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Labdoor analyzed nine best-selling milk chocolates for theobromine, caffeine, flavonoids, phenylethylamine, nutrition, Salmonella, and heavy metal (arsenic, cadmium, lead, mercury) contamination.

Of the nine products tested, three reported a claim for % cacao. Based on our estimates, we concluded that those three products met their % cacao claims. All products exceeded recommendations for calories and sugar in a "sweet snack". Two products met "sweet snack" recommendations for calcium and three products met those recommendations for iron based on US federal health data1,2,7. On average, products recorded 9 mgserving of caffeine, 104 mgserving of theobromine, a mild stimulant8, and 45 mgserving of flavonoids, compounds that might help with chronic disease prevention9.

All products passed heavy metal screenings for arsenic, cadmium, lead, and mercury3. Only one product recorded any additives that were listed in CSPI's (Center for Science in the Public Interest) list of additives to "avoid"4.



2 of every 3 products did not provide claims for % cacao, either on labels or when we contacted brands directly.

Three of nine products in this testing batch reported a claim for % cacao, either on product labels or after we contacted their manufacturers. We concluded that based on our best estimates, those three products met their label claims for % cacao.

Because cacao is a mixture of ingredients and different processing methods affect this composition, a standard for testing % cacao has not yet been established. We estimated % cacao using the following methods:

First, we used published research to build a statistical model of how theobromine content relates to cacao content (line fit was 0.85 R-squared), and then we estimated % cacao from there using our own measured theobromine values5. Secondly, we estimated cacao content by subtracting out weights of all other ingredients from each product's total serving size weight assuming FDA labelling rules6. Estimates from these two methods were averaged to provide a final estimation of the product's % cacao within a range of error, and this was compared to label claims, if available.



All products passed screenings for arsenic, cadmium, lead, and mercury.

All products passed heavy metal screenings for arsenic, cadmium, lead, and mercury. California Proposition 65 publishes proposed and established limits for safe consumption of these heavy metals in a full day. A product passes heavy metal screenings if its heavy metal levels in one serving do not meet or exceed those daily limits3.

We also tested each product for Salmonella contamination. Salmonella was not detected in any product.



Calories in this testing batch ranged from 200 kcalserving to 280 kcalserving.

Based on data from federal health organizations, a "sweet snack" for an adult typically consists of at least 8.5% of a day's worth of fiber (1.7 g), protein (2.4 g), and vitamins and minerals (based on NIH recommendations2), as well as no more than 8.5% of a day's worth of calories (170 kcal), fat (6.6 g), saturated fat (1.9 g), carbohydrates (25.5 mg), sugar (4.25 g), sodium (108 mg), or cholesterol (25.5 mg)1,7.

Overall, products measured an average of 224 total calories and 23 g of sugar per serving. Two products met the "sweet snack" recommendation for calcium (365 Everyday Value Organic Milk Chocolate and Lindt Classic Recipe Milk Chocolate) and three products met the recommendation for iron (Hershey's Milk Chocolate Kisses, Hershey's Milk Chocolate Bar, and See's Candies Classic Milk Chocolate).



Only one product recorded any additives listed on CSPI's list of additives to "avoid".

Products were penalized for additives based on the Center for Science in the Public Interest (CSPI)'s safety ratings for additives. Only one product recorded any additives on CSPI's "avoid" list. M&M's Milk Chocolate Candies recorded artificial food dyes linked to adverse health effects like behavioral problems in children and allergic reactions4.

Common allergens in milk chocolates include milk sources and soy. Please consult your doctor to confirm your risk for any allergies.



Products measured an average of 45 mg of flavonoids per serving.

CAFFEINE: Products measured an average of 9 mg of caffeine per serving. For scoring purposes, caffeine measurements were compared to caffeine in half a cup of coffee, which has about 48 g8.

THEOBROMINE: Products measured an average of 104 mg of theobromine per serving. Theobromine is a precursor of caffeine and a mild stimulant. For scoring purposes, theobromine measurements were compared to theobromine in 100% pure eating chocolate, which has about 518 mg per 100 g of chocolate5.

FLAVONOIDS: Products measured an average of 45 mg of flavonoids per serving. The class of compounds known as polyphenols, which includes flavonoids, has been found in several research studies to contribute to the prevention of chronic diseases like cardiovascular disease, cancers, and osteoporosis. For scoring purposes, flavonoid measurements were compared to flavonoids in 100% pure eating chocolate, which has about 103 mg per 100 g of chocolate9.

PHENYLETHYLAMINE (PEA): Products measured an average of 1.1 mg of PEA per serving. PEA is a mood-enhancing compound that is quickly broken down into inactive components upon consumption10,11. After extensive research, we've concluded that there isn't enough evidence yet for an effective dosing recommendation for PEA in humans.



  • 10 Janssen PA, et al. (1999). Does phenylethylamine act as an endogenous amphetamine in some patients?. Int J Neuropsychopharmacol. 2(3):229-240.
  • 11 Irsfeld M, et al. (2013). B-phenylethylamine, a small molecule with a large impact. Webmedcentral. 4(9):pii4409.
  • 1 ODPHP. (2016). Scientific Report of the 2015 Dietary Guidelines Advisory Committee.
  • 2 NIH. (2017). Dietary Supplement Fact Sheets.
  • 3 CA OEHHA. (2016). Proposition 65.
  • 4 Center for Science in the Public Interest. (2016). Chemical Cuisine.
  • 5 USDA. (2017). Nutrient Lists - Theobromine.
  • 6 FDA. (2016). CFR - Code of Federal Regulations Title 21.
  • 7 World Health Organization. (2015). Guideline: Sugars Intake in Adults and Children.
  • 8 Ludwig IA, et al. (2014). Variations in caffeine and chlorogenic acid contents of coffees: what are we drinking?. Food & Function. 5:1718-1726.
  • 9 Engler MB, et al. (2003). Flavonoid-Rich Dark Chocolate Improves Endothelial Function and Increases Plasma Epicatechin Concentrations in Healthy Adults. Journal of the American College of Nutrition. 3:197-204.