Pepsin

NutraPedia - Evidence-Based Supplement Research

Back to Table of Contents
Health Goals: digestion detox immunity

Research Overview

Recent pepsin research clusters into three heavily studied areas: (1) molecular-level characterization of pepsin–ligand interactions, (2) pepsin’s role in laryngopharyngeal reflux disease (LPR/LPRD) pathophysiology and related upper aerodigestive inflammation, and (3) food/digestion and processing applications where pepsin-driven proteolysis alters structure and bioactivity. Multiple spectroscopy- and simulation-based studies examine binding of dietary polyphenols and supplements (e.g., quercetin, apigenin, tetrahydrocurcumin) to pepsin, typically reporting specific binding sites, defined dominant forces (hydrogen bonding/van der Waals vs hydrophobic interactions), and measurable conformational changes that can translate into altered enzymatic activity. In parallel, food science work uses pepsin as a controlled pre-treatment to modulate hydrolysis outcomes (e.g., generating peptide profiles with antioxidant and enzyme-inhibitory activities) and to model early gastric events such as κ-casein hydrolysis–induced milk coagulation as a function of pH and enzyme concentration. A smaller but notable methodological theme is physical modulation of pepsin activity/structure (e.g., ultrasound-induced activation and structural perturbation with partial recovery over time).

The strongest evidence in these abstracts supports (i) pepsin’s capacity to bind diverse small molecules with consequent conformational and functional effects measurable by orthogonal methods (fluorescence/absorbance, CD, kinetics, docking/MD), and (ii) a substantive role for pepsin in LPR-related mucosal injury beyond acid alone, consistent with clinical observations that proton pump inhibitors incompletely relieve symptoms in a substantial subset of patients. Importantly, translational evidence is emerging that pepsin can be pharmacologically inhibited: high-throughput screening/crystallography and an in vivo mouse LPR model indicate that certain FDA-approved HIV protease inhibitors (e.g., fosamprenavir, darunavir) bind and inhibit pepsin and reduce pepsin-mediated laryngeal damage, supporting pepsin as a druggable target and motivating local (e.g., inhaled) delivery strategies. In food/digestion contexts, controlled experiments provide quantitative kinetic and rheological evidence that pH and pepsin concentration govern κ-casein hydrolysis rates, coagulation timing, and gel microstructure, strengthening mechanistic understanding of early gastric-like transitions.

Key gaps include: establishing clinical causality and patient stratification in LPR (e.g., defining when pepsin vs acid vs bile acids/trypsin predominates, and validating biomarkers such as salivary pepsin alongside impedance–pH monitoring); expanding in vivo and human studies that connect pepsin exposure to chronic outcomes (including the debated link to laryngeal neoplasia) with clear dose–response and mechanistic pathways; and advancing pepsin-targeted therapeutics from proof-of-concept to optimized formulations, safety, and efficacy in controlled clinical trials. At the molecular level, more work is needed to reconcile how different classes of dietary ligands modulate pepsin under physiologic gastric conditions (pH, ionic strength, substrates present), and to determine whether observed inhibition/structural changes meaningfully affect digestion or bioavailability in vivo. In processing applications, translating peptide “bioactivity” from in vitro assays and in silico predictions to validated physiological effects, along with standardization of hydrolysis conditions and reproducibility across matrices, remains an important research need.

1. What conditions has Pepsin been studied for?

  • Laryngopharyngeal reflux (LPR) / laryngopharyngeal reflux disease (LPRD) and extra-esophageal reflux: Multiple abstracts focus on pepsin as a refluxate component implicated in laryngopharyngeal inflammation and symptoms, including nonacid reflux where PPIs may be less effective.

  • Laryngeal injury/inflammation models related to reflux: A mouse LPR model used pepsin instillation (at neutral pH) to induce laryngeal damage and test pepsin-targeted inhibitors.

  • Laryngeal squamous cell carcinoma (SCC) / carcinogenesis mechanisms: Cell and translational studies examined whether pepsin exposure promotes proliferative and carcinogenesis-related signaling in laryngeal/hypopharyngeal cells, and pepsin detection in cancer biopsies.

  • Cancer cell behaviors (in vitro): In laryngeal carcinoma cell lines (Hep-2, Tu212), pepsin was studied for effects on proliferation, migration, inflammatory cytokines (notably IL-8), and epithelial-mesenchymal transition (EMT).

