Dietary supplements of the sort sold in stores are largely useless, and those that do provide benefits have a far smaller effect than either exercise or calorie restriction. Past the point of maintaining something along the lines of the Reference Daily Intake, such as is provided by a multivitamin produce, the balance of evidence suggests that most of these supplements do little for long term health and longevity. In many cases modest extension of life observed in some animal studies (not not in others) can be explained away by inadvertent calorie restriction or other artifacts. In the case of antioxidant supplements the current consensus is that these in fact harm beneficial processes that depend upon the use of low levels of oxidants as signals.
Here is a study to show that a range of currently popular supplements do absolutely nothing to various measures of human metabolism:
Dietary supplements are widely used for health purposes. However, little is known about the metabolic and cardiovascular effects of combinations of popular over-the-counter supplements, each of which has been shown to have anti-oxidant, anti-inflammatory and pro-longevity properties in cell culture or animal studies. This study was a 6-month randomized, single-blind controlled trial, in which 56 non-obese men and women, aged 38 to 55 yr, were assigned to a dietary supplement (SUP) group or control (CON) group, with a 6-month follow-up.
The SUP group took 10 dietary supplements each day (100 mg of resveratrol, a complex of 800 mg each of green, black, and white tea extract, 250 mg of pomegranate extract, 650 mg of quercetin, 500 mg of acetyl-l-carnitine, 600 mg of lipoic acid, 900 mg of curcumin, 1 g of sesamin, 1.7 g of cinnamon bark extract, and 1.0 g fish oil). Both the SUP and CON groups took a daily multivitamin/mineral supplement.
The main outcome measures were arterial stiffness, endothelial function, biomarkers of inflammation and oxidative stress, and cardiometabolic risk factors. Twenty-four weeks of daily supplementation with 10 dietary supplements did not affect arterial stiffness or endothelial function in nonobese individuals. These compounds also did not alter body fat measured by DEXA, blood pressure, plasma lipids, glucose, insulin, IGF-1, and markers of inflammation and oxidative stress. In summary, supplementation with a combination of popular dietary supplements has no cardiovascular or metabolic effects in non-obese relatively healthy individuals.