Interest in dietary collagen peptides as a tool for correcting age-related skin changes is growing rapidly: skincare specialists, dermatologists, and their patients are increasingly turning to oral supplements in search of visible skin improvement. Clinical observations support this effect — yet the question "why does it actually work?" has long gone without a comprehensive answer.
A new review by Huang et al., published in Molecules (2026), consolidates the accumulated evidence and offers a fresh perspective on the cellular mechanisms of collagen peptide action — with a particular focus on lysosomes and mitochondria as key target organelles [1].

Collagen peptides and skin: what the evidence shows

Collagen is the primary structural protein of the skin's extracellular matrix (ECM). Collagen peptides are short chains of 2 to 20 amino acid residues obtained through the hydrolysis of collagen. A substantial body of clinical evidence has now accumulated regarding their efficacy: a large systematic review with meta-analysis, published in 2021, pooling data from numerous clinical trials, demonstrated that oral intake of hydrolyzed collagen significantly improves aging skin — increasing hydration, reducing the appearance of wrinkles, and enhancing elasticity [2].

Yet even against this backdrop, the question of how exactly this occurs at the molecular level remains without a complete answer. It is precisely this gap that the review under discussion sets out to address: the authors synthesize a decade of data and offer a new perspective on the cellular mechanisms underlying the anti-aging effects of collagen peptides.

Absorption and bioavailability: do peptides actually reach the skin?

Before discussing mechanisms of action, a key question must be answered: do orally ingested collagen peptides reach the skin in a biologically active form? The answer is yes — though the full picture is yet to emerge.

Following oral administration of collagen to rats (4,000 mg/kg body weight), bioavailability was approximately 50%, with more than 63.4% absorbed in the intestine in peptide form [3]. The key peptides — Gly-Pro-Hyp (glycine-proline-hydroxyproline) and Pro-Hyp (proline-hydroxyproline) — were detected in blood plasma after a single dose (300 mg/kg body weight): the former predominated in the bloodstream, the latter in the skin [4]. Perhaps the most compelling evidence comes from a radiolabeled ¹⁴C experiment: after ingestion of labeled peptides, their levels rose rapidly in plasma and were subsequently detected in the kidneys and skin — with elevated skin concentrations persisting 14 days after the last dose [5].

Nevertheless, Huang et al. [1] draw attention to significant gaps in this area:

• bioavailability studies and anti-aging efficacy studies are methodologically almost entirely disconnected: the former do not assess anti-aging outcomes, while the latter do not measure how much of the substance actually reaches the skin;
• it remains unknown how molecular weight, electric charge, and hydrophobicity of peptides affect their stability during digestion, intestinal transport, and ultimate concentration in target tissues;
• there are no standardized protocols for dosage, formulation, or duration of supplementation.

Mechanisms of systemic action: from ROS neutralization to organelle activation

The authors describe the anti-aging action of collagen peptides as a systemic, multi-level process encompassing several interconnected mechanisms.

Neutralization of reactive oxygen species and suppression of inflammation

Excessive accumulation of reactive oxygen species (ROS) is one of the primary molecular triggers of skin aging.

Collagen peptides possess direct antioxidant activity: they act as antioxidants, directly scavenging ROS and thereby reducing oxidative stress in skin cells.

Simultaneously, collagen peptides suppress chronic skin inflammation. This inflammation develops, in part, through the activation of two key intracellular signaling cascades. The first is the NF-κB (nuclear factor kappa-B) pathway, which triggers the production of pro-inflammatory cytokines and plays a central role in sustaining the inflammatory background characteristic of aging skin. The second is the MAPK (mitogen-activated protein kinase) pathway, which, beyond its role in inflammation, regulates the activity of transcription factor AP-1 (c-Jun/c-Fos) — a driver of matrix metalloproteinase (MMP) production, the enzymes responsible for degrading collagen and other ECM components.

