I was very impressed with this product. I did gain up to 5kg (muscle mass) in about 2 months. My strength also improved. But it was not the product alone. It was a good diet, high in protein, training hard and religiously combined with this product that made the difference. Taking this (or any supplement) without the proper diet and hard work will not bring results. I would strongly recommend this to any serious "bodybuilder". (Posted on 6/28/09)