Low Stomach Acid vs High Stomach Acid: How to Tell the Difference
What Is Stomach Acid?
Stomach acid (hydrochloric acid, or HCl) plays a central role in digestion. It helps break down protein, activates digestive enzymes, kills incoming pathogens, and signals downstream digestive processes in the small intestine.
When stomach acid levels are optimal, digestion runs smoothly. When they’re too low (a state known as hypochlorhydria), symptoms can appear that are often mistaken for “too much acid.”
When food is smelt, chewed, and enters the stomach, it prompts the release of hydrochloric acid (HCl). HCl is instrumental in many functions such as digestion of food, nutrient absorption, microbial defense* and protein breakdown.
*Low stomach acid is a common cause of SIBO.
Is Heartburn a Sign of Low Stomach Acid?
Contrary to common belief, both excess and insufficient stomach acid can contribute to acid reflux or heartburn, characterised by a burning sensation in the chest.
Many people assume symptoms like heartburn, nausea, or reflux mean they produce too much stomach acid. They’re often told to take a PPI (proton pump inhibitor) or another type of acid blocker to “handle their issue”. In reality, low stomach acid can cause very similar symptoms.
When acid levels are insufficient, food isn’t broken down properly. This can lead to fermentation, gas production, delayed stomach emptying, and pressure pushing stomach contents upward, triggering reflux-like symptoms even in the absence of excess acid.
Why Do We Need Stomach Acid?
An often overlooked fact is the vital role stomach acid plays in maintaining good gut health. Prolonged use of antacids can have significant adverse effects.
There are crucial multiple digestive functions that rely on an adequate amount of stomach acid, making the long-term use of proton pump inhibitors (PPIs) come with certain consequences, namely nutrient deficiencies. If you need help weaning off PPIs, please have a look at my article on How to Get off PPIs Safely.
Note that as we age, stomach acid production declines. The older you are, the more likely your reflux is caused by too little stomach acid (hypochlorhydria) instead of too much. In younger individuals and children, the same symptoms could be due to true hyperchlorhydria.
Why You Might Have Been Misdiagnosed
I often see people with symptoms of low stomach acid who have been told they produce too much acid and need to suppress it. It’s often not the case. While excess acid does occur in some cases, it is not the most common driver of reflux-like symptoms in otherwise healthy individuals.
Adequate stomach acid plays a key role in coordinating digestion. It helps break down protein, signals the release of bile and pancreatic enzymes, and supports normal gastric emptying into the small intestine through coordinated hormonal and nervous system pathways.
When stomach acid is insufficient, digestion becomes less efficient. Food may linger in the stomach longer than intended, increasing fermentation and gas production. This leads to gastric distension and pressure, which is a well-established trigger for relaxation of the lower esophageal sphincter (LES).
LES relaxation allows stomach contents — whether highly acidic or not — to move upward into the esophagus, creating symptoms commonly labeled as heartburn or acid reflux. In this context, the problem is not excess acid production, but impaired digestion and delayed gastric emptying.
This overlap in symptoms is one reason low stomach acid is frequently mistaken for high stomach acid.
A word on GERD (Gastroesophageal Reflux Disease)
Gastroesophageal reflux disease (GERD) is a real medical condition and, in some cases, acid suppression is appropriate and necessary. It is particularly important when there is esophageal inflammation, ulceration, severe gastritis or confirmed acid injury.
However, not all reflux symptoms meet criteria for GERD, and not all heartburn is caused by excess stomach acid. In functional or non-erosive reflux, factors such as impaired digestion, delayed gastric emptying, gut-brain signaling, and pressure dynamics often play a larger role than acid levels alone.
This is why symptom-based treatment without assessing digestive function can sometimes miss the underlying issue.
Symptoms of Low Stomach Acid (Hypochlorhydria)
In cases of Low Stomach Acid, the following symptoms can occur:
Bloating, burping or gas shortly after meals
Feeling full quickly
Fatigue after meals
Undigested food in stool
The main consequences of hypochlorhydria can be divided in 3 main categories:
Digestive issues
Insufficient stomach acid can impede proper food breakdown, leading to fermentation and gas production. This can exert pressure on the lower esophageal sphincter (LES), allowing stomach acid to reflux into the esophagus.
