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Dark chocolate is chocolate with a high share of cocoa solids and less sugar and milk than milk chocolate. So, is dark chocolate healthy? It can fit in a healthy diet in small portions: USDA data show a 70 to 85 percent bar supplies fiber, iron, magnesium and a lot of copper, but it is also dense in calories and saturated fat and still contains sugar. The research on dark chocolate benefits is mostly about cocoa flavanols, and the largest trial tested a cocoa extract pill, not chocolate. This guide covers dark chocolate nutrition by cacao percentage, caffeine and theobromine, what studies actually show, and the heavy metal findings shoppers ask about.
Peptide Labs does not sell chocolate or cocoa products. This article is general nutrition information, not medical advice.
Key Takeaways
- US rules have no standard for the words "dark chocolate"; the cacao percentage on the wrapper tells you more.
- In USDA data, one ounce of 70 to 85 percent dark chocolate has about 170 calories, 3 grams of fiber, 19% of the Daily Value for iron and 56% for copper.
- A Cochrane review found flavanol-rich cocoa lowered blood pressure by about 2 points on average in short trials, with a smaller effect in people with normal blood pressure.
- The COSMOS trial of a cocoa extract supplement did not significantly reduce total cardiovascular events.
- A 2024 peer-reviewed study found lead or cadmium above California's strict Prop 65 levels in a share of dark chocolate products; most stayed under FDA reference levels for lead.
- Dark chocolate contains caffeine and theobromine, and it is dangerous for dogs.
What counts as dark chocolate?
Chocolate starts as cacao beans that are fermented, dried, roasted and cracked into nibs. Ground nibs become chocolate liquor (a paste, no alcohol involved), which can be pressed into cocoa butter and cocoa powder. FDA standards of identity in 21 CFR Part 163 define milk chocolate as at least 10 percent chocolate liquor, sweet chocolate as at least 15 percent, and semisweet or bittersweet chocolate as at least 35 percent. White chocolate is made from cocoa butter, dairy and sugar with no chocolate liquor. There is no separate legal definition of “dark chocolate”, so one brand’s dark bar can be much sweeter than another’s.
The percentage on the front of the bar is the share of the weight that comes from cacao (liquor, butter and powder combined). A higher number generally means less room for sugar and more of the bitter, mineral-rich cocoa solids, though a bar with extra cocoa butter can have a high percentage with fewer solids. For a less processed option, see our guide to https://peptidelabs.live/cacao-nibs/, which are simply cracked roasted beans.
Dark chocolate nutrition by cacao percentage
USDA’s SR Legacy database lists dark chocolate in three cacao ranges. Values below are per 1 ounce (28.35 grams), with the FDA Daily Value (%DV) in brackets. Total sugars has no Daily Value.
| Per 1 oz (USDA SR Legacy) | Dark 70-85% (FDC 170273) | Dark 60-69% (FDC 170272) | Dark 45-59% (FDC 170271) | Milk chocolate (FDC 167587) |
|---|---|---|---|---|
| Calories | 170 | 164 | 155 | 152 |
| Saturated fat | 6.9 g (35%) | 6.2 g (31%) | 5.2 g (26%) | 5.2 g (26%) |
| Total sugars | 6.8 g | 10.4 g | 13.6 g | 14.6 g |
| Fiber | 3.1 g (11%) | 2.3 g (8%) | 2.0 g (7%) | 1.0 g (3%) |
| Iron | 3.4 mg (19%) | 1.8 mg (10%) | 2.3 mg (13%) | 0.7 mg (4%) |
| Magnesium | 65 mg (15%) | 50 mg (12%) | 41 mg (10%) | 18 mg (4%) |
| Copper | 0.50 mg (56%) | 0.35 mg (39%) | 0.29 mg (32%) | 0.14 mg (15%) |
| Caffeine | 23 mg | 24 mg | 12 mg | 6 mg |
| Theobromine | 227 mg | 179 mg | 140 mg | 58 mg |
Three patterns stand out. Sugar drops and minerals rise as the cacao percentage goes up. Calories barely change, because cocoa butter replaces the sugar. And saturated fat is high: a single ounce of the darkest range covers about a third of the Daily Value. The 2020-2025 Dietary Guidelines for Americans advise keeping both saturated fat and added sugars under 10 percent of daily calories, which is why chocolate is usually framed as an extra rather than a staple. White chocolate (FDC 167571) has almost no iron, magnesium, caffeine or theobromine, since it contains no cocoa solids.
The iron in chocolate is non-heme iron, the plant form, which the body absorbs less readily than iron from meat; our guide to https://peptidelabs.live/foods-high-in-iron/ explains the difference. Chocolate also shows up in our https://peptidelabs.live/foods-high-in-magnesium/ list, but nuts, seeds, beans and whole grains supply magnesium without the sugar.
Caffeine in dark chocolate, and theobromine
Cocoa contains two related stimulants: caffeine and theobromine. In USDA data, an ounce of 70 to 85 percent dark chocolate has about 23 milligrams of caffeine, a modest amount next to a cup of coffee, and about 227 milligrams of theobromine. FDA cites 400 milligrams of caffeine a day as an amount not generally linked to negative effects in healthy adults; our guide on https://peptidelabs.live/how-much-caffeine-is-too-much/ covers who should aim lower, such as people who are pregnant, sensitive to caffeine or taking certain medicines. Theobromine is a milder stimulant in people, but an evening square of very dark chocolate may still matter if you are sensitive.
