Itching is one of the most common problems faced by dogs, often linked to atopic dermatitis, a chronic inflammatory skin condition. Conventional treatment is complex, involving medications and long-term management. A 2025 randomized, double-blind, placebo-controlled trial published in Animals tested whether nutritional supplementation with an indole-rich postbiotic could reduce subclinical itching and support overall skin health in dogs.
The study, led by Aylesse Sordillo and colleagues, focused on dogs exhibiting elevated but non-pathological scratching. Over a 28-day period, dogs were randomly assigned to receive either the postbiotic supplement or a placebo. Researchers tracked scratching frequency, owner-reported itching using the Pruritus Visual Analog Scale, skin and coat quality, and changes in the gut microbiome.
Results showed that dogs receiving the postbiotic supplement had a 20% reduction in scratching compared to baseline and a 27% decrease in owner-reported itching compared to the placebo group by Day 28. Improvements in skin and coat quality were already visible by Day 14. Additionally, gut microbiome analysis revealed increased diversity by the end of the study, supporting the role of the gut–skin axis in canine health.
These findings suggest that postbiotics containing indole compounds—metabolites produced by beneficial gut microbes—may help reduce itching and improve skin condition in dogs. Beyond dermatological benefits, the study highlights the potential for such supplements to support immune-related conditions more broadly, offering a promising adjunct to conventional veterinary care.
Source: Sordillo, A., Heldrich, J., Turcotte, R., & Sheth, R. U., Animals, July 1, 2025. https://doi.org/10.3390/ani15141342
