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Neither whole colostrum nor an immunoglobulin-standardized powder has been shown to reduce itching in dogs, so choose on label transparency, tolerance and dosing. The "immunoglobulin" products are bovine colostrum with a stated level: PupRx 25% IgG and Peak Pets 20% immunoglobulins. Four Leaf Rover states none.
Itch itself comes from fleas, environmental or food allergy, mites, or skin infections, and no colostrum product treats any of these directly. Itchy paws and skin and vet and OTC itch options cover what comes before a supplement.
What is in whole and standardized colostrum?
Bovine colostrum is naturally rich in immunoglobulins. A 2025 review in Animals (opens in a new tab) reports total immunoglobulins in bovine colostrum ranging widely, from about 40 to 200 mg per mL, with IgG1 making up over 75% of them. It also contains lactoferrin, proline-rich polypeptides (PRPs), growth factors and some lactose. Standardized products keep all of that; the brand tests the batch and states the immunoglobulin level.
| Four Leaf Rover | PupRx | Peak Pets | |
|---|---|---|---|
| Type | Whole bovine colostrum | Whole bovine colostrum, standardized | Bovine colostrum, standardized |
| Stated level | None | 25% IgG | 20% immunoglobulins |
| Source as stated | New Zealand, grass-fed (brand); colostrum shared with the calves | Grass-fed, USA-sourced (product title) | Made in the USA (product title); cattle origin not stated |
| Dosing | Teaspoon by weight: 1/8 tsp (1-30 lb) to 3/4 tsp (91 lb and over) daily, current label | 500 mg scoop per 25 lb, half dose for the first three days | 500 mg scoop chart, but the product page also shows a different teaspoon chart |
| Main strength | Single ingredient, NASC seal on the label | Highest stated IgG on our list, plus a stated origin | Stated immunoglobulin level |
| Main gap | Potency cannot be checked | Newer product, shorter track record | Smaller brand; two conflicting dosing charts |
What does an IgG percentage tell you?
Three useful things. It shows how much of the powder is immunoglobulin, which matters because natural colostrum varies so much. It lets you estimate a daily amount: a 500 mg Peak Pets scoop at 20% works out to roughly 100 mg of immunoglobulins, and a 500 mg PupRx scoop at 25% IgG to about 125 mg of IgG, if the standard holds. And it shows the brand tests for it, which is a fair quality signal.
It does not tell you whether the powder helps itching. No dog study has tested colostrum, standardized or not, against itch, paw licking or skin scores. Nor does it measure lactoferrin or PRPs, the components brands often credit for immune balance. The largest dog trial, run by Nestle Purina researchers, used whole colostrum added to food and measured gut IgA, gut bacteria and vaccine response (Satyaraj et al., British Journal of Nutrition (opens in a new tab)). It did not compare IgG levels or measure itching, and neither did the smaller puppy and Beagle studies summarized in colostrum for dogs.
Which one should you buy?
- Four Leaf Rover if a single ingredient with nothing else on the label matters most and you accept that potency is not stated.
- PupRx if you want the highest stated IgG level along with a stated origin, and do not mind a newer brand.
- Peak Pets if you want a stated immunoglobulin level and will follow the directions printed on the jar you receive.
- None of them for a dog with a dairy or beef allergy, a dog in an elimination diet trial, or a dog with kidney disease, unless your vet approves.
Follow the chart on your own label and start at half for the first week. Never carry a teaspoon amount over to a scoop-based product.
Four Leaf Rover Bovine Colostrum
by Four Leaf Rover
Dogs- Form
- Unflavored powder, 1.04 oz (29.5 g) jar; 1 tsp = 1.97 g
- Key actives
- 100% New Zealand bovine colostrum (label: no inactive ingredients); IgG % not stated
- Best for
- Raw/fresh-fed dogs and owners who want a single-ingredient, ethically sourced colostrum
- Watch for
- Small jar (about 15 teaspoons); no stated IgG %; bovine dairy proteins; label says safety in pregnant or breeding animals is not proven
Four Leaf Rover is the whole-colostrum option: a 1.04 oz (29.5 g) jar, about 15 teaspoons. Dose from the chart on your jar; the dosage calculator works out the amount by weight. The review separates what is on the label from what only the brand's website says.
PupRx Colostrum for Dogs (25% IgG)
by PupRx
Dogs- Form
- Powder
- Key actives
- Whole bovine colostrum standardized to 25% IgG (product page: grass-fed, USA sourced)
- Best for
- Owners who want a stated immunoglobulin (IgG) percentage on the label
- Watch for
- Newer product with a shorter track record than the established brands
PupRx is the pick for a stated IgG number. One 500 mg scoop per 25 lb, starting at half for the first days as its label suggests.
Peak Pets Bovine Colostrum for Dogs (90 g)
by Peak Pets
Dogs- Form
- Powder, 500 mg per scoop
- Key actives
- Bovine colostrum standardized to 20% immunoglobulins
- Best for
- Owners who want a standardized immunoglobulin level and a weight-based scoop chart
- Watch for
- Smaller brand; fewer reviews
Peak Pets states 20% immunoglobulins with a 500 mg scoop. Its product page shows a scoop chart and a teaspoon chart that do not agree, so use the directions printed on your jar. The full field of brands is compared in best colostrum for dogs.
FAQ
Do bovine antibodies fight my dog's allergies?
Not in any direct way. Antibodies in bovine colostrum come from cows and are not specific to dog pathogens or to the allergens bothering your dog. The idea behind colostrum is local support of the gut immune system.
Is 25% IgG stronger than 20% immunoglobulins?
Not necessarily. IgG is one type of immunoglobulin, so the two numbers measure different things. What your dog gets also depends on how much powder is in each daily dose.
What should I try first for an itchy dog?
A vet visit to find the cause, then flea control and the plan your vet suggests. Among supplements, fish oil has more research behind it for skin than colostrum.