Supplement analysis backed by scientific evidence · PT

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Moderate evidenceGut health

Resistant Starch

A starch that escapes digestion and is fermented in the colon, where it feeds butyrate-producing bacteria. Effects on the microbiome are consistent; effects on blood sugar and inflammation are small and depend on the type used.

Evidence last reviewed: August 2026

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What the science says

  • Fermentation and butyrate-producing bacteria Moderate evidence

    A randomized, double-blind, placebo-controlled human trial with resistant starch from high-amylose wheat showed shifts in the intestinal environment consistent with increased fermentation. Similar microbiome changes appear across trials, though the size varies a lot between individuals and starch types.

  • Glycemic control Moderate evidence

    A systematic review and meta-analysis found that resistant starch produced small improvements in fasting glucose and insulin sensitivity, with the clearest effects in people who already had impaired glucose metabolism.

  • Inflammatory markers Limited evidence

    A meta-analysis of randomized trials of resistant starch type 2 found no reliable effect on most circulating inflammatory mediators, with heterogeneous and mostly small studies.

Dosage & safety

Studied doseTrials generally used 15–40 g per day of resistant starch (roughly 20–50 g of a high-amylose or green banana/potato starch powder). Start low and build up over two weeks.
SafetyGas, bloating and rumbling are common in the first days and dose-dependent. People with SIBO or on a low-FODMAP diet often tolerate it poorly.

Scientific references

Where to buy

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