Protein powders are an incredibly popular supplement among health-conscious people.

Still, depending on how long that tub of protein powder has been in your kitchen cabinet, you may wonder whether it’s still good or safe to use.

This article discusses whether protein powder expires and if it’s safe to consume beyond its expiration date.

Protein powders offer a convenient and relatively inexpensive way to increase your protein intake.

Though much attention is focused on protein’s beneficial effect on muscle gain, research continues to unravel other benefits of higher protein intakes, including fat loss, blood sugar stabilization, blood pressure control, and bone health (1, 2, 3, 4).

Protein powders come from a variety of sources, including:

  • milk — in the form of whey or casein
  • soy
  • collagen
  • pea
  • rice
  • egg white

Products typically contain one source of protein but may also provide protein from multiple sources to reduce cost or alter the absorption rate.

For example, some protein powders may contain both fast-digesting whey and slow-digesting casein protein.

Protein powders also include varying levels of other nutrients, such as fats, carbs, vitamins, and minerals.

Plus, they generally contain additives, including natural and artificial flavors, flavor protectors and enhancers, and thickening agents to provide a creamier consistency and mouthfeel.


Protein powders come from a variety of animal- and plant-based sources. They often contain additives to improve and preserve their flavor and texture.

Shelf life generally refers to how long food retains optimal quality after production.

Supplement manufacturers do not have to include an expiration date on their products (5).

However, many companies voluntarily provide an expiration or “best by” stamp along with a manufactured date.

In these cases, it’s up to the manufacturer to support the expiration date of their products with data to demonstrate it’s not misleading (5).

Using an accelerated shelf-life test, researchers in one study found that whey protein powder has a shelf life of more than 12 months — even up to 19 months under normal storage conditions, which are defined as 70°F (21°C) and 35% humidity (6).

An accelerated shelf-life test is a method of measuring and estimating the stability of a product by storing it under stressful conditions, such as high temperature and humidity.

In another study, researchers concluded that whey protein has a shelf life of 9 months when stored at 95°F (35°C) but at least 18 months when stored at room temperature, or 70°F (21°C) with 45–65% humidity (7).

Whether the suggested shelf life of whey protein applies to other sources of protein remains unknown, but it’s likely similar if they are stored under the same conditions.

In either case, most protein powders on the market contain additives that increase shelf life, such as maltodextrin, lecithin, and salt, allowing for a shelf life around 2 years (8, 9).


Based on the available research, whey protein powder has a shelf life of 9–19 months when stored under normal conditions. Most protein powders contain additives that extend the shelf life for up to 2 years.

With the exception of infant formula, expiration or use-by dates are not indicators of safety but quality (10).

Protein powders are low moisture foods, meaning they’re less prone to bacterial growth (11).

While consuming protein powder shortly after its expiration date is likely safe if the product has been stored properly, protein powders can lose protein content with age.

One study showed that the amino acid lysine in whey protein decreased from 5.5% to 4.2% in 12 months when stored at 70°F (21°C) with 45–65% humidity (7).

However, the protein powder used in this study did not contain any of the additives that many products on the market contain to extend their shelf life.

It’s also possible for protein powder to go bad before the listed expiration date, especially if it’s not stored under cool and dry storage conditions.

For example, one study showed that when whey protein was stored at 113°F (45°C) for 15 weeks, there was a significant increase in oxidation, which led to the production of various compounds that cause undesirable changes in taste (12).

Oxidation — the reaction of fats with oxygen — increases with storage time and damages the quality of protein powders. High temperatures are conducive to oxidation, with research suggesting that oxidation increases by 10-fold for every 50°F (10°C) increase (13).

Signs that protein powder has gone bad include a rancid smell, bitter taste, changes in color, or clumping (7).

Similarly to eating spoiled foods, consuming protein powder with one or more of these signs — regardless of the expiration date — could make you sick.

If you notice any signs that your protein powder has gone bad, it’s best to throw it out.


Protein powder is likely safe to consume shortly after its expiration date if there are no signs that it has gone bad. However, the protein content of protein powders may decline with age.

Protein powders are popular supplements that come from a variety of animal- and plant-based sources.

Though research suggests that whey protein has a shelf life of 9–19 months, many protein powder manufacturers list an expiration date of 2 years after production, which is likely made possible due to additives that extend shelf life.

Consuming protein shortly after its expiration date is likely safe if there are no signs that it has gone bad, which include a rancid smell, bitter taste, changes in color, or clumping.

If these signs are present, it’s best to toss your tub and purchase a new one.