Prolylhydroxyproline (Pro-Hyp) and hydroxyprolylglycine (Hyp-Gly) are compounds gaining recognition for their roles in human health. These small protein fragments, known as dipeptides, originate primarily from the breakdown of collagen, the most abundant protein in the human body. Understanding these collagen-derived molecules is important for those interested in supporting various bodily functions. Their presence after consumption of collagen-rich sources highlights their potential physiological significance.
Understanding Prolylhydroxyproline and Hydroxyprolylglycine
Prolylhydroxyproline (Pro-Hyp) and hydroxyprolylglycine (Hyp-Gly) are dipeptides. Pro-Hyp, for instance, specifically combines proline and hydroxyproline residues, while Hyp-Gly is formed from hydroxyproline and glycine. These particular dipeptides originate from the enzymatic breakdown of collagen, comprising approximately 30% of total protein in the body.
Collagen is characterized by a repeating sequence of amino acids, often including glycine, proline, and hydroxyproline. When collagen from dietary sources or supplements is broken down, it yields smaller fragments, including these specific dipeptides. Unlike larger proteins that are fully dismantled into individual amino acids, Pro-Hyp and Hyp-Gly are considered “bioactive” because they maintain their structure and can exert biological effects after absorption. Their small molecular weight contributes to their high absorption rates and ability to act as signaling molecules within the body.
Where These Compounds Are Found
Prolylhydroxyproline and hydroxyprolylglycine are found in sources rich in collagen. The most common natural dietary sources include various animal connective tissues, such as those found in bone broth, gelatin, and certain cuts of meat like beef, pork, and chicken. Marine sources, including fish skin and scales, are also increasingly recognized for their collagen content, which yields these beneficial peptides.
Beyond whole foods, collagen supplements, often labeled as collagen hydrolysate or collagen peptides, represent a concentrated and convenient source of these specific dipeptides. These supplements are produced by processing animal collagen, typically from bovine, porcine, or marine origins, into smaller, more easily digestible fragments through hydrolysis. After ingestion, these dipeptides, due to their low molecular weight, are efficiently absorbed from the small intestine into the bloodstream. This rapid and efficient absorption allows them to reach various tissues throughout the body, making them available for their specific physiological actions.
How the Body Utilizes These Dipeptides
Once absorbed into the bloodstream, prolylhydroxyproline and hydroxyprolylglycine play distinct roles in supporting various bodily functions, primarily by signaling cellular activities rather than simply providing raw building blocks. These dipeptides have been shown to influence cells responsible for collagen and elastin production, which are proteins that contribute to tissue structure and elasticity. Their presence in the circulation after ingestion of collagen hydrolysates promotes biological responses within target tissues, acting as messengers to promote repair and regeneration.
In skin health, these dipeptides are recognized for their ability to enhance the body’s natural collagen synthesis, which can lead to improved skin elasticity and hydration. Clinical trials have shown that oral intake of collagen peptides containing Pro-Hyp and Hyp-Gly can significantly reduce wrinkle volume and increase skin moisture, contributing to a more youthful appearance. Pro-Hyp, in particular, has been observed to directly bind to proteins like Foxg1, promoting the production of Runt-related transcription factor 2 (Runx2), which influences cell function and differentiation. This stimulation helps maintain the skin’s structural integrity and firmness, reducing signs of aging such as decreased epidermal thickness and increased fine lines.
Regarding joint and bone health, these dipeptides offer supportive functions for cartilage and bone matrix. Collagen is a significant component of cartilage, providing strength and structure to joints, and these dipeptides are able to reach and accumulate in joint tissues like articular cartilage. Pro-Hyp and Hyp-Gly are believed to stimulate chondrocytes, the cells in cartilage, to produce new collagen and other matrix components, thereby supporting joint integrity and mobility. Research indicates that collagen peptide supplementation can lead to improvements in joint pain and increased mobility, particularly in individuals with conditions like osteoarthritis, by reducing inflammation and supporting cartilage maintenance. A clinical study found an overall reduction in pain and a significant increase in mobility in elderly women with mild-to-moderate knee osteoarthritis after six months of oral collagen peptide administration.
The influence of these dipeptides extends beyond skin, joints, and bones, with emerging research indicating other potential benefits. Pro-Hyp has been associated with improved wound healing by acting as a low molecular weight growth-initiating factor for fibroblasts at injury sites, accelerating the proliferative phase of healing. Animal studies and human clinical trials have demonstrated that the ingestion of gelatin or collagen hydrolysate can enhance the healing of pressure ulcers and improve delayed wound healing in diabetic animals. There are also indications that hydroxyprolyl peptides may have anti-inflammatory and antioxidant properties, and some studies suggest an impact on glucose tolerance and the differentiation of metabolically active beige adipocytes. These broader effects underscore the multifaceted influence of these specific collagen-derived dipeptides on overall physiological well-being.