SBI Protect: Dosage, Benefits & How It Compares

Quick answer: SBI Protect® is Ortho Molecular Products' dairy-free source of immunoglobulin G (IgG), made from serum-derived bovine immunoglobulin protein isolate (ImmunoLin®). It is built for adults who want nutritional support for the gut barrier and the immune tissue that lines the intestine. Ortho's suggested use is 4 capsules a day, or 1 scoop (2.5 g) of the powder in 4 ounces of water twice a day, unless your practitioner directs otherwise.

Clinical review pending — Holistic Health Partners

"Is this the dairy one or the other one?" Teresa Lindqvist asked, holding up two printouts at the pharmacy counter. A 52-year-old court reporter who can type 225 words a minute, she had cut milk out of her diet two years earlier and wasn't about to let it back in through a capsule. The pharmacist circled one line on the second sheet, serum-derived, dairy-free, and told her to ask the clinic whether it fit what she was already taking. That question, which IgG and where it comes from, is the one most people never think to ask.

SBI Protect® by Ortho Molecular Products is a single-ingredient immunoglobulin supplement. Its active ingredient is ImmunoLin®, a protein isolate taken from bovine serum (the liquid part of cattle blood), not from milk or colostrum. Ortho describes it as the only purified, dairy-free source of IgG available as a dietary supplement, and says pure IgG helps maintain a healthy intestinal immune system by binding a broad range of microbes and toxins within the gut lumen. It comes as 120 vegetable capsules or as an unflavored SBI Protect Powder in two sizes.

What is SBI Protect and what does it do?

SBI Protect is concentrated IgG that works inside the digestive tract rather than in the bloodstream. IgG is the most common antibody type in the body. When you swallow it, a share of it survives digestion with its binding sites intact and can attach to microbial fragments and other material in the gut lumen, the open space inside the intestine. Ortho positions SBI Protect for two related jobs: supporting a normal intestinal barrier and supporting balanced immune activity in the gut lining.

The "SBI" stands for serum-derived bovine immunoglobulin. That is the whole formula. There are no probiotic strains, no glutamine, no herbs and no flavoring to account for, which makes it easy for a practitioner to judge on its own or layer into a plan you already follow.

What is in SBI Protect, and how does IgG work in the gut?

Each serving delivers one functional ingredient, ImmunoLin®, standardized for its IgG content. Here is what the labels list:

• Capsules (per 4-capsule serving): 10 calories, 2 g protein, serum-derived bovine immunoglobulin concentrate (ImmunoLin®) supplying 1.15 g IgG. Other ingredients: vegetable capsules and magnesium stearate.
• Powder (per 1-scoop, 2.5 g serving): 10 calories, 2 g protein, less than 5 mg cholesterol, 15 mg sodium, 2.5 g ImmunoLin® supplying 1.2 g IgG. Other ingredients: none. Free of gluten, corn, yeast, and artificial colors and flavors.

Does the IgG survive digestion?

Partly, and that is the point. A 2015 review of human studies in Nutrition Journal found that the amount of intact IgG recovered in stool after oral doses ranged from trace amounts up to 25% of what was swallowed. The authors note that IgG can only bind its targets in the gut if its binding region (the Fab structure) has not been fully broken down by stomach acid and digestive enzymes. So oral IgG is not absorbed to boost blood antibody levels; its work happens along the way through the intestine.

What does binding accomplish?

A 2014 review in Clinical and Experimental Gastroenterology laid out the proposed mechanism for serum-derived bovine immunoglobulin/protein isolate, the same type of ingredient as ImmunoLin®: the immunoglobulins bind microbial components in the lumen, which reduces how much of that material reaches the intestinal lining and the immune cells beneath it. Less contact means less immune signaling at the barrier. The review also discusses its role as a nutrition source, since the isolate is mostly protein.

What does newer lab research add?

A 2024 study in Nutrients used stool samples from 24 adults in a lab gut model combined with intestinal and immune cell layers. Serum-derived bovine immunoglobulin at human-equivalent amounts of 2 and 5 g per day supported barrier integrity in the cell layer, lowered two immune-signaling markers (TNF-α and CXCL10), and increased short-chain fatty acids such as acetate, propionate and butyrate. An earlier 2023 study by the same group found the isolate resisted small-intestine digestion better than other bovine plasma proteins and fed a narrow group of gut microbes. These were lab models, not clinical trials, and they tested the ingredient rather than the finished SBI Protect product, so read them as mechanism, not as a promise of how you will feel.

How do you take SBI Protect?

Take SBI Protect capsules at 4 per day, or the powder at 1 scoop twice a day, as Ortho's labels suggest, unless your health care professional gives you a different plan.

