Reishi is one of the most famous functional mushrooms in the world, and one of the easiest to overstate.
It has a long history of traditional use and a large scientific literature, but that literature includes laboratory studies, animal research, different Ganoderma species, extracts, powders and human trials of varying quality.
Those are not interchangeable forms of evidence.
What is Reishi?
Reishi commonly refers to mushrooms in the Ganoderma group. The name is often used as if it identifies one perfectly standardized ingredient, but taxonomy and product preparation can vary.
Reishi contains multiple classes of compounds that researchers study, including polysaccharides and triterpenes.
What does human research show?
Human evidence exists, but it is not strong enough to justify the sweeping promises often attached to Reishi products.
A 2025 systematic review and meta-analysis evaluated 17 randomized controlled trials involving 971 participants. It found some changes in selected outcomes, but no significant effects across several commonly discussed metabolic and inflammatory measures. Importantly, the authors rated the certainty of evidence as very low across outcomes.
That is a useful reality check: "studied in humans" does not automatically mean "proven to work for every marketed benefit."
See the review on PubMed: Jafari et al., 2025.
What about stress, sleep and calm?
Reishi is frequently marketed around stress and sleep. Those themes may be part of traditional use or early research discussions, but the evidence does not support promising that a cup of Reishi coffee will treat insomnia, anxiety or another medical condition.
That distinction matters especially in foods, where marketing language can make a product sound more clinically established than it is.
How Urban Calm uses Reishi
Reishi appears in two Urban Calm blends:
- Centered Medium Roast: Chaga + Reishi
- Dreamer Dark Roast: Lion's Mane + Reishi
Both use organic 100% fruiting body mushroom extracts with no mycelium-based mushroom ingredients, and Urban Calm's mushroom extracts are third-party tested.
We use practical language around calm and everyday wellness because those are the reasons many people are curious about Reishi, while avoiding the claim that Reishi coffee treats stress disorders or sleep conditions.
Does Reishi change the taste of coffee?
It can contribute subtle earthy notes depending on the extract and formula, but it does not need to dominate the cup. Urban Calm builds the mushroom ingredient into the roast rather than expecting customers to tolerate a medicinal flavour.
Read Does Mushroom Coffee Taste Like Mushrooms? for a full taste guide.
Who should be cautious?
Functional mushroom products may not be appropriate for everyone. If you are pregnant, breastfeeding, taking prescription medication, preparing for surgery or managing a health condition, discuss mushroom products with a qualified healthcare professional.
For the full four-mushroom overview, read Lion's Mane, Reishi, Chaga and Cordyceps: A Practical Guide. To compare Urban Calm blends, see Meet Urban Calm's Four Mushroom Coffees.
This article is educational and is not medical advice.
