How to Choose a Colostrum Supplement for Adults: Value by the Gram of IgG

You’re standing in front of two jars of colostrum. One costs $30 and says 40% IgG. The other costs $40 and says 30%. The cheaper jar with the bigger number looks like the obvious buy, and it can easily be the worse deal.

This guide gives you a way to judge any colostrum supplement without trusting anyone’s marketing, including ours. You’ll learn what the IgG percentage actually measures, how to work out the cost per gram of IgG in about a minute, which label lines should make you put a jar back, and how the doses used in research compare with what’s in a typical scoop.

The one number that tells you what colostrum really costs

The number you want is the cost per gram of IgG. Immunoglobulin G is the antibody fraction that colostrum labels are standardised to, so it’s the only ingredient you can reliably count from one brand to the next. Sticker price and cost per serving both mislead you, because every brand decides for itself how big a serving is.

Here’s the calculation. It needs three numbers from the supplement facts panel and the price.

1. Find the colostrum per serving, in milligrams.
2. Find the IgG percentage, or the milligrams of IgG if the label states them.
3. Multiply the two to get milligrams of IgG per serving.
4. Multiply that by the servings per container, then divide by 1,000 to get the total grams of IgG in the jar.
5. Divide the price by those grams. That’s your cost per gram of IgG.

A worked example with two jars

Take the two jars from the opening. The figures are illustrative, not any real brand, but the label layout is exactly what you’ll see on a shelf.

Label line	Jar one: powder	Jar two: capsules
Price	$40	$30
Servings per container	30 scoops	60 capsules
Colostrum per serving	2,000 mg	500 mg
IgG percentage	30%	40%
IgG per serving	600 mg	200 mg
Total IgG in the container	18 g	12 g
Cost per serving	$1.33	$0.50
Cost per gram of IgG	$2.22	$2.50

The capsule jar wins on sticker price, on percentage and on cost per serving, and it still costs you about 13% more for every gram of IgG you actually swallow. It’s like buying fuel by the tank rather than by the litre: the smaller tank always looks cheaper at the pump.

What the IgG percentage actually measures

Colostrum is the milk a cow makes in the first few days after calving, and it’s rich in immunoglobulins, antimicrobial peptides and growth factors, as the review of bovine colostrum’s constituents by Playford and Weiser sets out. IgG is the main immunoglobulin in cow’s colostrum and the easiest part of it to measure, which is why manufacturers standardise to it.

The percentage tells you concentration: how much of each gram of powder is IgG. It doesn’t tell you how much you get. A 40% capsule holding 500 mg gives you 200 mg of IgG, while a 25% scoop of 2,300 mg gives you 575 mg. Concentration only means something once you multiply it by the weight of the serving.

IgG also isn’t the whole product. Lactoferrin, lysozyme and growth factors travel with it, and none of them show up in the IgG figure. That’s worth knowing, because it means two powders with identical IgG can still differ. It’s also why IgG works as a yardstick for value and not as a complete measure of quality. If you want the rest of the picture, read about the bioactive growth factors in colostrum.

Label red flags that should make you put the jar back

Most bad colostrum purchases aren’t scams. They’re labels that make the calculation above impossible, and a product you can’t value is a product you can’t compare. These are the lines to look for.

• No IgG figure at all. Without a percentage or a milligram amount, you can’t work out what you’re paying per gram of the compound the category is built on.
• Colostrum inside a proprietary blend. When colostrum is one of several ingredients under a single combined weight, you don’t know how much of the blend it is, let alone how much IgG it carries.
• A percentage without a serving weight. “40% IgG” on the front means nothing until the back tells you how many milligrams are in a serving.
• Vague immunoglobulin wording. Check whether the percentage refers to IgG specifically or to immunoglobulins in total, and whether it applies to the serving or to the raw material.
• Processing claims with no detail. Heat matters: when researchers heated raw colostrum, holding it at 60°C or above began to denature part of the IgG while cutting bacterial counts. “Low-heat” is a reasonable claim, but ask the brand what it means.
• Silence on testing. You want to know the product was checked by a third-party lab for what’s in it and for what shouldn’t be, such as heavy metals and microbes. If the page says nothing, ask for a certificate of analysis.

A brand that clears all six gives you what you need to make a decision. A brand that fails one or two might still be a good product, but you’re paying partly on trust, and you should know that before you decide.

Powder or capsules: what you actually trade

A capsule holds roughly half a gram of colostrum. That single physical fact explains most of the difference between the two formats, and it matters more than any marketing about absorption.

Powder wins on value and on dose. A scoop can carry two grams or more, there’s no capsule shell to pay for, and if you ever want to take more, you just use a bigger scoop. The trade is that you have to mix it, and colostrum tastes faintly of milk, which some people like and some don’t.

Capsules win on convenience. There’s nothing to measure, nothing to taste, and a bottle travels well. The trade is that every extra half gram means another capsule, so capsules make sense when the dose you want is small and consistency is the thing you’re protecting.

If you’re torn, let the dose decide. Work out how many grams of colostrum you want a day, divide by half a gram, and ask whether you’ll really swallow that many capsules every morning for three months.

The doses research used, and what that means for your budget

Here’s the part most colostrum marketing leaves out. The human trials were run at doses measured in whole grams, usually far more than a typical capsule or scoop provides.

