I've been seeing quite a few reviews and
comments on collagen powder where people say it caused cystic acne.
Not exact matches
(protein intake, high metabolic rate,
collagen - rich bone broths, niacin and B6 intake) Any
comments on his diet hypothesis?
The Empowered Sustenance blog post «Balance Hormones with
Collagen Hydrolysate and Gelatin» has many such
comments from readers (do a search
on the page for «cystic» or «acne» to find them quickly), and the Great Lakes
Collagen Hydrolysate Amazon listing has some reviews about it.
I had seen tons of
comments on sites from women breaking out after starting
collagen supplements (although every «professional» says it doesn't do that).