Table 1.
Characteristics of the included studies.
Source: Authors, 2026
| Author, year (study design, Country) | Age (years) | N |intervention/control | Mean age (years) ± SD (intervention/control) | Duration (months) | Type of intervention | Dose/frequency/route of administration | Type of control used | Conclusion | ||
|---|---|---|---|---|---|---|---|---|---|---|
| Samavat et al.8] (RCT, USA) | 50–70 | 463 / 473 |
60.02 ± 4.89/ 59.65 ± 5.04 |
12 | Capsules containing a decaffeinated green tea extract (GTE) catechin complex | Decaffeinated GTE was administered for 12 months (1.315 mg of catechins/day; 843 mg of EGCG), in two capsules after breakfast and two after dinner. | Placebo capsules composed mainly of maltodextrin and cellulose. | Supplementation with GTE significantly reduced total cholesterol and LDL, particularly in individuals with elevated baseline levels. | ||
|
Dostal et al. [12] (RCT, USA) |
50–70 | 117 / 120 |
60.09 ± 0 0.45/ 60.6 ± 0.47 |
12 | Capsules containing a decaffeinated green tea extract (GTE) catechin complex | Each capsule contained 328 ± 30 mg of catechins (211 ± 11 mg of EGCG), for a total daily intake of 1.315 ± 116 mg of catechins (843 ± 44 mg of EGCG), equivalent to five 240-mL cups of green tea, administered as two capsules in the morning and two in the evening. | Placebo capsules containing 816 mg of maltodextrin, 808 mg of cellulose, and 8 mg of magnesium stearate as a flow agent. | Decaffeinated GTE reduced fasting insulin without altering body weight or hormonal levels; high COMT activity may increase insulin and reduce adiponectin. | ||
|
Dostal et al. [13] (RCT, USA) |
50–70 | 61 / 60 |
60.7 ± 0.60/ 60.0 ± 0.65 |
12 | Capsules containing a decaffeinated green tea extract (GTE) catechin complex | Decaffeinated GTE: 1.315 ± 116 mg/day of catechins (843 ± 44 mg of EGCG), equivalent to approximately five 240-mL cups of green tea, administered as two capsules in the morning and two in the evening. | Placebo capsules containing 816 mg of maltodextrin, 808 mg of cellulose, and 8 mg of magnesium stearate as a flow agent. | GTE did not reduce total adiposity or improve BMD, but may benefit the reduction of gynoid fat in women with higher BMI. | ||
|
Tadayon et al. [14] (RCT, Iran) |
45–60 | 39 / 40 |
53.7 ± 4.1/ 52.9 ± 3.6 |
1 | Green tea capsules | Green tea extract capsules: 400 mg per capsule (40–47 mg of polyphenols). Taken twice daily, after breakfast and dinner, for 4 weeks. | Placebo capsules containing starch and with an appearance similar to the green tea capsules. | GTE reduced total cholesterol, LDL, and triglycerides in postmenopausal women with mild lipid abnormalities, without significant adverse effects. | ||
| Rondanelli et al. [15] (RCT, Italy) | Not reported | 14/14 |
56.92 ± 5.7/ 60.57 ± 7.28 |
2 | Greenselect Phytosome® | GSP: 150 mg per tablet; 2 tablets/day (before lunch and before dinner), standardized to ≥ 19% catechins, ≥ 13% EGCG, and ≤ 0.1% caffeine. | Identical capsules containing microcrystalline cellulose, administered following the same instructions as the intervention group. | GSP supplementation improved lipolysis and reduced total, visceral, and abdominal fat in postmenopausal women with overweight or class I obesity. | ||
| Takahashi et al. [16] (RCT, Japan) | 62–73 | 11/11 |
66.6 ± 1.2/ 66.5 ± 0.6 |
1 | Catechin-rich green tea beverage | 350 mL/day of green tea, providing 615 mg of total catechins (125.9 mg EGCG) and 77 mg of caffeine, consumed with breakfast for 4 weeks. | 350 mL/day of a placebo beverage containing 92 mg of total catechins (15 mg EGCG) and 85.2 mg of caffeine, consumed with breakfast for 4 weeks. | Daily intake of catechin-rich green tea for 4 weeks reduced postprandial glucose and increased serum thioredoxin levels, without altering oxidative stress markers, in healthy postmenopausal women. | ||
|
Wu et al. [17] (RCT, USA) |
Not reported |
Group 400 EGCG: 37 Group 800 EGCG: 34/32 |
Group 400 mg EGCG: 59.6 years ± 6.36 Group 800 mg EGCG: 62.0 years ± 9.42/57.7 years ± 6.29 |
2 | Oral green tea extract supplement (PPE®) rich in EGCG. | Each capsule contained 200 mg of EGCG and other catechins; the 800 mg group took 4 capsules/day and the 400 mg group took 2 capsules/day for 2 months. | Placebo capsules contained pregelatinized starch, colloidal silicon dioxide, and magnesium stearate; administered in the same manner as the intervention groups | In postmenopausal women, green tea supplementation (400–800 mg/day for 2 months) reduced LDL and improved glycemic markers. | ||
SD: standard deviation; N: total number of participants; RCT: randomized clinical trial; USA: United States of America; GTE: Green Tea Extract Catechin Complex; LDL: low-density lipoprotein; EGCG: epigallocatechin-3-gallate; COMT: catechol-O-methyltransferase; mL: milliliters; mg: milligrams; BMI: body mass index; tab: tablet; PPE®: Polyphenon E®; BMD: bone mineral density; GSP: Greenselect® Phytosome®, a standardized green tea extract containing ≥ 19% catechins and ≥ 13% EGCG; p < 0.05 was considered statistically significant