Reviewed by: 69Fun Health Editors
Clinical Guideline Standard: ATA / AACE 2026 Reference Protocol
Do you bloat in your upper abdomen within 30 minutes of a protein meal? Are your iron or ferritin levels still low even on high-dose supplements? Are your fingernails brittle and ridged? For people with Hashimoto’s thyroiditis, those are classic signs of hypochlorhydria — low stomach acid — a problem that interferes with nutrient breakdown and with dissolving your thyroid hormone tablet.
The Immune Overlap: Hashimoto’s and Atrophic Gastritis
In healthy digestion, gastric parietal cells release concentrated hydrochloric acid (HCl), which brings stomach pH down to 1.5 to 2.2. You need that acidity to:
- Break dense dietary proteins down into usable peptide chains.
- Free elemental iron (Fe2+), zinc, calcium, and vitamin B12 from the protein complexes in food.
- Kill pathogens swallowed with food, which helps prevent small intestinal bacterial overgrowth (SIBO).
- Dissolve synthetic levothyroxine tablets.
But there’s an autoimmune overlap. Between 35% and 54% of Hashimoto’s patients make anti-parietal cell antibodies (APCA). Those antibodies gradually damage the acid-producing pumps in the stomach lining, and the result is hypochlorhydria or, in the worst cases, complete achlorhydria.
The Betaine HCl with Pepsin Titration Challenge
With guidance from an integrative endocrinologist or functional medicine physician, patients can test for low stomach acid using the graded Betaine HCl titration protocol:
- Eat a meal with at least 20 grams of solid protein (chicken, fish, beef, or tofu).
- Halfway through the meal, take one 500 mg capsule of Betaine HCl with pepsin.
- Watch how you feel over the next 45 minutes.
If your stomach acid is healthy, you’ll feel a mild, clear warmth or heartburn in your chest or stomach. That means your baseline acidity is normal, and you should stop. If you feel no warming or burning at all, that points to low acid — your stomach isn’t making enough of its own.
On later protein meals, you raise the dose by 1 capsule per meal until you reach that faint warming point. That dose becomes your maintenance dose.
Critical Safety Contraindication
Never take Betaine HCl if you have active peptic ulcer disease or gastritis, or if you regularly take NSAIDs (such as ibuprofen or naproxen) or corticosteroids. The combination can damage the stomach lining.
You can check your nutrient status here:
This article is educational only and is not medical advice. Please see your doctor before trying Betaine HCl or any similar protocol.