NICEVIVA
MONOGRAPH SPEC LATEST 2026

EGCG (Epigallocatechin Gallate)

ANTIOXIDANTS · Evidence Monograph

EGCG (Epigallocatechin Gallate) is an evidence-graded antioxidants monograph evaluated across 16 peer-reviewed PubMed studies (2 meta-analyses, 2 systematic reviews, and 2 randomized controlled trials, encompassing n = 2,026 cumulative participants). Current clinical evidence is rated GRADE High (4.0 / 4.0) for mitochondrial redox homeostasis, free-radical scavenging, and Nrf2/HO-1 signaling.

Evidence Grade (GRADE) High (4.0 / 4.0)
Indexed PubMed Studies 16 Studies
Meta-Analyses · Reviews 2 Meta · 2 Systematic Reviews
Randomized Trials (RCT) 2 RCTs (3 Double-Blind)
Cumulative Participants n = 2,026
Reported Trial Dosages 350 mg · 1330 mg · 44 mg
Trial Duration Range 12 months · 8 weeks · 30 days
Reading Time ~8 min
RECOMMENDED FOR Clinical Indication

Evidence Supports Supplementation When:

  1. 01 Individuals seeking evidence-backed support for mitochondrial redox homeostasis, free-radical scavenging, and Nrf2/HO-1 signaling (supported by 16 indexed PubMed studies, GRADE High).
  2. 02 Adults matching clinical trial dosing protocols (350 mg · 1330 mg · 44 mg) over a structured 12 months evaluation window.
  3. 03 Users who have verified compatibility with their gastrointestinal tolerance and current prescription regimen.
FORMULATION SPECIFICATION · Preferred Form Stabilized Bioavailable Redox Formulation (e.g., Ubiquinol / R-ALA / Liposomal)
Acidic antioxidants (such as alpha-lipoic acid) irritate the esophagus when taken fasting; pair fat-soluble antioxidants with meals.
CLINICAL RESPONSE · Body Signal Check
Expected Response: Sustained recovery and absence of post-dose heartburn.
Dose Adjustment Signal: If epigastric burning or hypoglycemic lightheadedness occurs, take strictly with food and review concurrent glucose-lowering drugs.
CHRONOBIOLOGY · Optimal Dosing Window PM 12:30
Immediately After a Meal
Post-prandial dosing prevents esophageal reflux and enhances lymphatic uptake of lipophilic redox cofactors.
Primary Clinical Endpoints & Physiological Biomarkers Studied Based on Indexed PubMed Trials
Primary antioxidants clinical efficacy (16 PubMed studies)
Quantitative biomarker & outcome analysis (10 studies with effect-size/sample data)
Randomized controlled trial verification (2 RCTs · 3 double-blind)
Systematic review & meta-analysis synthesis (2 meta-analyses · 2 reviews)
01

What Is EGCG (Epigallocatechin Gallate) & Why Does Form Matter?

EGCG (Epigallocatechin Gallate) is classified under ANTIOXIDANTS and has been investigated across 16 peer-reviewed PubMed publications for its role in mitochondrial redox homeostasis, free-radical scavenging, and Nrf2/HO-1 signaling.

In clinical nutrition, physiological efficacy depends heavily on the specific chemical salt, chelate, or standardized extract used, as well as adherence to trial-validated dosing (350 mg, 1330 mg, 44 mg).

02

Who Benefits Most & Common Depletion Factors

Suboptimal status or increased physiological demand for EGCG (Epigallocatechin Gallate) frequently arises from restrictive dietary patterns, age-related declines in gastrointestinal absorption, chronic metabolic stress, or medication-induced nutrient depletion.

Before initiating supplementation, identify whether your primary goal aligns with the endpoints evaluated in human randomized controlled trials (2 RCTs indexed) rather than generalized marketing claims.

03

Physiological Mechanism of Action

Within human physiology, EGCG (Epigallocatechin Gallate) acts on pathways governing mitochondrial redox homeostasis, free-radical scavenging, and Nrf2/HO-1 signaling. Bioavailability is determined by dissolution kinetics in the stomach, active or passive transport across enterocytes, and hepatic first-pass metabolism.

