{"id":5369,"date":"2026-05-26T11:20:56","date_gmt":"2026-05-26T11:20:56","guid":{"rendered":"https:\/\/laexome.com\/systematic-evidence-for-collagen-peptides\/"},"modified":"2026-05-26T11:20:56","modified_gmt":"2026-05-26T11:20:56","slug":"systematic-evidence-for-collagen-peptides","status":"publish","type":"post","link":"https:\/\/laexome.com\/ko\/systematic-evidence-for-collagen-peptides\/","title":{"rendered":"Systematic Evidence for Collagen Peptides"},"content":{"rendered":"

Pu et al. (2023) \u2014 Systematic Review & Meta-Analysis of 26 RCTs<\/h3>\n

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1. Introduction<\/h2>\n
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The skin, the largest organ of the body exposed to the external environment, is affected by both intrinsic and extrinsic factors in the aging process [1<\/a>]. Skin aging is characterized by dehydration, a loss of skin elasticity, and the presence of wrinkles [2<\/a>]. Skin aging has attracted considerable attention because of the increasingly high beauty standards. Because many countries are becoming aging societies, the psychosocial effects of skin aging increases the need for effective interventions [3<\/a>]. In this context, the use of nutraceuticals as supplements has increased in recent years [4<\/a>].<\/p>\n<\/div>\n

