Supplement analysis backed by scientific evidence · PT

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Limited evidenceGut health

Humic Acid

A soil- and peat-derived mixture of organic acids sold for gut and immune support. Almost all of the research is agricultural; there is essentially one small human study, and it measured bacteria, not health.

Evidence last reviewed: August 2026

What the science says

  • Colonic microbiota Limited evidence

    An open-label study followed 14 healthy volunteers taking an oral humic acid preparation for 45 days and found total colonic bacterial concentrations rose while individual microbial profiles and diversity stayed unchanged. There was no control group and no clinical outcome was measured.

  • Immune support Limited evidence

    Claims about immunity rest on livestock and laboratory work; no controlled human trial has tested humic or fulvic acid supplements against infection rates or any immune endpoint.

  • Detoxification and heavy metals Limited evidence

    Humic substances bind metals in soil and water, which is the source of the marketing claim, but no human trial shows that oral supplementation removes heavy metals from the body, and the raw material can itself carry contaminants.

Dosage & safety

Studied doseThe single human study used 3 × 800 mg/day for 10 days followed by 3 × 400 mg/day for 35 days. Label doses vary widely and are not based on dose-finding work.
SafetyNo serious adverse events were reported in the one small study, but safety data in humans are minimal. Because humic and fulvic products are extracted from soil, peat or shale, heavy metal contamination is a genuine concern; choose third-party tested products. Avoid in pregnancy, breastfeeding and children given the absence of data.

Scientific references

Where to buy

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