If your dog finds it hard to relax, you're not alone. One large study of nearly 13,700 dogs found that around three in four showed some form of anxious behaviour, with noise sensitivity and general fearfulness the most common (Salonen et al., 2020). So it's no surprise that more owners are asking about Lion's Mane and Reishi for dogs, two natural mushrooms now turning up in calming dog food and supplements.
Here’s the honest version. While these mushrooms show promise, most research so far is in people or in the lab rather than in dogs. They’re there to support, not replace, the basics like training, routine and a conversation with your vet.
What they may do is gently support a calmer, more focused frame of mind as part of a balanced diet. This guide explains what each mushroom is, what the evidence does and doesn't show, and how we use them at Harringtons.
What are Lion's Mane and Reishi?
Lion's Mane (Hericium erinaceus) is a shaggy white mushroom that looks a little like a pom-pom. Reishi (Ganoderma lucidum) is a hard, woody, reddish bracket fungus. Both are what people call functional or medicinal mushrooms, which means they're eaten less for everyday nutrition and more for the natural compounds they contain, such as beta-glucans and triterpenes (Coile, 2026).
They’ve been used in traditional medicine for centuries, but tradition isn’t the same as evidence, and science is still catching up. And just to be clear from the start, this is about cultivated, carefully prepared mushrooms in food and supplements, never wild ones. If you'd like the full safety picture on foraged fungi, we've covered that separately in our guide to whether dogs can eat mushrooms.
Lion's Mane for dogs: focus and the nervous system
Lion's Mane is the one people link with the brain. It contains compounds called hericenones and erinacines, which in laboratory studies appear to encourage nerve growth factor, a protein involved in keeping nerve cells healthy (Coile, 2026). That's the mechanism behind its reputation for focus and mental sharpness.
In a double-blind human study, adults who took Lion's Mane performed faster on a mental-speed task within an hour, and after 28 days the researchers noticed a trend towards lower stress, though it didn't quite reach statistical significance (Docherty et al., 2023). It's early, encouraging work rather than the final word, and there's very little research in dogs specifically.
So what does that mean for your dog? Lion's Mane for dogs may help support focus and a settled nervous system, and there's particular interest in older dogs whose sharpness naturally fades with age. We'd frame it as a gentle helping hand, not a treatment for any behavioural or medical condition.
Reishi for dogs: calm and resilience
Reishi plays a different role. It's often described as an adaptogen, the idea being that it helps the body cope with stress and stay in balance. A systematic review of Reishi reported a broad range of effects across studies, including immune-balancing and antioxidant activity, while the authors were careful to point out that strong human trials are still limited (Thuy et al., 2023).
The calming side is where the evidence is thinnest, and honesty matters here: the adaptogen label is popular but not firmly proven. What we can reasonably say is that Reishi may help support a calm, balanced temperament, sitting alongside its better-studied links to everyday immune health. For most owners, it's the steady, supportive quality that makes it an interesting addition rather than any single dramatic effect.
Can mushrooms really help calm a dog?
This is the question most owners actually want answered, so let's be straight about it. Food can influence how a dog feels, but it doesn't control behaviour on its own. At the heart of it is the gut–brain axis, a natural, two-way conversation between your dog’s digestive system and their brain.
Research in dogs suggests gut health and certain nutrients can play a part in mood and anxiety-related behaviour, although the findings are still emerging and far from settled (Sacoor et al., 2024). Nutrients like tryptophan, a building block for the calming chemical serotonin, are part of that picture too.
So can Lion's Mane and Reishi calm a dog? They may help support a calmer temperament for some dogs, as one piece of a much bigger puzzle. Anxious behaviour usually has several roots, and the most dependable results come from working on the whole picture rather than leaning on any single ingredient.
Helping a hyperactive or anxious dog: the bigger picture
There isn’t a single dog food that can simply “switch off” a high-energy dog. But the right diet can help support a steadier, calmer baseline. Think of food as one part of the picture, with the day-to-day basics doing most of the heavy lifting:
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Plenty of physical exercise to burn off energy
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Mental stimulation, like puzzle feeders, scent games and training
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A predictable routine, since unpredictability tends to fuel stress
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A settled gut, supported by a consistent, balanced diet
We go into the practical side in our guides on reducing stress in your dog and helping a nervous dog. A calming recipe can play its part alongside all of this. It’s there to support, not to replace the basics.
Mushrooms in food versus supplements
You can buy Lion's Mane and Reishi as powders, capsules and chews, or you can choose a complete food that already includes them. Both have their place, but a couple of things are useful to know.
First, quality varies a lot. The most useful compounds, the beta-glucans, are concentrated in the fruiting body of the mushroom, the part you'd recognise, rather than the grain-grown mycelium that some cheaper supplements are based on (Coile, 2026). If you do go down the supplement route, it pays to check what the product is actually made from.
Second, with a complete recipe, the mushrooms are already measured and balanced into your dog's daily meal, so there's nothing extra to dose, sprinkle or weigh out. It also means you never need to give your dog raw or whole mushrooms at home, which are harder to digest and best left off the menu.
How Harringtons uses Lion's Mane and Reishi
We include a gentle blend of Lion's Mane and Reishi in our Superfoods wet recipes. Each tray starts with freshly prepared meat as the main event, then adds the mushroom blend alongside other natural superfoods like sweet potato, pumpkin, blueberries and spinach.
The thinking is simple: good food first, with a little extra support for brain function and a calm, settled temperament. You can pick a single flavour your dog loves, like Chicken or Salmon, or keep mealtimes varied with the Mixed pack.
If your dog's restlessness might be linked to diet sensitivities rather than mood, simplifying the menu can help you spot what doesn't agree with them. Our Just 6 recipes use only six key ingredients, which makes them an easy starting point for dogs with more delicate tummies. All our recipes are developed by our in-house pet nutritionists, and we'd always suggest involving your vet for anything behaviour-related.
Safety, dosage and when to speak to your vet
For most healthy dogs, well-sourced Lion's Mane and Reishi are considered safe, and true allergic reactions to food are uncommon in dogs (Mueller et al., 2016). A few situations call for extra care, though.
Both mushrooms may have a mild effect on blood clotting, so they're best avoided, or used only with veterinary guidance in dogs taking non-steroidal anti-inflammatories, anticoagulants or certain other medications, and in the run-up to surgery (Coile, 2026). Dogs on medicines that affect the immune system, or with an existing health condition, also need a vet's input first.
There’s no single amount that suits every dog, as it depends on their size and the product you’re using. The good news is that with complete food, that’s all worked out for you. If you’re considering a supplement, or your dog is on medication, it’s always worth a quick chat with your vet for peace of mind.