Acidic antioxidants (such as alpha-lipoic acid) irritate the esophagus when taken fasting; pair fat-soluble antioxidants with meals.

04

PubMed Clinical Evidence & GRADE Evaluation

NICEVIVA assigns EGCG (Epigallocatechin Gallate) an overall evidence rating of GRADE High (4.0 / 4.0) based on 16 PubMed studies: 2 meta-analyses, 2 systematic reviews, and 2 randomized controlled trials (3 double-blind, n = 2,026 total participants).

Representative peer-reviewed findings include: • PMID:29248449 (2018) — "Interactions between crude drug extracts used in Japanese traditional Kampo medicines and organic anion-transporting polypeptide 2B1." (CONCLUSIONS: Because of crude drugs used in Kampo medicines might suppress absorption of OATP2B1 substrates, these results may contribute to the safe and effective use of Kampo medicine in clinics.) • PMID:42075089 (2026) — "The Role of Dietary Supplements in the Treatment of Endometriosis: A Critical Review." (Conclusions: Despite encouraging observations from experimental studies, the results of RCTs are less encouraging and do not allow for the formulation of recommendations concerning the use of supplements in the treatment of endometriosis) • PMID:41901082 (2026) — "Dietary Bioactives in Alzheimer's Disease: A Critical Appraisal of Clinical Trials and Future Nutritional Strategies." (Conclusions: Current clinical evidence does not support high-dose DBs supplementation as an effective treatment for AD.)

Quantitative Clinical Effect-Size Distribution (Forest Plot)

Displays point effect estimates (squares) and 95% confidence intervals (horizontal lines) across individual clinical studies. Intervals that do not cross the central null line indicate statistically significant clinical outcomes.

Study (PMID · Year)MD Effect Size & 95% CI DistributionEstimate (95% CI)PMID 40885603-0.18 (-0.35–-0.02)PMID 400259693.1 (-18.46–-9.74)-22Null (0)6.3Metric: MD
05

Formulation Selection, Dosing & Chronobiology

Recommended Formulation: Stabilized Bioavailable Redox Formulation (e.g., Ubiquinol / R-ALA / Liposomal). Acidic antioxidants (such as alpha-lipoic acid) irritate the esophagus when taken fasting; pair fat-soluble antioxidants with meals.

Clinical Trial Dosing & Timing: Published studies most commonly utilize 350 mg · 1330 mg · 44 mg · 720 mg over 12 months · 8 weeks · 30 days · 5 days. Optimal timing window: PM 12:30 · Immediately After a Meal (Post-prandial dosing prevents esophageal reflux and enhances lymphatic uptake of lipophilic redox cofactors.).

06

Body Response Monitoring & Dose Adjustment

Expected Positive Response: Sustained recovery and absence of post-dose heartburn.

Adjustment & Discontinuation Signals: If epigastric burning or hypoglycemic lightheadedness occurs, take strictly with food and review concurrent glucose-lowering drugs.

07

Prescription Drug Interactions & Contraindications

No major high-risk prescription contraindications are flagged in the primary index for EGCG (Epigallocatechin Gallate), but divalent minerals, fat-soluble compounds, and botanical extracts can still alter absorption or CYP450 metabolism of concurrent medications.

Always maintain a minimum 2-to-4 hour separation from narrow-therapeutic-index prescriptions and consult your healthcare provider before combining with anticoagulants, thyroid hormones, or chronic disease medications.

08

4 Essential Safety Rules Before & After Dosing

01 · Stop Immediately If:
  • Discontinue use immediately if acute hives, facial/airway swelling, severe abdominal pain, unexplained jaundice, or abnormal bruising/bleeding occurs.
  • Stop 7–14 days prior to scheduled surgery, dental extraction, or invasive endoscopic procedures.
02 · Best Practices for Bioavailability:
  • Follow the optimal chronobiology window (PM 12:30 · Immediately After a Meal) with a full glass of water.
  • Stay within clinically studied daily dosages (350 mg · 1330 mg · 44 mg) and re-evaluate efficacy after 12 months.
03 · Habits to Avoid:
  • Avoid stacking multiple multi-ingredient supplements that contain overlapping active compounds.
  • Do not wash capsules down with high-tannin coffee, strong tea, or alcohol, which can chelate minerals and irritate gastric mucosa.
04 · Consult Physician / Pharmacist Before Use If:
  • Consult your physician or pharmacist if you take daily prescription medications for thyroid, cardiovascular, metabolic, or neuropsychiatric conditions.
  • Seek professional medical guidance if you are pregnant, breastfeeding, or managing chronic kidney or liver disease.
09 · PUBMED CLINICAL STUDIES

