The conventional HCL challenge test involves the ingestion of Betaine Hydrochloride in order to gauge if the parietal cells of your stomach are producing adequate amounts of stomach acid. The test typically involves taking one HCL pill with food and then increasing by one per day until a burning occurs. If burning takes place at a low dose it is thought that this is because your stomach is producing adequate HCL. And if a burning occurs at a higher dose it is thought that it is due to low levels of HCL production in the stomach.
The problem is that this is absolutely not what is really happening with this test.
In fact, if a small dose of HCL produces burning, it is not because you have adequate HCL at all. If HCL supplements produce burning it indicates rather that your mucosal barrier is damaged! The HCL is producing burning because the acid is burning exposed tissues.
Under normal, healthy circumstances, a person should be able to tolerate a lot of Betaine HCL. HCL only contains about 2-3% hydrogen. The clinical response that occurs with Betaine HCL supplementation is more due to the Betaine than from HCL! If you are experiecing burning with only 500-3,500 mg of HCL, your gastro intestinal mucosal barrier is in a state of distress. Many researchers believe that a person with a healthy mucosal barrier should be able to tolerate upto 26 capsules of Betaine HCL!
People who are recommending HCL supplementation to people that having burning sensations after an HCL challenge test are only contributing to the breakdown of the mucosa. It is possible (and likely) that a person with a damaged mucosal barrier may have low levels of HCL being produced by their stomach, and have a need for more stomach acid. However, the mucosal barrier needs to be repaired first! Otherwise the implications are not good.
The Heidelberg ph test is probably the most accurate way to gauge HCL insufficiency. However this test is invasive and the Heidelberg machines are not easy to find. Blood tests can identify Hypochlorhydria fairly well, especially if the chloride value is less than 100, and if the Co2 level is greater than 27. However, chloride and Co2 values also identify other variables in the body. If the person has clinical signs of HCL insufficiency (gas, bloating after eating, undigested food ins stools) and their blood test correlates, then HCL insufficiency is likely.
Another way to accurately gauge HCL insufficiency is through HTMA (Hair Tissue Mineral Analysis). Clinicians have identified direct correlations between the Heidelberg ph test and low HTMA values.