How to Choose the Best High Polyphenol Olive Oil in the UK

In short: 

High-polyphenol olive oil isn’t defined by what the label says. It comes down to verified lab results (mg/kg), a fresh early harvest, and a naturally peppery, slightly bitter taste that signals quality. From there, it’s about choosing an oil you’ll actually use day to day, balancing polyphenol level with flavour and consistency rather than chasing the highest number on the bottle.

Most people shopping for high-polyphenol olive oil are looking for the same thing: a genuinely good oil that does what it claims. The problem is the term isn't regulated, so it gets used loosely - and two bottles at similar price points can contain very different amounts of the compounds that matter.

What actually separates them isn't the label. It's the lab result, the harvest timing, and how the oil tastes. Get those three things right and the rest tends to fall into place.

What actually matters when choosing olive oil

To separate a standard oil from a genuinely good one, look at this:

1. Lab-tested polyphenol level (mg/kg)

This is the number to look for. It's measured in milligrams per kilogram and tells you exactly how much of the beneficial compounds (polyphenols) are in the bottle - no guesswork needed.

How to make sense of it:

If there's no mg/kg figure on the label or the producer's website, you can't compare it to anything - and that alone tells you something.

2. Harvest date and freshness

Freshness has a direct impact on quality. Early harvest oils (typically October to November, when olives are still green) naturally contain higher levels of beneficial compounds, but those levels decline over time once the oil is produced. What matters most is when the olives were actually pressed, not just how long the oil is set to last on the shelf.

A harvest date is the thing to look for, as a best-before date on its own doesn't tell you enough.

3. Flavour

Taste is one of the most reliable quality checks. Higher polyphenol oils typically have a peppery finish at the back of the throat and a gentle bitterness - both signs the polyphenols are still present.

On the other end, a very mild, neutral oil is usually a sign that fewer of those compounds made it to the bottle.

4. Intended use

This is the part most buying guides miss. The right oil depends on how you’ll actually use it - and that should guide the level of polyphenols you go for.

Which oil suits you?

If you’re wondering how to choose, start with this question: 

How are you actually going to use it day to day?

Cooking most nights and want something you'll actually reach for every day?

A balanced oil in the 400-800 mg/kg range gives you meaningful polyphenol content without the flavour becoming overpowering. Masworth Family Groves EVOO (965 mg/kg) sits above this range, but its smooth, everyday flavour makes it an easy everyday choice for salads, roasting and finishing dishes.

Looking for the strongest independently verified bottle you can get?

Go for 800 mg/kg+, early harvest, with a published lab result to back it up. You’ll notice a more assertive peppery finish - that's the polyphenols doing their thing. November Polyphenols EVOO (1200+ mg/kg) sits at the top of the Masworth range, independently tested by the World Olive Centre for Health in Athens.

Then ask: 

How much do polyphenols matter to you specifically?

General quality and everyday health benefits?

The 500-800 mg/kg range is well supported by various studies, like the EUROLIVE randomized trial and the Bond University high‑polyphenol EVOO crossover study, and more than sufficient for most people. What matters most is consistency - not chasing the highest figure. A 700 mg/kg oil used daily will deliver far more benefit than a 1200 mg/kg bottle used occasionally.

Targeting something specific, like inflammation, joint health, or hormonal balance?

Go for the highest independently verified mg/kg you can find, and use it raw or as a finishing oil rather than cooking it off. November at 1200+ mg/kg is the natural fit here, and subscribing to our monthly plan means you’ve always got a steady supply of freshly pressed oil on hand without needing to think about reordering each time.

For more on how olive oil can be used, see our guides on olive oil and arthritis and olive oil for women’s health.

How to read a bottle quickly

When you know what to look for, it only takes a few seconds to separate a proper oil from marketing noise.

Signs of a well-made oil:

• A published mg/kg polyphenol figure, not just claims on the front label

• A clear harvest date or season, not just a best-before date

• Olive variety stated (Koroneiki olives are often a strong indicator of higher polyphenols)

• A noticeable peppery finish, which is a simple sign the compounds are present

Worth being cautious about:

• No polyphenol figure anywhere on the label or website

• Very long shelf life claims on “early harvest” oils - polyphenols don't hold at peak levels that long

• Prices that seem low for what's being claimed - genuine early-harvest oil reflects the cost of careful production

Three common mistakes when choosing olive oil

Most confusion comes from assuming the label tells you everything. In reality, a few small details make a big difference:

1. Treating “extra virgin” as the full measure of quality

EVOO only tells you about acidity and extraction method, not polyphenol content. Most supermarket oils don’t publish a figure because it wouldn’t reflect the actual levels inside.

2. Overlooking the harvest date

An oil can still be in its best-before date while being well past its peak. Polyphenol levels naturally decline the longer it’s been since harvest.

3. Using high-polyphenol oil for high-heat cooking

Polyphenols are sensitive to heat. If you’re buying for their benefits, it makes more sense to use the oil raw or as a finishing drizzle, and keep a separate, more affordable EVOO for the hob.

A quick summary

The Masworth range

Both oils are early harvest, independently lab-tested, and published with full polyphenol data - so you’re comparing verified numbers rather than relying on what’s written on the label.

Masworth Family Groves EVOO - 965 mg/kg

High in polyphenols with a smooth, well-rounded flavour. Easy to use day to day across cooking, salads, and finishing.

November Polyphenols EVOO - 1200+ mg/kg

The highest polyphenol option in the range, with a more pronounced, peppery finish. Best kept for raw use or as a finishing oil, especially if polyphenol content is the priority. 

Both sit well above the EU's 250 mg/kg health-claim threshold, with full harvest and production details available alongside the lab results.

FAQ

Do higher polyphenols always mean better flavour?

Not always. Higher polyphenol oils tend to be more peppery and bitter - which many people prefer once they've tried them, but it comes down to taste rather than being a straight upgrade. What it does reliably point to is freshness and quality.

Can you cook with high polyphenol olive oil?

Yes, though heat does affect polyphenol levels. For a full breakdown of how cooking impacts them and how to get the most from your oil, see our November Olive Oil guide.

How long do polyphenols last after opening?

They start reducing once the bottle is open, as exposure to air and light speeds things up. A good rule is to use it within four to six weeks, store it somewhere cool and dark, and keep the cap on between uses.