Taking protein powder? The hidden dangers no one tells you

We are in the midst of a protein boom. From popcorn to Pop-Tarts, you will see ‘high-protein’ labels on almost every food you consume. While the awareness around this macronutrient is great from a nutritional perspective, most of the time people go overboard with it. Case in point: protein supplements, especially protein powders. For many, the day begins with a glass of milk or a smoothie blended with a scoop of protein powder. It is considered a simple way to boost health. But do these supplements truly deliver on their health claims? A scoop of chocolate or vanilla protein powder may seem convenient, but does that come at a hidden cost? Are protein supplements better than protein from food sources? Let’s find out.

(Representative image generated using AI)

Let’s start with the basics: what’s in your protein powder? Protein powders are derived either from plant or animal sources. Plant sources include soybeans, peas, rice, potatoes or hemp. Animal sources include eggs or milk (casein or whey protein). Along with this, there may be other ingredients such as added sugars, artificial flavourings, thickeners, vitamins and minerals. Depending on the brand, one scoop may contain 10 to 30 grams of protein. Muscle-building protein powders may contain relatively more protein, while supplements used for weight loss contain relatively less.

There are numerous risks associated with protein supplements, especially protein powders. Some of the risks include:

One of the biggest concerns surrounding protein powders is the lack of strict regulation. Protein powder is a dietary supplement, and dietary supplements are not subjected to the same rigorous testing as medicines. The FDA leaves it up to manufacturers to evaluate the safety and labelling of products. So, you never know if a protein powder contains what it actually claims.

A 2023 University of Toronto study found that some commonly used muscle-building dietary supplements, such as whey protein, are under-regulated in Canada. “We identified many gaps in the current policy that put young people at risk. Namely, there lacks a serious and consistent method of ensuring manufacturing sites and products are safe and unadulterated or contaminated,” the researchers said.

A recent investigation by Consumer Reports found that more than two-thirds of the protein powders and ready-to-drink shakes they tested had dangerously high levels of the toxic heavy metal lead. The team tested 23 protein powders and shakes; 16 of these products exceeded the group’s daily lead safety threshold of 0.5 micrograms per serving, some by more than 10 times. Even protein supplements from top brands contained unsafe levels of lead. Naked Nutrition’s Mass Gainer powder had 77.7 µg per serving, which is 1,570% of the daily limit. Another popular brand, Huel’s Black Edition powder, had 6.3 µg per serving, which is 1,290% above the safety threshold. Even plant-based products were not safe. In fact, organic products averaged three times the lead of non-organic ones.
Lead has no safe exposure level. It can impair brain development, raise blood pressure and suppress immunity. In adults, long-term exposure to lead can result in kidney damage and reproductive issues. In children, it can lead to impaired learning and other neurological problems.

In 2025, the Clean Label Project, a non-profit organisation, tested 165 products for 130 types of toxins. They found that many popular brands of protein powders contained heavy metals such as lead, arsenic, cadmium and mercury. They also found the presence of bisphenol A (BPA), which is used to make plastic. Some of the products also contained pesticides or other contaminants linked to cancer and other health conditions.
The five most contaminated protein powders contained far higher levels of heavy metals compared to the 16 cleanest ones. How much higher per serving?

• 45.9 times more cadmium
• 38.4 times more lead
• 31.5 times more arsenic
• 2 times more mercury
  

There is limited scientific evidence on the possible long-term side effects of consuming high protein intake through supplements. We simply do not know what the long-term impact may be.

Protein powder may cause digestive problems in some individuals. Those with dairy allergies or lactose intolerance may experience gastrointestinal discomfort if they consume a milk-based protein powder.

Protein powders may also contain added sugars. Some brands have little or no sugar, while others may have a lot (as much as 23 grams per scoop). When mixed with a glass of milk, it can turn into a drink with more than 1,200 calories. This can lead to weight gain and an unhealthy spike in blood sugar.