High Polyphenol Dark Chocolate: A Guide to Polyphenols and Antioxidants
First published 19 Apr 2024|Last Updated 29 Oct 2026
By Ben Popple, founder of Mr Popple’s Chocolate · Updated October 2026 · 7 min read
🍫 The 60-second answer
High polyphenol dark chocolate takes more than a high percentage, because roasting and alkalising (dutching) remove a share of cacao’s polyphenols. Look for plenty of cacao, little sugar and no “alkalised” on the label. Our unroasted Pure Peruvian measured 2,718mg of polyphenols per 100g, the highest of five bars in an independent Oxford Brookes test.
Ask most people how to find high polyphenol dark chocolate and they’ll point you to the number on the front: the higher the percentage, the better. It’s a reasonable rule and it’s half right, because the percentage tells you how much cacao went into the bar but not what happened to that cacao on the way.
Most cacao starts out full of polyphenols; the real question is how many survive the factory. Roasting and alkalising chip away at them, sugar dilutes what’s left, and none of that shows up in the percentage. Here’s what polyphenols are, how much dark chocolate holds, what the research says and how to tell a high polyphenol bar from one that’s merely dark.
What are polyphenols and antioxidants?
Polyphenols are a large family of natural compounds made by plants, found in tea, coffee, fruit, red wine and, in large amounts, cacao. Many of them work as antioxidants in lab tests, meaning they can neutralise free radicals, the unstable molecules that can damage cells. Antioxidant capacity is a measure of how much of that a food can do in a test tube.
Cacao’s main polyphenols are flavanols such as epicatechin, along with longer chains of them called procyanidins. A good share of the bitter, drying edge in dark chocolate comes from these compounds, so a little bitterness is no bad sign.
🔍 Decoder: “flavanols”
Flavanols are one family within cacao’s polyphenols, led by epicatechin. They’re the ones most cocoa health studies measure, so you’ll meet the word more often than “polyphenols” in the research.
How many polyphenols are in dark chocolate?
Dark chocolate averages about 1,860mg of polyphenols per 100g in the Phenol-Explorer food database, more than twice the figure for milk chocolate. Dark chocolate polyphenol content varies widely, though: individual dark chocolates in the database range from 1,173mg to 4,437mg, so two equally dark bars can be a long way apart.
Food
Total polyphenols, average per 100g
Cocoa powder
5,624mg
Dark chocolate
1,860mg
Milk chocolate
854mg
Blueberries (highbush, raw)
223mg
Red wine
215mg (per 100ml)
Source: Phenol-Explorer, averages measured by the Folin method.
Gram for gram, dark chocolate holds around eight times the polyphenols of fresh blueberries. That’s no reason to swap the fruit bowl for a chocolate drawer, since nobody eats chocolate by the punnet, but it does show how much cacao starts with.
Cocoa powder tops the table because most of the cacao butter has been pressed out, which concentrates what’s left. Milk chocolate falls behind because milk powder and sugar take up room the cacao would otherwise fill.
What are the health benefits of dark chocolate polyphenols?
The best-studied benefit is blood flow. UK law authorises the claim that “Cocoa flavanols help maintain the elasticity of blood vessels, which contributes to normal blood flow”, with a daily intake of 200mg of cocoa flavanols. Trials also suggest flavanol-rich cocoa may lower blood pressure slightly, while the evidence on inflammation is still mixed.
That wording comes with conditions: it applies only to cocoa drinks and dark chocolate shown to provide 200mg of cocoa flavanols a day, so it describes the compounds rather than chocolate in general. Our piece on high flavanol cocoa looks at chocolate made to keep more of them.
On blood pressure, a Cochrane review of 40 trials found flavanol-rich chocolate and cocoa products had “a small (2 mmHg) blood pressure-lowering effect in mainly healthy adults in the short term”, in the authors’ words. They suggest it might contribute to reducing the risk of cardiovascular disease, but no trial in the review measured heart attacks or strokes, so any effect on the risk of heart disease is still untested.
Inflammation is less settled. A 2024 review of controlled trials concluded that dark chocolate and cocoa may improve inflammation markers in adults, while noting that findings so far are inconsistent. For the gut side of the story, see our guide to choosing dark chocolate for gut health.
What makes dark chocolate high in polyphenols?
Three things make a big difference: how much cacao is in the bar, whether the beans were roasted, and whether the cacao was alkalised. More cacao gives you more polyphenols to start with, while hot roasting and alkalising both remove a share before the chocolate is made. The percentage only tells you about the first of the three.
The cacao percentage
The percentage is the share of the bar that comes from cacao, and in most dark chocolate the rest is largely sugar. A higher cocoa percentage leaves less room for sugar, which matters because sugar dilutes the cacao rather than adding polyphenols of its own. Our dark chocolate percentage guide explains what each number means.