Notably, dysfunctional mitochondria are themselves capable of activating the NF-κB pathway, creating a vicious cycle of inflammation. Collagen peptides break this cycle by inhibiting both pathways. In particular, fish scale-derived collagen peptides protected keratinocytes from cytotoxic and inflammatory damage through the simultaneous suppression of ROS, MAPK, and NF-κB [1].

Protection of the extracellular matrix and stimulation of its synthesis

Collagen peptides act on the skin's ECM through several parallel mechanisms:

1. Inhibition of ECM degradation:
• with age, MMPs — primarily MMP-1 and MMP-3 — break down collagen and other ECM components;
• collagen peptides suppress MMP activity, reducing matrix degradation;
• oral administration of chicken bone collagen peptides (200–1,000 mg/kg) significantly decreased MMP-1 and MMP-3 expression in mouse skin [1].
2. Stimulation of collagen synthesis:
• in parallel, the peptides activate the transforming growth factor-beta (TGF-β)/Smad pathway — the key signaling cascade that drives new collagen production by fibroblasts;
• in the same chicken bone peptide experiment, MMP suppression was accompanied by activation of the TGF-β/Smad pathway [1].
3. Restoration of skin hydration:
• collagen peptides stimulate hyaluronic acid synthesis by fibroblasts — the primary moisture reservoir of the dermis; tilapia scale peptides (500–1,000 mg/kg) significantly reduced UVB-induced skin dehydration in mice [1];
• sea bream scale peptides increased ceramide and natural moisturizing factor (NMF) content in the stratum corneum in human volunteers [1].

Inhibition of melanogenesis

Melanin is produced by melanocytes in response to UV radiation and other stimuli. Its excessive accumulation is a hallmark of photoaging. Evidence indicates that collagen peptides can suppress melanogenesis, reducing melanin production. According to the authors, this effect is likely also mediated by reduced oxidative stress and inhibition of pro-inflammatory cascades — though the direct mechanisms require further investigation [1].

Lysosomes and mitochondria: emerging cellular targets

The central and most original concept of this review is that lysosomes and mitochondria may be the key organelles through which collagen peptides exert their anti-aging effects.

Lysosomes are intracellular organelles responsible for the degradation of damaged proteins and organelles. With age, their function deteriorates: dysfunctional mitochondria and protein aggregates accumulate within cells, amplifying oxidative stress. Activation of the lysosomal autophagy pathway allows the cell to clear these components. In an experiment with oral chicken bone collagen peptides (200–1,000 mg/kg), transcriptomic analysis revealed significant enrichment of lysosomal pathway genes in mouse skin, indicating activation of lysosomal processes [1]. Disruption of lysosomal homeostasis has also been documented in keratinocytes with collagen VII deficiency, further reinforcing the link between the skin's collagen status and lysosomal function [1].

Mitochondria — the cell's energy and metabolic hubs — also lose function with age: membrane potential declines, ROS production increases, and biosynthesis is impaired. In UVA-irradiated dermal fibroblasts, reduced mitochondrial function directly leads to insufficient production of type I collagen and fibrillin-1. Polypeptides from the scallop Chlamys farreri protected human skin fibroblast mitochondria from UVB damage and maintained transmembrane potential, with the protective effect increasing with peptide concentration [1]. Fish collagen oligopeptides (25–100 µg/mL) protected fibroblast mitochondria, suppressed inflammation, and maintained cellular homeostasis through the NAD+/SIRT1/PGC-1α signaling pathway [1]. Metabolomic analysis of mouse skin following chicken bone collagen peptide supplementation showed significant enrichment of the pyruvate and tricarboxylic acid (TCA) cycle metabolic pathways, further pointing to mitochondria as a key site of action [1].

The authors propose the following sequence of events: collagen peptides with antioxidant activity first neutralize ROS and suppress inflammation → then activate the lysosomal autophagy pathway to clear damaged organelles and protein aggregates, further reducing ROS levels → and finally, by restoring mitochondrial function, provide the cell with the energy and substrates needed for robust biosynthesis of collagen, hyaluronic acid, and other ECM components.

