Protein powder is often a big staple in the everyday diets of strength athletes. You may go through your tubs pretty quickly and regularly. But then you come across one you forgot about in the back of the cabinet. Figuring out how long it’s been there might feel like an urgent task. Naturally, you want to know whether it’s safe to toss old protein powder into a protein shake.
There are different types of protein powder, so whether it’s a whey or a plant-based alternative, your mileage may vary. Many packages will list a “best by” or “use by” date. But navigating what exactly that means — and figuring out whether protein powder goes bad — can be tricky. Turns out that it depends on more than how long it’s been in the cabinet. And your protein powder may last longer than you think.
Editor’s Note: The content on BarBend is meant to be informative in nature, but it should not be taken as medical advice. When starting a new training regimen and/or diet, it is always a good idea to consult with a trusted medical professional. We are not a medical resource. The opinions and articles on this site are not intended for use as diagnosis, prevention, and/or treatment of health problems. They are not substitutes for consulting a qualified medical professional.
What Is Protein Powder?
Protein powder is an efficient way to meet your protein intake goals. Athletes reach for it to help hit their macros, improve athletic performance, and post-training muscle growth. (1) It can be made from different types of ingredients, generally divided by dairy and non-dairy ingredients.
The idea behind protein powder is that it can be hard to get in as much protein as you need to accomplish your muscle-building or body recomposition goals. You might focus very hard on getting plenty of tofu or chicken breast in your daily diet, but it can be tough to eat as much as you need to support your desired gains.
[Read More: How Much Protein Do You Actually Need Per Day?]
Whether you don’t love eating a lot of meals each day or you love it but need to eat on the go, protein powder is a convenient, efficient way to significantly increase your intake. This is particularly important when you’re on a fitness journey focused on muscle growth, fat loss, or increasing strength.
To incorporate it into their diets, strength athletes often toss protein powder into their post-workout shakes or smoothies. But it’s not only about shaker bottles. Athletes also scoop protein powder into everything from their oatmeal to their protein-packed pancakes.
Protein powder is a unique supplement in that it can be used alone or as part of a recipe. That being said, protein powder alone in water is often sandy at best and totally gross at worst, so you’ll probably enjoy it more if you mix it with other ingredients to make a shake, smoothie, or even pancakes. If you’re trying to boost your calorie intake without feeling too full, stick with a liquid option. Adding it to a solid food, on the other hand, will be more filling. (2)
Animal-based protein powders, like whey, are commonly derived from milk, but some varieties use powdered egg whites, beef, or fish protein. Plant-based, vegan protein powder is made from other sources such as peas, hemp, or rice.
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Some protein powders come just as they are — pure protein powder, for example, may come unflavored and unaccompanied by any other ingredients. On the other hand, other protein powders come with a wide array of other ingredients, ranging from natural sugars and artificial sweeteners to digestive enzymes and amino acids.
Types of Protein Powder
Protein powder can be made from animal sources or plant sources. Both types of protein powder can be beneficial for athletes who may need a higher level of protein intake than folks without fitness-oriented goals, but they’re just as helpful for non-athletes who need a quick, portable source of protein. (3)(4)
Before dismissing vegan protein sources outright, it’s worth noting that research shows that combining different sources of vegan protein provides benefits that are comparable to animal-based sources of protein. (3)
Animal-Based Protein Powders
Plant-Based Protein Powders*
* These powders are often made from blends of plant-based ingredients, including brown rice, pumpkin seeds, and chia seeds.
Is Protein Powder Safe?
Protein powder is completely safe and highly beneficial for most people when taken within recommended doses and according to the label’s instructions. However, some powders contain ingredients that can cause bloating, gas, or serious allergic reactions in people with food allergies. (4)
Lactose and Inulin Can Cause Digestive Issues
Whey protein concentrate and whey protein blends contain lactose, which causes digestive discomfort in people with lactose intolerance. Casein and whey isolates contain very little lactose, so they’re usually tolerable, but they still would pose a serious risk to someone with a milk allergy. (5)
Some protein powders boost their fiber content with inulin in the form of chicory root. This potent prebiotic can support gut health, but gut microbes can produce a lot of gas while they’re breaking it down. The gas and bloating don’t pose a health risk, but they can be quite unpleasant. (6)
Many Powders Contain Food Allergens
Many powders are likely to contain some of the most common food allergens — like milk, eggs, or soy — and some may also include ingredients derived from fish, shellfish, wheat, or nuts. It’s important for people with food allergies to check the list of ingredients and allergen warnings before choosing a protein powder.
Any Supplement Can Be Contaminated
Supplements — including protein powders — carry a higher risk of contamination and inaccurate labeling compared to foods or drugs. For example, they could include banned substances or a lower protein content than what’s listed on the label.
You can avoid this risk by choosing protein powders that carry an NSF or United States Pharmacopeia (USP) label, which indicates that they’ve been third-party tested for purity and won’t contain banned substances. (7)
Does Protein Powder Expire?