  • Digestion/food science and protein hydrolysis: Pepsin was studied in milk digestion (κ-casein hydrolysis and casein micelle coagulation) and in generating bioactive peptide hydrolysates from beef liver (as a pre-treatment to enhance downstream bioactivity).

  • Interactions with dietary polyphenols/supplements: Several abstracts studied binding and functional effects of compounds on pepsin (quercetin, apigenin, tetrahydrocurcumin), including inhibition/structural changes of pepsin.

  • Enzyme modulation by ultrasound: Ultrasound exposure was studied for its ability to alter pepsin activity and structure (activation reported for pepsin, unlike inhibition for some other enzymes).

2. Does it work in treating those conditions? Summarize the evidence.

From these abstracts, pepsin itself is generally studied as a pathogenic factor in reflux-related laryngeal disease and as a digestive enzyme in food/protein processing. It is not presented as a therapeutic agent for LPR/LPRD; rather, inhibiting pepsin is explored as treatment.

  • LPR/LPRD treatment: Evidence in these abstracts supports pepsin inhibition (not pepsin supplementation) as a potential therapy. A 2023 study reported that FDA-approved HIV protease inhibitors (fosamprenavir and darunavir) bind and inhibit pepsin and reduced pepsin-mediated laryngeal damage in a mouse LPR model (inhibitor delivered by gavage or aerosol; small sample size noted in the abstract, n = 3).

  • Why PPIs may fail in some LPRD patients: A review abstract notes PPIs fail to relieve symptoms in up to 40% of LPRD patients and highlights growing attention to nonacid reflux constituents including pepsin, implying that acid suppression alone may not address pepsin-related injury.

  • Cancer-related outcomes: The abstracts do not show pepsin “treating” cancer; instead they suggest pepsin exposure may promote carcinogenesis-related changes. One translational study found pepsin altered expression of 27 carcinogenesis-implicated genes and 22 microRNAs, increased S-phase distribution (proliferation) in both SCC cells and normal laryngeal epithelial cells, and detected pepsin in 60% (3/5) of laryngeal cancer biopsies but not controls (0/5). Another in vitro study reported pepsin promoted proliferation/migration and EMT markers in laryngeal carcinoma cell lines, with EMT effects reduced when pepsin was inhibited by pepstatin and partially mediated via IL-8.

  • Digestive/food processing “works”: In food science contexts, pepsin effectively hydrolyzes proteins (e.g., κ-casein in milk; beef liver proteins as a pre-treatment), influencing coagulation kinetics and peptide profiles. This is functional/industrial evidence rather than clinical treatment evidence.

Bottom line: In these abstracts, pepsin is not supported as a treatment for LPR/LPRD; instead, targeting/inhibiting pepsin shows preclinical promise. Pepsin’s “effectiveness” is well supported for protein digestion/hydrolysis in experimental systems.

3. What health benefits does it have?

  • Core physiological role in digestion: One abstract explicitly notes pepsin “plays an important role in nutrient metabolism,” consistent with its role as a primary gastric protease.

  • Generation of potentially beneficial peptides (indirect benefit): In beef liver processing, pepsin pre-treatment (including ultrasound-assisted pepsin hydrolysis) increased degree of hydrolysis and free amino acids and was associated with hydrolysate fractions showing higher antioxidant and inhibitory activities against enzymes linked to cardiometabolic health (ACE-I, ECE-I, DPP-IV, neprilysin). This suggests pepsin can help produce peptide mixtures with multifunctional bioactivities in vitro/ex vivo, though this is not direct evidence of clinical benefit in humans.

  • Food digestion mechanics: In milk, pepsin-driven κ-casein hydrolysis contributes to casein micelle coagulation during early gastric transition conditions; the study mapped how pH and pepsin concentration affect hydrolysis rate and coagulation time, improving understanding of digestion processes (mechanistic benefit rather than a therapeutic one).

Important limitation: None of the provided abstracts demonstrate that taking pepsin as a supplement improves clinical outcomes in humans; the “benefits” shown are primarily physiological (digestion) or related to producing bioactive hydrolysates in food science experiments.

4. Does it have any downsides or side effects?

  • Laryngeal/pharyngeal mucosal injury in reflux: Multiple abstracts describe pepsin as a harmful refluxate constituent in LPR/LPRD, contributing to inflammation and tissue damage, including in nonacid reflux contexts where PPIs may be insufficient.

