What are phytosomes and how do they work?
Phytosome Technology: The Solution for Poorly Absorbed Plant Compounds
The most popular herbal extracts in the supplement world, such as berberine, turmeric, quercetin, boswellia, and milk thistle, have something in common besides their therapeutic potential: our digestive system absorbs them terribly. In more scientific terms, they have low “bioavailability”: you may ingest them, but only a very small percentage reaches the bloodstream, limiting their overall effectiveness.
The reason for this poor absorption is that the active compounds, such as curcumin, quercetin, silybin, or green tea catechins, are poorly soluble in both water and fat. As a result, they are barely absorbed in the intestinal environment and fail to enter the bloodstream effectively. In addition, some compounds form large and unstable aggregates, making it even more difficult for them to pass through the intestinal wall. Furthermore, certain phytonutrients are rapidly broken down or metabolized in the intestines and liver before they reach their target tissues.
Over time, various solutions have been developed to address this issue, some more effective than others. Ultimately, it was the Italian company Indena that developed the most effective solution by far. The company exists for more than 100 years and was founded with the goal of combining science and nature by developing unique botanical extraction methods.
After years of research, the company introduced its patented Phytosome® technology, specifically designed to significantly improve the absorption and bioavailability of poorly absorbed plant compounds.
How Does It Work?
The basic concept is that the active compound from the plant extract is bound to phospholipids derived from lecithin. Phospholipids are fat-like molecules that closely resemble the building blocks of our cell membranes. This prevents both the plant compound and the phospholipid from clumping together. Since cell membranes are also composed of these fat-soluble phospholipids, the plant compound can be transported through the lipid-permeable cell membranes of the gastrointestinal tract and enter the bloodstream more efficiently.
Benefits
Phytosomes offer several advantages over standard herbal extracts. Three key benefits are:
1. Improved absorption for better bioavailability. Every phytosome has been shown to provide superior absorption compared to its non-bound counterpart — the plant compound on its own. The poorer the absorption of the original extract, the greater the difference in absorption between the phytosome and its non-complexed counterpart.
2. Enhanced effectiveness. Better absorption means more of the active compound is available for use by the body. In short: better absorption = greater effectiveness. In addition, the effect is often more consistent.
3. Potentially lower dosage requirements. Because more of the active compound is absorbed and utilized by the body, a lower amount of herbal extract may be required while still delivering greater effectiveness.
Discover the Phytosome Products in the Smeets & Graas Range
Smeets & Graas offers 9 unique phytosome products, available both as standalone supplements and as part of combined formulations.
Curcumin Phytosome (Meriva®)
Curcumin, the primary bioactive compound in turmeric, is currently one of the most extensively researched phytonutrients. It has built a strong scientific foundation and has attracted attention for years because of its broad applications in nutrition, supplementation, and herbal medicine.
A well-known disadvantage of regular curcumin is that the body absorbs it poorly. Although researchers searched for years for ways to improve its bioavailability, practical success remained limited. Phytosome technology represented an important breakthrough: Meriva® is a form of curcumin bound to phosphatidylcholine from sunflower lecithin, significantly increasing absorption in the body.
In a randomized crossover study, curcumin phytosome was compared with standard curcumin. The results showed that blood levels of curcuminoids after intake of the phytosome preparation were on average 29 times higher than after ingestion of non-complexed curcumin.
Curcumin phytosome has also been extensively studied in clinical trials. With more than 30 clinical studies, it is among the best researched enhanced-absorption curcumin products on the market.
Berberine Phytosome (Berbevis®)
Berberine is an alkaloid found in several plants, including various Berberis species. The most commonly used berberine is extracted from *Berberis aristata*. Like many phytonutrients, berberine also suffers from poor absorption. Another drawback experienced by some users is mild intestinal irritation after taking standard berberine supplements.
Berbevis®, the phytosome form of berberine, addresses both of these issues. Research shows that it is absorbed nearly 10 times better than standard berberine extract.
Milk Thistle Phytosome (Siliphos®)
Silybum marianum (milk thistle) contains unique flavonoids, of which silybin is the most potent. Milk Thistle Phytosome consists of silybin bound to phospholipids and was the first phytosome developed by Indena.
