The Gut-Brain Connection: How Your "Second Brain" Shapes How You Feel

The gut-brain connection is one of those things that sounds like a wellness buzz phrase until you actually look at the physiology behind it, at which point it turns out to be one of the more well-established relationships in the body. Your gut and your brain are in constant, two-way contact, and how one is doing genuinely shapes how the other feels. This is a look at what that connection actually is, and an honest account of where two of our mushrooms, Lion's Mane and Chaga, fit into it.

What is the gut-brain connection, really?

Your gut has its own nervous system, called the enteric nervous system, with more neurons than either your spinal cord or your peripheral nervous system. That's a large part of why it's sometimes nicknamed the body's "second brain." It doesn't think in the way your brain does, but it runs an enormous amount of independent activity, and it stays in constant contact with your brain, mainly through the vagus nerve, which runs directly between the two.

That contact goes both ways. A stressed or anxious state can genuinely disrupt digestion, which is why nerves so often show up as a knotted stomach rather than just a racing mind. Just as real, digestive discomfort and gut imbalance can leave you feeling foggier and less like yourself, even when nothing appears to be wrong upstairs. Neither direction is imagined. It's one connected system, communicating in both directions, all day, every day.

Where Lion's Mane fits

Lion's Mane (Hericium erinaceus) is what most people are familiar about for the brain side of this connection: focus and mental clarity. It's the mushroom most people turn to when they want to feel less scattered and more mentally present through a demanding day, and it's one of the most researched functional mushrooms for that kind of use. We've gone into Lion's Mane properly in Mushrooms for Focus and a Clear, Calm Mind if you want the full picture, including how it compares to Reishi and how long it typically takes to notice a difference.

Lion's Mane also contains beta-glucans, a compound class found across most of the mushrooms we work with, which act as prebiotics and feed the gut side of this connection too. Its best-studied effects are still around focus and mental clarity, which is why that's the lead here, but it's a good example of why this connection doesn't split neatly down the middle. The same mushroom can genuinely be doing more than one job.

Where Chaga fits

Chaga (Inonotus obliquus) is where the gut side of this connection shows up most clearly in our range, and it's a mushroom that doesn't get talked about nearly as much as Lion's Mane. That's a shame, because the way it actually grows is genuinely unusual. Most of the mushrooms we work with grow on dead or decaying wood. Chaga does the opposite: it grows as a parasite on living birch trees, often for decades, slowly drawing compounds from its host as it goes. That's part of why it can't be commercially cultivated. Every batch we use is wild-harvested from birch forests in Siberia.

That unusual growing process is also why Chaga's compound profile looks different to most other mushrooms. Alongside beta-glucans, it's notably rich in melanin, which is largely responsible for its dark, charcoal-like appearance, and in polyphenols and betulinic acid, a compound it draws from the birch bark it grows on. Together, these are a big part of why Chaga has such a long history of traditional use for gut and digestive support and as a source of antioxidants, often brewed as a tea across northern climates long before it turned up in a capsule.

Chaga isn't the only mushroom in our range that supports gut health this way. Turkey Tail is actually one of the higher beta-glucan mushrooms we carry, with its own long track record here. Chaga's particular combination of melanin, polyphenols and betulinic acid is simply what makes it a good fit for this specific routine.

Two sides of one connection

None of this means one mushroom is quietly doing the other's job. Lion's Mane's best-studied effects are on focus and mental clarity. Chaga's are on gut and digestive support. What actually ties the two together isn't a single ingredient trying to cover everything at once, it's the two-way relationship between gut and brain itself. Supporting one side of that relationship and supporting the other are two different ways of looking after the same connected system, which is a big part of why the two are so often used together rather than as alternatives to each other.

Covering both sides in one routine

If you want both sides of this covered without managing two separate products, Flow brings Lion's Mane and Chaga together with Cordyceps and Reishi in a single powder, with each mushroom still doing its own specific job. Singles suit people who want to dial in exactly what they need. A blend suits people who'd rather cover more ground in one scoop. Neither approach is better; it depends on what you're actually trying to support.

Where to start

If focus and mental clarity are the priority, Lion's Mane capsules are the place to start: fruiting body only, dual extracted, and third-party tested here in New Zealand. If gut support is what you're actually after, Chaga capsules do that job well. And if you'd rather cover both in one daily scoop, Flow gives you all four mushrooms together. Whichever you choose, give it a proper run of a few weeks before you judge it. That's when most people say they actually notice a difference.

Disclaimer: It is important to consult a health professional before taking supplements if you have a health condition, are taking medication, are pregnant, or nursing.