Published in Frontiers in Nutrition, the study examined the effects of Vital Proteins CP supplementation in premenopausal female endurance athletes, a group which experiences cyclical hormonal fluctuations and elevated risk of low energy availability, which can independently and interactively influence bone turnover and inflammation.
“These factors create a distinct physiological environment in which osteoblast and osteoclast activity, as well as cytokine dynamics, may respond differently to nutritional interventions compared to other populations,” stated the researchers from Fitchburg State University and University of Connecticut, in the US.
Resulting data indicated short-term CP supplementation increased a marker of bone formation, altered osteoclast-related signaling, and reduced IL-6, a key inflammatory cytokine linked to decreased risk of cardiovascular events.
“These findings support the potential for CP-mediated modulation of bone turnover and inflammatory activity and warrant further investigation in larger, adequately powered trials incorporating structural bone outcomes,” stated the report.
Bone metabolism in female distance runners
Female distance runners are at elevated risk for impaired bone remodeling due to high mechanical loading, potential low energy availability, and sustained inflammatory stress, according to the researchers in the current study.
Collagen peptide (CP) supplementation has been proposed as a nutritional strategy to support type I collagen synthesis and modulate osteoimmune signaling alongside typically consumed supplements - protein, calcium, and vitamin D.
Collagen peptides (CPs), derived from enzymatically hydrolyzed type I collagen, have gained attention as a potential adjunct strategy. CPs are rich in glycine, proline, and hydroxyproline and can be absorbed as bioactive di- and tripeptides that circulate systemically and may stimulate osteoblast activity and extracellular matrix synthesis.
However, research in premenopausal women has remained sparse, with most research conducted in men or postmenopausal females.
The study
In this randomized, double-blind, placebo-controlled trial, a sample of 22 active female adults (18–35 years), running more than 35 miles per week were randomized to take 20g of CP (Vital Proteins) or placebo per day, ingesting within one hour of waking.
Participants recorded dietary intake, including total calories and macronutrients, using the MyFitnessPal app. Exercise energy expenditure during training sessions or competitions was tracked using a heart rate monitor to facilitate the calculation of energy availability (EA).
Pre- and post-intervention assessments were conducted in the early follicular phase of the participants’ menstrual cycles to reduce variations in bone turnover markers (BTMs), related to fluctuations in estradiol and progesterone.
The assessments included serum procollagen type I N-terminal propeptide (P1NP), plasma C-terminal telopeptide of type I collagen (CTX-1), serum soluble receptor activator of nuclear factor-κB ligand (sRANKL), osteoprotegerin (OPG), the sRANKL/OPG ratio, and interleukin-6 (IL-6). Repeated-measures ANCOVAs were performed, adjusting for accumulated running distance and vitamin D status.
Resulting data indicated collagen consumption increased serum procollagen type I N-terminal propeptide (P1NP), a key marker of bone formation, without altering C-terminal telopeptide of type I collagen (CTX-1), a marker of bone breakdown. This was accompanied by stabilization of the sRANKL/OPG ratio, a clinical and biological marker of bone metabolism, turnover, and vascular health, and a reduction in circulating IL-6.
“Together, these findings support the biological plausibility that CPs may influence osteoblast activity and osteoimmune regulation in a population exposed to repetitive mechanical loading and elevated skeletal stress,” the report stated.
Although limited by sample size, short duration, and absence of imaging-based outcomes, the magnitude and direction of the observed effects justify further investigation, the researchers stated.
“Larger, longer-term trials incorporating structural bone measures and expanded mechanistic biomarkers are warranted to determine whether these early biochemical changes translate into meaningful skeletal adaptations and reduced injury risk in female endurance athletes,” said the report.
Source: Frontiers in Nutrition, doi: 10.3389/fnut.2026.1825906, “Effects of collagen peptide supplementation on bone turnover, cytokine, and inflammatory markers in female distance runners: a randomized pilot study”, Authors: Kuhlman, N.M. et al
