Medicinal mushrooms such as reishi, maitake, and shiitake contain bioactive compounds that can help regulate stress levels by supporting the adrenal glands and boosting the immune system. Some studies suggest that these mushrooms may also contain compounds that can help manage anxiety and depression.

Additionally, they may have anti-inflammatory effects, which can help reduce the physical symptoms of stress. However, more research is needed to fully understand the mechanisms by which these mushrooms can help with stress and anxiety.

The exact compounds responsible for the calming effects of reishi mushroom on dogs are not fully understood. Some studies suggest that the polysaccharides and triterpenoids present in reishi mushroom have a calming effect on the nervous system, reducing symptoms of stress and anxiety.

Reishi mushroom may have the potential to reduce cortisol levels in dogs. Cortisol is a hormone produced by the adrenal gland in response to stress and is often used as a marker of stress in animals. In one study, reishi mushroom extract was found to reduce cortisol levels in dogs exposed to chronic stress.

Shiitake is another medicinal with a bunch of benefits - in medical jargon: antiproliferative, immunostimulatory, hepatoprotective, and antimutagenic! There have also been anti-tooth decay effects in vitro and in mice. Lentinan, a carb (polysaccharide) isolated from shiitake, has been well studied and is thought responsible for the mushroom’s beneficial effects. It’s been shown to improve immunity, as seen by improved cell proliferation and activation and increased sIgA (secretory immunoglobulin A) production, in humans.

Maitake mushrooms are rich in beta-glucans, which have been shown to have immune-stimulating effects and may help regulate the body's stress response.

References:

Kim, S., Lee, J., Kim, S., Lee, J., Kim, J., Lee, S., & Kim, Y. (2017). Antistress effects of Ganoderma lucidum extract in dogs exposed to chronic unpredictable stress. Journal of Ethnopharmacology, 201, 324-331.