Written and medically reviewed by Dr Zeeshan Afzal (MBBS) — Medical Doctor & Medical Content Lead, Welzo
Part of our digestive health guides · Shop gut health supplements
Evidence-based · Honest about what's proven and what isn't · UK-focused
Last updated: July 2026 · Reading time: ~15 minutes
Colostrum is the first milk a cow produces after calving, and it is nothing like ordinary milk. It's dense in immunoglobulins, lactoferrin and growth factors — which is why it has become one of the fastest-growing supplements in the UK gut health and probiotics aisle.
The evidence is real but narrower than the marketing suggests. A 2024 meta-analysis of ten randomised trials found bovine colostrum significantly reduced intestinal permeability on the standard lactulose/rhamnose test (Hajihashemi et al., Dig Dis Sci), and a separate meta-analysis of seven trials found a 36% lower risk of upper respiratory tract infections (Hałasa et al., 2022).
There is also a problem almost no buying guide mentions: the doses used in those trials are far higher than what capsules deliver. We've ranked every colostrum supplement currently in stock at Welzo, and worked out what each actually costs per gram.
Table of contents
Colostrum is produced in the first 24 to 72 hours after a mammal gives birth. In cattle, that first milking is compositionally very different from the milk that follows: far higher in protein, and packed with bioactive compounds a newborn calf needs before its own immune system comes online.
The plausible mechanism for the gut effects is straightforward: growth factors that stimulate epithelial repair, applied directly to the intestinal lining. That's why colostrum shows up repeatedly in research on gut barrier function rather than, say, digestion or bloating.
Colostrum's bioactive fraction degrades with heat. Products processed at high temperature lose much of what makes colostrum interesting, which is why low-temperature spray drying and freeze drying are consistently promoted. "First milking" matters because IgG concentration falls sharply with each subsequent milking. Both claims are meaningful — but neither tells you how much IgG you're actually getting unless the label states a percentage.
This is where colostrum has genuine, repeated human evidence. A 2024 systematic review and meta-analysis pooled ten randomised clinical trials and found a significant reduction in the urinary lactulose/rhamnose ratio — the standard laboratory measure of a leaky gut barrier — after colostrum supplementation.
The mechanistic trials behind that pooled result are worth knowing. In a randomised crossover study, indomethacin caused a roughly three-fold rise in gut permeability in healthy volunteers, and co-administering colostrum substantially blunted it (Playford et al., 2001). A later Imperial College trial found colostrum reduced the increase in gut permeability caused by heavy exercise. If you take regular NSAIDs, our guide to ibuprofen and stomach damage is relevant context.
The honest caveat: heterogeneity in that meta-analysis was very high (I² = 99%), meaning the individual trials disagreed considerably. And at least one trial found the opposite — 60g/day of colostrum during eight weeks of running training increased the lactulose/rhamnose ratio compared with whey and control, which the authors suggested may reflect colostrum promoting macromolecular transport rather than damaging the barrier. The direction of effect is probably real, but this is not a settled question. See our discussion of whether leaky gut is real.
A 2022 meta-analysis of seven randomised trials (445 participants) found colostrum reduced URTI risk with a risk ratio of 0.64 — around a 36% reduction. An earlier meta-analysis focused on people in regular exercise training found colostrum cut the rate of upper respiratory symptom days by 44% and episodes by 38% over 8 to 12 weeks (Jones et al., 2016).
Two caveats. Almost all this research is in athletes and regularly training adults, not the general population — so it may not transfer to a sedentary office worker. And four of the five trials in the 2016 analysis were judged at moderate or high risk of bias. More on the mechanism in gut health and the immune system.
Colostrum is marketed for skin, hair, body composition, menopause and general "anti-ageing". Human trial evidence for these is minimal to non-existent. Treat those claims as marketing, not medicine.
| Use | Evidence | Key finding |
|---|---|---|
| Gut barrier / permeability | Moderate–good | 10 RCTs; significant reduction, but I² = 99% |
| NSAID-induced gut injury | Moderate | Blunted a 3-fold indomethacin-induced rise |
| URTIs in active adults | Moderate | RR 0.64; symptom days down 44% |
| Exercise-induced GI symptoms | Preliminary | Small trials, mixed direction of effect |
| Skin, hair, body composition | Not supported | No meaningful human trial evidence |
This is the single most useful thing to understand before you buy, and almost no buying guide says it.
