In this article, we will describe the effects of collagen supplementation on muscle strength, function and body composition.
To our knowledge, Zdzieblik et al. (2015) were the first to find positive effects of CS combined with RE on muscle strength and body composition in sarcopenic elderly after 12 weeks. Specifically, quadriceps muscle strength, total fat-free mass (FFM) and fat mass (FM) showed to be improved after a 12-week resistance training programme with CS compared to placebo. Studies by Jendricke et al. (2019), Kirmse et al. (2019) and Oertzen-Hagemann et al. (2019) also found significant increases in FFM by CS with RE compared to placebo in premenopausal women and active men after 12 weeks.
Increase in strength...
In addition, Krimse et al. (2019) found a significant increase in strength in both treatment groups, with a slight non-significant increased effect in the collagen group compared to control. Comparable results were also found by Oertzen-Hagemann et al. (2019) and Jendricke et al. (2019), who showed that compared to placebo, CS resulted in increased leg strength in active men, and more pronounced leg strength and significantly increased hand grip strength in premenopausal women, respectively. As there is no consensus on the effect size of the increase in muscle strength, the effects of CS with RE on muscle strength remain unclear. It appears that CS with RE increases only FFM significantly.
With a similar study design, they found results partly in line with those of Zdzieblik et al. (2015). Specifically, they also found a significant increase in FFM and a slight increase in strength compared to placebo. Upon examining the muscle fibre cross-sectional area of type II muscle fibres, which could show hypertrophy of those fibres, Kirmse et al. (2019) found hypertrophy to be significantly increased but not due to treatment. Therefore, it was assumed that the adaptation of passive tissue components such as tendons and ECM is naturally enhanced by RE as a physiological mechanism. The role of CS herein remains unclear. However, the authors suggested this physiological mechanism may possibly be more enhanced as a result of increased collagen intake (Kirmse et al., 2019). In addition, Oertzen-Hagemann et al. (2019) even suggested that the beneficial effects found from CS are associated with improved force transmission via passive structures, which may possibly result in higher muscle strength. This is in line with the aforementioned hypothesis regarding the association between adapted passive structures such as ECM and muscle function and force transmission. This indicates that CS with RE appears promising for enhancing muscle function, strength and force transmission after exercise via passive structures.
The aforementioned studies all supplemented with a collagen peptide dose of 15 grams/day (g/d) (Jendricke et al., 2019; Kirmse et al., 2019; Oertzen-Hagemann et al., 2019; Zdzieblik et al., 2015). In 2020, Oikawa et al. even supplemented with 30 g daily for 6 days, and in 2018 with the same dose 2x a day for 5 weeks. As no adverse effects were reported in any of these studies, a collagen peptide dose ranging from 15-30 g/d appears to be safe. However, potential differential effects between doses remain undefined and still need to be explored. To fully explore the potential side effects of CS, more long-term research is needed. It is important to mention that, to our knowledge, there are currently no interventions combining CS with endurance or a different type of exercise than RE.
Thus, it appears there is a large knowledge gap in the literature concerning the association between CS and functional muscle adaptations to exercise. In addition, to date, there is a lack of scientific knowledge on the effects of CS on other muscular factors such as markers of muscle damage and soreness. A study by Clifford et al. (2019) looked at the association between CS with RE and post-exercise muscle damage, inflammation and bone turnover after 9 days of CS with RE in males. They found a large but non-significant decrease in muscle soreness and an increase in jump height recovery at 48 hours post-exercise compared to placebo.