Curcuminoids are the family of yellow-orange polyphenol compounds found in turmeric, and curcumin is simply the most abundant member of that family. Turmeric itself has coloured and flavoured South Asian kitchens, and featured in Ayurvedic tradition, for thousands of years, and the curcuminoids are the pigments behind that famous golden hue. Understanding the difference between curcuminoids, curcumin and turmeric helps you read a label properly, judge an extract, and supplement sensibly. This is a clear, composition-based explainer of what curcuminoids are as a matter of plant chemistry, how extracts are made, and what the UK safety view says.
Reviewed and updated: 24 July 2026
What are curcuminoids? The quick answer (TL;DR)
- What they are: a group of three related yellow polyphenols in turmeric root, called curcuminoids.
- The main one: curcumin is the most abundant curcuminoid; the term curcuminoids covers the whole trio.
- Why extracts exist: raw turmeric is low in curcuminoids, so concentrated extracts are standardised to deliver a consistent amount.
- The catch: curcuminoids absorb poorly on their own, which is why black pepper (piperine) is so often added.
Curcuminoids are a group, curcumin is the main one
Turmeric (Curcuma longa) is a root that contains a family of related yellow-orange plant compounds called curcuminoids, which are a type of polyphenol. The group has three main members:
- Curcumin (diferuloylmethane), the most abundant and most studied.
- Demethoxycurcumin, the second most common.
- Bisdemethoxycurcumin, present in the smallest amount.
So curcumin is one specific curcuminoid, the headline one, while curcuminoids is the umbrella term for the whole trio. A review describes turmeric as the major dietary source of the polyphenol curcumin (Hewlings and Kalman, 2017, DOI).
How the three curcuminoids break down
The three are not present in equal amounts. When the curcuminoid content of turmeric supplements has been measured in the laboratory, curcumin makes up roughly four-fifths of the total, with demethoxycurcumin around 15 percent and bisdemethoxycurcumin a few percent (Skiba and colleagues, 2018, DOI). Curcumin is therefore the dominant compound, which is why most of the science and most labels focus on it, even though all three sit under the curcuminoid banner.
The chemistry: what curcuminoids actually are
Chemically, curcuminoids are diarylheptanoids: two aromatic rings joined by a seven-carbon chain. They are responsible for turmeric's intense yellow colour, which is also why purified curcumin is used as a natural food colouring (listed as E100). They are fat-soluble rather than water-soluble, exist in a keto-enol form that shifts with acidity, and are sensitive to light and heat, which is part of why turmeric powder fades and why extract quality and storage matter.
How much of turmeric is actually curcuminoids?
This is the part that surprises people. The curcuminoids make up only a small fraction of the turmeric root by weight, with the rhizome being mostly carbohydrate; curcuminoids account for around 3 to 5 percent of the rhizome, with curcumin the most abundant of them (Phipps and colleagues, 2019, DOI). This is exactly why concentrated turmeric extracts exist: they are standardised to a much higher curcuminoid percentage (often stated as a figure such as 95 percent curcuminoids) so each dose delivers a consistent, measured amount rather than variable raw powder.
How curcuminoid extracts are made
Getting from a 3 to 5 percent root to a 95 percent extract is a concentration and isolation process. In broad terms, dried turmeric rhizome is milled and the curcuminoids are pulled out using a solvent extraction step, because curcuminoids are fat-soluble and do not dissolve in water. The crude oleoresin that results is then purified and crystallised to remove most of the carbohydrate, oils and other plant matter, leaving a powder standardised to a stated curcuminoid percentage. A simple turmeric powder, a standardised curcuminoid extract, and an isolated single curcumin are therefore three different things by concentration and by how much processing they have had.
The absorption catch
Curcuminoids, and curcumin in particular, are poorly absorbed on their own. The chemistry is unhelpful: curcumin is highly water-insoluble, is rapidly metabolised, and is quickly eliminated, so very little reaches the bloodstream after a normal oral dose (Hewlings and Kalman, 2017, DOI). This is why curcumin is so often paired with piperine from black pepper, which has been shown to improve curcumin uptake substantially by slowing its breakdown. We explain that pairing in what piperine is and what it does and in why turmeric needs black pepper.
