Should You Be Concerned About Heavy Metals in Dark Chocolate?
Chocolate 101 7 min read

Should You Be Concerned About Heavy Metals in Dark Chocolate?

Stephanie Garr

25th of March 2023

Quick answer: probably not. Here’s why:

  • Concerns about the amount of cadmium and lead in chocolate have been overblown. The guidelines under California’s Prop 65 are extremely cautious—you would have to ingest 1,000 times the Prop’s maximum allowable dose level (MADL) to still remain at a safe (“no observable effect”) level. It’s safe to say that would be nearly impossible to achieve, even if you solely consumed dark chocolate every day.
  • To’ak regularly tests its chocolate for heavy metals. Most recently, Medallion Labs in Minnesota found that our 75% Rain Harvest 2019 bar and 75.5% Rain Harvest 2021 bar contained 2.762 mcg and 2.7 mcg of cadmium in one 12.5-gram serving, respectively. They also tested our Alchemy Caramelized Pop Amaranth 65% bar, which contained 2.044 mcg in one 14-gram serving. These results are well under California’s tight limit of 4.1 mcg per day and far below the EU’s threshold. The same lab tested for lead and found an amount less than 0.01 mg/kg, which means either zero or an insignificant amount of lead.
  • You’re likely consuming more heavy metals in everyday food staples like grains, leafy vegetables, potatoes, and legumes than you would in your daily dark chocolate indulgence.

Let’s dig deeper into why you should enjoy that dark chocolate stress-free …

wooden board with to'ak dark chocolate, tea pot and tea cup


A 2022 Consumer Reports investigation brought a rather shocking headline to chocolate lovers worldwide: Lead and Cadmium Could Be in Your Dark Chocolate.

The article from the long-standing consumer organization begins with all the warm and cozy attributes so many of us love to slap on chocolate: “it’s a mood lifter, an energy booster … a favorite holiday gift.” They mention dark chocolate’s healthy, antioxidant-rich reputation, too. “But there’s a dark side to this ‘healthier’ chocolate,” they warn.

This comes after Consumer Reports’ scientists tested 28 dark chocolate bars from both huge corporations (like Lindt, Hershey’s, and Dove) and somewhat smaller organic makers (Mast, Beyond Good, and Alter Eco). In nearly every bar, they found high concentrations of toxic heavy metals—at least, according to California’s maximum allowable dose level (MADL) for lead (0.5 micrograms) and cadmium (4.1 mcg). Of 23 of the 28 bars tested they found that eating just one ounce a day would put an adult over a level that “public health authorities and CR’s experts say may be harmful for at least one of those heavy metals.”

pile of fresh cacao beans

Though this investigation has not been peer-reviewed, it’s caused quite a commotion, especially among conscious chocolate consumers. This is because most chocolate—even from the purest, most organic sources—is not necessarily immune. Understandably, we’ve had a number of people reach out to us wondering our thoughts on this report and whether To’ak dark chocolate contains cadmium or lead.

Below, we dive deep into how heavy metals get into chocolate, what the Consumer Reports study failed to take into account, and whether or not you should be concerned.

Is this news to chocolate makers?

Nope. Chocolate makers are already well aware of the potential for heavy metals in cacao. In fact, almost all producers have their chocolate regularly tested (including To’ak). If you’re a chocolate maker that wants to sell you products in Europe, for example, you must prove that your chocolate does not exceed the EU’s guidelines of 0.80 mg/kg of cadmium for dark chocolate with over 50% cacao (and 0.60 mg/kg for cacao powder). 

chocolate being poured from chocolate-making machine

How do heavy metals get into chocolate in the first place?

Both cadmium and lead are natural elements concentrated in the Earth’s crust. Any heavy metal found in a plant—including the cacao tree—typically starts in the soil. Volcanic soils tend to have higher levels of cadmium, which is why chocolate from Latin America may show an increased concentration of cadmium versus cacao from regions like West Africa. Other factors, like low zinc levels in the soil can increase cadmium uptake in cacao trees. 

However, human interference—in the form of mining, manufacturing, and industrial agriculture—has led to an overall increase in heavy metals (especially lead) throughout the air, water, and soil.

Back in 2015, the advocacy group As You Sow filed a lawsuit against Mars, Hershey, and See’s claiming that carcinogenic heavy metals were added to their chocolate, that the levels were more than what is naturally occurring in soil, and that these companies failed to label their products with the appropriate warning label. While all companies denied that metals were added during processing, the lawsuit was settled in 2018, requiring more research on the sources of cadmium and lead in chocolate products.

cacao farmers in Ecuador in front of pile of cacao pods

What about other foods that contain heavy metals?

Simply put, if you eat plants, it’s nearly impossible to avoid heavy metals. If you eat fish, you are undoubtedly consuming mercury, too. So, no matter how high your dark chocolate consumption, it likely doesn’t even come close to competing with other nutrient-dense, metal-containing foods in your diet. 

A 2018 study on 12,500 American consumers found that most cadmium intake came from cereals and bread (34%), leafy vegetables (20%), potatoes (11%), legumes and nuts (7%), and stem/root vegetables (6%). As far as the biggest cadmium boost? Good, old lettuce. A 2016 study in Thailand also found that most cadmium exposure comes from rice and grains, shellfish and seafood, meat and offal, and vegetables.


