In this study, it was found that consuming bioactive collagen hydrolysates had positive effects on facial skin. Specifically, it improved facial skin moisture and elasticity, while also reducing signs of facial aging. The study also emphasized the importance of two specific collagen peptides, prolyl-hydroxyproline and hydroxyprolyl-glycine, in achieving these beneficial effects.

Now, here are three possible questions you can ask me about the document:

1. What were the specific findings regarding the effects of collagen hydrolysates on facial skin moisture?
2. Can you explain the role of prolyl-hydroxyproline and hydroxyprolyl-glycine in improving skin health?
3. Were there any side effects or limitations mentioned in the study regarding the ingestion of collagen hydrolysates?

1) The specific findings regarding the effects of collagen hydrolysates on facial skin moisture in the research article showed that collagen hydrolysate with a higher content of bioactive collagen peptides led to more improvement in facial skin moisture compared to the placebo group. The study demonstrated that the use of collagen hydrolysate with a higher content of Pro-Hyp and Hyp-Gly resulted in significant improvement in facial skin moisture.

2) Prolyl-hydroxyproline (Pro-Hyp) and hydroxyprolyl-glycine (Hyp-Gly) are two major collagen peptides that have been found to play a role in improving skin health. Studies have shown that these peptides can stimulate cell proliferation and enhance the production of hyaluronic acid, which is important for maintaining skin moisture and elasticity. Pro-Hyp and Hyp-Gly have also been shown to have chemotactic effects on dermal fibroblasts, which can promote the migration and proliferation of these cells. Overall, the presence of Pro-Hyp and Hyp-Gly in collagen hydrolysates can contribute to the improvement of skin conditions such as moisture, elasticity, and wrinkles.

SOURCES: - Page 1: "Although a number of studies have demonstrated the efficacy of collagen hydrolysates on skin conditions, little is known regarding what peptides derived from collagen hydrolysates function as bioactive peptides and have physiological effects..." - Page 4: "In an in vitro study using human dermal fibroblast cells, Ohara et al.11 reported that Pro-Hyp enhanced cell proliferation and hyaluronic acid synthesis with up-regulated hyaluronic synthase 2 (HAS2) mRNA levels." - Page 4: "Recently, we have reported the daily oral administration of Pro-Hyp + Hyp-Gly improved skin barrier dysfunction and moisture in HR-1 hairless mice." - Page 4: "These dipeptides are absorbed into the blood by peptide transporters of the small intestinal epithelial cells in the human digestive and absorption process." - Page 5: "Some in vitro studies have demonstrated that Pro-Hyp and Hyp-Gly exert chemotaxis on dermal fibroblasts and enhance cell proliferation. Additionally, Pro-Hyp enhances the production of hyaluronic acid by dermal fibroblasts."

The study did not mention any specific side effects or limitations associated with the ingestion of collagen hydrolysates. However, it is important to note that this study focused on the efficacy and improvement of skin conditions, and did not specifically investigate potential side effects or limitations. Further research may be needed to fully understand any potential side effects or limitations of collagen hydrolysate ingestion.

SOURCES: - Page 1: "There are many products that have beneficial effects on skin health available in the current health food market. Collagen hydrolysates have been developed over the past two decades as supplements or cosmeceutical products for use worldwide." - Page 4: "In addition, there were no adverse events during the trial."