With the American obsession over protein, it’s no surprise that protein powders have become one of the biggest supplement sellers. They are marketed as an easy way to hit your macro goal in the pursuit of packing on more lean body mass. The variety of options on the market is staggering—powders made from everything from grass-fed beef to hemp in a bounty of flavors. We can blend up a delicious post-gym shake that tastes like salted caramel. There is now something for everyone. One could argue that they are a centerpiece of the multibillion-dollar protein craze. But you might be getting more than just protein when you scoop it up. Many protein powders on the market may contain troubling amounts of heavy metals such as lead and cadmium, according to two recently released investigations into this ultra-popular supplement category.

Testing by Clean Label Project, a consumer product safety non-profit, which analyzed 160 protein powder products from 70 top-selling supplement brands, discovered lead and cadmium in a majority of the protein powders that were examined. These are heavy metals that can contribute to developmental disorders and certain health conditions, including cancer and heart disease. Not something you want to eat a lot of, to say the least. The study found that 47% of the proteins tested had levels of these heavy metals that exceeded at least one federal or state safety regulation.

Additionally, over 20% of proteins exceeded the regulations of California’s Prop 65–the legislation that requires all businesses, including those involved in food production, to alert consumers to chemical exposure in products. According to the report, 79 percent of organic protein powders, 77 percent of plant-based protein powders made from rice, peas, or soy, and 65 percent of chocolate-flavored protein powders tested over the California Proposition 65 safety thresholds. Organic products, on average, had three times more lead and twice the amount of cadmium compared to products that were not labeled organic.

Whey protein and collagen protein were on the lower end of the spectrum, with 28% and 26%, respectively, clocking in over the Prop 65 limit for lead, per the report. Chocolate-flavored protein powders contained four times more lead and up to 110 times more cadmium than vanilla-flavored powders. Unfortunately, the report did not include the names of the brands that were tested.

More awful PR for protein powders comes from a newly released Consumer Reports investigation involving food safety researchers, which found about 70% of the protein powder samples tested had over 120% of California Prop 65’s maximum allowable dose level for lead, which is 0.5 micograms per day. A total of 23 protein powders and ready-to-drink shakes from popular brands were sent to an accredited lab for testing. Some samples contained over 10 times the amount considered a safe daily intake. Once again, plant-based protein supplements fairly more poorly in that they contained higher lead levels than dairy and animal-based products.

The lead levels in plant-based products were, on average, nine times the amount found in those produced with dairy proteins like whey, and twice as high as beef-based ones. Three products also exceeded their level of concern for cadmium and inorganic arsenic. Unlike the Clean Label Project investigation, this one named names. You can see which products tested better than others here. Consumer Reports goes so far as to say that certain options from a few brands should not be consumed at all or no more than once a week. Half of the dairy-based powders tested still had high enough levels of contamination that CR’s experts advise against daily use. The good news is that all the examined products met or exceeded their label claim of protein, delivering between 20 to 60 grams of protein per serving.

Why the Toxin Load?

You might be scratching your head as to why the big tub of powder in your pantry could be playing a heavy metal tune. To break things down, all plants contain a varying degree of heavy metals due to the mineral content of the soil that plants grow in. Some of these metals are released into the soil from natural occurrences, including the degradation of rocks, and some of the metal accumulation occurs due to human activities, including mining and agriculture.

So if a crop of soybeans or peas is being grown in soil with high levels of lead, there is a good chance some of that metal will end up in the plant. Further, whole green peas will likely have less heavy metals than the concentrated pea protein isolate. It can be assumed that animal-based protein powders are lower on the heavy metal spectrum because when animals eat the plants, a certain amount of these compounds is filtered out during digestion and processing. So less lead or cadmium is going to end up in the milk of a cow that eventually will be used to make whey protein.

The reports that the chocolate-flavored powders contain more heavy metals are most likely related to the fact that cocoa powder used in the flavoring of these items also contains heavy metals. As a result, these have a higher metal content than the non-chocolate powders.

Growing conditions may not be the only source of heavy metals in these items. Manufacturing processes could also introduce them into certain protein powder products. Extracting concentrated protein is a multi-step, mechanized process, and with every additional process, there’s a chance of introducing contaminants.

Why it appears that plant-based protein powders that are made using protein sourced from organically grown crops are at the highest risk of being contaminated is not yet known. Perhaps it has something to do with where these plants are typically grown or the type of organic fertilizer that is applied.

So, Should You Shelve the Protein Powders?

Generally speaking, it’s a good idea to cut down on lead and other heavy metal exposure when you can. This, however, may leave you wondering if you should be concerned that your favorite chocolate protein powder may expose you to potentially dangerous metals.

Yes, you ought to be concerned, to an extent. But you don’t necessarily have to figure out another way to drink your protein. It’s best not to panic just yet. Here are a few things to keep in mind when pondering the results of these studies.

