Alkaline Water for Pepsin and Silent Reflux: What the Research Actually Shows
Short answer: In lab studies, high-pH water switched pepsin off. In people, the only study combined alkaline water with a diet change, so we can't tell how much the water itself did. Alkaline water is a reasonable, low-risk add-on during a low-acid phase, but it doesn't replace the rest of your care.
In this post
Why pepsin matters in silent reflux
What the lab studies found
What happened when people tried it
What about bicarbonate mineral water for heartburn?
How I'd use it, if you want to try it
The takeaway
If you have silent reflux (laryngopharyngeal reflux, or LPR), you've probably seen "pH 8.8 water" recommended somewhere online. Some posts make it sound like the answer. Others call it a gimmick.
The research sits in between. The lab science is interesting, the human evidence is thin, and the water is a low-risk thing to add if you understand what it can and can't do. Here's what each study found, what it can't tell us, and how I'd use alkaline water myself.
Why pepsin matters in silent reflux
Pepsin is a digestive enzyme your stomach makes to break down protein. When reflux travels up into your throat, pepsin can come along with it and settle into the tissue there.
Pepsin needs acid to work. Once it's sitting in throat tissue, it can be switched back on whenever acid shows up again, from the next reflux episode or from acidic foods and drinks. That's one reason throat symptoms like clearing, hoarseness and a burning feeling can linger even when heartburn is under control.
I dealt with constant throat clearing and a burning throat that no one could explain. If that sounds familiar, read why you're always clearing your throat and why PPIs often don't work for LPR. PPIs lower the amount of acid your stomach makes, and they don't address the pepsin that has already reached your throat.
What the lab studies found
Both studies in this section were done in a lab, in test tubes, not in people.
Johnston, 2007. This lab study looked at how pepsin behaves at different pH levels. Pepsin was inactive at pH 6.5 and above, but it stayed stable up to pH 8.0, so it could come back. Pepsin held for 24 hours at pH 7.0 and body temperature (37°C) regained 79% (±11%) of its activity when it was re-acidified to pH 3.0.
In plain words: bringing the pH up to around neutral quiets pepsin for a while, but when acid returns, most of that pepsin can switch right back on.
Koufman, 2012. This lab study tested a naturally alkaline artesian water with a pH of 8.8 that contains bicarbonate. In the test tube, the pH 8.8 water irreversibly inactivated human pepsin, meaning it didn't come back when acid was added. The water's acid-buffering capacity (its ability to absorb acid without its pH dropping) also far exceeded that of two popular bottled waters.
Together, these two studies are where the "pH 8.8" idea comes from. Water above pH 8 behaved differently from water near neutral. That's a real and interesting finding, and it happened in a test tube. A test tube can't show us what happens when you drink water and it passes through your throat on its way to your stomach.
What happened when people tried it
Zalvan, 2017. This is the only study in people, and it looked back at patient charts rather than running a new trial. It compared two groups of people with LPR symptoms, each treated for 6 weeks:
85 people treated with a PPI plus standard reflux precautions
99 people treated with alkaline water (pH above 8.0), a 90% plant-based Mediterranean-style diet, and standard reflux precautions
The main measure was a reflux symptom score. A clinically meaningful drop (6 points or more) happened in 54.1% of the PPI group and 62.6% of the diet group, which was not a significant difference. The average reduction in symptom score was 27.2% in the PPI group and 39.8% in the diet group, which was a significant difference.
The fair summary: the diet group did about as well as the PPI group.
There are limits to keep in mind:
The water and the diet were combined. There's no way to separate what the water did from what the diet did.
It wasn't randomized. The two groups were treated in different years, so other differences between them could explain some of the results.
The water was pH above 8.0, so this study doesn't tell us anything about a specific brand or pH.
No randomized trial has tested alkaline water on its own for LPR or GERD. That's the honest state of the evidence.
What about bicarbonate mineral water for heartburn?
