Bodybuilders are well aware of the benefits of whey protein for recovery and muscle growth. But even if you’re not hitting the weight room, adding a whey protein supplement can offer other benefits. Drinking whey protein before a meal may help balance your blood sugar and help you feel full, which could lead to eating less. Older adults may also turn to whey protein to help preserve muscle as they age.
Just like with other supplements, some whey protein powders are better than others. If you take a close look at the ingredient label on your favorite whey protein powder, check for added sugars that make it taste better. The label might not specifically list “sugar,” but watch for processed carbohydrates like maltodextrin, which ranks high on the glycemic index and can spike your blood sugar quickly.
To reduce calories while still providing sweetness, many protein powders use artificial sweeteners such as sucralose, aspartame, or acesulfame potassium. Although some studies have shown health risks in animals, Johns Hopkins Medicine says these sweeteners are generally safe for humans. You may also see sugar alcohols, which could be the culprit behind any gas or bloating. While many of these ingredients are common in protein powders, others are less common or may not be listed on the label at all.
Strange ingredients you’ll find in some whey protein powders
The tastier the protein powder, the more food additives you’re likely to find. That’s because plain whey protein actually smells and tastes pretty bad on its own, according to AGN Roots. To make it more palatable, supplement companies often add things like xanthan gum, which boosts flavor and masks the unpleasant taste. You’ll also find xanthan gum in products like toothpaste. Because it’s a fermented sugar, xanthan gum can sometimes cause gas or bloating.
Some protein powders go all out with wild flavors like Fruity Pebbles to spark some childhood nostalgia. But do you really want edible glitter in your post-workout shake? To recreate that ultra-processed cereal flavor, some powders include gum arabic, which is a tree sap used to thicken and stabilize foods. These fun flavors may also have artificial dyes like Red 3, Red 40, Blue 1, and Yellow 5, but these synthetic food colors are set to be banned in the next few years.
(Here are other ingredients you don’t want to see in your protein powder.)
Then there’s zinc oxide, the same stuff found in many sunscreens. It’s also used as a food additive in some whey protein powders. A 2023 article in Antioxidants tested tiny particles of zinc oxide in lab settings and found they may slightly stress or damage the gut lining. On the flip side, it might also help your body absorb zinc more easily. That doesn’t mean it’s necessarily harmful, but the long-term effects of consuming zinc oxide in food aren’t fully understood yet.
Heavy metals are found in most protein powders
Some of the ingredients in your protein powder won’t be listed on the label. A 2025 report from the Clean Label Project tested 160 protein products from 70 top-selling brands and found that 47% didn’t meet California’s Prop 65 safety standards for toxic metals. Ironically, the products labeled “organic” tended to have three times the lead and twice the cadmium compared to their non-organic counterparts. And switching from whey protein to vegan protein powders doesn’t automatically solve the problem. Vegan options had three times more lead than whey. If you’re turning to chocolate protein powder to crush a sweet craving, those flavors were found to have four times more lead than non-chocolate ones.
Unlike flavor-boosting food additives, heavy metals aren’t added on purpose. They’re naturally present in the environment where they build up in the air, water, and soil. The metals eventually make their way into the food supply, including protein powders. The Clean Label Project has only certified eight brands of protein powder, including Genetic Nutrition, Ritual, and Oziva.
By now, you might have ditched plastic bottles and containers in favor of BPA-free alternatives, but BPA can still sneak into some protein powders. The good news? BPA and its chemical cousin, BPS (another type of bisphenol), have dropped significantly since the Clean Label Project’s last report in 2018. Back then, 55% of protein powders had some type of bisphenol, but in the latest report, it was found in less than 2% of products.
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