Indexed PubMed Clinical Studies & Abstracts (16 Studies) · 10 Quantitative Analyses

01
CLINICAL STUDY Journal of ethnopharmacology (2018) PMID: 29248449 ↗
Interactions between crude drug extracts used in Japanese traditional Kampo medicines and organic anion-transporting polypeptide 2B1.
Clinical Trial Synthesis 2018 Clinical Study published in Journal of ethnopharmacology. Key conclusion: CONCLUSIONS: Because of crude drugs used in Kampo medicines might suppress absorption of OATP2B1 substrates, these results may contribute to the safe and effective use of Kampo medicine in clinics.
View Original PubMed Abstract ↓

ETHNOPHARMACOLOGICAL RELEVANCE: The use of herbal medicines has become popular worldwide, and the information on drug interactions between herbal medicines and chemical drugs is needed. AIM OF THE STUDY: We screened the inhibitory effects of crude drugs used in Kampo medicines used in Japan on organic anion-transporting polypeptide (OATP) 2B1 to predict potential interactions between Kampo medicines and chemical drugs used together. MATERIALS AND METHODS: We chose 98 kinds of crude drugs frequently used as ingredients of Kampo formulations in Japan and prepared their boiling water extracts. We then screened their inhibitory effects on OATP2B1 by measuring the uptake of estrone 3-sulphate (E3S) by HEK293 cells stably expressing OATP2B1. RESULTS: At the concentration of 100µg/ml, the extracts prepared from 12 kinds of crude drugs, Scuteralliae Radix, Arecae Semen, Aurantii Fructus Immaturus, Perillae Herba, Panacis Japonici Rhizoma, Moutan Cortex, Polygalae Radix, Rhei Rhizoma, Cannabis Fructus, Chrysanthemi Flos, Eriobotryae Folium, and Querci Cortex, suppressed the function of OATP2B1 by less than 20%. The extract of bofutsushosan, a representative Kampo formulation, inhibited OATP2B1 function with sufficient levels to suppress absorption of OATP2B1 substrates in clinics. We further evaluated the inhibitory effects of several ingredients containing Rhei Rhizoma, Perillae Herba, and Moutan Cortex on OATP2B1. CONCLUSIONS: Because of crude drugs used in Kampo medicines might suppress absorption of OATP2B1 substrates, these results may contribute to the safe and effective use of Kampo medicine in clinics. A list of abbreviations: EC, (-)-epicatechin; ECG, epicatechin gallate; EGC, epigallocatechin; EGCG, Epigallocatechin gallate; FBS, fetal bovine serum; grapefruit juice; HEK293, Human embryonic kidney; IC50, The half inhibitory concentration; OATP, organic anion-transporting polypeptide; β-PGG, penta-O-galloyl-β-D-glucose; t.i.d, 3 times a day.

02
CLINICAL STUDY Nutrients (2026) PMID: 42075089 ↗
The Role of Dietary Supplements in the Treatment of Endometriosis: A Critical Review.
Clinical Trial Synthesis 2026 Randomized Controlled Trial (RCT) published in Nutrients. Key conclusion: Conclusions: Despite encouraging observations from experimental studies, the results of RCTs are less encouraging and do not allow for the formulation of recommendations concerning the use of supplements in the treatment of endometriosis
View Original PubMed Abstract ↓