Two practical notes. First, the powder at its label dose supplies roughly twice the daily IgG of the capsules, so the two forms are not interchangeable scoop-for-capsule. Second, because there is nothing in the powder but ImmunoLin®, it has no flavor of its own to cover; a small amount of water is easiest, and a cold drink works if you prefer.

Who is SBI Protect for, and who should skip it?

SBI Protect fits adults who want concentrated IgG and need it to be dairy-free. That includes:

• People who avoid milk proteins and so can't use colostrum or whey-based IgG products.
• People who want gut barrier support without adding live probiotic organisms.
• Anyone working with a practitioner on a gut-focused plan who wants one ingredient with a clearly labeled IgG amount.

Who should skip it or check first

• Pregnant or nursing: Ortho's label caution reads, "If you are pregnant or nursing, consult your health care professional before taking this product."
• Vegetarians and vegans: the capsule shell is plant-based, but the ingredient comes from cattle.
• Anyone allergic to beef or sensitive to bovine proteins: "dairy-free" does not mean "bovine-free." Microbiome Labs' label for a similar serum-derived ingredient tells people with a beef allergy not to use it. Apply the same caution here and talk to a practitioner first.
• Anyone avoiding animal-derived products for religious or personal reasons: ask about the source before you start.
• Children: the SBI Protect labels do not give a pediatric dose. Ask a practitioner.
• Anyone on prescription medications: Ortho lists no known interactions on the label, but your prescriber should still see what you plan to add.

Mild digestive changes are possible with any new protein supplement. If something new shows up, stop and check in with your practitioner rather than adjusting the dose on your own.

How does SBI Protect compare with other immunoglobulin supplements?

The main difference among IgG supplements is the source: bovine serum or bovine colostrum (milk). That one fact decides whether a product is dairy-free. Here is how SBI Protect lines up against two core-brand options we carry.

Mega IgG2000 by Microbiome Labs uses the same type of serum-derived ingredient and is the closest match. It is a good fit when you want dairy-free IgG without the clinic step, or need a product labeled for children 2 and up. Colostrum 40% IgG by Pure Encapsulations® comes from milk, so it is off the table for anyone avoiding dairy. For people who tolerate dairy, colostrum also carries other naturally occurring compounds that serum-derived products do not, which some practitioners prefer.

Ortho Molecular Products, Microbiome Labs and Pure Encapsulations each make a well-built product here. The choice comes down to source, dose and how you plan to take it, not which brand is better.

Capsules or powder: which SBI Protect form fits you?

Choose the capsules if you want a simple daily routine and a lower daily IgG amount; choose the powder if your practitioner wants a higher daily IgG amount or you'd rather not swallow four capsules.

• Capsules deliver 1.15 g IgG in a 4-capsule daily serving, and one bottle covers a month.
• Powder delivers 1.2 g IgG per scoop and 2.4 g per day at the label dose, with no other ingredients. The smaller container lasts about two weeks at that dose, so the larger size suits a longer plan.

Is SBI Protect dairy-free?

Yes. Ortho Molecular Products describes SBI Protect as dairy-free because the IgG is purified from bovine serum, not from milk or colostrum. That is the feature that separates it from most immunoglobulin products. It is still an animal-derived ingredient, so dairy-free should not be read as vegan or as safe for anyone with a beef allergy.

Why is SBI Protect available only through our clinic?

Ortho Molecular Products distributes its formulas only through licensed health care practitioners. Our partner clinic, Holistic Health Partners, is how Covenant Health Products customers get access. You can book a free appointment, or join the clinic and save 20%, and a member of the clinical team will look at what you already take before adding anything new. Ortho's own Ortho Biotic probiotic is a common companion product to discuss at the same visit.

Is SBI Protect worth asking about?

If you want concentrated IgG and you avoid dairy, SBI Protect is the most direct option we carry: one ingredient, a clearly labeled IgG amount, and both a capsule and a powder form. The research on its ingredient points to a sensible mechanism, binding microbial material inside the gut before it reaches the lining, while the newest studies are still lab models. If you tolerate dairy and simply want general immune and gut support, colostrum may be enough. Either way, a short conversation with the clinic is the fastest way to find the right one rather than another bottle on the shelf.

Results vary, and supplements aren't cures, but the right guidance and high-quality products can make a meaningful difference in how you feel and function.

Keep reading

• Ortho Molecular Ortho Biotic: Probiotic Support for Gut & Immune Health
• Total Gut Restoration Kit by Microbiome Labs: Your Complete Guide
• Betaine & Pepsin by Ortho Molecular: Ingredients & Dosage

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.