Research & Insights
Brewer's Yeast for Skin and Coat in Pet Food: What the Evidence Supports
Published
In short: brewer's yeast does not act on skin by itself. It supplies nutrients that skin and hair depend on, including protein, zinc and B-complex vitamins, and a cell wall that carries beta-1,3/1,6-glucans. In a double-blind trial in atopic dogs, a purified beta-1,3/1,6-glucan at 800 ppm in dry food reduced clinical signs more than the control diet (Beynen et al., 2011). A formulator can use these facts to build a skin and coat formula, as long as the claim matches what the evidence shows.
This brief is for pet food R&D teams, nutritionists and ingredient buyers in the UK, EU, Australia and the US who are building or reviewing a skin and coat recipe.
Why do skin and coat formulas use brewer's yeast?
Coat condition is the first thing an owner sees. Dullness, scaling and itching are also among the first signs of a nutrient gap. Formulators therefore look for ingredients that deliver several skin-relevant nutrients in one material, with a clean origin story. Brewer's yeast fits that brief. It is a co-product of beer production, it carries protein, minerals and vitamins, and owners already know the name.
The risk is overclaiming. A supplement label that says "for a shiny coat" is easy to write. A technical file that supports it takes more work. The sections below separate what is measured from what is inferred.
Which nutrients in brewer's yeast matter for skin and hair?
| Nutrient | Role in skin and coat | What brewer's yeast contributes | Source |
|---|---|---|---|
| Zinc | Cofactor of delta-6 desaturase, which converts linoleic acid; deficiency is linked to zinc-responsive dermatosis, dry coat and seborrhoea | Average 114 mg/kg dry matter, range 55 to 154 mg/kg across five samples | Pereira et al. (2021); Feedipedia |
| Zinc with linoleic acid | Supplemented together in healthy dogs, improved coat gloss and scale and lowered transepidermal water loss | Zinc only; linoleic acid comes from the fat source | Marsh et al., cited in Pereira et al. (2021) |
| B-complex vitamins | Biotin showed a positive effect in dogs with skin disease when given in a zinc-containing supplement | Described as an excellent source of B-complex vitamins | Pereira et al. (2021); Feedipedia |
| Beta-1,3/1,6-glucans | Recognised by dectin-1 receptors on immune cells; studied for atopic dermatitis in dogs | Structural part of the yeast cell wall | Amaral et al. (2024) |
| Protein | Hair is built from keratin, so protein supply affects coat growth | 40 to 46% crude protein in TBESBY | TBESBY specification |
Two cautions apply. First, the Feedipedia zinc figure rests on five samples, so ask your supplier for a measured value on the lot you buy. Second, zinc status depends on bioavailability, not only on content. Pereira et al. (2021) note that body zinc reserves are small, so dogs depend on a steady dietary supply.
What does the beta-glucan research show?
The clearest canine trial is Beynen et al. (2011). Privately owned dogs with atopic dermatitis received a complete dry food with or without 800 ppm of a purified beta-1,3/1,6-glucan preparation for eight weeks. The trial was double-blind and placebo-controlled, with 15 dogs in the test group and 16 in the control group. All dogs had flea treatment three times to rule out flea-bite allergy. Owners scored itching, redness, scaling, thickening and stripping of the skin.
Both groups improved from baseline. The test group improved more on every sign, and when the changes were summed, the extra improvement from the glucans was 63% (P<0.001). The authors concluded that 800 ppm in dry food is safe and beneficial for atopic dogs.
A 2024 review by Amaral and colleagues at the University of São Paulo collected the dog and cat studies on beta-glucans and skin. Beyond Beynen, most are case reports or small studies, some with an undeclared glucan source. The evidence is promising but thin. Our MOS and beta-glucans guide explains where these compounds sit in the cell wall.
The key point for a formulator is dose. Beynen tested a purified preparation. Whole brewer's yeast carries its glucans inside an intact cell wall, together with protein and other cell components. To relate a whole-yeast inclusion rate to the 800 ppm trial level, you need the beta-glucan content of the yeast you buy, measured by a stated method. Without that number, a skin claim cannot borrow the trial result.
Does brewer's yeast affect acceptance and digestibility?
A skin formula only works if the animal eats it. Davenport, Block and Adolphe (2023) fed extruded diets with 10% dried whole-cell Saccharomyces cerevisiae yeast to dogs and cats. In cats, two-day intake was 1,778 g of the yeast diet against 851 g of the control, a ratio of 2.09 to 1 (P = 0.001). In dogs, more animals chose the yeast diet first on both days (11 against 5, P = 0.005). Stool scores did not differ, and protein digestibility stayed close to the control in both species. More detail is in our palatability guide.