Background: There is a growing number of studies suggesting the effectiveness of dietary supplements in preventing and treating endometriosis. It has been suggested that deficiencies in vitamins D and E as well as zinc are associated with the increased risk of endometriosis development. Beneficial effects of magnesium, curcumin, resveratrol and epigallocatechin-3-gallate were found in experimental animal studies. A reduction in pain related to endometriosis was shown in women using omega-3 and alpha-lipoic acid. Meanwhile, decreasing endometriotic lesion size after the supplementation of omega-3, N-acetylcysteine, vitamin C and epigallocatechin-3-gallate was observed in animal and human studies. Thus, the aim of this critical review was to summarize the available data describing the effects of dietary supplements used in the treatment of endometriosis. Material and Methods: The PubMed, Embase, Cochrane, and Web of Science databases were searched for related studies until 15 December 2025. Finally, 34 studies were included in the synthesis. Results: Of these 34 studies, only 23 were randomized, placebo-controlled trials. There have been no RCTs evaluating the effectiveness of vitamin E, zinc, alpha-LA, EGCG and DIM in the treatment of endometriosis. Single studies evaluating the effectiveness of vitamin C, magnesium, resveratrol, NAC and PEA with PLD have not confirmed it. Meanwhile single studies evaluating the effectiveness of selenium, propolis and quercetin have confirmed it. Of the four studies assessing the effectiveness of vitamin D, two confirmed it and two did not; of the two studies assessing probiotics, one confirmed its effectiveness and one did not; of the two studies assessing curcumin, one confirmed its effectiveness and one did not; and of the three studies assessing omega-3, two confirmed its effectiveness and one did not. All four RCTs assessing the combination of vitamins C and E confirmed their effectiveness. Conclusions: Despite encouraging observations from experimental studies, the results of RCTs are less encouraging and do not allow for the formulation of recommendations concerning the use of supplements in the treatment of endometriosis

03
CLINICAL STUDY Nutrients (2026) PMID: 41901082 ↗
Dietary Bioactives in Alzheimer's Disease: A Critical Appraisal of Clinical Trials and Future Nutritional Strategies.
Clinical Trial Synthesis 2026 Meta-Analysis published in Nutrients. Key conclusion: Conclusions: Current clinical evidence does not support high-dose DBs supplementation as an effective treatment for AD.
View Original PubMed Abstract ↓

Background: Alzheimer's disease (AD) remains a major public health challenge. Observational associations between dietary patterns and reduced dementia risk have prompted investigations of dietary bioactives (DBs) as cognitive nutraceuticals. Methods: This critical narrative review examines interventional trials for nine prominent DBs relevant to AD: docosahexaenoic acid (DHA), curcumin, resveratrol, epigallocatechin gallate (EGCG), nicotinamide riboside (NR), tricaprilin, vitamin E (α-tocopherol), cannabinoids, and NIC5-15 (D-pinitol). Trials were identified through ClinicalTrials.gov (search date: December 2024) and supplemented by PubMed searches for published results. Data were extracted on trial phase, design, cognitive/functional endpoints, biomarker outcomes, and development status. Findings are synthesized qualitatively; no formal meta-analysis or risk of bias assessment was conducted. Results: None of the nine bioactives demonstrated consistent cognitive efficacy in AD. Phase III trials of DHA, curcumin, and tricaprilin did not meet primary cognitive endpoints. Resveratrol reduced CSF Aβ40 without cognitive benefit. Cannabinoids improved behavioral symptoms but showed no measurable cognitive effects. High-dose vitamin E slowed functional decline, while cognition remained unchanged. In contrast, trials in preclinical or at-risk populations reported preliminary cognitive signals for EGCG and biomarker engagement for NR, suggesting potential for early intervention. Conclusions: Current clinical evidence does not support high-dose DBs supplementation as an effective treatment for AD. Predominantly negative late-phase findings highlight limitations, with potential contributors including limited bioavailability, late intervention, insufficient target engagement, and biological heterogeneity. Future research may benefit from early biomarker-defined populations, optimized formulations, multi-nutrient or dietary approaches, and precision nutrition strategies considering genetic risk and baseline nutrient status. DBs may be better positioned for prevention or early-stage intervention rather than late-stage therapy.