You may also see mineral water recommended for heartburn. That's a different product with a different study behind it.
Labenz, 2023. This randomized trial of 148 people with frequent heartburn compared a bicarbonate-rich mineral water with a conventional mineral water that had far less mineral content. In the bicarbonate group, 84.72% of people met the study's definition of a responder, compared with 63.51% in the comparison group.
Three things to know before you apply this to silent reflux:
It tested a bicarbonate mineral water, not high-pH alkaline water.
It measured heartburn, not throat symptoms from LPR.
It was funded by the company that makes the water.
It's a useful result for heartburn, and it doesn't tell us anything about pepsin in your throat.
How I'd use it, if you want to try it
I think of alkaline water as an add-on during a temporary low-acid phase. That's a window of time when you eat and drink fewer acidic foods and drinks while irritated tissue settles. It's a phase, not a forever diet.
During that window, alkaline water can be one of your drinks. It fits alongside the rest of the plan (meal timing, the foods you eat, how you breathe and sleep) and doesn't replace any of it. For the food side, start with my list of silent reflux foods to avoid.
If you have a medical condition that affects your fluid or mineral balance, check with your care team before adding it.
My picks: alkaline pH drops
Buying pH 8.8 bottled water every day gets expensive. What I like, and what I use with clients, is alkaline pH drops added to regular water: Alkalife or Alkazone. They're a convenient way to raise the pH of water at home. Follow the label for how many drops to use.
To be clear about the evidence: pH drops are not the product the studies tested. Koufman used a pH 8.8 artesian bicarbonate water, and Zalvan used water above pH 8.0. The drops are a practical way to make higher-pH water, not a studied treatment.
You can find both in my Amazon storefront: https://www.amazon.com/shop/zucchini.who. This is my Amazon storefront, and I may earn a small commission if you buy through it, at no extra cost to you.
The takeaway
Alkaline water has interesting lab science behind it and very little human evidence. If you want to try it, use it as one drink during a temporary low-acid phase, alongside the rest of your plan. Don't use it in place of that plan. pH drops in regular water are the easiest way to start.
Pepsin is one piece of the silent reflux picture, and it's the piece most people never hear about. If you want a plan that addresses all of it, apply to work 1:1 with our team of reflux dietitians at https://www.mollypelletier.com/acid-reflux-specialist, or start with the Reflux Relief Masterclass at https://www.mollypelletier.com/acid-reflux-relief-masterclass.
With love,
Molly Pelletier, MS, RD
Verified Citations
Johnston N, Dettmar PW, Bishwokarma B, Lively MO, Koufman JA. Activity/stability of human pepsin: implications for reflux attributed laryngeal disease. Laryngoscope. 2007;117(6):1036-1039. In vitro. PMID 17417109. https://doi.org/10.1097/MLG.0b013e31804154c3
Koufman JA, Johnston N. Potential benefits of pH 8.8 alkaline drinking water as an adjunct in the treatment of reflux disease. Ann Otol Rhinol Laryngol. 2012;121(7):431-434. In vitro. PMID 22844861. https://doi.org/10.1177/000348941212100702
Zalvan CH, Hu S, Greenberg B, Geliebter J. A Comparison of Alkaline Water and Mediterranean Diet vs Proton Pump Inhibition for Treatment of Laryngopharyngeal Reflux. JAMA Otolaryngol Head Neck Surg. 2017;143(10):1023-1029. Retrospective. PMID 28880991. https://doi.org/10.1001/jamaoto.2017.1454
Labenz J, Anschütz M, Walstab J, Wedemeyer RS, Wolters H, Schug B. Heartburn relief with bicarbonate-rich mineral water: results of the randomised, placebo-controlled phase-III trial STOMACH STILL. BMJ Open Gastroenterol. 2023;10(1). Funded by Fachingen Heil- und Mineralbrunnen GmbH. PMID 36849190. https://doi.org/10.1136/bmjgast-2022-001048
