I have been taking Serracor NK & Serra-RN80 for about 3 years now. It has definitely helped me and I feel so much better. About 4 years ago I was told something that scared me to death. Now I atribute this success to the effectiveness of Serracor-NK & Serra RN80 in keeping me healthy. I am still able to do the 6 min walk succesfully and live a more fullfilled life.