  • Potential pro-carcinogenic signaling (mechanistic and associative evidence): Cell/translational studies report pepsin exposure increased proliferation and altered cancer-related gene/miRNA expression; pepsin was detected in a majority of a small set of laryngeal cancer biopsies (3/5) and absent in controls (0/5). Another study found pepsin promoted EMT and migration in laryngeal carcinoma cell lines, with involvement of IL-8 signaling and reversal/attenuation when pepsin was inhibited (pepstatin) or IL-8 was blocked. These findings suggest potential downsides of pepsin exposure outside the stomach, but they do not prove causality for human cancer.

  • Interaction with dietary polyphenols (functional downside depending on context): In the apigenin-pepsin study, apigenin inhibited pepsin activity, and pepsin decreased apigenin’s antioxidant activity. This indicates pepsin can alter the functional activity of certain dietary antioxidants during digestion (direction and clinical relevance uncertain).

  • Structural/activity modulation by physical processing: Ultrasound was reported to activate pepsin activity and alter secondary/tertiary structure; prolonged treatment suggested partial recovery/resistance. This is mainly relevant to processing/industrial contexts, but it underscores that pepsin activity can be modified in ways that could change proteolysis intensity.

Evidence limitations: The reflux/cancer-related findings are largely from reviews, animal models, and in vitro/translational studies. The abstracts do not provide robust human clinical trial data quantifying pepsin-specific adverse effects, nor do they evaluate pepsin supplementation safety.

5. Is it beneficial or harmful for any genetic variations (pharmacogenomics)?

The provided abstracts do not report pharmacogenomic findings (e.g., genetic variants that modify response to pepsin exposure, pepsin inhibitors, or pepsin-related disease risk). While one study reports pepsin altered expression of carcinogenesis-related genes and microRNAs in exposed cells, this reflects gene expression changes rather than inherited genetic variation affecting response.

  • No variant-specific guidance: No data in these abstracts identify specific genotypes that predict benefit/harm from pepsin or pepsin-targeting therapies.

  • Research gap: Pharmacogenomic implications for pepsin-targeted approaches in LPR/LPRD remain unclear based on the provided evidence.

