Colostrum
Bovine colostrum (Bos taurus first milk)
Bovine colostrum, the antibody- and growth-factor-rich first milk of cows, has moderate evidence for reducing exercise-induced gut permeability and upper respiratory infections in athletes, and preliminary evidence in infectious diarrhea and NSAID gut damage.
At a Glance
- Best known for
- Reduces exercise- and heat-induced increases in intestinal permeability, Fewer upper respiratory tract infection days in athletes (several RCTs), Shortens infectious diarrhea in children in some trials (including hyperimmune colostrum)
- Evidence
- Moderate
- Typical dose
- 20 g powder daily for 2 weeks before and during intense training
- Type
- Compound
What is Colostrum?
Colostrum is the thick, yellowish first milk produced by mammals in the days after giving birth, uniquely rich in antibodies, antimicrobial proteins and growth factors that protect the newborn before its own immune system matures. Bovine colostrum, collected from dairy cows in the first 24–48 hours after calving (after the calf's needs are met), is processed by low-temperature pasteurization and spray-drying into supplements. Cows, unlike humans, do not transfer antibodies across the placenta, so their colostrum is extraordinarily concentrated in IgG, which is why it is used medicinally. Bovine colostrum has been used in Ayurvedic and folk medicine for centuries, was used to treat infections before antibiotics, and became popular with athletes in the 1990s; 'hyperimmune' colostrum from cows vaccinated against specific pathogens is a distinct research product.
Known Health Benefits
How It Works
Colostrum immunoglobulins survive partly intact through the stomach, especially when taken with food or in enteric formulations, and bind pathogens and toxins in the gut lumen, neutralizing them locally (passive immunity) without being absorbed. Growth factors, particularly EGF, TGF-β and IGF-1, stimulate repair and proliferation of the intestinal epithelium and increase tight junction protein expression, which is the proposed mechanism for reduced gut permeability under exercise, heat or NSAID stress. Lactoferrin and lysozyme add direct antimicrobial and anti-inflammatory effects. Colostrum oligosaccharides act as prebiotics. Proline-rich polypeptides modulate cytokine production and have been studied for immune regulation. Secretory IgA from colostrum may increase salivary IgA, consistent with the respiratory infection findings in athletes.
What Research Says
A 2014 systematic review of clinical applications identified 51 trials but noted they were small and heterogeneous. The most consistent findings are in exercise science: several double-blind trials in athletes and military recruits found 10–20 g daily of colostrum for 2–12 weeks reduced the rise in intestinal permeability caused by intense exercise or heat by around 50–80%, and a 2016 meta-analysis of 5 RCTs found colostrum reduced upper respiratory infection incidence and duration in athletes. In children with infectious diarrhea (rotavirus, E. coli), both standard and hyperimmune colostrum shortened illness in several trials, though a 2022 systematic review rated the evidence low-to-moderate. Small trials show reduced NSAID-induced gut permeability, benefit in HIV-associated diarrhea, and improved weight gain in malnourished children. Claims for muscle mass, strength and anti-aging are weakly supported; most athletic performance trials found no advantage over whey protein. Safety is good apart from dairy sensitivity. A 2021 review in Nutrients summarizes constituents and uses comprehensively.
Active Compounds
Immunoglobulins (IgG 20–40% of protein, IgA, IgM), lactoferrin, lysozyme, lactoperoxidase, growth factors (IGF-1, TGF-β, EGF), proline-rich polypeptides, oligosaccharides, cytokines, vitamins and minerals
Forms & Bioavailability
A substantial fraction of colostrum IgG is degraded by stomach acid and pepsin, but studies show 10–30% reaches the small intestine intact and more survives when taken with a meal or in buffered or enteric-coated forms; the antibodies act in the gut lumen rather than being absorbed. Growth factors such as IGF-1 are partly absorbed and partly act locally on the gut lining. Processing matters: low-heat pasteurization and freeze- or spray-drying preserve activity, whereas high-heat processing destroys much of it. Look for products stating IgG percentage and collection within the first 24 hours.