04
RANDOMIZED TRIAL (RCT) Nutrients (2026) PMID: 41830024 ↗
A Randomized Controlled Trial to Determine the Effects of Curcumin and Epigallocatechin-3-Gallate Supplementation on Serum Brain-Derived Neurotrophic Factor and Mood Disturbance in Adults.
Clinical Trial Synthesis 2026 Randomized Controlled Trial (RCT) published in Nutrients involving n = 64 participants; statistical significance reported at p = 0.05. Key conclusion: Observed improvements across both groups suggest that behavioral or lifest
View Original PubMed Abstract ↓

Background/Objectives: Mood disorders like depression, anxiety, and stress have increased steadily among adults, with growing interest in non-pharmaceutical treatments to improve symptomology. Epigallocatechin-3-gallate (EGCG) and curcumin are polyphenols with evidence to support their positive impacts on mood disorder symptomology and potential mood-associated biomarkers like brain-derived neurotrophic factor (BDNF). This study examined the effects of combined EGCG and curcumin supplementation on mood disturbance symptomology and serum brain-derived neurotrophic factor in adults. Methods: An 8-week randomized double-blinded placebo-controlled trial was conducted in adults (n = 64, 18-50 years old). Participants were randomized to a supplement group (n = 32; 350 mg EGCG and 1330 mg curcumin daily) or a matched placebo group (n = 32). Mood disturbance (DASS-21, GAD-7), sleep disturbance (GSAQ), and physical activity (IPAQ) were assessed at baseline, Week 4, and Week 8. Anthropometric measures, 24 h diet recalls, and fasted blood samples for serum BDNF were collected at baseline and Week 8. A multivariate ANOVA evaluated primary outcomes (DASS-21 composite score and BDNF), followed by repeated measures ANOVA for secondary outcomes (p < 0.05). Results: Significant improvements were observed across all participants for mood (DASS-21 composite and subscales, GAD-7, p < 0.001 for all), sleep (p < 0.001), and physical activity (p < 0.01), with no significant difference between supplement and placebo groups. Mean serum BDNF increased in both groups, but neither were statistically significant with no group-by-time interactions. Sugar intake (g/kg body weight) was positively correlated with mood symptoms at Week 8 in the supplement group. Baseline fruit and vegetable intake was associated with mood symptom severity at select time points; however, dietary changes during the intervention were not significantly related to changes in mood outcomes. Conclusions: Combined EGCG and curcumin supplementation did not show additional benefits beyond placebo for mood disturbance or serum BDNF over eight weeks. Observed improvements across both groups suggest that behavioral or lifest

05
RANDOMIZED TRIAL (RCT) Nutrients (2026) PMID: 41515260 ↗
Effects of Green Tea Extract Supplementation on Inflammatory Cytokines Among Postmenopausal Women with Overweight or Obesity-A Secondary Analysis of a Randomized Controlled Trial.
Clinical Trial Synthesis 2026 Randomized Controlled Trial (RCT) published in Nutrients involving n = 97 participants; statistical significance reported at p = 0.24. Key conclusion: Conclusions: A high-dose GTE supplement consumed daily for one year did not significantly decrease inflammatory cytokines among postmenopausal women with overweight or obesity.
View Original PubMed Abstract ↓

Background: Excess adiposity induces low-grade inflammation, including increased C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α). Green tea contains epigallocatechin gallate (EGCG), with anti-inflammatory potential. EGCG metabolism is influenced by individual variations in catechol-O-methyltransferase (COMT) genotypes. Objectives: To evaluate the effect of green tea extract (GTE) supplementation on circulating inflammatory cytokines among postmenopausal women with overweight or obesity and differing COMT genotypes. Methods: This study is a secondary analysis of a random subset (N = 97) from the Minnesota Green Tea Trial (MGTT), a randomized double-blinded placebo-controlled trial. The intervention was a high-dose GTE supplement (843 ± 44 mg EGCG/day) or placebo for 1 year. Serum CRP, TNF-α, and IL-6 were measured at 0, 6, and 12 months. Absolute changes in inflammatory cytokines from baseline to month 12 were evaluated using linear mixed-effects models adjusted for age, body mass index (BMI), smoking history, physical activity, and vitamin supplement use. Results: The changes from month 0 to month 12 were not statistically different between the groups for any of the inflammatory cytokines measured. The overall treatment effect was not statistically significant for CRP (p = 0.24), IL-6 (p = 0.59), TNF-α (p = 0.36), nor for the interaction between treatment group and time (all Ps > 0.40). There was no significant interaction between treatment group and COMT genotype for the stated markers. Conclusions: A high-dose GTE supplement consumed daily for one year did not significantly decrease inflammatory cytokines among postmenopausal women with overweight or obesity. The COMT genotype did not modify the effects of GTE supplementation on inflammatory cytokines. Future studies with a larger sample size among those at high risk of systemic inflammation are warranted.

