tea

EGCG (pronounced "E-G-C-G") stands for epigallocatechin-3-gallate, a specific type of polyphenol found most abundantly in green tea. Chemically, it belongs to a group called catechins — plant-made molecules that often act like mild protective chemicals for the plant and, when we consume them, can interact with our bodies in interesting ways. If you drink green tea or matcha, EGCG is one of the main active ingredients you’re getting.

At a practical level, EGCG is known for two broad properties: it can act as an antioxidant and it can influence cellular signalling. As an antioxidant, EGCG can neutralize some reactive molecules that damage cells (often called free radicals). But more importantly, it also turns on the body’s own protective systems — for example, cellular pathways that boost the production of enzymes that clean up oxidative stress. Beyond that, EGCG can change how cells talk to each other by modifying signalling pathways that control inflammation, growth, and survival. In plain terms, it can damp down excessive inflammatory signals in some situations and can slow down abnormal cell growth in others.

A lot of the excitement around EGCG comes from laboratory and animal studies showing it affects processes linked to heart health, brain health, metabolism, and cancer. In cells and animals, EGCG has been shown to reduce inflammation, protect nerve cells, improve blood vessel function, and interfere with pathways that cancer cells use to grow. However, what happens in a test tube or a mouse does not always happen the same way in people. When humans drink green tea, EGCG is partially broken down in the gut and liver into other compounds, and the amounts that reach different tissues are smaller and more complex than the pure compound used in lab experiments. That’s why clinical evidence in people is more mixed and why researchers are careful about making strong health claims.

How you consume EGCG matters. Drinking green tea delivers EGCG together with water, caffeine, and other tea compounds, and this is generally considered safe for most people. Concentrated supplements deliver much higher doses of EGCG than a few cups of tea and have been linked, in rare cases, to liver problems. EGCG can also interfere with the absorption of non-heme iron (the kind found in plants) and can interact with certain medications. Because of this, supplements should be used cautiously and ideally under medical advice.

Another important point is that EGCG doesn’t act alone. The gut microbes in your intestines transform EGCG into other molecules, and those transformations can influence what effects occur in your body. So the final biological activity you get from green tea depends not only on the EGCG amount but also on how your body and your microbiome process it.

In short, EGCG is a biologically active compound in green tea with antioxidant and cell-signalling effects that may support aspects of health. Most evidence supports drinking green tea as a safe way to get modest amounts of EGCG; high-dose supplements are more uncertain and carry more risk. If you’re considering concentrated EGCG products for health reasons, it’s wise to talk with a healthcare professional first.

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There is suggestive evidence that oolong tea can help some inflammatory skin problems—most convincingly for atopic dermatitis (eczema)—but the data are limited, and for psoriasis the evidence is largely preclinical or anecdotal rather than proven in clinical trials.

Longer, medical-style explanation:

Oolong tea is derived from Camellia sinensis and contains a mix of tea polyphenols (catechins and their oxidation products), modest amounts of caffeine, and a range of other bioactive molecules. Those polyphenols have antioxidant, anti-inflammatory and “antiallergic” actions in laboratory studies: they can reduce proinflammatory cytokine signaling, stabilize or reduce mast-cell activation, and scavenge reactive oxygen species — mechanisms that are plausibly relevant to inflammatory skin diseases such as atopic dermatitis. Reviews of tea polyphenols and focused papers on the catechin EGCG summarize these pathways and the experimental evidence supporting them. (PMC)

Clinical human data for oolong and eczema are modest but noteworthy. A controlled clinical series conducted in Japan reported improvement in a substantial fraction of patients with treatment-resistant atopic dermatitis who drank oolong tea daily; roughly two-thirds showed marked or moderate improvement after one month and more than half maintained a response at six months in that observational/clinical series. The protocol, as used in published descriptions and integrative dermatology summaries, involved steeping a defined amount of dried oolong leaves and drinking the infusion divided through the day. These results are encouraging but must be read in context: the study was relatively small, not a large double-blind randomized controlled trial, and confounding (diet, concurrent treatments, placebo effects) cannot be fully excluded. (PubMed)

Laboratory and animal research strengthens biological plausibility. Recent preclinical work comparing tea extracts shows that oolong and other tea extracts can reduce scratching, epidermal hyperplasia, mast cell counts and key inflammatory mediators in mouse models of allergic dermatitis. Separate mechanistic studies find that both systemic and topical administration of tea catechins (especially EGCG) reduce acute and chronic itch and downregulate inflammatory signaling in keratinocytes and immune cells — findings that help explain the clinical signals seen in some human reports. (MDPI)

When it comes to psoriasis the picture is different. Psoriasis is a Th17-driven, hyperproliferative disorder of epidermis and immune signaling; laboratory and animal studies show that EGCG and other polyphenols can attenuate psoriasiform inflammation in mouse models and modulate pathways (STAT3, NF-κB, IL-17 axis) relevant to psoriasis. However, high-quality clinical trial evidence of benefit for oral oolong tea in people with psoriasis is essentially lacking, and available human reports tend to be anecdotal or extrapolated from green tea/EGCG work or small topical formulation studies. Thus, while the molecular data and animal models support the possibility that tea polyphenols could help, clinical proof for oolong in psoriasis is currently insufficient. (SpringerLink)

