Immunoglobulins

ProteinBest with a meal

What is it

Immunoglobulins (also called antibodies) are Y-shaped proteins produced by the immune system. In supplements, they are usually concentrated from bovine serum or colostrum to provide oral antibody activity in the gut.

Evidence for 2 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Chronic loose stools (IBS-D, HIV enteropathy)

Good Evidence

Serum-derived bovine immunoglobulin is FDA-regulated as a medical food for management of chronic loose stools and has clinical trial support in IBS-D and HIV-associated enteropathy at 5 to 10 g/day.

Gut barrier support

Limited Evidence

Limited human data and animal studies suggest immunoglobulins may bind lipopolysaccharide and reduce intestinal permeability markers; clinical relevance varies.

How it works

Oral immunoglobulin supplements work primarily in the lumen of the small intestine, where the antibodies bind to bacterial toxins (lipopolysaccharide), pathogenic bacteria, and viral particles. Because they are proteins, immunoglobulins are largely digested before reaching the bloodstream, so their effects are local rather than systemic. The main supplemental form is serum-derived bovine immunoglobulin (SBI), a powder containing more than 50 percent immunoglobulin G (IgG) plus other proteins. SBI is also sold as a medical food (EnteraGam) for management of chronic loose stools in HIV-associated diarrhea and IBS-D. Bovine colostrum is a related source that contains immunoglobulins alongside growth factors, lactoferrin, and oligosaccharides. Colostrum-based products have lower IgG concentrations than purified SBI.

Dosage

Serum-derived bovine immunoglobulin doses are 2.5 to 10 g/day in clinical studies. Colostrum doses are usually 10 to 20 g/day to deliver a similar amount of IgG. Effects on diarrhea typically appear within 1 to 2 weeks of consistent use.

When and how to take it

Take immunoglobulin powders or capsules with meals to maximize binding to gut antigens during digestion. Splitting the daily dose across 2 or 3 meals is common in clinical use. Consistent daily use over at least 2 weeks is needed to assess effect on GI symptoms.

2 commercial forms

Compare the main delivery options and what they’re best suited for.

Serum-derived bovine immunoglobulin (SBI)

Powder mixed in water; medical food brand EnteraGam is the regulated version. Also sold as supplement under names like ImmunoLin.

Greater than 50 percent IgG; works locally in gut, not absorbed systemically.

Bovine colostrum

Available as powder, capsule, or chewable. IgG content varies by source and processing.

Lower IgG concentration than SBI but includes growth factors and lactoferrin.

Safety

Generally well tolerated. Mild gas, bloating, and constipation are reported. Not suitable for people with milk allergy (colostrum) or bovine plasma allergy. SBI is dairy-free in the trace-free sense (no lactose, no casein), but those with severe milk allergy should consult a clinician.

Who should be cautious

People with known bovine protein allergy should avoid. Pregnant and breastfeeding women have limited data; medical food formulations are typically restricted to adults. Vegans cannot use these products (animal-derived).

Interactions

No significant drug interactions reported. Theoretically, immunoglobulins might bind some oral medications in the gut; separate other oral medications by 1 to 2 hours if concerned.

Food sources

Bovine colostrum

Amount
10 g
%DV
—

Human breast milk (especially colostrum, first days)

Amount
100 mL
%DV
—

Frequently asked questions

Do oral immunoglobulins get absorbed into my blood?⌄

No, not in adults. They work locally in the gut by binding pathogens and toxins. Newborns can absorb some immunoglobulins from breast milk, but this gut closes within the first day or two of life.

Is SBI the same as colostrum?⌄

Both contain bovine IgG, but SBI is purified from bovine serum and has a higher IgG concentration. Colostrum contains IgG alongside other bioactive proteins.

References

Immunoglobulins on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Immunoglobulins (PubMed search) — PubMed link

Track Immunoglobulins with Pilora

Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.