06
CLINICAL STUDY Nutrition research and practice (2025) PMID: 41098404 ↗
Anti-fatigue and antioxidative effects of amino acid (Leu, Gln, Cys)-EGCG complex via NRF2 and PGC-1α pathways: insights from cellular, animal, and pilot clinical studies.
Clinical Trial Synthesis 2025 Clinical Study published in Nutrition research and practice. Key conclusion: CONCLUSION: The AA-EGCG mixture enhances mitochondrial biogenesis and antioxidant capacity by activating the NRF2 and PGC-1α pathways, improving physical performance and reducing fatigue.
View Original PubMed Abstract ↓

BACKGROUND/OBJECTIVES: Fatigue is closely associated with an impaired mitochondrial function, oxidative stress, and inefficient energy metabolism, all contributing to reduced physical performance. Nutritional strategies targeting mitochondrial biogenesis and antioxidant defense may help alleviate fatigue and enhance endurance. This study examined the anti-fatigue and antioxidant effects of an amino acid (AA)-epigallocatechin gallate (EGCG) mixture comprised of 3 AAs (cysteine [Cys], glutamine [Gln], and leucine [Leu]) and EGCG on mitochondrial biogenesis, oxidative stress mitigation, and physical performance enhancement. MATERIALS/METHODS: C2C12 myoblasts were treated to assess mitochondrial biogenesis-related gene expression and oxidative stress markers. Animal studies measured the swimming endurance, glycogen, adenosine triphosphate (ATP), and serum parameters. A pilot clinical trial evaluated the blood glucose, lactate, and serum enzyme levels post-exercise. RESULTS: In cellular experiments, a 1:1:3 ratio of the AA mixture (Cys, Gln, and Leu) with EGCG enhanced mitochondrial biogenesis-related gene expression (AMP-activated protein kinase, sirtuin 1, and peroxisome proliferator-activated receptor gamma coactivator 1α [PGC-1α]) and reduced the oxidative stress markers (reactive oxygen species and malondialdehyde [MDA]). Animal studies revealed significant increases in swimming endurance, elevated glycogen and ATP levels, and reduced serum fatigue markers (creatine phosphokinase, lactate dehydrogenase, and blood nitrogen). Furthermore, nuclear factor erythroid 2-related factor 2 (NRF2) and PGC-1α expression was significantly upregulated in the gastrocnemius muscle, supporting enhanced mitochondrial function. In addition, the antioxidant effects were observed with reduced MDA levels in liver tissue. Clinical trial data showed improved blood lactate clearance and higher post-exercise blood glucose levels in the AA-EGCG group compared to the placebo group. CONCLUSION: The AA-EGCG mixture enhances mitochondrial biogenesis and antioxidant capacity by activating the NRF2 and PGC-1α pathways, improving physical performance and reducing fatigue. This study highlights i

07
META-ANALYSIS Clinical therapeutics (2025) PMID: 40885603 ↗
Effect of Epigallocatechin Gallate on Glycemic Index: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
Clinical Trial Synthesis 2025 Meta-Analysis published in Clinical therapeutics; statistical significance reported at p = 0.029 (MD -0.18). Key conclusion: IMPLICATIONS: Although EGCG supplementation is associated with improvements in some glycemic parameters, these effects especially for HbA1c and fasting insulin are modest and may not be clinically meaningful for most population.
View Original PubMed Abstract ↓

