Is green coffee bean extract helpful for weight loss ? diabetes, cholesterol...

Better options: Green coffee or tea extract may help but there is no valid scientific data to support these claims. For the three things you mentioned, exercise, healthy diet, and if needed, medications are more effective. Weight loss, through exercise and diet is the best approach.

Not really.: Although I can't say that for you it would have no effect, general studies have shown that there's no magic in green coffee bean extract for weight loss or for the medical conditions you mentioned. It might lighten your wallet, but that's about it.