What Is Pepsin? How This Digestive Enzyme May Contribute to LPR, Chronic Cough, and Bronchiectasis
Many people living with bronchiectasis, chronic cough, chronic throat clearing, hoarseness, or laryngopharyngeal reflux (LPR) have heard the term silent reflux. Unlike classic acid reflux, LPR often causes symptoms in the throat rather than heartburn.
For years, stomach acid was considered the primary cause of damage. Today, researchers believe another substance may play an equally important role: pepsin.
What Is Pepsin?
Pepsin is a digestive enzyme produced in the stomach. Its normal job is to break down proteins in the food we eat. Inside the stomach, pepsin is both necessary and beneficial.
Problems begin when reflux carries pepsin into areas where it doesn’t belong.
During episodes of laryngopharyngeal reflux, pepsin may travel into the throat, voice box (larynx), sinuses, and even the airways. Unlike the stomach, these tissues have very little protection against digestive enzymes.
Why Pepsin Is Different From Stomach Acid
Many people assume that once stomach acid is gone, the damage stops. Pepsin behaves differently.
Research suggests that pepsin can adhere to tissues in the throat and remain there long after a reflux episode has ended. At a neutral pH, the enzyme becomes inactive, but it does not necessarily disappear.
How Pepsin Can Become Active Again
One of the most fascinating aspects of pepsin is its ability to reactivate.
If pepsin attached to throat tissue is exposed to acid during a future reflux episode, it may become active again. Even relatively small amounts of acid may “switch it back on.”
This means today’s reflux event may reactivate pepsin that reached the throat yesterday or even earlier.
This may help explain why many people with LPR continue to experience chronic throat symptoms even when they don’t feel active reflux.
Why the Throat Is So Sensitive
Your stomach is built to withstand acid and digestive enzymes. It has a thick protective lining and specialized defense mechanisms.
The throat and voice box do not.
Because the tissues of the larynx and pharynx are so delicate, even small amounts of pepsin may contribute to:
Chronic throat clearing
Chronic cough
Hoarseness
Voice changes
A sensation of a lump in the throat (globus)
Persistent throat irritation
Pepsin, Microaspiration, and Bronchiectasis
Researchers are increasingly studying the relationship between reflux, pepsin, microaspiration, and chronic lung diseases such as bronchiectasis.
Although many questions remain unanswered, one leading theory is that refluxed material containing pepsin may reach the upper airway—and, through microaspiration, potentially the lungs—where it may contribute to airway irritation and inflammation.
This is one reason many bronchiectasis specialists pay close attention to reflux management, including meal timing, sleeping position, airway protection, and other strategies that may reduce reflux events.
The Bottom Line
Pepsin is much more than a digestive enzyme. When it reaches the throat through laryngopharyngeal reflux (LPR), it may remain in the tissue long after acid has disappeared.
Rather than asking only, “Is my throat acidic right now?” researchers are increasingly asking another important question:
“Has pepsin reached tissue where it doesn’t belong?”
Understanding the role of pepsin helps explain why silent reflux, chronic cough, hoarseness, and throat clearing can persist even when acid exposure appears minimal.
As research continues to explore the connection between LPR, pepsin, microaspiration, and bronchiectasis, pepsin remains one of the most important and intriguing pieces of the reflux puzzle.
Want to Learn More about Bronchiectasis?
The BE CLEAR® Guide to Bronchiectasis is designed to help you understand and manage your chronic lung condition at your own pace. Whether you’re newly diagnosed or looking to strengthen your daily routine, the guide offers expert-informed content, practical suggestions, and compassionate support every step of the way.
