Green tea extract, derived from the leaves of Camellia sinensis, is a concentrated source of powerful antioxidants, particularly catechins like epigallocatechin gallate (EGCG). These compounds help combat oxidative stress, protecting cells from damage and promoting overall health.
Renowned for its health benefits, green tea extract supports weight management by enhancing metabolism and promoting fat oxidation. It also contributes to heart health by lowering cholesterol and reducing inflammation. Additionally, it helps regulate blood sugar levels and supports cognitive function, potentially protecting against age-related decline. These benefits make it a valuable addition to a balanced lifestyle.
Several studies showed chronic green tea extract, with or without caffeine, may aid weight loss by increasing fat oxidation and energy expenditure¹. Meanwhile, a 12-week high-dose green tea extract treatment resulted in significant weight loss and reduced waist circumference in women with central obesity, potentially due to the inhibition of ghrelin secretion and increased adiponectin levels. Adiponectin is a hormone that helps regulate metabolism, enhance fat burning, and improve insulin sensitivity, which may contribute to weight loss. The study showed high-dose green tea extract (856.8mg daily) significantly reduced body weight, BMI, and waist circumference in obese women after 12 weeks².
Green tea consumption has been linked to significant reductions in total cholesterol and LDL cholesterol levels in both healthy individuals and those at risk of cardiovascular issues, supporting its positive impact on lipid profiles³,⁴. A comprehensive literature review found significant variation in the doses of green tea catechins across studies, ranging from 150mg to 2500mg per day. This wide range made it difficult to determine the ideal dose for improving blood lipid profiles, as there is no consensus on the optimal quantity³. Studies also suggest that green tea extract enhances LDL-receptor binding activity and increases LDL-receptor protein levels, potentially improving cholesterol clearance⁵.
Green tea supplementation significantly improves blood sugar profile across various clinical trials⁶. Research suggests that green tea extract may help manage type-2 diabetes by increasing serum adiponectin levels and improving weight, BMI, and HbA1C in individuals with T2DM. The study showed patients with type-2 diabetes who consumed 1500mg of green tea daily for 8 weeks demonstrated notable improvements in glycemic response⁷.
Studies indicate that individuals with obesity and high blood pressure experienced significant reductions in blood pressure, triglycerides, total cholesterol, and LDL cholesterol after green tea extract supplementation compared to a placebo group. The study using a dosage of 379mg of green tea extract daily for three months showed a reduction in blood pressure⁸. The antioxidants in green tea also may help reduce inflammation and support blood pressure regulation⁹.
The antioxidants in green tea extract, have been shown to protect brain cells from oxidative stress¹⁰. This protection may help reduce the risk of cognitive decline and neurodegenerative diseases like Alzheimer’s and Parkinson’s¹⁰,¹¹. Study found green tea extract improve cognitive function, particularly working memory, by enhancing brain plasticity in parieto-frontal connections. The study found that consuming 27.5g of green tea extract improved brain connectivity and working memory in healthy individuals¹².
Several studies suggest green tea extract supplementation can reduce liver enzymes in patients with NAFLD. Research indicates that green tea extract could be a potential treatment for improving serum liver enzyme levels in individuals with NAFLD¹³,¹⁴. In a study with 80 NAFLD patients (ages 20–50), participants who received 500mg of green tea extract daily for 90 days showed a decrease in liver enzymes¹³.
Green tea extract is generally safe. However, it may cause caffeine-related side effects such as anxiety, tremors, and sleep disturbances, especially in sensitive individuals or when taken in large doses. The specific dosage at which these side effects occur can vary based on individual sensitivity and the concentration of the extract. It is advisable to start with a lower dose and monitor your body’s response. Excess consumption may also lead to liver issues, presenting symptoms like jaundice (yellowing of the skin and eyes), nausea, and stomach pain. If these symptoms
occur, discontinue use and consult a healthcare provider¹⁵.
There is no standard dosage for green tea extract supplements, and the dosage may vary depending on the the safe intake level for solid extracts is 338mg EGCG content per day, while for beverages, an Observed Safe Level (OSL) of 704mg EGCG per day has been suggested¹⁷.
Blood Thinners (eg. Warfarin):
Green tea extract may affect blood clotting process.
Theophylline:
Combination of green tea extract and theophylline may reduce its effectiveness.
Caffeine:
Additional caffeine from other products (e.g. coffee, tea, soft drinks, chocolate) as it may increase heart rate and
Green tea extract is generally safe. However, it may cause caffeine-related side effects such as anxiety, tremors, and sleep disturbances, especially in sensitive individuals or when taken in large doses. The specific dosage at which these side effects occur can vary based on individual sensitivity and the concentration of the extract. It is advisable to start with a lower dose and monitor your body’s response. Excess consumption may also lead to liver issues, presenting symptoms like jaundice (yellowing of the skin and eyes), nausea, and stomach pain. If these symptoms
occur, discontinue use and consult a healthcare provider¹⁵.
There is no standard dosage for green tea extract supplements, and the dosage may vary depending on the the safe intake level for solid extracts is 338mg EGCG content per day, while for beverages, an Observed Safe Level (OSL) of 704mg EGCG per day has been suggested¹⁷.
Blood Thinners (eg. Warfarin):
Green tea extract may affect blood clotting process.
Theophylline:
Combination of green tea extract and theophylline may reduce its effectiveness.
Caffeine:
Additional caffeine from other products (e.g. coffee, tea, soft drinks, chocolate) as it may increase heart rate and
The material is prepared for informational purposes only and should not be construed as a piece of personal medical advice. Owing to each person’s varying health needs, a physician should be consulted before acting on any information provided in this material. Although every effort is made to ensure that this material is accurate, it is compiled for internal use only and should not be considered definitive. Neither VitaHealth nor its employees, or information providers shall be responsible or liable for any errors, inaccuracies, or other defects in the information contained in this publication.
Hop extract, is the extract of hops which in turn are the dried, flowering parts of the hops plant (Humulus lupulus). This plant is twining