That doesn't make capsules useless. It does mean you should be clear about what you're buying. A capsule product is a low-dose, general-support approach with no direct trial evidence at that dose. If your goal is specifically the gut barrier effect seen in the research, only a powder makes trial-level intake practical — and even then, the cost is significant.
Be honest with yourself about which you want. If it's general daily support and you like the convenience, capsules are fine on their own terms. If you want the effect the studies measured, budget for powder. And if the underlying issue is intestinal permeability, colostrum is one option among several — compare it against other supplements for leaky gut and glutamine vs collagen before committing.
Every product below was in stock at the time of writing. We excluded 17 sold-out lines.
Best Overall: Double Wood Supplements Colostrum, 120 x 500mg — £29.17
Best for Gut Barrier Dosing: APE Nutrition Grass-Fed Colostrum, 150g Powder — £45.05
Best Budget: G&G Vitamins Colostrum Plus, 60 Capsules — £17.02
Best High-Dose Capsule: Osavi Colostrum 1000mg
Best for Immune Support: Osavi Colostrum Immuno 800mg
Best Premium Sourcing: Ancestral Supplements Grass Fed Colostrum, 180 Capsules — £105.52
Colostrum is priced in wildly different units — capsules, grams, millilitres — which makes shelf prices almost meaningless. This table normalises to cost per gram of colostrum.
| Product | Price | Total colostrum | Cost per gram |
|---|---|---|---|
| APE Nutrition powder | £45.05 | 150g | £0.30 |
| Double Wood | £29.17 | 60g (120 × 500mg) | £0.49 |
| Osavi Colostrum 1000mg | Varies by size | 120g (120 × 1000mg) | See product page |
| Osavi Colostrum Immuno | Varies by size | 48g (60 × 800mg) | See product page |
| Ancestral Supplements | £105.52 | 180 capsules | Highest here |
Prices correct at time of writing. Capsule strengths as stated by each manufacturer. G&G Vitamins Colostrum Plus is excluded from this comparison as the per-capsule strength is not stated on the collection listing — check the product page.
Price: £29.17 · Reviews: 66 · Where to buy: Available from Welzo
120 capsules at 500mg, from the first post-calf milking, sourced from grass-fed cows and standardised to 15% immunoglobulins.
Why it's the best: It is the only product in this comparison that states an immunoglobulin percentage on the label. That matters more than any other single claim. "Grass-fed" and "first milking" are used by nearly every brand and neither tells you the concentration of the fraction the research is actually about — a standardised 15% IgG figure does. It means a 500mg capsule delivers roughly 75mg of immunoglobulins, and you can calculate what you're taking rather than guessing.
On top of that it's second-cheapest per gram at £0.49, and the 120-capsule count gives a sensible two-month supply at two daily. It isn't the cheapest option and it isn't a powder — but for someone who wants a capsule and wants to know what's in it, nothing else here competes on transparency.
| Pros | Cons |
|---|---|
| Only product here with a stated IgG percentage (15%) First post-calf milking, grass-fed Second-lowest cost per gram (£0.49) 120 capsules — two months at two daily |
1g/day is far below trial doses Capsules can't practically reach 20g+ Contains dairy — not for cow's milk allergy |
Price: £45.05 · Reviews: 94 · Where to buy: Available from Welzo
Why we like it: This is the only in-stock format that makes a research-level dose achievable, and it's also the cheapest per gram at £0.30. Powder lets you scale from 2g for general support up to the 10–20g used in the gut permeability trials — something no capsule product here can do without swallowing forty capsules a day.
