smell.
For the best quality and maximum nutrient retention, store your protein powder in a cool area with low relative humidity.