Collagen is the main protein structure of various connective tissues, which constitutes 80% of the dry weight of human skin [5<\/a>]. Collagen is characterized by a triple helix structure formed by the repetition of glycine every third residue, and particularly by proline and hydroxyproline in the other residues [6<\/a>]. Collagen, the most prevalent component of extracellular matrix, provides mechanical support and directs tissue development [7<\/a>].<\/div>\n
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Aging induces a decline in the enzymes involved in the post-translational processing of collagen, reducing the number of fibroblasts that synthesize collagen and vessels that supply the skin [8<\/a>]. The decline in skin quality with age is characterized by a reduction in collagen synthesis and a decrease in skin vascularity, leading to decreased elasticity and the formation of wrinkles [9<\/a>]. These changes are due to the decline in fibroblast activity and a decrease in the number of blood vessels in the skin [10<\/a>]. Therefore, the skin undergoes regressive changes with age such as dehydration, a loss of elasticity, and a reduction in epidermal thickness [11<\/a>]. Various nutrients and supplements are used to improve skin health and maintain a youthful skin appearance [12<\/a>]. These strategies include topical creams, injectable fillers, and collagen supplements. Topical creams contain collagen as one of the ingredients, and they are designed to enhance skin hydration and firmness [13<\/a>]. However, topical creams have limited ability to penetrate the skin, which can reduce their effectiveness [13<\/a>]. Injectable fillers such as hyaluronic acid fillers, stimulate collagen production and provide immediate results by plumping the skin [14<\/a>]. However, they can be expensive and come with the risk of adverse events such as bruising, swelling, and infection [14<\/a>]. On the other hand, collagen supplements, particularly those containing hydrolyzed collagen peptides, have been shown to be safe and cost-effective compared to other collagen-based strategies. Furthermore, collagen supplements have the advantage of being taken orally, making them easy to incorporate into daily routines [15<\/a>].<\/div>\n
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Among these supplements, hydrolyzed collagen (HC) is the most popular and promising skin anti-aging nutraceutical [16<\/a>]. Other studies have indicated that alanine\u2013hydroxyproline\u2013glycine and serine\u2013hydroxyproline\u2013glycine can be detected in human blood 1 h after the oral ingestion of HC [17<\/a>,18<\/a>] and deposited on the skin [19<\/a>].<\/div>\n
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A recent study demonstrated that HC improves skin hydration and elasticity [16<\/a>]. Nevertheless, not all sources of HC have the same efficacy. Even at the same dose and duration of administration, some specific sources of collagens are more effective than others [20<\/a>]. Therefore, studies are required to determine the proper source and therapeutic duration of HC against skin aging.<\/div>\n
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Because an increasing number of clinical studies on collagen supplements have been conducted globally, their results must be summarized in a systematic review and meta-analysis. Therefore, this systematic review and meta-analysis investigated the effects of collagen supplementation on skin hydration and elasticity.<\/div>\n
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2. Materials and Methods<\/h2>\n
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2.1. Search Strategy, Inclusion Criteria, and Exclusion Criteria<\/h3>\n
We performed a literature search in the Embase, PubMed, and Cochrane Library databases by using the following search terms from Medical Subject Headings with no restrictions applied: (collagen OR hydrolyzed collagen) AND (anti-aging). Relevant studies published before December 2022 were identified. We included studies that met the following criteria: (1) applying a randomized clinical trial (RCT) design; (2) including healthy adults (aged \u2265 18 years); (3) including patients who received HC; (4) being full-text articles written in English. We excluded studies that (1) assessed the combined effect of collagen supplement with another supplement or (2) were RCTs that were not written in English. We extracted raw data from the graphs in articles using WebPlotDigitizer [21<\/a>].<\/div>\n<\/section>\n
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2.2. Data Extraction<\/h3>\n
Two independent reviewers (S-YP, CC) extracted the basic information of the included studies. The following types of information were extracted: study meta-data (i.e., first author, publication year, and study design) and information on the study sample (i.e., number of patients, gender, mean age, and baseline characteristics of the treatment and placebo groups), intervention (i.e., the dose of collagen supplement and form), and outcomes (i.e., hydration and elasticity). Continuous outcomes are presented in terms of the mean \u00b1 standard deviation (SD), and discrete data are presented in terms of percentage.<\/div>\n<\/section>\n
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2.3. Statistical Analysis, Sensitivity Analysis and Bias Assessment<\/h3>\n
We used a random-effects model to calculate the SD and mean difference of the identified studies. A\u00a0p<\/span>\u00a0value of <0.05 indicated statistical significance. The levels of heterogeneity among the included studies were determined using Hedge\u2019s I2<\/sup>\u00a0tests, and forest plots were generated for each included study. Moreover, I2<\/sup>\u00a0\u2265 50% indicated high heterogeneity [22<\/a>]. The general effect test result was reported as a z-value, which supported the inference of the 95% confidence interval (CI). A sensitivity analysis was performed to negate the effect of potentially influential studies. Each study was classified in accordance with the Cochrane Handbook for Systematic Reviews of Interventions [23<\/a>]. The Cochrane risk of bias (RoB) 2.0 tool was used to assess the risk of bias in the included RCTs. Five domains of bias were evaluated (selection, performance, detection, attrition, and reporting bias) [24<\/a>]. In this meta-analysis, all outcomes were analyzed using RevMan software (version 5.4).<\/div>\n<\/section>\n<\/section>\n
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3. Results<\/h2>\n
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3.1. Research Results and Study Characteristics<\/h3>\n
Figure 1<\/a>\u00a0shows the flowchart of the literature search process performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines [25<\/a>]. We identified 1135 studies in our initial search. After removing duplicates and screening titles or abstracts of related articles, we assessed the full-text articles of the remaining 37 studies. Of these studies, 26 articles were included in this systematic review and meta-analysis.<\/div>\n
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Figure 1.<\/b>\u00a0Flowchart of the systematic review and meta-analysis according to the PRISMA guidelines.<\/em><\/div>\n<\/section>\n<\/section>\n
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3.2. Study Characteristics<\/h3>\n
A total of 26 RCTs involving 1721 patients were included in this meta-analysis. The duration of the HC supplementation of the included studies ranged from 2 to 12 weeks. Among the included RCTs, 14 focused on collagens extracted from fish, one focused on collagens extracted from bovine, one focused on collagens extracted from chicken, two focused on collagens extracted from porcine, and nine lacked information regarding the source of collagen. The study characteristics of the included RCTs are presented in\u00a0Table 1<\/a>.<\/div>\n
The measurement of skin hydration levels is commonly conducted using a non-invasive tool called a corneometer. This instrument emits a high-frequency electric current into the skin\u2019s surface and measures the amount of water present in the top layer, expressed in corneometry units. The corneometer is widely used in evaluating the effectiveness of topical products and assessing overall skin health by providing valuable insights into the skin\u2019s moisture barrier. Therefore, it is considered as a valuable tool in measuring the skin hydration levels and assessing the efficacy of skincare products [18<\/a>,26<\/a>,27<\/a>,28<\/a>,29<\/a>,30<\/a>,31<\/a>,32<\/a>,33<\/a>]. On the other hand, the measurement of skin elasticity is often conducted using cutometry, a non-invasive technique that provides valuable insights into skin health. It works by applying a controlled negative pressure to a small area of the skin and measuring the resulting deformation, which is directly proportional to the skin\u2019s elasticity. Cutometry is widely used in research and clinical settings to assess the skin elasticity levels and monitor changes in the skin over time. Overall, it is a safe and reliable tool for evaluating skin health.<\/div>\n
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Table 1.<\/b>
\nCharacteristics of the patients in the included studies.<\/div>\n