I am a 36 year old woman and hardcore fitness and nutrition fanatic. I know exactly what to look for in a collagen supplement and Yonder collagen, scores in all the right areas. They have a clean, diverse amino acid profile from the most potent and pure hydrolyzed bovine collagen type I & III. I take anywhere from 5-10 unflavored grams a day, mostly in my smoothies and tea. This definitely works for me, both internally and externally. My hair and skin look great and I am as flexible, as I was at 19.