It’s clear that these supplements can be a source of exposure to these potentially dangerous compounds. It’s important to know this, and, hopefully, companies will continue to work to reduce the amounts in their products. It’s concerning when protein powder manufacturers automatically try to brush away the results of these investigations and try to convince us that there is absolutely nothing to fret about. While the FDA requires that supplement manufacturers keep their products free of harmful contaminants, it largely leaves it up to these companies to decide what counts as dangerous and test their own products for compliance. It’s largely why the supplement industry is fraught with purity and contaminant issues.

Although these reports may be alarming, it’s essential to understand their context. Despite the presence of some toxins, we don’t have any reliable data to show that the amount typically consumed from protein powders poses a significant health risk or will lead to lead poisoning. The detection of contaminants does not necessarily equate to a bona fide health risk. As they say, ‘the dose is in the poison.’ Keep in mind that too much of anything, even water, can be bad news. While no amount of lead or cadmium is technically safe, the real risk may come from continuous exposure, so for those who are taking in multiple scoops of protein power daily. I would be inclined to worry less if someone is just using a serving or two of protein powder, and maybe not every single day.

In other words, don’t live on the stuff.

California Proposition 65, frequently referenced in both of these findings, imposes limits that are uniquely stringent and not necessarily aligned with federal guidelines. For instance, the 0.5 microgram per day target for lead is set to include a generous safety factor below the level at which no harmful effects have been observed. In other words, California’s law has a wide safety margin. In the absence of broad federal guidelines setting dietary and supplement lead limits for the adult population, the Consumer Reports team used this limit because they say it is the most health-protective limit available, and our exposure should be as low as possible. However, there is a possibility that it creates a misleading impression of risk.

It’s worth noting that both of these investigations were independent reports not published in a peer-reviewed journal and did not go through the institutional review board approval process. It’s concerning that Clean Label Project did not disclose any of the protein powders tested, but still manages to recommend only brands that pay for their independent certification. Also, the lack of declared methodology means their findings cannot be reproduced, which should raise the proverbial red flag from a scientific methods perspective. The CR report was much more transparent with their methodology, which you can geek out on here. Although they are not shy about telling us they essentially think protein powders are a waste of money and we can get all the protein we need from food.

Several brands are claiming that the findings of the aforementioned studies are “inconsistent” with their regular testing results. And some, including the popular brand Momentous, whose CEO, Jeff Byers, released a statement addressing this issue, have changed the sourcing of their raw materials which could clean up their products. For instance, using pea protein from vegetables grown in North America instead of China could noticeably alter heavy metal levels in the protein powder. Because the results from lab testing are based on an average of samples, which were collected over a specific period of time, they may not mirror current contaminant levels in the products. As you can see by now, this is a very nuanced subject.

Always keep in mind that protein powders are far from the only food related product that harbor these compounds. Everything from rice to chocolate to dairy to vegetables to fruits have been found to contain contaminants like arsenic and lead. And then there is the whole concern about microplastics in our food and beverage supply. It’s just the nature of the food environment we live in. So even if you ditch the protein powder it’s no guarantee you are in the clear. It’s just that if you are very regularly using a protein powder with high levels it might put you over the threshold.

There is also the chance that if you are using these powders to sustain an active lifestyle then this might cancel out some of the health effects of these contaminants. In other words, the dangers of lead and arsenic on the body might be worse for a couch potato than for someone who is working out hard on most days. Similar to how the heaps of sugar that professional cyclists take in to sustain their huge efforts on the bike pose less of a health risk. If you and I were to take in the pure volume of simple carbs that these lycra-clad athletes consume, we’d have diabetes by the end of the day. This is just speculation, as we don’t have any data on how lifestyle impacts the health impacts of consistent heavy metal exposure. But we do know that lead exposure is especially dangerous for children and pregnant women since this heavy metal can cause harm during growth and development.

The Take-Home Message

Yes, most protein powders on the market have a certain level of potentially harmful heavy metals such as lead, but as it stands, we can’t say that this is definitely problematic and that you must stop using this category of supplement.

If you’re truly concerned about exposure, and you are not eating solely plants, you can use animal-based powders, including whey and egg, more often than plant-based options, as these have consistently tested for lower levels. You can also choose flavors other than chocolate.

Another tactic is to use two or more different products to spread the love. This way, you avoid going all in on a single product, which may (or may not) expose you to higher contaminant levels. So, perhaps, you blend in a whey protein powder into one of your daily shakes and then a plant-based protein powder into another shake. Or one protein powder for smoothies and another for other uses, such as baking, stirring into oatmeal, or making protein pancakes. If you are going all in on plants, you can switch things up to get protein sources from various sources, including soy and pea.

Before making a purchase, you can check to see if there are any independent test results for the product available on their website. But be warned: It is a rarity for companies to make their heavy metal testing results public. However, some companies will provide results upon request. To obtain certification by the National Sanitation Foundation (NSF), a dietary supplement must adhere to the group’s limits of 10 micrograms per day for lead and inorganic arsenic, and 4.1 micrograms per day for cadmium.

At the very least, these results should encourage us to get the majority of our protein from whole foods instead of relying so heavily on supplements. Just because an influencer says you need to pound the protein shakes to hit your macro goals means you necessarily have to.