Immune mechanism

Beyond their direct effects on fibroblasts and the ECM, collagen peptides engage an additional mechanism — immunological. Remodeling of the skin matrix is impossible without the timely removal of its damaged components, and this task falls to macrophages — key immune regulators controlling the clearance of cellular debris and matrix renewal. Depending on microenvironmental signals, they can switch between two functional phenotypes:

• M1 phenotype ("pro-inflammatory") — activates the removal of dead cells and initiates an inflammatory response;
• M2 phenotype ("pro-regenerative") — suppresses inflammation and participates in ECM remodeling, i.e., the renewal and restructuring of connective tissue.

According to data from Barati et al. [6], oral collagen peptide intake can induce regulatory T cells (Tregs), which drive macrophage differentiation toward the M2 phenotype. This enhances the resolution of tissue inflammation and promotes skin renewal — through both oral and non-oral immune tolerance mechanisms.

The authors of the review [1] regard this pathway as promising, but emphasize that the evidence base remains limited and requires further development.

Limitations

The authors are candid about significant gaps in the field. Bioavailability studies and clinical efficacy studies are methodologically almost entirely disconnected. The majority of mechanistic research continues to reproduce the same signaling pathways — TGF-β/Smad, MAPK, NF-κB — without attempting to move beyond them. There are no standardized protocols for dosage, formulation, or duration of supplementation. The roles of lysosomes and mitochondria as specific targets of collagen peptides are currently supported only by indirect evidence and require direct experimental proof.

Conclusion

The review by Huang et al. offers a systemic perspective on the anti-aging mechanisms of collagen peptides and brings lysosomes and mitochondria to the forefront as key intracellular targets — ones that have until now remained in the shadow of the better-known NF-κB, MAPK, and TGF-β/Smad signaling cascades. This shifts the research focus from reproducing established mechanisms toward an organelle-centered paradigm of anti-aging therapy.

For the practicing specialist, this review holds value on several levels:

• scientific rationale for oral collagen: peptides do reach the skin in a biologically active form — this is experimentally confirmed, not a marketing claim;
• a new perspective on the mechanism of action: collagen functions not merely as a "building material" but as a regulator of intracellular processes — at the level of organelles, signaling pathways, and immune cells;
• a reference point for future protocols: the concept of mitochondria and lysosomes as targetable structures opens the prospect of more precise, pathogenetically grounded anti-aging regimens;
• an honest assessment of limitations: the authors explicitly acknowledge the gaps — the absence of standardized dosing protocols, the lack of bioavailability data linked to clinical outcomes — helping practitioners critically evaluate existing products and protocols.

This means that the specialist recommending oral collagen today stands on solid evidence-based ground — and simultaneously on the threshold of far more precise and scientifically grounded protocols that are already taking shape.

References

1. Huang W., Ran J., Du Y., Cao C. New insights into the anti-aging mechanism of collagen peptides — emphasis on lysosomes and mitochondria function. Molecules 2026; 31(5): 763.
2. de Miranda Roseane B., Patricia W., Rossi R.C. Effects of hydrolyzed collagen supplementation on skin aging: a systematic review and meta-analysis. Int J Dermatol 2021; 60(12): 1449–1461.
3. Wang L., Wang Q., Qian J. et al. Bioavailability and bioavailable forms of collagen after oral administration to rats. J Agric Food Chem 2015; 63(16): 3752–3756.
4. Yazaki M., Ito Y., Yamada M. et al. Oral ingestion of collagen hydrolysate leads to the transportation of highly concentrated Gly-Pro-Hyp and its hydrolyzed form of Pro-Hyp into the bloodstream and skin. J Agric Food Chem 2017; 65(11): 2315–2322.
5. Watanabe-Kamiyama M., Shimizu M., Kamiyama S. et al. Absorption and effectiveness of orally administered low molecular weight collagen hydrolysate in rats. J Agric Food Chem 2010; 58(2): 835–841.
6. Barati M., Jabbari M., Navekar R. et al. Collagen supplementation for skin health: A mechanistic systematic review. J Cosmet Dermatol 2020; 19(11): 2820–2829.