Can a mushroom boost your brain? Lion's mane put to the test

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Participants must self-assess themselves as being in good health * Participants must be aged 18 to 45 at the time of giving consent * Understand and are willing to participate in all scheduled visits and to adhere to the trial procedures outlined in the subject information sheet * Are fluent in English (equivalent to IELTS Level 6) Exclusion Criteria: * Have any pre-existing medical condition/illness which will impact taking part in the study. There may be other, unforeseen, exceptions and these will be considered on a case-by-case basis, i.e., participants may be allowed to progress to screening if they have a condition/illness which would not interact with the active treatments or impede performance so it's worth discussing any medical conditions with the researcher prior to booking lab appointments. NOTE: the explicit exceptions to this is controlled hayfever, asthma, hypo/hyperthyroidism, high blood pressure, high cholesterol, reflux. * Are currently taking prescription medications NOTE: the explicit exceptions to this are contraceptive treatments, and those taken 'as needed' in the treatment of asthma and hay fever. There may be other instances of medication use which, where no interaction with the active treatments is likely, and which would not be expected to have any impact on brain function, participants may be able to progress to screening. * Have a history of experiencing difficulty swallowing tablets including in capsule form * Have high blood pressure (systolic over 139 mm Hg or diastolic over 89 mm Hg) * Have a Body Mass Index (BMI) outside of the range 18.5-35 kg/m2 (unless waist to hip ratio is less than or equal to 0.85 (female) or 0.90 (male)) * Engage in the extreme dietary habit of intermittent fasting, as judged by the Investigator * Are pregnant, seeking to become pregnant or lactating * Have been diagnosed with a neurological condition, or assessed as having a learning/behavioural or neurodevelopmental difference such as dyslexia, autism, or ADHD * Have a visual impairment that cannot be corrected with glasses or contact lenses (including colour-blindness) * Use illegal/recreational drugs * Have relevant food allergies/intolerances/ sensitivities * Consume over 500mg of caffeine per day * Have taken dietary supplements e.g., Vitamins, omega 3 fish oils etc. in the last 4 weeks (Note: participation is possible following a 4-week supplement washout prior to participating and for the duration of the study on the proviso that the supplements they are taken are out of choice and not medically prescribed or advised). NOTE - Vitamin D and iron supplements are allowed for this trial if they have been advised by GP to increase levels to a normal range and have been taken for at least 4 weeks consistently and will be taken consistently throughout the trial. * Are currently participating in any other chronic clinical or nutrition intervention studies, or have done so in the past 4 weeks * Have taken antibiotics within the past 4 weeks * Has been diagnosed with/ undergoing treatment for alcohol or drug abuse in the last 12 months * Have been diagnosed with/ undergoing treatment for a psychiatric disorder in the last 12 months (including medically diagnosed anxiety, depression or stress-related disorders). * Have any health condition that would prevent fulfilment of the study requirements (this includes non-diagnosed conditions for which no medications may be taken) * Suffers from frequent migraines that require medication (more than or equal to 1 per month) * Not be a native speaker of English or at least fluent in English * Smoke tobacco or vape nicotine or use nicotine replacement products * Have worked night shift the night prior to attending the laboratory * Are unable to demonstrate adequate minimal performance on lab, computer-based cognitive tasks * Have any known active infections * Do not have a bank account (required for payment)