People often tell me they’ve heard anything 70% and over is good for you. I agree it’s a big step up from milk chocolate, then point out that a 70% bar still leaves room for up to 30g of sugar in every 100g. Sugar levels like that don’t destroy any polyphenols, but they do mean less cacao in every bite.
Roasting
Most chocolate is roasted at 120 to 150°C to build flavour, and research shows roasting reduces cacao’s total polyphenols and its epicatechin, the main flavanol. A raw bar is made from cacao that has never been near a roaster. Ours stays below 42°C from bean to bar, and that choice started with a feeling.
I didn’t start making raw chocolate back in 2007 because of the flavour. It was the way unroasted cacao made me feel, a lift that ordinary chocolate never gave me, and I wanted to know why. The same four names came up wherever I looked: tryptophan (the amino acid linked to serotonin), plus phenylethylamine (PEA), theobromine and anandamide.
Dutching, or alkalising, treats cacao with an alkaline salt to darken it and mellow its flavour. It costs polyphenols: a study of commercial cocoa powders found alkalising cut their total flavonoid content by 60% on average. Natural cocoa skips the step, while alkalised cocoa usually says “alkalised” or “processed with alkali” on the label.
Alkalising makes cocoa darker, and darker cocoa looks richer, which is rather the point. Our cacao is never alkalised. Our guide to dutched cocoa covers where the process came from.
If you’d like your cacao unroasted and undutched with a touch of sweetness, Atey Ate% is 88% cacao, sweetened with low GI yacon syrup.
How to choose high polyphenol dark chocolate
Read the back of the wrapper as well as the front. Choose a high cocoa content, check that sugar sits low in the ingredients list, avoid anything marked “alkalised” or “processed with alkali”, and favour makers who tell you how hot their beans got. Raw or unroasted cacao skips the roasting step altogether.
What to check
Why it matters
70% cocoa solids or more
More cacao, less room for sugar
Where sugar sits in the ingredients
UK labels list ingredients by weight, so lower down means less sugar
No “alkalised” or “processed with alkali”
Alkalising strips out a large share of the flavonoids
Roasting temperature, or “unroasted”
Lower heat leaves more of the cacao’s polyphenols in place
The ingredients list is more honest than the front of the wrapper, because it has to run in order of weight. Any high polyphenol chocolate starts there, and high-quality dark chocolate usually has a short list.
“Roasting is how most makers get the same flavour from beans that vary. Leave it out and the bean has to be good enough to taste of itself.”
Ben Popple, founder of Mr Popple’s Chocolate
Raw cacao, stone-ground and never roasted
Want to try chocolate made this way? Here’s our dark range, unroasted and never alkalised, from 100% down:
Pure Peruvian
Pure Peruvian 100% uncut, nothing but stone-ground, unroasted Peruvian Criollo. Bold and intense.
Atey Ate% Dark
Atey Ate% 88% raw cacao, sweetened with low GI yacon syrup. Low in sugar, dark and balanced.
Signature Seventy
Signature Seventy 70% raw cacao with yacon syrup and creamy lucuma. The original Mr Popple’s bar.
Euphoric Orange
Euphoric Orange 70% raw cacao with sweet orange oil. Bright and aromatic.
Dark Mylk
Dark Mylk 61% raw cacao with a dairy-free mylk of gluten-free oat and rice flours: dark and rich with no bitter edge.
Free UK delivery over £25 · Plastic-free packaging · Top 14 allergen free · BDA organic certified
Frequently Asked Questions
Does cocoa powder have more polyphenols than dark chocolate? Yes, gram for gram. Phenol-Explorer averages 5,624mg of polyphenols per 100g for cocoa powder against 1,860mg for dark chocolate, because most of the cacao butter has been pressed out. If you’re after high polyphenol cocoa, choose natural cocoa powder, since alkalised (Dutch-processed) powder loses a large share of its flavonoids.
Does milk chocolate have polyphenols? Yes, but fewer. Phenol-Explorer’s average for milk chocolate is 854mg of polyphenols per 100g, under half the 1,860mg for dark chocolate, because milk powder and sugar take up room the cacao would otherwise fill. White chocolate contains no cocoa solids at all.
Is Mr Popple’s cacao alkalised? No. Mr Popple’s Chocolate never alkalises its cacao: it isn’t Dutch-processed and no alkali is added. We also keep it unroasted, below 42°C throughout, and stone-grind and conch it for 60 to 80 hours in small batches, so nothing is done to change its natural colour.
Has Mr Popple’s Chocolate been tested for polyphenols? Yes. Mr Popple’s Chocolate’s Pure Peruvian 100% was independently tested by Oxford Brookes Centre for Nutrition and Health: significantly higher polyphenol content than 4 other leading UK dark chocolate brands, and the highest average antioxidant capacity of the five bars tested. It measured 2,718mg of polyphenols per 100g.