How should a skin and coat claim be built?
| Step | What to do |
|---|---|
| Set the nutrient base | Meet the zinc, linoleic acid and B-vitamin levels in the nutrient guideline you follow, such as FEDIAF or AAFCO, before adding any functional story |
| Measure the yeast | Ask for crude protein, zinc and beta-glucan on the certificate of analysis, with the method named |
| Match the dose | Compare the beta-glucan you deliver per kg of food with the 800 ppm used by Beynen et al. (2011) |
| Word the claim | Describe the nutrient contribution, for example "with zinc and B vitamins for skin and coat"; avoid any wording that suggests treatment of a disease |
| Keep the file | Hold the trial references, the analysis and the calculation in the claim dossier |
Claims for atopic dermatitis belong to veterinary diets and their own rules. For general pet food, our pet food marketing claims guide covers what can be said in the EU, UK and US. Where you add the yeast also matters: our kibble guide compares inclusion in the mix with coating.
TBESBY Inactive Dried Brewer's Yeast for pet food
TBESBY Inactive Dried Brewer's Yeast is made from fresh brewer's yeast from international breweries in Vietnam, drum-dried at our own facilities in Vietnam. The process is receiving, drum drying, milling and sieving, packing, with laboratory testing. The specification is 40 to 46% crude protein, moisture below 10%, ash below 6%, fat max 0.5%, fibre max 1.5% and lysine 30.5 g/kg, with a 12-month shelf life. Packing is 25 kg bags or 600 to 1,200 kg jumbo bags. TBESBY is U.S. FDA registered, certified to ISO 22000:2018 and non-GMO.
Use levels by species are in our pet food guide, and the safety tests to request are in our safety specs checklist.
Frequently asked questions
Does brewer's yeast improve a dog's coat?
It supplies protein, zinc and B-complex vitamins that skin and hair need. A coat benefit depends on the whole diet. Direct canine evidence exists for purified beta-1,3/1,6-glucans in atopic dogs (Beynen et al., 2011), not for brewer's yeast alone.
How much beta-glucan did the canine atopy trial use?
800 ppm of a purified beta-1,3/1,6-glucan in a complete dry food, fed for eight weeks.
Is brewer's yeast suitable for cat skin and coat formulas?
Cats accepted a diet with 10% dried yeast well, eating about twice as much as the control in a two-day test (Davenport et al., 2023). Skin outcomes in cats were not measured in that study.
What should I ask a brewer's yeast supplier for?
A specification, a certificate of analysis that includes zinc and beta-glucan with methods named, and the safety tests on our checklist.
Sources
- Beynen, A.C., Saris, D.H., Paap, P.M., Van Altena, F., Visser, E.A., Middelkoop, J., De Jong, L. and Staats, M. (2011). Dietary beta-1,3/1,6-glucans reduce clinical signs of canine atopy. American Journal of Animal and Veterinary Sciences, 6(4), 146-152. https://doi.org/10.3844/ajavsp.2011.146.152
- Amaral, A.R., Risolia, L.W., Rentas, M.F., Marchi, P.H., Balieiro, J.C.C., Vendramini, T.H.A. and Brunetto, M.A. (2024). Translating human and animal model studies to dogs' and cats' veterinary care: beta-glucans application for skin disease, osteoarthritis, and inflammatory bowel disease management. Microorganisms, 12(6), 1071. https://doi.org/10.3390/microorganisms12061071
- Pereira, A.M., Maia, M.R.G., Fonseca, A.J.M. and Cabrita, A.R.J. (2021). Zinc in dog nutrition, health and disease: a review. Animals, 11(4), 978. https://doi.org/10.3390/ani11040978
- Davenport, G.M., Block, S.S. and Adolphe, J.L. (2023). Effects of extruded pet foods containing dried yeast (Saccharomyces cerevisiae) on palatability, nutrient digestibility, and fecal quality in dogs and cats. Translational Animal Science, 7(1), txad107. https://doi.org/10.1093/tas/txad107
- Feedipedia (INRAE, CIRAD, AFZ, FAO). Brewers yeast datasheet. https://www.feedipedia.org/node/72
Building a skin and coat recipe? Ask for the specification sheet and a quote.