The most important factors for the expiration of protein powders are the temperature and humidity level at which they were stored. Though dairy-based foods and products may call to mind a quick expiration period, since protein powders are dry, they can last a lot longer and still be microbiologically safe. (8)(9)(10) Protein powders often include other additives to help them last longer, as well.
Best Before Vs. Use By
When you’re desperate to figure out whether it’s safe to scoop that tub of protein powder that’s been sitting on your back shelf for goodness knows how long, you’ll likely look to find a stamped date. It’s important to note the language used on packaging when you’re checking the expiration date on your protein powder.
The phrase “best before” generally means the product has a long shelf life. Some foods, even dairy, marked “best before” have been found to still be microbiologically safe six months after their date. (11) However, while safe, the quality of the food may still deteriorate, and therefore not be preferable for those looking for optimal performance.
The phrase “sell by” is used if the food or product can spoil quickly and cause direct harm to human health when used after the date. (11) So if you’re considering whether to consume something after its sell-by date, you might want to proceed with even more caution compared to your “best before” options.
Yes, it’s dairy-based — but that doesn’t mean it’s going to go bad quickly. Whey protein powder has been found to have a shelf life of 12 to 19 months when stored at about 70 degrees Fahrenheit and humidity of 35 percent. (8) As long as you store your protein powder at a normal temperature and keep it dry, it can last up to two years.
Temperature makes a big difference when you’re storing whey concentrate powder. The whey concentrate stored at 95 degrees Fahrenheit lasted nine months, which isn’t too terrible. However, the powder stored at 70 degrees Fahrenheit lasted up to 18 months. (9)
At nine months, the powder in this study stored at 95 degrees was thrown out because its appearance began to yellow and become unsatisfactory. It also showed a lysine decrease and an increase in water activity. (9) If you take a peak in an old tub and find it yellowed, it might be time to part ways with it.
Studies on whey isolate are limited, but depending on storage, research suggests that these can last anywhere from eight to 15 months. (10) If your whey isolate is within that time range, you can also use your senses to assess it. Signs of protein powder gone bad include bad smell and taste, as well as clumping and a change in color. (9)
Casein is derived from bovine milk. (12) It is a dairy-based protein but is still dried in the process of turning it into powder. This drying makes it less susceptible to bacterial contamination. When stored at correct temperatures, it may have a similar shelf life to whey proteins.
Compared to whey and casein, egg white powder appears to be a little less shelf-stable. In one study, the powder changed significantly after two months at 77 degrees Fahrenheit and above, especially when exposed to moisture. It fared best at 39 degrees Fahrenheit, so it’s probably a good idea to keep your egg white powder refrigerated. (13)
Pea protein is a non-dairy source of protein that can be turned into powder. Vegetables can eventually expire, but much like dairy-based powders, vegan powders also include additives to help its shelf life last longer.
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While research is limited regarding when pea protein becomes unsafe to ingest, you might choose to follow the rules of smell and appearance. Ask yourself how close it looks to its appearance when you initially purchased it. Without any milk present, there’s less danger of microbiological damage, even past the expiration date.
Hemp seeds may not have as much protein as other sources, but they are still another option for a vegan protein powder. A study showed that they’ve been found to have a similar amount of amino acids as other grains and nuts. (15)
There are limited studies on hemp protein powder and whether or not it can expire. Hemp seeds, like anything else, can expire after a while. If you keep your hemp protein powder in a cool, dry storage area, you should be safe.
Soy protein has been shown to be equally as effective as whey protein when building muscle mass and strength in combination with resistance training. (16) Soy protein powder, like many other types, usually has an expiration date of up to two years from the time of purchase. While it doesn’t have any dairy in it, it is still susceptible to mold if not kept in a cool, dry space.
Rice protein powder boasts a shelf life of at least two years if kept sealed at temperatures below 80 degrees Fahrenheit, though this might be shorter once the package has been opened. (14)
How to Tell if Your Protein Powder Is Expired
While there may not be a way to test with certainty, studies suggest that if you’ve been storing your protein powder at 70 degrees and in dry conditions, it will likely hold up for between eight and 19 months. Egg white powder should be refrigerated, though, and rice protein powder may last even longer than two years in the right conditions. (8)(9)(10)(13)(14)
If your powder is labeled with a “sell by” date, err on the side of caution when consuming it afterward. But if it has a “best by” date, research suggests that even non-powdered dairy may be alright as long as six months after.
[Read More: The 12 Best Supplements for Muscle Growth ]
When you discover that old powder in the corner of your garage gym, here are some signs to look for (in addition to checking the date and considering the average storage temperature).
- Yellow color or other discoloration from what it looked like when you purchased it;
- A foul or sour smell;
- A clumpy appearance;
- A rancid taste.
If these signs are showing up in your powder, don’t pass go. But if they’re not, you may well be alright to scoop some into your next shake.
Is It Safe to Drink Expired Protein Powder?
If your powder has passed the smell check and looks normal past the “best by” date, it’s probably safe. But if you notice that it’s been exposed to moisture, it has almost certainly been the site of some microbial growth.