• A 2026 systematic review of 13 clinical trials found colostrum given at 10 to 60 g a day, and its authors suggested future trials standardise on 20 to 25 g a day (Goluch and colleagues, systematic review of colostrum trials, 2026).
• Two randomised trials in healthy adults used 20 g a day, one for four weeks and one for twelve (Davison and colleagues, oral bovine colostrum and IGF-1, 2019).
• The five trials pooled in a meta-analysis of colostrum and upper-respiratory symptoms in people who train regularly all ran for 8 to 12 weeks (Jones and colleagues, bovine colostrum and upper respiratory symptoms during exercise training, 2016).

So be honest with yourself about what a one-gram serving is. It may well be a sensible daily amount, but nobody has tested whether it does what the 20 g trials did. If your goal is to match the research, you’re buying powder, and the cost per gram becomes the whole decision.

Run the numbers before you commit. At 25% IgG, 20 g of colostrum is 5 g of IgG a day, so at $2.00 to $3.00 per gram of IgG you’d spend $10 to $15 a day. That’s why this guide keeps coming back to one figure. At research doses, a small difference in cost per gram becomes a large difference in what you pay each month.

Who benefits, and what the evidence actually shows

Colostrum isn’t a stimulant and it won’t make up for a poor foundation. Enough food, enough carbohydrate from fruit and roots, enough salt and enough sleep will do more for you than any powder. Once those are in place, the evidence points to a few specific uses.

If you train hard

This is where the evidence is strongest. In the Jones meta-analysis, people in regular exercise training who took colostrum for 8 to 12 weeks logged 44% fewer days with upper-respiratory symptoms than those on placebo. The reviewers were candid that four of the five trials carried a moderate or high risk of bias, so treat this as promising support for normal immune function during heavy training, not a settled fact.

It’s also worth knowing what colostrum doesn’t seem to do. A 2020 meta-analysis of immunological outcomes in athletes found little or no change in blood immunoglobulin levels, so the benefit, whatever drives it, probably isn’t a simple top-up of your own antibodies.

If your gut is the reason

The most interesting gut finding comes from a small, double-blind crossover trial. Twelve volunteers took colostrum or placebo for 14 days before hard exercise, and the rise in gut permeability after exercise was about 80% smaller on colostrum (Marchbank and colleagues, colostrum and exercise-induced gut permeability, 2011). That was measured under heavy exertion, not in everyday life, so it supports colostrum for gut barrier function in hard training more than it proves anything about a quiet week at your desk. There’s more on this in colostrum for gut health.

If you’re worried about IGF-1

Colostrum contains IGF-1, and some people worry that supplementing will raise their own levels. In the Davison trials, 20 g a day for up to 12 weeks didn’t raise circulating IGF-1 in healthy adults. If you compete under anti-doping rules, check with your governing body anyway, because that decision isn’t yours or ours to make.

Putting it together: one reader, one decision

Say you lift four days a week, your stomach gets rough after the hardest sessions, and you’ve set aside about $40 a month. You’ve got two powders in your cart and a 500 mg capsule at 30% IgG that you like the look of.

Start with the goal. You’re after training support, so you want a serving you can take daily for at least 8 to 12 weeks, the length the trials ran. Then run the five steps on all three. The capsule gives you 150 mg of IgG a day; to get anywhere near a scoop’s worth, you’d need four capsules a day and a new 60-count bottle every fortnight, which blows the budget. Between the powders, the one with the lower cost per gram of IgG and a stated third-party test wins, even if its sticker price is a few dollars higher.

Take one scoop daily in something cool, keep a simple note of how your gut feels after hard sessions and how many days you feel run down, and judge it at twelve weeks rather than at two. For comparison, Monthlees Pure Colostrum Powder states 575 mg of IgG per 2.3 g scoop on its label, which gives you everything you need to run the math, and members pay less than the list price. If you’d rather see the calculation already done for three named brands, read ARMRA vs Vital Proteins vs Monthlees, compared label by label.

Before you buy anything, pick up the colostrum you already own or the one sitting in your cart, find the supplement facts panel, and run the five steps on the back of a receipt. It takes a minute, and it’ll tell you more than the front of the jar ever will.

Sources

• Bovine colostrum: its constituents and uses — Playford and Weiser, Nutrients, 2021.
• Effect of heat treatment of bovine colostrum on bacterial counts, viscosity, and immunoglobulin G concentration — Elizondo-Salazar and colleagues, Journal of Dairy Science, 2010.
• The effects of colostrum bovinum supplementation on human body fat content and/or blood lipid profile: a systematic review of clinical trials — Goluch and colleagues, Nutrients, 2026.
• Oral bovine colostrum supplementation does not increase circulating insulin-like growth factor-1 concentration in healthy adults — Davison and colleagues, European Journal of Nutrition, 2019.
• Bovine colostrum supplementation and upper respiratory symptoms during exercise training: a systematic review and meta-analysis — Jones and colleagues, BMC Sports Science, Medicine and Rehabilitation, 2016.
• Immunological outcomes of bovine colostrum supplementation in trained and physically active people: a systematic review and meta-analysis — Główka and colleagues, Nutrients, 2020.
• The nutriceutical bovine colostrum truncates the increase in gut permeability caused by heavy exercise in athletes — Marchbank and colleagues, American Journal of Physiology, 2011.