Ashwagandha in animals: stress and evidence

What is ashwagandha?

Ashwagandha (Withania somnifera), also known as Indian ginseng or winter cherry, is an adaptogenic herb that has been used for centuries in Ayurvedic medicine. The active substances — primarily withanolides — are concentrated in the root. The extract modulates the HPA axis (hypothalamus-pituitary-adrenal), the central stress regulation pathway, and additionally possesses antioxidant and immunomodulatory properties.

Standardised root extracts such as KSM-66 have been studied for longer in clinical research in humans. In dogs, research has only recently commenced.

Claims versus evidence in dogs

Stress and anxiety

The best-substantiated application is stress reduction. A randomised controlled study from 2022 investigated dogs with an elevated stress response and found a significant decrease in urinary cortisol compared to placebo after four weeks of supplementation [1]. Anxiety and pain scores, measured with validated questionnaires (CBARQ, CBPI), improved statistically significantly over the same period [1].

Ageing and oxidative stress

In healthy older dogs (geriatric studies from 2024 and 2025), the same researchers reported improvements in markers for oxidative stress, inflammatory cytokines and gut microbiome parameters [2][3]. This suggests broader health effects than solely stress reduction, but the mechanisms and clinical relevance for the average older dog are not yet sufficiently clarified.

Critical note

All published dog studies originate from a single Indian research group (Bharani KK et al.) and consistently use the same KSM-66 extract. Independent replication by other laboratories or in other populations is entirely lacking. Until such replication exists, the evidence — however positive — remains limited in strength.

Safety

In the published dog studies (up to 60 days), no adverse effects were reported with the use of standardised root extract [1][2][3]. This is an important distinction: in humans, cases of liver toxicity have been described, but almost exclusively with leaf extracts or non-standardised products. Product quality and extract type are therefore decisive.

Never give ashwagandha to pregnant bitches: at high doses, abortifacient effects have been documented in animal models. This is an absolute contraindication.

Interactions and precautions

Combination with the following agents always requires consultation with a veterinary surgeon:

• Sedatives and calming agents — risk of enhanced sedative effect
• Immunosuppressants — ashwagandha has immunomodulatory activity that may influence therapy
• Thyroid medication — possible interaction with thyroid hormone levels

What can you expect from your veterinary surgeon?

A veterinary surgeon considering ashwagandha will first rule out that stress or anxiety has a medical cause. Dosage and product choice are highly dependent on the dog's weight, health status and any concurrent medication — never administer a supplement on your own initiative without consultation. There is no validated dosage for the home situation outside clinical supervision.

The evidence is promising enough to take ashwagandha seriously as an adjunct to behaviour therapy and environmental management in stressed dogs, but not strong enough to present it as a proven first-line treatment.