Bacteria — like those that cause food-borne illness — grow best in humid, warm environments with little airflow. If this describes your kitchen cabinet, you should proceed with caution when drinking expired protein powder. (17)
No Expiration on Gains
Protein powders of all types will eventually expire. Risks of expiration include microbiological damage and mold growth, which can have a damaging effect on human health. Luckily, most types of protein powder can last up to two years. This is due to additives in some cases, but also the durability of a dry supplement stored at correct temperatures with minimal humidity.
When in doubt, check for clumps and foul smells in the protein powder you’ve had for a while. If it’s not too far past its expiration date, studies suggest that it should be okay to stir into your next post-workout shake.
- Kårlund A, Gómez-Gallego C, Turpeinen AM, Palo-Oja OM, El-Nezami H, Kolehmainen M. Protein Supplements and Their Relation with Nutrition, Microbiota Composition and Health: Is More Protein Always Better for Sportspeople? Nutrients. 2019 Apr 12;11(4):829.
- Tieken, S. M., Leidy, H. J., Stull, A. J., Mattes, R. D., Schuster, R. A., & Campbell, W. W. (2007). Effects of solid versus liquid meal-replacement products of similar energy content on hunger, satiety, and appetite-regulating hormones in older adults. Hormone and metabolic research.
- Hoffman JR, Falvo MJ. Protein – Which is Best? J Sports Sci Med. 2004 Sep 1;3(3):118-30.
- Ambulkar, P., Hande, P., Tambe, B., Vaidya, V. G., Naik, N., Agarwal, R., & Ganu, G. (2023). Efficacy and safety assessment of protein supplement – micronutrient fortification in promoting health and wellbeing in healthy adults – a randomized placebo-controlled trial. Translational and clinical pharmacology, 31(1), 13–27.
- Walsh, J., Meyer, R., Shah, N., Quekett, J., & Fox, A. T. (2016). Differentiating milk allergy (IgE and non-IgE mediated) from lactose intolerance: understanding the underlying mechanisms and presentations. The British journal of general practice : The Journal of the Royal College of General Practitioners, 66(649), e609–e611.
- Bonnema, A. L., Kolberg, L. W., Thomas, W., & Slavin, J. L. (2010). Gastrointestinal tolerance of chicory inulin products. Journal of the American Dietetic Association, 110(6), 865–868.
- U.S. Anti-Doping Agency. (n.d.). Third-Party Testing Guidance.
- Sithole R, McDaniel MR, Goddik LM. Rate of maillard browning in sweet whey powder. J Dairy Sci. 2005 May;88(5):1636-45.
- Tunick MH, Thomas-Gahring A, Van Hekken DL, Iandola SK, Singh M, Qi PX, Ukuku DO, Mukhopadhyay S, Onwulata CI, Tomasula PM. Physical and chemical changes in whey protein concentrate stored at elevated temperature and humidity. J Dairy Sci. 2016 Mar;99(3):2372-2383.
- Wright BJ, Zevchak SE, Wright JM, Drake MA. The impact of agglomeration and storage on flavor and flavor stability of whey protein concentrate 80% and whey protein isolate. J Food Sci. 2009 Jan-Feb;74(1):S17-29.
- Zielińska D, Bilska B, Marciniak-Łukasiak K, Łepecka A, Trząskowska M, Neffe-Skocińska K, Tomaszewska M, Szydłowska A, Kołożyn-Krajewska D. Consumer Understanding of the Date of Minimum Durability of Food in Association with Quality Evaluation of Food Products After Expiration. Int J Environ Res Public Health. 2020 Mar 3;17(5):1632.
- Miller MJ, Witherly SA, Clark DA. Casein: a milk protein with diverse biologic consequences. Proc Soc Exp Biol Med. 1990 Nov;195(2):143-59.
- Zhang, T., Tang, Y., Ge, H., Zhang, D., Li, T., Cheng, D., Liu, J. and Yu, Y. (2023), Storage impact on egg white powder’s physical and functional properties. J Sci Food Agric, 103: 3799-3811.
- U.S. Food and Drug Administration. (n.d.). GRAS Notice 000609 – Rice Protein. FDA.
- Messina M, Lynch H, Dickinson JM, Reed KE. No Difference Between the Effects of Supplementing With Soy Protein Versus Animal Protein on Gains in Muscle Mass and Strength in Response to Resistance Exercise. Int J Sport Nutr Exerc Metab. 2018 Nov 1;28(6):674-685.
- House JD, Neufeld J, Leson G. Evaluating the quality of protein from hemp seed (Cannabis sativa L.) products through the use of the protein digestibility-corrected amino acid score method. J Agric Food Chem. 2010 Nov 24;58(22):11801-7.
- Qiu, Y., Zhou, Y., Chang, Y., Liang, X., Zhang, H., Lin, X., Qing, K., Zhou, X., & Luo, Z. (2022). The Effects of Ventilation, Humidity, and Temperature on Bacterial Growth and Bacterial Genera Distribution. International journal of environmental research and public health, 19(22), 15345.
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