Curcuminoids vs curcumin vs turmeric: clearing up the terms
These three words are used loosely, so here is the plain version. Turmeric is the whole root (and the spice). Curcuminoids are the small group of yellow polyphenols inside it. Curcumin is the single most abundant curcuminoid. A turmeric powder, a standardised curcuminoid extract, and an isolated curcumin are therefore three different things by concentration.
What to look for on a label
Three composition points matter when comparing turmeric products: whether it is a standardised extract or just raw root powder, the stated curcuminoid content, and whether an absorption aid such as black pepper is included. Quality also matters: a marketplace analysis of turmeric supplements found wide variation in curcuminoid composition between products and, in rare cases, raised lead and solvent-residue quality flags, which is why purity testing is worth caring about (Skiba and colleagues, 2018, DOI).
The UK safety view: what the COT says about curcumin
Turmeric used as a food and in normal culinary amounts is well established and well tolerated. The picture is more nuanced for concentrated, high-dose curcumin supplements, especially highly bioavailable formulations. The UK Committee on Toxicity (COT), which advises the Food Standards Agency, has reviewed curcumin in food supplements and noted reports of liver effects in a small number of users, considering whether enhanced-absorption products warrant particular caution (COT statement on curcumin). The practical, honest reading is that culinary turmeric is not the concern, but if you take a concentrated curcumin or curcuminoid supplement, stick to the label dose, do not stack several turmeric products, and stop and seek advice if you feel unwell.
Safety and who should be cautious
Beyond the liver note above, a few groups should take particular care with concentrated turmeric or curcumin. It can affect how some medications work, including blood thinners, and is best avoided in higher supplement doses by people with gallstones or active gallbladder problems. If you are pregnant or breastfeeding, take regular medication, or manage a health condition, speak to your GP or pharmacist before taking a concentrated turmeric supplement.
How our turmeric is formulated
Our Turmeric combines turmeric with black pepper extract and ginger, so the curcuminoid content is paired with piperine to support uptake. It is formulated in the UK and manufactured in a GMP-certified facility. You can browse the wider range on our home page, or read why turmeric and ginger are combined.
Frequently asked questions
Are curcuminoids the same as curcumin?
Not quite. Curcuminoids is the group name for the three yellow polyphenols in turmeric: curcumin, demethoxycurcumin and bisdemethoxycurcumin. Curcumin is the single most abundant one, so the words are often used loosely, but curcuminoids covers all three.
How much curcuminoid is in turmeric?
Curcuminoids make up only about 3 to 5 percent of the turmeric root by weight, which is why concentrated extracts standardised to a high curcuminoid percentage are used to deliver a consistent dose.
Why is black pepper added to turmeric?
Curcuminoids are poorly absorbed on their own. Piperine from black pepper has been shown to improve curcumin uptake substantially, which is why the two are commonly paired.
What does 95 percent curcuminoids mean on a label?
It means the extract has been concentrated and standardised so that 95 percent of it is curcuminoids, giving a consistent, measured amount per dose rather than variable raw root powder.
Is high-dose turmeric safe for the liver?
Culinary turmeric is not the concern. For concentrated curcumin supplements, the UK COT has noted rare reports of liver effects, so stick to the label dose, avoid stacking turmeric products, and seek advice if you feel unwell or take other medication.
Signed, Dr. Miron, Founder of Pure Vitamins UK.
Sources retrieved from PubMed, journal pages and the UK Committee on Toxicity; see the links above. This article is for general information and composition education, not medical advice. Food supplements should not be used as a substitute for a varied, balanced diet and a healthy lifestyle. If you are pregnant, breastfeeding, taking medication or managing a medical condition, speak to your GP or pharmacist before starting a new supplement.