Dosage Guidance
| Use Case | Dosage |
|---|---|
| Gut permeability (athletes, heat stress) | 20 g powder daily for 2 weeks before and during intense training |
| Upper respiratory infection prevention | 10–20 g daily for 8–12 weeks |
| Infectious diarrhea (children, adjunct) | 3–7 g 2–3x daily for 5–7 days |
| NSAID gut protection | 125–250 mL liquid colostrum or 10–20 g powder daily during NSAID use |
| General immune support (capsules) | 500–2000 mg daily |
Always consult a healthcare provider for personalized dosing.
Natural Food Sources
- Bovine colostrum itself (traditional foods: Indian 'kharvas'/'junnu', Finnish 'leipäjuusto' made from colostrum milk)
- Human breast milk colostrum (for newborns)
- Not present in ordinary milk or dairy products
Potential Side Effects
Generally well tolerated; nausea, bloating or flatulence in some; contains lactose and milk proteins (problematic in lactose intolerance and milk allergy); theoretical concern about IGF-1 content for hormone-sensitive cancers
Who Should Avoid It
- Cow's milk protein allergy
- Lactose intolerance (some products are lactose-reduced)
- Hormone-sensitive cancers (theoretical, due to IGF-1 and growth factor content)
- Competitive athletes under WADA rules — advised against, not banned
- Immunocompromised patients should avoid raw/unpasteurized colostrum
Pregnancy & Lactation
Bovine colostrum is a dairy food and small amounts are presumably safe, but no studies have evaluated supplement-level doses in pregnancy or breastfeeding, and the growth factor content means caution is sensible. Pregnant and nursing women should avoid raw colostrum because of Listeria and other infection risks. Note that a breastfeeding mother produces her own colostrum for her infant; bovine colostrum is not a substitute.
Known Drug Interactions
None well documented; may modestly enhance immune function (theoretical interaction with immunosuppressants); contains IGF-1 — caution noted for athletes subject to anti-doping rules (WADA advises against use though it is not banned)
Evidence Classification
Supported by cohort studies, case-control studies, or multiple observational studies with consistent findings.
Frequently Asked Questions
Does colostrum help 'leaky gut'?
In the specific setting of intestinal permeability caused by hard exercise, heat or NSAIDs, several controlled trials show colostrum substantially blunts the increase in permeability, which is the best evidence any supplement has for this. Whether it helps the vaguely defined 'leaky gut' of chronic symptoms or autoimmune disease has not been tested, and improving permeability markers has not yet been linked to clinical outcomes in those conditions.
Is colostrum better than whey protein for muscle?
No. Head-to-head trials in athletes generally found similar effects on muscle and performance, with colostrum having a slight edge in a few sprint and recovery measures and none in most. Colostrum costs far more per gram of protein. Its distinct benefits are in gut and respiratory protection, not muscle building.
Why do athletes' anti-doping rules mention colostrum?
Colostrum contains IGF-1 and other growth factors. WADA does not ban colostrum, but advises against it because the growth factor content could theoretically affect blood markers, and because supplement contamination is a general concern. Studies show oral colostrum does not meaningfully raise blood IGF-1, but athletes should be aware of the advisory.
Does taking colostrum from the first milking really matter?
Yes. IgG and growth factor concentrations fall rapidly over the first 48 hours after calving, so colostrum collected at the first milking (6–12 hours) has several times more active content than 'colostrum' collected on day 2 or 3. Quality products specify collection time and IgG percentage (20–40% is typical for good products) rather than just 'colostrum powder'.
References
- Bovine Colostrum: Its Constituents and Uses. Playford RJ, Weiser MJ. Nutrients (2021)
- Clinical applications of bovine colostrum therapy: a systematic review. Rathe M, Müller K, Sangild PT, Husby S. Nutr Rev (2014)
- Bovine colostrum supplementation and upper respiratory symptoms during exercise training: a systematic review and meta-analysis of randomised controlled trials. Jones AW, March DS, Curtis F, Bridle C. BMC Sports Sci Med Rehabil (2016)
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This entry is for educational purposes only. It is not medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement regimen, especially if you take medications or have health conditions.