4 Simple Ways to Test Stomach Acid at Home
- Marnie
- 4 days ago
- 5 min read
If you struggle with bloating, reflux, indigestion, nutrient deficiencies, or recurring gut issues, low stomach acid may be a missing piece of the puzzle.
Stomach acid isn’t just about breaking food down — it plays a vital role in:
Digesting protein
Absorbing nutrients like iron, B12, zinc, magnesium, and calcium
Preventing bacterial (SIBO) and yeast overgrowth
Supporting healthy enzyme production and gut motility
When stomach acid is low (a condition called hypochlorhydria), digestion slows down, food ferments instead of breaking down, and a cascade of symptoms can follow. Many of these symptoms don’t start in the stomach — they show up as energy dips, nutrient deficiencies, or recurring infections.
Here are four simple, practical ways to test your stomach acid levels at home, along with a deeper look at how low stomach acid often feels in everyday life.
Common Signs of Low Stomach Acid (And What This Looks Like in Real Life)
Low stomach acid shows up differently in each person. You do not need to have all of these signs — even one or two can indicate that your digestion needs support.
Here are the most common patterns my clients experience:
Bloating after meals
This can vary from person to person, some have slight bloating and others may experience bloating that makes you feel 3–6 months pregnant after eating.
You may notice:
Pressure or fullness high in the abdomen
Gas that feels trapped
Tight waistbands after meals
Bloating that increases as the day goes on
👉 This happens because food isn’t breaking down properly and starts fermenting in the stomach.
Feeling overly full quickly
Clients often describe this as:
“I take a few bites and feel done.”
“When I eat, I feel like my food just sits there.”
👉 Low stomach acid slows gastric motility, which can make even small meals feel overwhelming.
Reflux or burning (from pressure, not excess acid)
With low stomach acid, food ferments and gas builds up. That pressure pushes acid upward — even if acid levels are actually low.
This can look like:
Burning in the chest after meals
Nighttime reflux
Needing to sleep propped up
Burping acid into the throat
A sour taste after eating
👉 Many people are shocked when reflux improves by supporting stomach acid, not suppressing it.
Undigested food in stool
If you regularly see undigested food in your stool, it is a sign that your food isn’t being broken down well.
Clients often say:
“It looks like my meal went right through me.”
“I see bits of food all the time.”
👉 Some vegetable particles are normal — but consistent undigested food is a sign of low stomach acid or low enzymes.
Constipation or diarrhea
Because digestion starts in the stomach, low stomach acid affects every step that follows.
It can cause:
Constipation → from slowed digestion and motility
Diarrhea → from irritation, fermentation, or bacterial imbalance
👉 Some people alternate between constipation and diarrhea, which is a common sign of dysbiosis related to low stomach acid. In the gastrointestinal world, this pattern is often labeled as Irritable Bowel Syndrome (IBS), and many are prescribed Prilosec or another PPI — which can actually worsen the underlying issue by further lowering stomach acid.
Fatigue or weakness after meals
Clients often describe this as:
“I crash after eating.”
“I need a nap after lunch.”
“My body feels heavy after meals.”
👉 Poor digestion requires more energy. When you aren’t absorbing nutrients well, your body has little to work with, which leads to tiredness and mid-afternoon slumps.
Nutrient deficiencies that don’t improve with supplements
This is one of the biggest red flags I see.
Low stomach acid can prevent absorption of:
You might notice:
Brittle nails
Cracks in the corners of the mouth
Pale tongue
Weakness or dizziness
Many clients tell me:
“I keep taking supplements, but nothing changes.” If stomach acid is low, you will not absorb what you’re taking very well, so you will not reap the benefits!
4 Simple Ways to Test Stomach Acid at Home
These at-home tests give you valuable insight into how your digestion is working.
1. The Baking Soda Test - A quick morning screening tool
How to do it:
Before food or drinks, mix ¼ tsp baking soda in 4–6 oz water.
Drink it.
Time how long it takes to burp.
What it means:
Burping within 1–3 minutes → likely normal stomach acid
No burping after 5 minutes → possible low stomach acid
👉 Not a diagnosis, but a good starting point.
2. The Protein Tolerance Test - A real-life digestion check
Stomach acid is essential for breaking down protein. When levels are low, protein meals feel heavy or unpleasant.
Signs to look for after eating protein:
👉 If protein consistently feels hard to digest, low stomach acid may be part of the picture. Many people even develop an aversion to protein — not because they dislike it, but because their body intuitively remembers how heavy, uncomfortable, or overly full it makes them feel.
3. The Apple Cider Vinegar Challenge - Does adding acid improve digestion?
How to do it:
Mix 1 tsp–1 Tbsp of raw apple cider vinegar in water
Drink before a meal
What it means:
Digestion improves → likely low stomach acid
Burning or discomfort → stop (may indicate irritation or an ulcer)
4. The Betaine HCl Trial - The most accurate at-home method — do this with guidance
A supervised trial of Betaine HCl with Pepsin helps determine if adding acid improves digestion.
You may notice:
Less bloating
Better tolerance of protein
More energy after meals
Avoid this method if you:
Have ulcers
Take NSAIDs or PPIs
Have known gastritis
This is a test I commonly use alongside blood work and GI-MAP testing.
Why Low Stomach Acid Leads to Bigger Gut Issues
When food isn’t properly broken down, it affects everything below the stomach.
Low stomach acid can lead to:
SIBO (Small Intestinal Bacterial Overgrowth)
Yeast and parasite overgrowth
Food sensitivities from undigested proteins
Chronic inflammation in the gut
Nutrient deficiencies
👉 Supporting digestion from the top down is often the missing link for people who feel stuck.
Low stomach acid is incredibly common — especially in times of chronic stress, hormonal shifts, and nutrient depletion. The good news? It’s also very addressable once you know what’s really going on.
These four simple at-home tests are a powerful place to start. If you see yourself in these symptoms or want deeper insight into your digestion, I offer a full root-cause approach using:
Targeted nutrient and digestive support
A personalized plan based on your unique needs
👉 You don’t have to guess. I’m here to help you feel better, digest better, and understand what your body is trying to tell you.