Understanding Pepsin’s Role in Laryngopharyngeal Reflux (LPR)

Many of us living with bronchiectasis, chronic cough, throat clearing, hoarseness, or reflux have heard the term LPR (laryngopharyngeal reflux). 

---

Sometimes called “silent reflux,” LPR occurs when stomach contents travel up into the throat and voice box.

For years, most of the attention was focused on stomach acid. But researchers now believe another culprit may play an important role: pepsin.

What Is Pepsin?

Pepsin is a digestive enzyme produced in the stomach. Its job is to break down proteins in the food we eat. In the stomach, pepsin is perfectly normal and helpful. The problem begins when pepsin travels to a place it doesn’t belong.

When reflux occurs, pepsin can be carried up into the throat, voice box, sinuses, and even the airways. Unlike the stomach, these tissues were never designed to handle digestive enzymes.

Why Pepsin Is Different From Acid

Many people assume that if their throat is no longer acidic, the danger has passed. Unfortunately, pepsin doesn’t always leave when the reflux episode ends. Research suggests that pepsin can attach itself to tissues in the throat and remain there long after the acid has disappeared. At neutral pH levels, pepsin may become inactive, but it doesn’t necessarily go away.


The Reactivation Problem

Here’s where things get interesting. Pepsin can remain stable in throat tissue and then become active again if it encounters acid later. Even a small amount of acid exposure may “wake it up.” In other words, today’s reflux episode may reactivate pepsin that arrived yesterday or even earlier.
This may help explain why some people continue to experience symptoms even when they aren’t actively feeling reflux.

Why the Throat Is So Vulnerable

Your stomach is designed to handle acid and digestive enzymes. It has a thick protective lining and specialized defenses.
Your throat and voice box do not.

The tissues of the larynx and pharynx are delicate and lack many of the protective mechanisms found in the stomach. As a result, even relatively small amounts of pepsin may contribute to irritation, inflammation, chronic throat clearing, cough, hoarseness, or the sensation of a lump in the throat.

What Does This Mean for People With Lung Disease?

Researchers are increasingly interested in the relationship between reflux, pepsin, and respiratory diseases such as bronchiectasis.
While many questions remain unanswered, one theory is that refluxed material containing pepsin may contribute to airway irritation and inflammation when it reaches the upper airway and lungs through microaspiration.

This is one reason many bronchiectasis specialists pay close attention to reflux symptoms, sleeping position, meal timing, and other strategies that may reduce reflux events.

Pepsin is more than just a digestive enzyme. When it reaches the throat, it may linger long after the reflux event has ended.
The important question isn’t simply, “Is my throat acidic right now?”
The question may also be, “Has pepsin reached tissue where it doesn’t belong?”

Understanding pepsin helps explain why LPR can be so frustrating. Symptoms may persist even when acid exposure appears minimal because the enzyme itself can remain behind, waiting for another opportunity to become active.

As researchers continue to learn more about reflux and airway disease, pepsin remains one of the most fascinating pieces of the puzzle.