The absorption of Siliphos® has been investigated in several studies, showing that this phytosome form is many times more bioavailable than standard extracts. It produces higher blood concentrations of active silymarin compounds and their isomers, resulting in significantly greater effectiveness.
Green Tea Phytosome (GreenSelect®)
Polyphenols from green tea, including epigallocatechin gallate (EGCG) and other catechins, are isolated from decaffeinated green tea leaves (*Camellia sinensis*) and then bound to phospholipids.
In an absorption study involving 12 healthy volunteers, Green Tea Phytosome was compared with the exact same green tea extract not bound to phospholipids. Blood levels over a six-hour period were twice as high in the phytosome group as in the group receiving the non-complexed extract.
In addition to improved absorption, Green Tea Phytosome offers another advantage: its EGCG content is strictly standardized. Moreover, it is virtually caffeine-free (standardized to less than 0.1%).
Quercetin Phytosome (Quercefit®)
Quercetin, a flavonoid found in many foods, is known for its poor absorption. It was the Thorne brand that encouraged Indena to offer this substance as a phytosome as well.
In a study involving 12 healthy volunteers, Quercetin Phytosome demonstrated 20 times greater absorption than unbound quercetin. This makes Quercefit® a highly effective product. Due to full traceability of the raw materials, its purity is also guaranteed.
Boswellia Phytosome (Casperome®)
Boswellia is now well established in phytotherapy and it's mentioned regularly here in radio commercials. However, it is important to distinguish between the regular Boswellia extract and Boswellia bound to phosphatidylcholine.
A study showed that, depending on the boswellic acid measured, plasma concentrations were 3 to 7 times higher with the phytosome preparation compared to standard Boswellia extract.
The patented complex also ensures faster absorption, a full spectrum of active compounds, and standardized quantities of the key constituents.
Luteolin Phytosome
Luteolin is a flavonoid found in many plants, including chrysanthemums, which serve as the source of luteolin in Luteolin Phytosome. Although developed and produced by Indena, this ingredient does not have a patented brand name because it was specifically prepared for Thorne. It is one of the ingredients used in the product Advanced Testosterone Support.
An absorption study demonstrated that luteolin bound to phosphatidylcholine produced plasma luteolin concentrations 3.5 times higher than non-complexed luteolin.
Bergamot Phytosome (Vazguard®)
Citrus bergamia (bergamot), a citrus tree native to tropical Asia, is now cultivated throughout the Mediterranean region, with significant production in Southern Italy. The yellow-green bergamot fruit, roughly the size of a small orange, is a hybrid between bitter orange and lemon.
Bergamot is best known as the distinctive aromatic ingredient in Earl Grey tea. However, it is the fruit juice, with its high polyphenol content, that has recently attracted significant scientific attention.
An absorption study using the flavonoid naringin as a marker showed that absorption was 2.5 times higher with Bergamot Phytosome than with non-bound bergamot extract containing the same polyphenol content. Metabolic Health from Thorne contains Vazguard® Bergamot Phytosome.
Ginkgo Phytosome (Virtiva® Plus)
Ginkgo biloba is one of the most extensively researched herbs in the world. More than 400 scientific studies have investigated its effects. However, only highly concentrated, standardized Ginkgo biloba extracts demonstrate meaningful effectiveness.
The absorption and bioavailability of the flavone glycosides and terpene lactones in Ginkgo phytosome are significantly enhanced by the patented Phytosome® technology developed by the Italian manufacturer Indena.
The extract provides 24 mg flavone glycosides and 6 mg terpene lactones, while the lecithin contributes 55 mg phosphatidylserine.
This 24/6 ratio between flavone glycosides and terpene lactones is the ratio most commonly used in scientific research on Ginkgo biloba.
Thorne Memoractiv contains Virtiva® Ginkgo Phytosome.
This blog article is a translation and adaptation of a Take 5 Daily article on Thorne.com
Author Thorne: Kathi Head, ND
NL Editor: Marcella van der Wel
Published on: May 25, 2026