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Evidence rating: Preliminary — lion’s mane has small, encouraging human trials for cognition; the other nine mushrooms are along for the ride
What Roar Lion’s Mane Claims To Be
Roar is a ten-mushroom capsule sold for brain performance — sharper focus, better memory, less brain fog, reduced mental fatigue. Lion’s mane (Hericium erinaceus) is the headline act, and it’s the ingredient the marketing is built around.
There’s a real reason lion’s mane occupies this niche rather than, say, shiitake. It contains compounds (hericenones and erinacines) that stimulate nerve growth factor in laboratory models, which gives it a plausible mechanism for cognitive effects rather than just an antioxidant hand-wave. Whether that mechanism produces a noticeable difference in a healthy person’s day is where the evidence gets thin — but not empty.
What’s Actually In It
Ten mushroom ingredients, at two capsules per day, with no per-ingredient amounts disclosed:
- Lion’s Mane (Hericium erinaceus) — the only one with direct human cognitive trials
- Cordyceps — studied mostly for exercise performance and fatigue
- Reishi — studied mostly for immune markers and sleep
- Chaga, Turkey Tail, Maitake, Shiitake — immune-focused research literature
- Royal Sun Agaricus, White Button Mushroom, Wood Ear Fungus
Here is the thing to notice before comparing this to the studies below: the human trials on lion’s mane used 1 to 3 grams per day of lion’s mane by itself. A two-capsule serving split across ten mushrooms cannot plausibly deliver that much of any one of them. That gap between the studied dose and the likely dose here is the central issue with this product, and it isn’t a criticism of the ingredient — it’s arithmetic.
What The Research Shows
According to PubMed, the human evidence for lion’s mane is genuine but small-scale and short.
The most-cited trial found real improvement — in people who already had cognitive decline. A double-blind, placebo-controlled trial in 30 Japanese adults aged 50-80 with mild cognitive impairment gave the treatment group four 250 mg tablets of Hericium erinaceus powder three times daily (roughly 3 g/day) for 16 weeks. Cognitive function scores were significantly higher than placebo at weeks 8, 12, and 16, and improved progressively with duration. No adverse effects appeared on laboratory testing. DOI
But the benefit disappeared once people stopped taking it. In the same trial, scores dropped significantly four weeks after supplementation ended. Whatever lion’s mane was doing, it did not persist — which matters if you’re deciding whether this is a course of treatment or an indefinite subscription.
In healthy young adults, effects are subtler and inconsistent. A randomized, double-blind, placebo-controlled pilot in 41 healthy adults aged 18-45 using 1.8 g/day found faster performance on the Stroop task 60 minutes after a single dose, and a trend toward reduced subjective stress after 28 days (p = 0.051 — just short of significance). The authors were appropriately cautious, noting “null and limited negative findings were also observed” and that the small sample means the results should be interpreted with care. DOI
A second acute trial found narrow benefits. In a randomized, double-blind, placebo-controlled crossover study, 1 g of Nordic-grown lion’s mane improved reaction time on an N-Back working memory task and Go-stimulus reaction time on a Go/No-go task, plus subjective ratings of happiness — but in the same study a guayusa tea extract comparator outperformed it on mental clarity, focus, and concentration. DOI
What about the other nine mushrooms? They aren’t in the cognitive literature in any comparable way. Reishi, chaga, turkey tail, and maitake have their own research bases — largely immunological — but none of the human cognitive trials retrieved here tested them. Their presence broadens the label; it doesn’t strengthen the brain claim.
The Honest Verdict
What holds up: Lion’s mane is not a made-up nootropic. It has a plausible biological mechanism, a placebo-controlled trial showing cognitive improvement in adults with mild impairment, and two more recent randomized trials in healthy adults picking up small effects on reaction time and processing speed. Across all of them, it was well tolerated with no safety signals.
What doesn’t: The scale of the claims versus the scale of the evidence. The strongest trial had 30 participants; one healthy-adult study had 41 and described itself as a pilot. Effects in healthy people were narrow — a faster Stroop time is not the same as a better memory — and one measure missed statistical significance outright. The benefit also faded within a month of stopping. And the ten-mushroom format almost certainly dilutes lion’s mane below the studied dose, while adding nine ingredients with no cognitive trial data behind them.
Who this makes sense for: Someone curious about lion’s mane specifically, who understands they’re buying early-stage science, and who would treat it as an experiment rather than a solution. If you’re going to try it, the trials suggest giving it 8-16 weeks before judging — the improvements in the mild-impairment study built gradually.
Who should skip it: Anyone experiencing real memory changes they haven’t discussed with a doctor. Cognitive decline has causes worth identifying — thyroid, B12, sleep apnea, medication effects, depression — and a mushroom capsule is not the appropriate first step. Anyone with a mushroom allergy should also stay clear, and anyone wanting the studied dose would do better buying a single-ingredient lion’s mane product with the grams printed on the label.
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This article is for informational purposes only and is not medical advice. Dietary supplements are not intended to diagnose, treat, cure, or prevent any disease. These statements have not been evaluated by the Food and Drug Administration. Talk to your physician before starting any supplement, especially if you have a diagnosed condition or take medication.
Research cited via PubMed: