Remarkable new discoveries about EGCG, the active ingredient in green tea

What is epigallocatechin gallate (EGCG)?

EGCG, which stands for epigallocatechin gallate, is a molecule in the catechin family, a subgroup of the large polyphenol family. This plant pigment is found almost exclusively in green tea, regularly touted as the Japanese secret to longevity, and is its most potent and abundant active compound (1).

It has already been established that epigallocatechin gallate has a remarkable antioxidant action: it helps protect our bodies by strengthening the body's natural defences against the harmful effects of free radicals, and slows down the ageing of cells due to oxidative damage (2). It also supports cardiovascular health: in combination with regular physical activity, it improves blood circulation and helps maintain normal blood pressure (3). It is also to this that green tea owes its reputation as a slimming drink: in conjunction with a healthy diet and exercise, it promotes weight control, helps to reduce body fat (by increasing lipid oxidation) and helps normalise blood sugar levels (by regulating the storage and release of liver glycogen) (4-5).

But in light of the most recent scientific studies, EGCG may have revealed only a fraction of its virtues.

EGCG: the latest scientific findings on green tea's super-active ingredient

New hope for β-thalassaemia patients

β-thalassaemia is a genetic blood disorder which affects the synthesis of haemoglobin (the protein in red blood cells responsible for transporting oxygen), resulting in anaemia of varying severity. In the most severe forms, it requires repeated blood transfusions, leading to a number of complications, including iron overload and chronic oxidative stress. For the first time, an animal study published in 2022 demonstrated the potential value of green tea extracts rich in epigallocatechin-3-gallate in improving the efficiency of erythropoiesis (red blood cell production), correcting iron dysregulation and reducing pro-oxidant products in β-thalassaemic mice (6).

Modulatory effects on intestinal microbiota

What if EGCG interacted directly with our microbiota? This is the hypothesis explored by a team of scientists in an in vitro study published in 2020 (7). They observed that this catechin was rapidly broken down in the small intestine into a series of metabolites, including 4-phenylbutyric acid and phenylacetic acid, which could positively modulate the composition of the intestinal flora.

The results of the microbiome profiling suggest that they could stimulate several beneficial bacterial strains, including 5 species of the Bacteroides genus (which have essential metabolic and immunological functions), species of the Christensenellaceae genus (linked to a lower body mass index and increased longevity), as well as Clostridium symbiosum, Ruminococcus bromii and Bifidobacterium adolescentis. They could also suppress pathogenic strains from the Forsterygion, Bilophila and Enterobacteriaceae species.

Potential protection against the harmful effects of microplastics on fertility

Another study from 2024 looked at the effects of epigallocatechin gallate on the damage induced by polystyrene microplastics on testicular cells (8). The accumulation of these particles, which are ubiquitous in our environment, in the male reproductive system is thought to interfere with the spermatogenesis process, which explains the decline in fertility currently observed in men.

It appears that EGCG can mitigate these deleterious effects by mediating several cell signalling pathways, including Nrf2/HO-1 (involved in the antioxidant response), mTOR/Atg-7 (which activates autophagy, the degradation of defective cell components) and Cx-43/NOX-1 (which propagates inflammatory and pro-apoptotic 'cell death' messengers).

An advanced neuroprotectant

Research is also progressing in the field of neuroprotection. A 2024 study reported that EGCG could attenuate neuronal damage in animal models of ischaemic stroke and cell death in neurons exposed to glutamate, in a dose-dependent manner (9). Epigallocatechin gallate is thought to interfere with the expression of hippocalcin, a protein that ensures the proper functioning of the nervous system and controls cellular calcium concentrations in the cerebral cortex.

Is drinking tea a necessary step to reap the benefits of EGCG?

In theory, to reap the benefits of this catechin, you need to drink green tea frequently and regularly. Bear in mind, however, that various parameters affect the actual final EGCG content in the teapot: the variety of tea, the method of preparation, the quality of the leaves, etc.

That's why opting for standardised EGCG supplementation is a much better option for ensuring a more consistent intake over time.

• Our EGCG supplement contains 227 mg per capsule, compared with 20 to 100 mg on average in a cup of tea.