Immunoglobulin G
Immunoglobulin G (IgG) is the most common type of antibody in the blood. Supplements usually take it from bovine colostrum or serum.
What it is studied for
The strongest rated effects first. Bars show the size of the effect, the letter grades the evidence, and each rating lists the studies behind it.
What kind of IgG is covered here?
This page reviews oral serum-derived bovine immunoglobulin/protein isolate, or SBI. The studied material contains more than 50% immunoglobulin G alongside other serum proteins; it is not purified IgG alone. 1
Why people take it
SuppCo community snapshot, 2026-09-28. Reasons for use are not evidence that it works.
Questions people ask
Is oral SBI proven to repair a “leaky gut”?
The eight-week mechanistic study found no significant improvement in intestinal permeability. 2
Is it established for general immune support?
The studies reviewed here concern IBS with diarrhea, not prevention of everyday infections. 1 2
Does a pediatric pilot establish routine use in children?
No. The small three-week trial is preliminary and calls for larger, longer studies. 3