References

  1. Investigation of the interaction behavior between quercetin and pepsin by spectroscopy and MD simulation methods.
    Fatemeh Hashemi-Shahraki, Behzad Shareghi, Sadegh Farhadian (2023) - International journal of biological macromolecules
  2. Effects of acids, pepsin, bile acids, and trypsin on laryngopharyngeal reflux diseases: physiopathology and therapeutic targets.
    Yading Li, Gaofan Xu, Bingduo Zhou, Yishuang Tang, Xiaowen Liu, Yue Wu, Yi Wang, Jing Kong, Tingting Xu, Cong He, Shengliang Zhu, Xiaosu Wang, Jianning Zhang (2022) - European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery
  3. Exploration of binding mechanism of apigenin to pepsin: Spectroscopic analysis, molecular docking, enzyme activity and antioxidant assays.
    Jinying Guo, Chuanfa Gan, Bo Cheng, Bo Cui, Fankai Yi (2023) - Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy
  4. Effect of ultrasound and enzymatic pre-treatments on the profile of bioactive peptides of beef liver hydrolysates.
    Marta Gallego, Leticia Mora, Fidel Toldrá (2024) - Food research international (Ottawa, Ont.)
  5. Conformational alterations and functional changes of pepsin induced by a novel food supplement tetrahydrocurcumin: Multispectral techniques and computer simulations.
    Ruirui Cai, Jiaqing Luo, Chaolan Chen, Pei Ding, Xiaowei Wang, Kaiyu Yang, Xiner Zhu, Ying Guo, Baozhu Chi, Xun Tuo (2024) - International journal of biological macromolecules
  6. Effect of ultrasound on the activity and conformation of α-amylase, papain and pepsin.
    Zhi-Long Yu, Wei-Cai Zeng, Wen-Hua Zhang, Xue-Pin Liao, Bi Shi (2014) - Ultrasonics sonochemistry
  7. Oral and Inhaled Fosamprenavir Reverses Pepsin-Induced Damage in a Laryngopharyngeal Reflux Mouse Model.
    Nikki Johnston, Tina L Samuels, Christopher J Goetz, Leggy A Arnold, Brian C Smith, Donna Seabloom, Beverly Wuertz, Frank Ondrey, Timothy S Wiedmann, Nemanja Vuksanovic, Nicholas R Silvaggi, Alexander C MacKinnon, James Miller, Jonathan Bock, Joel H Blumin (2023) - The Laryngoscope
  8. Kinetics of pepsin-induced hydrolysis and the coagulation of milk proteins.
    Mengxiao Yang, Aiqian Ye, Zhi Yang, David W Everett, Elliot Paul Gilbert, Harjinder Singh (2022) - Journal of dairy science
  9. Pepsin promotes IL-8 signaling-induced epithelial-mesenchymal transition in laryngeal carcinoma.
    Jia-Jie Tan, Lu Wang, Ting-Ting Mo, Jie Wang, Mei-Gui Wang, Xiang-Ping Li (2019) - Cancer cell international
  10. Advances in laryngopharyngeal reflux: Etiology, diagnosis, and management.
    Tina L Samuels, Jennifer Aoun, Inna Husain, Edgar Figueredo, David Richards, Nikki Johnston (2024) - Annals of the New York Academy of Sciences
  11. Pepsin promotes proliferation of laryngeal and pharyngeal epithelial cells.
    Nikki Johnston, Justin C Yan, Craig R Hoekzema, Tina L Samuels, Gary D Stoner, Joel H Blumin, Jonathan M Bock (2012) - The Laryngoscope
  12. Review article: reflux and its consequences--the laryngeal, pulmonary and oesophageal manifestations. Conference held in conjunction with the 9th International Symposium on Human Pepsin (ISHP) Kingston-upon-Hull, UK, 21-23 April 2010.
    J P Pearson, S Parikh, R C Orlando, N Johnston, J Allen, S P Tinling, N Johnston, P Belafsky, L F Arevalo, N Sharma, D O Castell, M Fox, S M Harding, A H Morice, M G Watson, M D Shields, N Bateman, W A McCallion, M P van Wijk, T G Wenzl, P D Karkos, P C Belafsky (2011) - Alimentary pharmacology & therapeutics
  13. Amprenavir inhibits pepsin-mediated laryngeal epithelial disruption and E-cadherin cleavage in vitro.
    Tina L Samuels, Simon Blaine-Sauer, Ke Yan, Nikki Johnston (2023) - Laryngoscope investigative otolaryngology
  14. The Protease Inhibitor Amprenavir Protects against Pepsin-Induced Esophageal Epithelial Barrier Disruption and Cancer-Associated Changes.
    Simon Blaine-Sauer, Tina L Samuels, Ke Yan, Nikki Johnston (2023) - International journal of molecular sciences
  15. Exploring the interactions of naringenin and naringin with trypsin and pepsin: Experimental and computational modeling approaches.
    Xiangrong Li, Hongyi Liu, Xinzhe Wu, Ruonan Xu, Xiaoyi Ma, Congxiao Zhang, Zhizhi Song, Yanru Peng, Tianjun Ni, Yongtao Xu (2021) - Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy
  16. Pepsin in gastroesophageal and extraesophageal reflux: molecular pathophysiology and diagnostic utility.
    Tina L Samuels, Nikki Johnston (2020) - Current opinion in otolaryngology & head and neck surgery
  17. Airway reflux.
    Nikki Johnston, Frank Ondrey, Rachel Rosen, Bryan P Hurley, Jon Gould, Jacquie Allen, John DelGaudio, Kenneth W Altman (2016) - Annals of the New York Academy of Sciences
  18. Pepsin: biomarker, mediator, and therapeutic target for reflux and aspiration.
    Nikki Johnston, Peter W Dettmar, Frank G Ondrey, Rahul Nanchal, Sang-Hyuk Lee, Jonathan M Bock (2018) - Annals of the New York Academy of Sciences
  19. Antioxidant and antihypertensive effects of garlic protein and its hydrolysates and the related mechanism.
    Xudong Gao, Zihan Xue, Qiqi Ma, Qingwen Guo, Lisha Xing, Ramesh Kumar Santhanam, Min Zhang, Haixia Chen (2020) - Journal of food biochemistry
  20. Pepsin enhances glycolysis to promote malignant transformation of vocal fold leukoplakia epithelial cells with dysplasia.
    Haitong Li, Shasha Zhang, Shuihong Zhou, Yangyang Bao, Xiaojuan Cao, Lifang Shen, Bin Xu, Weimin Gao, Yunzhen Luo (2023) - European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery


Want personalized supplement recommendations based on your genetics?
Upload Whole Genome Sequencing (WGS) raw DNA data today!
Or upload raw DNA data to get started with your free analysis!