Do the maths before you commit. At 20g/day, a 150g tub lasts seven and a half days, which works out at roughly £6 per day. That is a serious ongoing cost, and it's the honest reason most people end up on capsules instead. At a more moderate 5g/day it's a month's supply and considerably more sustainable. Relevant if you're an endurance athlete — see runner's trots.
| Pros | Cons |
|---|---|
| Lowest cost per gram here (£0.30) Only format that reaches trial-level doses Fully adjustable dosing Grass-fed sourcing |
~£6/day at 20g — expensive to sustain No stated IgG percentage Needs scales or an accurate scoop Less convenient for travel |
Price: £17.02 · Reviews: 84 · Where to buy: Available from Welzo
Why we like it: The lowest entry price of any in-stock colostrum product, from a long-established UK manufacturer. If you want to try colostrum without committing £45 to a tub of powder, this is the sensible first purchase — 60 capsules is roughly a month at two daily, enough to see whether you tolerate it and notice anything.
The limitation is transparency: the per-capsule strength isn't stated on the collection listing, so check the product page before comparing it on cost per gram. As with all capsule products, don't expect the effects measured in the permeability research at this dose.
| Pros | Cons |
|---|---|
| Lowest entry price (£17.02) Established UK manufacturer Low-risk way to trial colostrum Convenient capsule format |
Per-capsule strength not clearly stated No IgG percentage given Only 60 capsules |
Reviews: 44 · Price: varies by size · Where to buy: Available from Welzo
Why we like it: At 1000mg per capsule this is double the strength of most capsule products, which halves the number you need to swallow for any given intake. Two capsules give 2g — still well short of trial doses, but a more meaningful daily amount than the 500mg standard, and the most efficient capsule route here. Available in more than one size, so check the options before ordering.
| Pros | Cons |
|---|---|
| 1000mg per capsule — double most rivals Fewer capsules for the same intake Multiple pack sizes available |
No stated IgG percentage Fewest reviews here (44) Price varies — harder to compare |
Reviews: 56 · Price: varies by size · Where to buy: Available from Welzo
Why we like it: Positioned specifically around immune support, which is the indication with the more consistent trial evidence — the URTI meta-analyses used doses closer to 20g/day, but immune support is at least the use case where the direction of evidence is clearest. At 800mg per capsule it sits between the 500mg standard and Osavi's own 1000mg line.
Worth remembering that the URTI research was conducted almost entirely in athletes and regularly training adults, so if you're not in that group the transfer is uncertain.
| Pros | Cons |
|---|---|
| 800mg per capsule Targeted at the best-evidenced use case Multiple pack sizes |
Dose still far below URTI trial intakes No stated IgG percentage Evidence base is athlete-specific |
Price: £105.52 · Reviews: 114 · Where to buy: Available from Welzo
Why we like it: The most rigorous sourcing story here — pasture-raised New Zealand cows, grass-fed and grass-finished, hormone and pesticide free, freeze-dried or low-temperature spray dried, non-defatted, with no fillers or flow agents and third-party testing for purity. For anyone who cares about provenance and processing temperature, this is the specification to beat.
But be clear about the price. At £105.52 it is roughly six times the entry-level option, and the suggested serving is six capsules daily — which means a 180-capsule bottle lasts 30 days. That is a substantial monthly commitment for a supplement whose capsule-level dose still falls short of the research. Excellent sourcing does not overcome the dose gap. Buy it because you value the provenance, not because you expect a different clinical result.
| Pros | Cons |
|---|---|
| Best-documented sourcing and processing Freeze-dried / low-temperature dried No fillers or flow agents Third-party tested for purity |
By far the most expensive (£105.52) Six capsules per serving — 30 days only No stated IgG percentage Sourcing doesn't close the dose gap |
Availability note: 17 of the 23 colostrum products Welzo lists were out of stock at the time of writing, including all the Symbiotics, Kirkman, Jarrow and NOW Foods lines. If a product above is unavailable, check back — this category restocks regularly.
| Goal | Dose used in research | Realistic format |
|---|---|---|
| Gut barrier / permeability | 20–60g daily | Powder only |
| Upper respiratory support | ~20g daily, 8–12 weeks | Powder only |
| General daily support | No established dose | 1–2g via capsules |
Take colostrum on an empty stomach, ideally 20 minutes before food, so the bioactive proteins face less digestive competition. Mix powders into cool or room-temperature liquid — heat degrades immunoglobulins and growth factors, so never add it to a hot drink or cook with it. Trials ran for 8 to 12 weeks, so give it a fair trial period rather than judging after a fortnight.
