Benefits
Weight loss alongside a hypocaloric diet (Di Pierro 2009, blinding not stated)
In a 90-day controlled trial in 100 obese adults, 300 mg/day Greenselect Phytosome plus a hypocaloric diet was reported to produce about 14 kg of weight loss versus about 5 kg on the diet alone, with BMI falling in step. Read the design alongside the number: the paper describes a controlled trial and does not state that it was blinded, so participants and staff may have known who was taking the extract, which matters a great deal in a diet study. This is the largest of the three trials but the weakest design, and a 14 kg loss in 90 days is a very large effect for an unblinded study. The comparison was against diet alone, not against a standard green tea extract, so the trial cannot show that phytosome absorption is why the groups differed.
Cardiometabolic markers in a registry study
In a controlled registry study of 50 adults with borderline metabolic syndrome and raised oxidative stress markers, 150 mg/day for 24 weeks was followed by 68 percent of the treated group no longer meeting the metabolic syndrome profile, against 20 percent of controls, with movement in weight, blood lipids, blood pressure and waist circumference. A registry study is neither blinded nor randomized: participants and investigators know who is taking what, and people who choose a supplement may differ from those who do not in diet, activity and motivation. Read this as a signal worth testing properly, not as evidence that the ingredient treats or reverses a diagnosed condition.
EGCG bioavailability claim, not established by the references here
This comparison is not established by the references on this page. The only absorption reference cited here is a 1998 study of catechin absorption and plasma antioxidant status that predates the Greenselect Phytosome formulation, so it cannot show that the phytosome more than doubles peak plasma EGCG at an equal 240 mg catechin dose. The underlying problem is real: EGCG is poorly absorbed from ordinary green tea extract, and complexing catechins with phospholipid is a reasonable way to try to improve that. But the size of the improvement quoted here is not backed by any citation on this page, so a reader has no way to check it.
Post-menopausal metabolism claim (uncited)
Nothing cited on this page supports this. The respiratory quotient, resting energy expenditure, carbohydrate oxidation and lipid oxidation results described for sedentary post-menopausal women at 150 mg/day do not come from any of the four references listed here, so a reader has no way to check who was studied, how many, for how long, or whether the changes were statistically significant. Treat it as unverified until a citation is attached.
Caffeine-free for evening/sensitive use
≤0.1% caffeine specification (vs 1-5% in non-decaffeinated green tea extracts) makes Greenselect Phytosome suitable for evening dosing schedules and caffeine-sensitive populations. The low caffeine figure is a specification of the raw material rather than a measured outcome: none of the cited trials tested sleep, alertness or jitteriness.
Weight maintenance after weight loss (the one double-blind trial, 40 women)
This is the only double-blind placebo-controlled trial on the page, and it is also the smallest: 40 obese women, 20 per group, taking 150 mg twice daily together with 15 mg piperine for 3 months following a period of weight loss. The treated group lost a further 1.0 kg on average while the placebo group gained 0.3 kg, and 75 percent versus 45 percent held on to at least 5 percent of their earlier weight loss at the one-month mark. Two things a buyer should weigh: the difference between the groups is only about 1.3 kg, and the capsules also contained piperine, so the trial cannot tell you how much of the result belongs to the catechins. It is still the best-designed evidence here.
Mechanism of action
Phytosome bioavailability enhancement
Phytosome® technology complexes EGCG and other catechins with phosphatidylcholine, creating amphipathic structures that improve absorption through the intestinal epithelium. No head-to-head pharmacokinetic study appears among the references on this page, so the size of any absorption advantage over unformulated extract is not documented here.
Catechin-COMT inhibition (norepinephrine extension)
EGCG and other catechins inhibit catechol-O-methyltransferase (COMT), the enzyme that degrades norepinephrine. Extended norepinephrine action prolongs sympathetic-driven thermogenesis and lipolysis. Without caffeine, this effect is milder but free of caffeine-related side effects.
Fat oxidation upregulation
Catechins upregulate fatty acid oxidation enzymes (CPT1, ACO) in skeletal muscle and liver, supporting use of stored fat for energy. Combined with the thermogenic effect, this shifts metabolism toward fat utilization.
Antioxidant protection
Catechins are potent antioxidants — EGCG has one of the highest antioxidant capacities of all polyphenols. Antioxidant capacity of this kind is measured mostly in test-tube assays and does not by itself tell you what happens in a person. The registry study enrolled people selected for raised oxidative stress, and the 1998 human study measured plasma antioxidant status after catechin intake, but that 1998 study predates the phytosome formulation and the registry study was not blinded. The antioxidant category on this page is genuinely measured, but the evidence behind it is thin.
Clinical trials
90-day clinical trial in 100 obese patients comparing 300 mg/day Greenselect Phytosome + hypocaloric diet vs hypocaloric diet alone.
100 obese patients
90-day clinical trial in 100 obese patients comparing 300 mg/day Greenselect Phytosome + hypocaloric diet vs hypocaloric diet alone. The phytosome group lost about 14 kg against about 5 kg in the diet-alone group, with a corresponding fall in BMI. Design caveat that belongs next to that number: the paper describes a controlled trial and does not state that it was blinded, so participants and staff may have known their allocation, and expectation effects are hard to rule out in a diet study. The comparison arm was diet alone, not a standard green tea extract, so the study cannot show that phytosome absorption is the reason for the difference, nor can it be compared with what standard extracts achieve. Reference: PMID 19594224, Di Pierro 2009, whose lead author is affiliated with Velleja Research.
Controlled registry study in 50 asymptomatic borderline metabolic syndrome subjects with increased oxidative stress.
50 asymptomatic adults with borderline metabolic syndrome and raised oxidative stress markers, followed for 24 weeks.
Controlled registry study in 50 asymptomatic borderline metabolic syndrome subjects with increased oxidative stress. 150 mg/day Greenselect Phytosome (MonCam formulation) for 24 weeks. Outcome: 68% of treatment-arm subjects exited the metabolic syndrome profile vs 20% in controls. Improvements in weight, blood lipids, blood pressure, and waist circumference. Published in Evidence-Based Complementary and Alternative Medicine in 2013 (PMID 24348726). No side effects were reported. Because a registry study is neither blinded nor randomized, it cannot rule out that people who chose the supplement also changed diet or activity more than the controls did.