Practical clinical considerations and safety: if patients wish to try oolong as an adjunctive, a few practical points are important. Moderate consumption (a few cups daily) is generally well tolerated for most adults, but oolong contains caffeine and can interfere with sleep or exacerbate anxiety in sensitive individuals; tea also reduces non-heme iron absorption if taken with iron-rich meals and can contribute fluoride exposure if consumed in very large amounts. Patients with significant or progressive dermatitis or psoriasis should not stop standard prescribed therapies in favour of tea alone; instead oolong can be considered as a complementary measure and patients should discuss it with their dermatologist. Finally, topical preparations containing stabilized tea catechins are an active area of research and may offer different risk/benefit profiles compared with simply drinking tea. (PMC)

Bottom line: the best clinical signal for oolong tea is in atopic dermatitis, where limited human data plus supportive preclinical studies indicate a possible benefit; for psoriasis the evidence is mainly preclinical and anecdotal at present. The biological plausibility is strong because tea polyphenols are anti-inflammatory and immunomodulatory, but higher-quality randomized clinical trials and standardized dosing studies are still needed before oolong can be recommended as a proven treatment. (PubMed)

(...) Green tea has stronger and more consistent evidence (especially due to EGCG) for anti-inflammatory and topical benefits in skin conditions; oolong shows promise—notably for atopic dermatitis—but the clinical data are smaller and less robust.

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Oolong tea does appear to have healthful properties, although the strength of the evidence varies by outcome and much of the best mechanistic work comes from lab or animal studies rather than large, definitive human trials. At the chemical level, oolong is made from the same plant as green and black tea (Camellia sinensis) but is partially oxidized, which gives it a mix of polyphenols, catechins and theaflavins. These compounds act as antioxidants and mild anti-inflammatory agents; they can neutralize free radicals and influence metabolic and cellular pathways in ways that plausibly protect tissues from damage. Laboratory analyses and reviews of oolong’s phytochemistry describe this rich polyphenol profile and the tea’s measurable antioxidant activity. (PMC)

Because of those antioxidant and bioactive compounds, observational studies and some clinical research link regular tea drinking — including oolong — with lower risk markers for heart disease. People who drink moderate amounts of tea have been found, in population studies, to have lower rates of death from cardiovascular causes and better blood-lipid profiles; smaller trial data and animal work also hint that tea polyphenols can improve vascular function and reduce cholesterol and triglycerides. These associations don’t prove causation (tea drinkers may differ from non-drinkers in other healthy behaviors), but the pattern of observational findings plus plausible mechanisms makes a cardiovascular benefit one of the more consistent and credible claims. (The Nutrition Source)

Oolong is often discussed for its effects on weight and metabolism. Some trials and animal studies report modest decreases in body fat and improvements in markers of lipid metabolism after regular oolong consumption or supplementation with oolong extracts; caffeine plus certain tea polyphenols can slightly increase energy expenditure and fat oxidation, which may help with weight control when combined with diet and exercise. The human studies are usually small and short, so any weight effects should be seen as potentially helpful but not dramatic or guaranteed. (PubMed)

The picture is mixed for blood sugar and diabetes. Several large observational studies and meta-analyses find that regular tea drinking (especially when averaged across tea types) is associated with a lower risk of type 2 diabetes, but studies focused specifically on oolong have produced inconsistent results — a few reported no benefit and at least one older study even reported a higher diabetes risk in a subgroup of heavy oolong drinkers, though that finding has not been universally replicated and may reflect confounding or regional differences in preparation and lifestyle. Overall, tea may help glucose metabolism for some people, but the evidence for oolong specifically is variable and more research is needed. (PMC)

Beyond those areas, animal and lab studies suggest oolong polyphenols might support cognitive function, influence the gut microbiome, and show anti-cancer or bone-protective effects in early experiments, but human data are preliminary. There are also practical cautions: oolong contains caffeine (less than coffee but enough to matter for sensitive people), tea can reduce absorption of non-heme iron when consumed with iron-rich plant foods, and very large amounts of any tea can add fluoride or interact with medications. For most people, moderate oolong intake (a few cups a day) is a low-calorie, antioxidant-rich choice that can be part of a healthy diet, while pregnant people, those with iron-deficiency, or people sensitive to caffeine should moderate intake and consult their clinician if unsure. (ScienceDirect)

In short, oolong tea brings antioxidant and polyphenol-driven effects that plausibly support heart and metabolic health and may modestly aid weight control; many findings are promising but not definitive, so think of oolong as a healthy beverage choice rather than a cure-all.

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Herbal Teas :

The teas involved in helping to heal psoriasis and eczema are natural herbal teas that affect the internal cleansing process and aid in the restoration of the intestinal walls. Most herbal teas do not contain caffeine, theobromide, or tannin, which are potentially harmful ingredients that can lead to nervousness, insomnia, rapid heartbeat, and disruption of blood-sugar levels. Popular commercial teas, however, do contain these unhealthy elements and should, therefore, be avoided by the psoriatic.

The most beneficial herbal teas are American yellow (not Spanish) saffron tea and slippery elm bark powder tea. Discussion of these teas and their preparation appears in chapter 7. 

Supplemental Herbal Teas :

Other herbal teas may include watermelon seed tea, chamomile, mullein, and decaffeinated green or black tea. Oolong tea has been cited as being very helpful in cases of eczema.

Pagano, John O. A.. Healing Psoriasis: The Natural Alternative (pp. 97-98). Turner Publishing Company.

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