Colostrum is generally well tolerated. The most common effects are mild and transient: bloating, wind, nausea or loose stools in the first few days, usually settling as you continue.
Do not take colostrum if you
Lactose intolerance is different from milk allergy. Colostrum contains lactose, so it may cause symptoms if you are intolerant — but this is a digestive issue, not an immune one, and low-lactose or defatted products may be tolerated. See lactose intolerance supplements. If you are vegan or avoid dairy entirely, colostrum is not suitable and zinc carnosine may be a better route to gut lining support.
One further consideration: colostrum naturally contains IGF-1. The amounts in supplements are small and oral IGF-1 is largely digested, but if you have a hormone-sensitive condition it is worth raising with your doctor before starting. On labelling, colostrum is sold in the UK as a food supplement and no health claims are authorised on the GB register — a regulatory position on claim wording, not a verdict on the science.
See your GP — or seek urgent care — if you have:
Read more on when to see a GP about stomach symptoms, and see NHS — Food allergy.
For most people the Double Wood Supplements Colostrum is the strongest all-round choice at £29.17, because it is the only product here that states its immunoglobulin content — standardised to 15% IgG — and it comes second on cost per gram. If your goal is specifically the gut barrier effect seen in the research, the APE Nutrition powder is the only format that makes a trial-level dose practical.
The gut permeability trials used 20–60g daily and the respiratory trials around 20g. Most capsule products deliver 1–2g per day, which is far below those amounts. There is no established dose for general daily support at capsule level, so treat capsules as low-dose maintenance rather than a research-equivalent intake.
A 2024 meta-analysis of ten randomised trials found colostrum significantly reduced intestinal permeability on standard sugar-absorption testing, and it blunted NSAID-induced gut injury in controlled studies. However, heterogeneity between trials was very high and at least one study found the opposite effect. The signal is real but not settled — and the doses used were much larger than capsules provide.
Meta-analyses found around a 36% reduction in upper respiratory tract infection risk and a 44% reduction in symptom days. The important caveat is that nearly all this research was done in athletes and regularly training adults, so it may not transfer to the general population.
Possibly. Colostrum contains lactose, so it can cause bloating or loose stools if you're intolerant, though defatted or low-lactose products are often better tolerated. This is entirely different from cow's milk allergy, which is an absolute contraindication — colostrum can trigger a serious allergic reaction in that case.
No. Colostrum is a dairy product produced by cows, so it is not suitable for vegans or anyone avoiding animal products. There is no vegan equivalent, as the immunoglobulins and growth factors are specific to mammalian first milk.
On an empty stomach, ideally around 20 minutes before eating, so the bioactive proteins face less digestive competition. Never mix powder into hot liquid — heat degrades the immunoglobulins and growth factors that make colostrum worth taking.
The trials ran for 8 to 12 weeks, so allow at least two months before judging it. Any digestive side effects usually settle within the first week.
Yes. They work through different mechanisms — colostrum supplies immunoglobulins and growth factors to the gut lining, while probiotics introduce live organisms — and there is no reason to space them apart. Compare options in our best probiotics UK guide.
Colostrum naturally contains IGF-1, but the amounts in supplements are small and orally ingested IGF-1 is largely broken down by digestion. For most healthy adults this isn't a practical concern. If you have a hormone-sensitive condition, discuss it with your doctor first.
Medical disclaimer: This article is for general information and education only and does not constitute medical advice, diagnosis or treatment. Food supplements are not a substitute for a varied and balanced diet or a healthy lifestyle, and are not intended to diagnose, treat, cure or prevent any disease. Colostrum is a dairy product and must be avoided by anyone with a cow's milk allergy. Product specifications, prices and availability are correct at the time of writing and may change — always check the product page and label. Always seek advice from your GP, pharmacist or another suitably qualified clinician before starting a new supplement, particularly if you are pregnant, breastfeeding, immunocompromised, taking prescription medication or have an existing health condition.
About the author
Dr Zeeshan Afzal (MBBS) is a practising medical doctor and Welzo's Medical Content Lead. He writes and reviews Welzo's health content to ensure it is accurate, evidence-based and aligned with current UK clinical guidance, translating complex research into practical advice patients can trust.
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