Colostrum Benefits: The One Study That Moved Body Fat Used 60 Grams a Day. It Moved 0.4%.

Thirteen clinical trials have measured what bovine colostrum does to human body fat. Exactly one of them found a reduction. [1]

That study gave people 60 grams a day, for eight weeks. Body fat percentage fell by 0.4%. [1]

Sixty grams. A day. For four tenths of one percent.

The reviewers rate the whole thing very low

This is a 2026 systematic review, PRISMA, Cochrane risk-of-bias tools, GRADE — the standard machinery for working out how much confidence a body of evidence has earned. It covers trials published from 2001 to 2025. [1]

Its verdict on the certainty of its own findings: “predominantly very low”. [1] That is the bottom grade.

And the sentence that should end most conversations about this supplement, from the reviewers themselves: “the currently available evidence is insufficient to support firm conclusions regarding the independent effect of bovine colostrum supplementation on reducing body fat content or improving blood lipid profiles in adults.” [1]

On risk of bias, they are blunter still. Among the randomised trials, most had “some concerns or a high risk of bias”. Among the non-randomised ones: “all non-randomized studies were judged to be at critical risk of bias.” [1] Every single one.

In one trial, the placebo was whey protein

Here is the detail that reframes the numbers above, and it is the same structural problem we found in the krill oil trials and the red light ones.

Twenty-two physically active adults, eight weeks, 20 g a day of colostrum. The comparison group got 20 g of whey protein powder. [1]

Body fat went 18.8% to 17.6% on colostrum, and 18.7% to 20.2% on whey. Which looks like a win until you read the next clause: the difference between the groups was not statistically significant. [1]

More importantly, notice what question that trial answers. Not “does colostrum beat nothing”. It answers “does colostrum beat a scoop of whey” — and a reader deciding whether to buy a tub is asking the first question.

Go and read the dose on your own tub

The trials in this review used somewhere between 10 and 60 grams a day. When the reviewers set out what a proper future trial should look like, they recommend standardising on 20–25 g/day, with controlled calories, for at least six months. [1]

We are not going to tell you what is in the tub you are looking at, because we do not sell tubs and we have not measured yours. But that is the number to check. It is on the label, in grams, and the comparison takes about four seconds.

The gut claim is the strongest one, and it comes with a warning

Colostrum’s most-sold promise now is the gut. There is a meta-analysis, it is randomised, and it is positive: across ten trials, colostrum significantly reduced a measured marker of intestinal permeability — how much leaks across the gut wall, tested by drinking two sugars and measuring what turns up in urine. [2]

Now the warning, and it is a big one. The heterogeneity on that result was 99%. [2]

Heterogeneity is how much the trials disagreed with each other. Zero means they all found much the same thing. Ninety-nine per cent means they found almost entirely different things, and the pooled average sitting on top of them is a number with very little to describe.

And the marker of actual gut damage did not move

The same meta-analysis measured something else: I-FABP, a protein that shows up in blood when intestinal cells are actually being damaged.

No difference. And the range of plausible answers ran from −293.9 to +298.5. [2] That is not a null result so much as a measurement that could not see anything at all.

So the honest reading: colostrum may tighten a permeability measure in a urine test. Whether that corresponds to anything you would notice is a question these ten trials did not answer.

The verdict

Preliminary. There is real randomised evidence here and we are not going to pretend otherwise — a significant pooled effect on gut permeability is a genuine finding. But the body-fat evidence is thirteen studies rated very low, the one positive result needed 60 grams a day to move 0.4%, several trials compared colostrum against whey rather than against nothing, and every non-randomised study in the review was at critical risk of bias.

That is a supplement whose evidence has not caught up with its price, which is a different accusation from saying it does nothing.

What we did not check: colostrum’s oldest claim is immune support and fewer upper-respiratory infections. That literature exists, it is mostly small trials in athletes, and we have not read it yet. Nothing above should be taken as a verdict on it — when we read it, we will say what we found.

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