Nutrient Absorption
Low stomach acid may compromise the absorption of vital nutrients, contributing to indigestion and other digestive discomforts. If you have low vitamin B12 levels or low iron levels, it is a key indicator that digestion and/or absorption is impaired.
Bacterial Overgrowth:
As stomach acid is our first list of defense, when it is low, it allows for microbes to survive the stomach environment and make their way into our intestines, potentially causing overgrowth or infections. If you were able to get testing done and have found that you have Helicobacter Pylori or SIBO (Small Intestinal Bacterial Overgrowth), these are very good indicators that your reflux is likely due to lowered stomach acid production.
Symptoms of High Stomach Acid (Hyperchlorhydria)
Conversely, in cases of High Stomach Acid, we commonly see:
Classic Heartburn
Excessive stomach acid can overwhelm the LES, permitting acid to escape into the esophagus, resulting in the classic symptoms of heartburn. Some people may experience a sour taste in the mouth, nausea or vomiting.
Gastric Ulcers
Prolonged high acid levels may contribute to the development of gastric ulcers, intensifying discomfort and raising the risk of complications. A caveat that will get confusing here is that if you have H. Pylori, the gastric ulcer could be due to this infection damaging the lining of the stomach walls.
This is why it is important to test for this bacteria (through an urea breath test or via stool) if you have known ulcers or reflux symptoms.
Can You Test for Low Stomach Acid?
There is no reliable, simple at-home test that definitively diagnoses low stomach acid.
Clinical assessment by a practitioner may include:
Symptom patterns
Nutrient deficiencies
Response to dietary or digestive support
In some cases, functional lab testing can also provide important clues.
The Baking Soda Test
If your symptoms are mild, you can try an at-home Baking Soda test.
Note that this test hasn’t been proven scientifically yet but has obtained good anecdotal evidence. This is not a diagnostic tool and should only be used for general guidance only.
Some people even have no symptoms at all, or symptoms that seem unrelated such as cough, difficulty breathing or a feeling of a lump in their throat. This is known as Silent Reflux.
Common Food Triggers for Acid Reflux Symptoms
Certain foods can trigger reflux symptoms in many people, whether their acid levels are high or low. Common triggers include:
Acidic foods (e.g., citrus fruits and tomatoes)
Alcohol
Caffeine
Dark chocolate
High-fat foods
Peppermint and Spearmint
Spicy foods
If you’ve been diagnosed with acid reflux or GERD, it can be helpful to limit these triggers, especially during flare-ups. Avoiding meals within three hours of lying down or going to sleep may also reduce symptoms, as reflux is more likely when digestion is incomplete and the stomach is full.
Supporting Healthy Stomach Acid Levels
There are a few ways you can improve your situation without medication.
The goal here isn’t to force stomach acid higher, but rather to support normal digestive signaling. A few things that can help:
Dietary Adjustments
Including fermented foods and bitter herbs (there are many blends existing on the market) prior to meals can stimulate digestion and secretion of stomach acid. Ensure you have adequate protein intake for your needs. Addressing nutrient deficiencies is also a must. I highly recommend you work with a nutritionist or dietician for proper support. If your mucosa is irritated, avoid spicy foods, caffeine and alcohol.
Lifestyle Changes
Eat smaller meals, in a relaxed state, and chew thoroughly. Avoid lying down just after eating. A short walk post-meal does wonders. Stress management also contributes to optimal stomach acid function, so I usually recommend a few rounds of mindful breathing before eating.
Supplementation:
Acid supplementation should always be individualized. If herbal bitters don’t cut it for you, you could try supplementing with Betaine HCl. However, not everyone should use Betaine HCl, so only do so under the supervision of an experienced practitioner.
Heartburn isn’t always a sign of too much stomach acid. For many people, low stomach acid plays a major role in reflux, indigestion, bloating, and discomfort after meals. When digestion is incomplete, pressure builds in the stomach and symptoms can look identical to acid excess.
Restoring proper digestion by supporting stomach acid production, meal timing, and gut health can lead to fewer reflux episodes and more comfortable digestion. If symptoms persist despite lifestyle or dietary changes, it’s important to look beyond symptom suppression and explore what’s actually happening in the digestive system.
🧡 Found this information useful? You can buy me a coffee / leave me a tip to support my work. 🧡