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Ingredient guide

How long does colostrum take to work?

Written by the Full Measure editorial team, which sells supplements. Approved for publication by the Full Measure owners. Updated .

Drafted with AI assistance from the sources listed below. How we write these

Quick answer

In the colostrum trials we read, the shortest courses that changed a lab test lasted 14 to 20 days: 1 g a day for 20 days, or 20 g a day for 14 days, before a gut permeability test. Immune and training studies ran 8 to 12 weeks, and most measured lab tests, not how people felt.1,2,3,4

Key facts

  • Saliva antibody levels in distance runners were checked monthly over 12 weeks and had risen by the end.5
  • Traces of cow IgG turned up in stool 1 to 4 days after a dose, with no antibody activity left.6
  • Most studies found no rise in blood IGF-1 within hours of a dose or over 4 to 12 weeks.7
  • Immune measures in healthy adults were checked at 6 and 10 weeks and did not change at 1.2 g a day.8

How long trials lasted

Trial length and what was measured1,2,3,4,5,7,8,9
WhoDaily amountLengthMeasured
Athletes1 g20 daysA gut permeability urine test
Volunteers before a hard run20 g14 daysGut permeability after exercise
Healthy adults aged 40 to 801.2 g10 weeks, tested at 6 and 10Immune measures
Distance runnersNot given in the summary12 weeks, tested monthlySaliva antibodies
Endurance-trained men25 g12 weeksSaliva and blood antibodies
Adults in exercise training10 or 20 g8 to 12 weeksDays with illness
Adults aged about 59 in strength training60 g8 weeksStrength and lean mass

Two weeks is the shortest course in this list, so these trials cannot say whether anything changes in the first days.

What changed, and when

In 12 volunteers, a hard 20-minute run raised a urine test of gut permeability 2.5-fold after 14 days of placebo. After 14 days of colostrum at 20 g a day, the rise was 80% smaller.2,7

In 35 distance runners aged 35 to 58, 15 of them women, saliva antibody (IgA) rose by a median of 79% over 12 weeks of colostrum. The authors urge caution because the group was small and the measure varies widely.5

In 28 endurance-trained men, 25 g a day for 12 weeks raised saliva IgA after exercise but did not change antibody levels in blood.4

In the first low-dose trial, people in both the colostrum and placebo groups rated their general shape as good or very good, and as the same or better than before the trial.1

These are laboratory measures, and a change in a gut or saliva test is not something most people would notice.1,5

How long it stays in your body

Reviewers consider it unlikely that cow IgG is absorbed intact into the human bloodstream, so any effect is thought to happen in the gut.10

Small amounts of cow IgG were found in the stools of 3 of 8 healthy volunteers 1 to 4 days after they took a colostrum concentrate, with no antibody activity left.6

Whatever cow antibodies do happens while they pass through the gut. About a fifth reached the end of the small intestine still active in one study, and traces reached stool within 1 to 4 days in another.6,11

After you stop

We found no trial that followed people for long after they stopped colostrum to see how long a change lasted. The distance runners gave one more saliva sample 2 weeks after their course ended, and the summary of that study does not report what it showed.5

What's in ours

What’s in ours

  • Colostrum: Bovine Colostrum (25% Immunoglobulin G), 2,300 mg per serving, from the label

How long it is safe to take

No upper limit has been set for colostrum. Most trials used 10 to 20 g a day for up to 12 weeks, and a few used 60 g a day for 8 to 9 weeks. Reviewers describe it as generally well tolerated while noting that side effects were poorly reported.3,7,9,12

Daily use has been studied for up to 12 weeks in most trials, and for 107 days with breaks at a low dose. Ask your doctor about longer use, and stop if stomach problems do not settle.3,13

Questions people ask

How long should you take colostrum?

Most trials ran for 8 to 12 weeks, and the gut barrier trials for 20 days. We found no trial that tested whether longer use adds anything.1,3

How long does colostrum stay in your system?

