What Is Pepsin?
Pepsin is an enzyme – a type of protein that helps carry out a chemical reaction. More specifically, pepsin is a protease (also sometimes called a peptidase): an enzyme that helps break proteins down into smaller pieces [1, 2].
Pepsin is one of the three major protein-digesting enzymes in the digestive system – the other two are chymotrypsin and trypsin. Pepsin is the first to start digesting proteins from the food you eat. The other two take over after pepsin has done the initial work [3+].
- Aids protein digestion
- Helps correct low stomach acid
- Kills bacteria in the stomach
- Relieves chronic stomach inflammation (gastritis)
- May reduce symptoms of autism in combination with other enzymes
- Can act as a marker of acid reflux
- Not much evidence supporting the use of supplements
- Often used in combination with other enzymes
What Does it Break Down?
Broadly speaking, pepsin breaks down proteins .
Proteins are made up of lengthy chains of amino acid building blocks. Pepsin is able to sever the connections between amino acids, thus breaking long protein chains into shorter chains called peptides [1, 3+].
Aspartic peptidases like pepsin are thought to play a role in diverse diseases, from stomach ulcers to breast cancer to Alzheimer’s disease [3+].
After pepsin has done its job, the peptides it released pass to the intestine. Here other peptidases and proteases further break them down into amino acids you can absorb. Your body then uses these amino acids to build new proteins or burns them for energy [6, 7].
Where Is it Produced and Found?
In acid reflux, stomach contents make their way up the esophagus or food pipe. In such cases, pepsin can also be found in the esophagus, saliva, and even in the lungs and airways. This can cause damage and inflammation [9+, 10].
Pepsinogen to Pepsin
The normal production of pepsin in the body is quite tightly regulated. Your body has to ensure that pepsin doesn’t digest important proteins in cells, which would cause serious damage.
For this reason, cells first make an inactive precursor to the enzyme, called pepsinogen. Pepsinogen is then released from cells, secreted into the stomach, and only then transformed to the active pepsin as needed .
Pepsin Uses & Benefits
In a study of 92 people with indigestion without a clear biological cause (called “functional dyspepsia), a pepsin-based treatment decreased symptoms like abdominal pain after 6 weeks of treatment [12, 13].
2) Low Stomach Acid
Pepsin supplementation can help correct low stomach acid – called hypochlorhydria or achlorhydria – especially when combined with an acid supplement like hydrochloric acid (pepsin HCl), as well as dietary changes [14+, 15, 16].
In addition to helping with digestion and abdominal pain, resolving low stomach acid can also help prevent bacterial infections and intestinal inflammation; it may even play a role in combating malnutrition [14+, 17, 15].
3) Diagnosing Stomach Cancer
Low levels of pepsinogen are linked with a higher likelihood of developing stomach cancer. Some have proposed using pepsinogen levels in the blood to help in early cancer diagnosis – though there is debate as to the usefulness of this strategy [18, 19, 20, 21, 22].
In trials including over 147 children and adults with autism spectrum disorder, pepsin-containing supplements had a range of beneficial effects. Supplementation helped improve behavior and emotional responses while decreasing vomiting [23, 24].
5) Relieving Chronic Gastritis
In one study, 82 people with chronic gastritis – long-term irritation of the stomach – were given pepsin tablets after meals. Pepsin treatment was effective for 75% of the people .
6) Killing Bacteria
Pepsin has been shown to kill bacteria in the lab. It is thus plausible that, in the stomach, pepsin might also help destroy bacterial invaders .
7) As a Reflux Marker
Reflux is when contents from the stomach come up the esophagus, causing issues like heartburn .
Pepsin from stomach juice can damage the cells in the esophagus – but residual pepsin can also be used to diagnose reflux events. Leftover pepsin in the esophagus can indicate that stomach contents “refluxed” [31, 32, 9, 33].
8) In Industry and Labs
Because pepsin cuts up protein chains at a specific sequence, laboratories use it to produce specialized proteins like F(ab’)2 fragments – portions of antibodies that are useful in some lab assays [40, 40].
Pepsin Food Sources & Natural Boosters
Pepsin is not found in food since it would basically digest your food before you got a chance to eat it. The human body can produce all the pepsin it needs. But certain foods can up your natural pepsin production [9+, 3+].
Pepsin Dosage & Supplements
Typically, a capsule contains around 20 mg of the enzyme.
Pepsin supplements, primarily pills, are available and are marketed to “aid digestion.” There do not appear to have been rigorous trials of such supplements in people.
HCl with Pepsin
Pepsin only works at low pH – that is, in highly acidic environments. Although the stomach is usually naturally acidic, some pepsin supplements include HCl (hydrochloric acid) to ensure acidity in which the enzyme can function optimally – particularly in people with low stomach acid [42+, 43+].
Betaine HCl with Pepsin
However, you shouldn’t use Betaine HCl if you have normal gastric acid levels, as too much acid can damage the stomach lining and cause ulcers .
If you’re not sure whether your gastric levels are low, some practitioners recommend doing an “HCl challenge”: buy a supplement with betaine HCl (or betaine HCl with pepsin). Take 1 capsule before a large meal. If you feel burning or warmth in your stomach, indigestion, or an “acidic” sensation, you are probably producing enough gastric acid already. In that case, you shouldn’t take betaine HCl. If you don’t feel different, you may be deficient.
Practitioners recommend slowly increasing the dosage until you feel stomach warmth (but not to an unpleasant extent).
In addition to pepsin, Okra Pepsin contains extracts from okra, which has various health benefits, as well as fiber and mucilage.
This combined supplement does not appear to have been scientifically studied specifically, but it is often used to help aid in gut health.
Users of pepsin (alone or with betaine HCl) often report positive experiences, saying it helps relieve gut issues like heartburn. One user with poor digestion due to low stomach acid described betaine HCl with pepsin as the “best solution.”
However, other reviews are far less rosy. Users complained that supplementation didn’t improve their digestion at all.
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Pepsin is one of the most important protein-digesting enzymes. It starts working in your stomach and all the other enzymes that break down proteins in your intestines depend on it.
In combination with other digestive enzymes and/or Betaine HCl, supplemental pepsin can help with indigestion and low stomach acid, while it may also reduce symptoms of autism and kill harmful stomach bacteria. Ketogenic and high-protein diets might also boost your pepsin production.