The European Food Safety Authority (EFSA) similarly found that the greatest impact on dietary exposure to cadmium is food consumed in large quantities like grains, vegetables, and starchy roots. Chocolate products contributed to just 4.3% of mean dietary exposure. (Remember that Europeans are the highest consumers of chocolate!) They found that the greatest contributors in dietary exposure to lead include bread and rolls (8.5%), tea (6.2%), tap water (6.1%), potatoes (4.9%), fermented milk products (4.2%), and beer (4.1%).

And let’s not forget another toxic heavy metal, arsenic, which is prevalent in one of the world’s biggest food staples: rice. Overall, you are likely ingesting heavy metals daily, and far more from your other healthy food sources than chocolate.

Where did California (and Consumer Reports) get their numbers from?

California’s cadmium and lead warning levels come from the state’s Prop 65, also known as the Safe Drinking Water and Toxic Enforcement Act. The proposition, enacted back in 1986, was written by lawyers and environmentalists (not doctors) as a way to protect California’s citizens from exposure to chemicals in drinking water and everyday consumer products that may cause cancer, birth defects, or other reproductive harm. 

The maximum allowable dose level (MADL) for cadmium is derived from the idea that exposure of 4.1 mcg every day is equal to 1/1000 the amount that you can consume at a safe (“no observable effect”) level. In other words, these are very cautious guidelines. 

You could ingest 1,000 times that amount without showing any effects. Nevertheless, a product that exceeds 4.1 mcg of cadmium must include a Prop 65 label. Don’t believe us? Here’s a direct quote:

“Exposure at a level 1,000 times greater than the MADL [of cadmium] is expected to have no observable effect.” -Office of Environmental Health Hazard Assessment (OEHHA), Reproductive and Cancer Hazard Assessment Section, with respect to the cadmium limit of 4.1 µg/day

Even Consumer Reports itself has questioned the Prop’s usefulness—especially given that potential carcinogens are, at this point, ubiquitous.

How do our bodies absorb cadmium and lead?

When it comes down to your health, it’s not necessarily about the amount of cadmium and lead in your food, but how your bodies absorb these metals. 

According to the CDC, most people absorb only about 6% of ingested cadmium. This percentage decreases with the presence of iron, zinc, and chromium in your body. In other words, dietary intake of these nutrients will help block the metabolization of cadmium.

This is good news for chocolate lovers, because that piece of dark chocolate you just ate happens to be one of the world’s richest foods in iron, zinc, and chromium. It also contains high amounts of antioxidants, which help reduce free radicals caused by cadmium exposure. 

Lead, meanwhile, can have a much higher absorption rate, especially among children. Deficiencies of zinc, iron, and calcium can also increase the absorption of lead. Interestingly enough, adults can absorb up to 20% of ingested inorganic lead after a meal versus up to 60-80% on an empty stomach. While lead is typically very minimal in cacao products, you can at least try a dark chocolate pairing to ease any concerns. 

piece of to'ak dark chocolate on top of melted chocolate

Does To’ak dark chocolate contain cadmium or lead?

Most recently, we sent our Rain Harvest 2019 (75% cacao) bar and Rain Harvest 2021 (75.5% cacao) bar to Medallion Labs in Minneapolis, Minnesota. The results for the 2019 harvest revealed a cadmium level of 0.221 mg/kg (or mcg/g), equating to 2.762 mcg in one 12.5-gram serving. The results for the 2021 harvest revealed a slightly lower cadmium level of 0.216 mg/kg (or mcg/g), equating to 2.7 mcg in one 12.5-gram serving. We also sent our Caramelized Pop Amaranth 65% cacao bar, which revealed a level of 0.146 mg/kg (or mcg/g) cadmium, amounting to 2.044 mcg in a 14-gram serving.

All of these results are under California’s tight limit and far below the EU’s threshold. The same lab tested for lead and found an amount less than 0.01 mg/kg, meaning there is either zero or an insignificant amount of lead found in our chocolate.

Keep in mind that there is a high level of inaccuracies with this type of testing—something the Consumer Reports article does not mention. As noted by chocolate geek The Chocolate Alchemist, the range of accuracy is often quite large, which is a significant factor when you’re talking about such small numbers. Any measure could look either significantly better or worse than it actually is, not to mention there could also be potential interference in the lab.

It is our mission and duty to work directly with our farmers in Ecuador to continually ensure healthy soils and sustainable, regenerative practices. We will also continue to test our cacao on a regular basis, with various labs in the U.S. and Europe, and share our most updated findings with you.

So, should you be worried?

As we noted at the top of this post: probably not. The potential for cacao to contain heavy metals is nothing new to chocolate producers. Most companies (including To’ak) already test their cacao for cadmium and lead—and are required to if they want to sell their products in markets within the U.S. and Europe. 

On top of that, the guidelines under California’s Prop 65, the basis for Consumer Reports’ study, are extremely cautious. You would have to ingest 1,000 times the maximum allowable dose level (MADL) they provide for cadmium and lead to still remain at a safe (“no observable effect”) level. To’ak’s 100% Ecuadorian cacao falls well under this level and far below the EU’s threshold for cadmium and lead.

Both cadmium and lead are naturally occurring elements in soils around the world, with some regions showing higher concentrations of either. There’s a high chance that you are already consuming more heavy metals in everyday food staples like grains, leafy vegetables, potatoes, and legumes than you would in your daily dark chocolate indulgence. Even better, that dark chocolate is loaded with nutrients that help block the absorption of heavy metals. It’s also got an impressive number of other health benefits.