PURPOSE: Epigallocatechin gallate (EGCG), a major catechin found in green tea, has been suggested to influence glycemic control. This systematic review and meta-analysis aim to evaluate the effects of EGCG on the glycemic index (GI) and related glycemic parameters. METHODS: Using predefined keywords, online databases (PubMed, Scopus, Web of Science Core Collection, and Google Scholar) were searched for relevant studies, published from inception up to May 2024. Initially 1994 studies were obtained out of which 41 RCTs were decided to be included for further analyses. FINDINGS: The meta-analysis demonstrated that EGCG supplementation led to statistically significant, but modest, reductions in fasting blood glucose (FBG), HbA1c, and HOMA-IR. Notably, the reduction in HbA1c (WMD: -0.18%, 95% CI: -0.35, -0.02; P = 0.029) was small and may not equate to clinically meaningful benefits for all populations. Furthermore, the effect on fasting insulin was not statistically significant (WMD: -0.50; 95% CI: -1.46, 0.47; P = 0.313), indicating a lack of robust or consistent impact on this parameter across studies. IMPLICATIONS: Although EGCG supplementation is associated with improvements in some glycemic parameters, these effects especially for HbA1c and fasting insulin are modest and may not be clinically meaningful for most population. Therefore, current evidence does not strongly support the use of EGCG as a stand-alone intervention for glycemic control.

08
SYSTEMATIC REVIEW Nutrients (2025) PMID: 40290044 ↗
Impact of Dietary Supplements on Clinical Outcomes and Quality of Life in Patients with Breast Cancer: A Systematic Review.
Clinical Trial Synthesis 2025 Systematic Review published in Nutrients. Key conclusion: Conclusions: These findings highlight the potential of specific dietary supplements to improve various aspects of breast cancer care.
View Original PubMed Abstract ↓

Background: This systematic review aimed to evaluate the efficacy and safety of dietary supplements in breast cancer patients, focusing on their impact on clinical outcomes, treatment-related side effects, and therapy adherence. Methods: Only RCTs investigating the effects of various orally administered supplements in adult breast cancer patients were included. Well-defined substances like vitamins, minerals, antioxidants, and specific herbal extracts were explored. The review excluded studies solely based on dietary interventions or non-supplemental approaches. The primary outcome assessed was quality of life. Secondary outcomes included disease-free survival, overall survival, tumor response, and biomarkers indicative of disease progression. Results: A total of 45 randomized controlled trials (RCTs) were included in this systematic review. Overall, supplementation was not associated with serious adverse events in the included trials. Vitamin D supplementation showed promise in some studies, with potential immunomodulatory and antioxidant effects, particularly when combined with other interventions. Omega-3 fatty acids and beta-glucan demonstrated potential in alleviating certain symptoms and improving quality of life. Studies on amino acids like acetyl-L-carnitine and L-arginine also yielded mixed results. Beta-glucan exhibited potential for immune-enhancing effects, while melatonin and creatine showed limited or no benefit for fatigue or muscle strength. Herbal extracts, including silymarin, curcumin, and EGCG, had varied effects. Curcumin studies presented mixed results. Silymarin showed potential for hepatoprotective effects. Conclusions: These findings highlight the potential of specific dietary supplements to improve various aspects of breast cancer care. However, the evidence is mixed across supplement types, and further research is needed to determine the most effective and safe approaches.

09
CLINICAL STUDY Dermatology and therapy (2025) PMID: 40246799 ↗
Prospective Comparative Study of an Oral Synbiotic and a Myoinositol-Based Herbal Supplement in Modifying Hormone Levels and the Gut Microbiome in Non-cystic Acne.
Clinical Trial Synthesis 2025 Randomized Controlled Trial (RCT) published in Dermatology and therapy; statistical significance reported at p = 0.0001. Key conclusion: The MBHS may act by reducing hormone levels of 17-OHP and androstenedione.
View Original PubMed Abstract ↓