Dark chocolate benefits: what the research shows
Cocoa is rich in flavanols, a group of polyphenols (epicatechin and related compounds) studied for effects on blood vessels. Our https://peptidelabs.live/foods-high-in-antioxidants/ guide explains why lab antioxidant scores do not translate directly into health effects. Here is what the stronger human studies found:
- Blood pressure: a 2017 Cochrane review of 35 randomized trials (about 1,800 mostly healthy adults, 2 to 18 weeks) found flavanol-rich chocolate or cocoa lowered blood pressure by about 2 mmHg on average, rated moderate-quality evidence. The drop was clearer in people with high blood pressure and not significant in people with normal readings, and the authors noted some reporting bias from industry-linked trials.
- Heart outcomes (COSMOS): this 2022 randomized trial gave 21,442 US adults aged 60 and over a cocoa extract supplement or a placebo for a median of 3.6 years. Total cardiovascular events were not significantly reduced; cardiovascular deaths were lower, but that was a secondary endpoint. The trial was funded in part by Mars Edge, which also donated the pills, with infrastructure support from the National Heart, Lung, and Blood Institute. It tested a concentrated extract, not chocolate bars.
- Processing: a 2008 survey of cocoa powders found flavanols fall steadily with Dutch processing (alkalization), so the flavanol content of a given bar is unknown unless the maker tests and reports it.
Regulators have been cautious. In 2023 FDA allowed a qualified health claim for cocoa flavanols in a specific high flavanol cocoa powder, while stating that the scientific evidence is “very limited”; FDA said the claim does not apply to regular cocoa powder or to chocolate. The fair summary: cocoa flavanols are an active research area, and a bar of dark chocolate is a food to enjoy, not a health intervention. If you find yourself reaching for chocolate often, our guide on https://peptidelabs.live/how-to-stop-sugar-cravings/ may help.
Heavy metals in dark chocolate
Cacao can pick up cadmium and lead. A 2024 peer-reviewed study in Frontiers in Nutrition tested 72 dark chocolate and cocoa products bought in the US between 2014 and 2022. Measured against California’s Prop 65 levels, which are much stricter than federal reference points, 43 percent exceeded the lead level and 35 percent the cadmium level; none exceeded the arsenic level. At the same time, 70 of the 72 products were below FDA’s interim reference levels for lead, and median levels were below the Prop 65 limits, meaning a few outliers drove the results. Products labeled organic were more likely to have higher lead and cadmium.
The authors concluded that a single serving of most products may not pose an appreciable risk, but several servings a day, combined with other dietary sources, could add up. Practical steps are simple: keep chocolate an occasional food, vary brands, and be more cautious for young children and during pregnancy. Some companies publish third-party test results; our guide to https://peptidelabs.live/third-party-tested-supplements/ explains how to read testing claims.
Safety notes: allergies, pets and medicines
- Milk allergy: in a 2015 FDA survey, many dark chocolate products that did not list milk still contained it. FDA calls dark chocolate a high-risk food for people with milk allergy, even when the label says dairy-free. Nuts, peanuts and soy are also common in shared facilities.
- Dogs: FDA warns that theobromine and caffeine in chocolate can poison dogs, which clear these stimulants slowly. Baking chocolate and dark chocolate are the most dangerous. Signs include vomiting, diarrhea, a racing heart, restlessness, muscle spasms and seizures; call a veterinarian or an animal poison control center right away.
- Caffeine-sensitive people: anyone told to limit caffeine by a clinician should count chocolate and cocoa too.
Frequently Asked Questions
Is dark chocolate healthy?
It can fit in a healthy diet in small portions. It supplies fiber, iron, magnesium and copper, but it is high in calories and saturated fat and still contains sugar.
What are the main dark chocolate benefits shown in research?
The clearest finding is a small blood pressure drop in short trials of flavanol-rich cocoa, mainly in people with high blood pressure. Large trials of cocoa extract did not show a significant drop in total heart events.
How much caffeine is in dark chocolate?
USDA lists about 23 milligrams of caffeine in an ounce of 70 to 85 percent dark chocolate, plus theobromine, a milder related stimulant.
What percentage counts as dark chocolate?
There is no US legal definition. Bittersweet and semisweet chocolate must contain at least 35 percent chocolate liquor; many dark bars list 60 to 85 percent cacao.
Does dark chocolate contain lead?
Some products do. A 2024 study found lead or cadmium above California’s strict Prop 65 levels in a share of products, though most were under FDA reference levels for lead.
Is dark chocolate safe for dogs?
No. FDA warns that dark and baking chocolate are the most dangerous types for dogs. Contact a veterinarian right away if your dog eats chocolate.
Questions about a label? Contact us or read our Buyer’s Guide. Food comes first; follow the label and ask a healthcare provider before starting a supplement, especially if you take medicines, are pregnant or have a food allergy. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed October 2026.
Related guides: Cacao Nibs: Benefits, Nutrition and Cacao vs Cocoa Explained, Foods High in Magnesium: USDA Table of Seeds, Nuts, Beans and Greens, Foods High in Antioxidants: USDA Chart and What the Science Says, Types of Chocolate: FDA Standards and USDA Values per Ounce.