Enzyme

Pepsin (Aspergillus niger)

Also known as: fungal pepsin, microbial pepsin, Aspergillus niger pepsin, acid protease

Evidence

Pepsin is a proteolytic enzyme derived from Aspergillus niger fungus that breaks down proteins in acidic environments, primarily used in digestive support supplements. It is commonly paired with betaine HCl to support gastric protein digestion in individuals with low stomach acid.

Last reviewed June 2026 · Evidence graded from peer-reviewed research, not editorial opinion. Educational only — not medical advice.

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Primary uses

Protein digestion support
Digestive enzyme replacement
Hypochlorhydria support (low stomach acid)

How it works

Proteolytic enzyme that cleaves peptide bonds in acidic pH (optimal pH 1.5-2.5)
Breaks down dietary proteins into smaller peptides for improved absorption

Dosage

Typical range: 100-500 mg per dose
Timing: With meals, particularly protein-containing meals
With food: Must be taken with food; requires acidic gastric environment to be effective
Duration: May be used short-term or as ongoing digestive support; no established maximum duration
Special populations: Should not be used by individuals with peptic ulcer disease or severe gastritis without medical supervision

Forms

Capsule· 70/100
Tablet· 70/100

Safety

Common side effects

Generally well-tolerated
Rare: mild GI discomfort, nausea

Contraindications

Active peptic ulcer disease
Severe gastritis or esophagitis
Allergy to Aspergillus species

Products containing Pepsin (Aspergillus niger)

Top-scoring supplements in our catalog that list Pepsin (Aspergillus niger) on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.

Nutricost

Betaine HCI + Pepsin Capsules

Advanced Digestive Enzymes

See all products →

Evidence notes

Limited clinical evidence specific to Aspergillus niger-derived pepsin. General enzyme therapy shows modest evidence; fungal pepsin efficacy compared to animal-sourced pepsin is not well-established in RCTs. Most evidence is theoretical or from small studies.

Grade C: Mostly observational or small trials; mechanism is plausible but unproven at scale.

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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Individual needs and risks vary — consult a professional before starting, stopping, or combining supplements, especially if you are pregnant or nursing, taking medication, or managing a health condition.