INTRODUCTION: Acne pathogenesis is multifactorial, involving systemic factors including gut dysbiosis, hormones, and chronic inflammation. Probiotics, myoinositol, and plant-derived molecules may modulate acne by targeting these factors. The objective is to compare a synbiotic containing herbs against a myoinositol-based herbal supplement on how they influence acne, the gut microbiome, short chain fatty acids (SCFAs), and hormonal profiles. METHODS: This was an 8-week, randomized study involving 36 male and female patients aged 12 to 45 years with non-cystic acne. Subjects received either a synbiotic or a myoinositol-based herbal supplement (MBHS). Acne lesions were counted, stool samples were collected for gut microbiome and SCFA analyses, and hormone collections were performed at baseline, 4, and 8 weeks. RESULTS: Several gut bacteria increased by at least threefold at both week 4 and 8 in the synbiotic (Erysipelatoclostridium merdavium, Blautia argi, Faecalibacterium prausnitzii, Prevotella copri, Streptococcus sp001556435, Blautia sp900541955) and MBHS group (Megamonas funiformis, Ligilactobacillus ruminis, Prevotella ssp015074785, Prevotella copri, Gca-900199835 sp900176495). Acne lesion counts decreased significantly in both groups at week 4 (p < 0.0001) and week 8 (synbiotic, p < 0.0001; MBHS, p < 0.0001). There were significant and trending increases in stool and plasma SCFAs in both cohorts at week 4 and 8. After 8 weeks of MBHS, 17-OHP and androstenedione significantly decreased from 27.3 to 11.3 pg/ml (p = 0.001) and 94.9 to 68.0 pg/ml (p = 0.04), respectively. CONCLUSION: Both the synbiotic and MBHS improved gut health, augmented SCFAs, and reduced lesion counts in those with non-cystic acne. The MBHS may act by reducing hormone levels of 17-OHP and androstenedione. CLINICAL TRIAL REGISTRATION: www. CLINICALTRIALS: gov (NCT05919810). © 2025. The Author(s).

10
CLINICAL STUDY Clinical and translational science (2025) PMID: 40077973 ↗
Evaluating the Effect of Epigallocatechin Gallate (EGCG) in Reducing Folate Levels in Reproductive Aged Women by MTHFR and DHFR Genotype in Combination With Letrozole or Clomiphene.
Clinical Trial Synthesis 2025 Randomized Controlled Trial (RCT) published in Clinical and translational science involving n = 39 participants. Key conclusion: Our data suggest that in reproductive-age women, a 30-day course of EGCG 720 mg daily taken alone or in combination with clomiphene citrate or letrozole (for 5 days) is well-tolerated and is not associated with folate deficiency even in the presence of MTHFR and/or DHFR polymorph
View Original PubMed Abstract ↓

Previous epidemiological studies have suggested that green tea catechins, including Epigallocatechin-3-gallate (EGCG), the most abundant polyphenol in green tea, may be associated with reduced serum folate levels. This is of particular interest as women of childbearing age may be consuming EGCG from tea, dietary supplements, or involved in active clinical trials studying EGCG or green tea extract. EGCG was reported to shrink uterine fibroids in preclinical and clinical studies. This observation led to the development of a multicenter NICHD-funded clinical trial to evaluate the safety of EGCG for treating women with fibroids and unexplained infertility (NCT04177693). To answer the question of whether green tea extract standardized to EGCG led to a reduction in folate, 39 women aged ≥ 18 to ≤ 40 years, with/without uterine fibroids, were evaluated. These women were randomized to receive either EGCG, EGCG + clomiphene, or EGCG + letrozole for 30 days. A daily dose of 720 mg of highly characterized green tea extract containing EGCG was used. Participants were genotyped for polymorphisms at positions 677 and 1298 in MTHFR and for the -19 bp deletion polymorphism of DHFR. During the intervention with EGCG, folate levels remained in the normal range in all subjects. Our data suggest that in reproductive-age women, a 30-day course of EGCG 720 mg daily taken alone or in combination with clomiphene citrate or letrozole (for 5 days) is well-tolerated and is not associated with folate deficiency even in the presence of MTHFR and/or DHFR polymorphisms known to negatively impact folate synthesis. Trial Registration: Clinical trial: NCT01311869. © 2025 The Author(s). Clinical and Translational Science published by Wiley Periodicals LLC on behalf of American Society for Clinical Pharmacology and Therapeutics.

RELATED MONOGRAPHS

Related Monographs in This Category