Most people have formed the opinion that eating foods whole and in natural form is better than taking them in capsule form as food supplements.
In fact which of these is best varies from one food to another.
Many foods that are sold as extracts in capsule form are actually better for you than taking the whole food, because the nutrients are bound into the food so tightly that most are not released during digestion.
Many common nutrients are better absorbed from supplements. Vitamin K, folic acid and chlorophyll are examples. Other nutrients such as lycopene are better absorbed from tomatoes than from supplements.
Green tea falls into the latter category, and the strongest health benefits come from supplements. But this does not prevent green tea from rightly claiming to be one of the healthiest of all food stuffs.
Many of the benefits of green tea can be derived from drinking a few cups a day, and the largest studies into the effects of green tea have looked at the tea itself rather than the extract.
But if you are after the weight loss benefits specifically, evidence shows that you are better using capsules, as these deliver a much larger dose of the bioactive compounds in green tea. A large dose is necessary for the weight loss benefits, for other health benefits smaller doses are sufficient and these can be derived from drinking the tea alone.
But the antioxidant properties are also higher when using the capsules. Studies have shown that 60% more ECGC polyphenols and 90% more ECG polyphenols are absorbed from green tea extract capsules than from green tea beverages containing the same amount of nutrients.
Again, the strongest protection against cancer and heart disease from green tea comes drinking 10 cups or more a day. Most people will not drink this much. To derive the strongest health benefits, taking capsules of green tea extract is more convenient.
But drinking a smaller number of cups per day will still provide a percentage of the antioxidants, and a percentage of the cancer and heart disease protection that the capsules provide.
In short, both drinking green tea and taking the extract in capsules are extremely healthy. But the capsules are healthier than drinking the tea.
Useful references
Henning, S. M., Niu, Y., Lee, N. H., Thames, G. D., Minutti, R. R., Wang, H., … & Heber, D. (2004). Bioavailability and antioxidant activity of tea flavanols after consumption of green tea, black tea, or a green tea extract supplement. The American journal of clinical nutrition, 80(6), 1558-1564.