Green tea extract, derived from the leaves of Camellia sinensis, is a popular supplement known for its antioxidant, anti-inflammatory, and weight management properties. It is rich in catechins, primarily epigallocatechin gallate (EGCG), which is responsible for most of its therapeutic effects. Although green tea extract has been widely consumed in its natural form for centuries, its concentrated extract has gained attention in clinical studies for its role in supporting cardiovascular health, aiding weight management, and potentially reducing cancer risk. While green tea extract has not received direct FDA approval as a pharmaceutical drug, it is recognised as Generally Recognized as Safe (GRAS) for use in supplements and beverages. Clinical trials evaluating its efficacy in managing obesity and cardiovascular health have shown promising outcomes.

Green tea extract is commonly used as a dietary supplement for the following FDA-approved and widely acknowledged purposes:

• Promoting weight loss and fat metabolism
• Supporting cardiovascular health by lowering LDL cholesterol
• Reducing oxidative stress and inflammation
• Enhancing cognitive function and focus
• Improving skin health due to its antioxidant properties

Green tea extract is available in various forms, including capsules, tablets, powders, and liquid formulations. The typical dosage ranges from 250 mg to 500 mg of standardised extract (containing 50-90% catechins) per day. It is generally recommended to take green tea extract with food to minimise potential gastrointestinal discomfort. Higher doses should be taken under medical supervision to avoid adverse effects.

Common Side Effects:

• Nausea or stomach discomfort
• Headache or dizziness
• Increased heart rate or palpitations
• Insomnia or restlessness
   

Serious Side Effects:

• Hepatotoxicity (rare but possible with high doses)
• Increased bleeding risk in individuals taking anticoagulants
• Severe gastrointestinal disturbances in sensitive individuals

• Drug Interactions: May interact with blood thinners (warfarin), increasing bleeding risk.
• Caffeine Sensitivity: Individuals sensitive to caffeine may experience anxiety, palpitations, or insomnia.
• Iron Absorption: Can interfere with iron absorption; avoid taking with iron supplements or iron-rich meals.
• Liver Toxicity: Excessive consumption (>800 mg/day) has been linked to rare cases of hepatotoxicity.
• Pregnancy and Lactation: Not recommended due to potential risks associated with high caffeine intake.

Green tea extract should be used with caution in individuals with pre-existing conditions such as hypertension, heart disease, or anxiety disorders due to its caffeine content. To minimise the risk of liver toxicity, it is advisable to stick to recommended doses and avoid prolonged use of high concentrations. Those with anaemia or gastrointestinal conditions should take it between meals to prevent interference with nutrient absorption. If any adverse reactions occur, discontinuation and consultation with a healthcare provider are advised.

For optimal benefits, green tea extract should be taken with meals to reduce gastrointestinal discomfort. Those using it for weight management should combine it with a healthy diet and regular exercise. Individuals with underlying health conditions, especially liver disorders or cardiovascular issues, should consult a healthcare provider before starting supplementation. Avoid exceeding recommended doses to prevent potential side effects, especially liver-related issues.

1. https://www.nccih.nih.gov/health/green-tea
2. https://www.tandfonline.com/doi/abs/10.1080/07315724.2006.10719518
3. https://www.mdpi.com/1422-0067/21/5/1744
4. https://www.sciencedirect.com/science/article/abs/pii/009174359290041F

This information is for educational purposes only and should not be considered medical advice. Consult your healthcare provider before starting any new supplement, especially if you have existing health conditions or are taking medications.