Consumer Reports reports that there is no science to support that collagen supplements result in smoother skin, shinier hair, stronger nails, healthier joints, or more lean muscle mass.
And pain? What about pain? Only ever-so-slightly promising. For instance, they cite a small “positive” study… funded by a collagen supplement manufacturer. Examine.com is another notch more encouraging in their more substantive analysis:
Limited research suggests a small benefit for osteoarthritis patients and a modest benefit for those with rheumatoid arthritis.
And there are grave concerns about adulteration/contamination. CR again:
64 percent [of tested collagen supplements] had detectable levels of arsenic, about one-third tested positive for lead, and 17 percent had cadmium.”