Cow antibodies are not thought to reach the blood intact. In one study about a fifth of the IgG was still active at the end of the small intestine, and in another, traces reached stool 1 to 4 days after a dose.6,10,11

Will I feel colostrum working?

Maybe not. Most trials measured lab tests, such as sugars in urine or antibodies in saliva, rather than how people felt.1,5

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Sources

  1. Hałasa M, Maciejewska D, Baśkiewicz-Hałasa M, et al. Oral Supplementation with Bovine Colostrum Decreases Intestinal Permeability and Stool Concentrations of Zonulin in Athletes. Nutrients. 2017;9(4):370. Opened 2026-10-01.
  2. Marchbank T, Davison G, Oakes JR, et al. The nutriceutical bovine colostrum truncates the increase in gut permeability caused by heavy exercise in athletes. Am J Physiol Gastrointest Liver Physiol. 2011;300(3):G477-G484. Opened 2026-10-07.
  3. Jones AW, March DS, Curtis F, Bridle C. Bovine colostrum supplementation and upper respiratory symptoms during exercise training: a systematic review and meta-analysis of randomised controlled trials. BMC Sports Sci Med Rehabil. 2016;8:21. Opened 2026-10-01.
  4. Durkalec-Michalski K, Główka N, Podgórski T, Woźniewicz M, Nowaczyk PM. The effect of 12-week high-dose Colostrum Bovinum supplementation on immunological, hematological and biochemical markers in endurance athletes: a randomized crossover placebo-controlled study. Front Immunol. 2024;15:1425785. Opened 2026-10-07.
  5. Crooks CV, Wall CR, Cross ML, Rutherfurd-Markwick KJ. The effect of bovine colostrum supplementation on salivary IgA in distance runners. Int J Sport Nutr Exerc Metab. 2006;16(1):47-64. Opened 2026-10-07.
  6. Lissner R, Thürmann PA, Merz G, Karch H. Antibody reactivity and fecal recovery of bovine immunoglobulins following oral administration of a colostrum concentrate from cows (Lactobin) to healthy volunteers. Int J Clin Pharmacol Ther. 1998;36(5):239-245. Opened 2026-10-07.
  7. Davison G. The Use of Bovine Colostrum in Sport and Exercise. Nutrients. 2021;13(6):1789. Opened 2026-10-01.
  8. Wolvers DA, van Herpen-Broekmans WM, Logman MH, et al. Effect of a mixture of micronutrients, but not of bovine colostrum concentrate, on immune function parameters in healthy volunteers: a randomized placebo-controlled study. Nutr J. 2006;5:28. Opened 2026-10-01.
  9. Duff WR, Chilibeck PD, Rooke JJ, Kaviani M, Krentz JR, Haines DM. The effect of bovine colostrum supplementation in older adults during resistance training. Int J Sport Nutr Exerc Metab. 2014;24(3):276-285. Opened 2026-10-07.
  10. Playford RJ, Weiser MJ. Bovine Colostrum: Its Constituents and Uses. Nutrients. 2021;13(1):265. Opened 2026-10-01.
  11. Roos N, Mahé S, Benamouzig R, Sick H, Rautureau J, Tomé D. 15N-labeled immunoglobulins from bovine colostrum are partially resistant to digestion in human intestine. J Nutr. 1995;125(5):1238-1244. Opened 2026-10-07.
  12. Brinkworth GD, Buckley JD, Bourdon PC, Gulbin JP, David A. Oral bovine colostrum supplementation enhances buffer capacity but not rowing performance in elite female rowers. Int J Sport Nutr Exerc Metab. 2002;12(3):349-365. Opened 2026-10-07.
  13. Baśkiewicz-Hałasa M, Stachowska E, Grochans E, et al. Moderate Dose Bovine Colostrum Supplementation in Prevention of Upper Respiratory Tract Infections in Medical University Students: A Randomized, Triple Blind, Placebo-Controlled Trial. Nutrients. 2023;15(8):1925. Opened 2026-10-01.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.