The Science
The Science Behind Josie
Every ingredient in Josie is backed by peer-reviewed research. Here is the science, with direct links to the studies.
Lion's Mane Mushroom (Hericium erinaceus)
Lion's Mane contains two unique bioactive compounds, hericenones and erinacines, that have been studied for their ability to stimulate Nerve Growth Factor production in the brain. NGF supports the growth, maintenance, and repair of nerve cells, which underlies improvements in focus, memory, and cognitive performance.
Key studies:
Cognitive function in healthy adults (2023) A randomized, double-blind, placebo-controlled study found that a single dose of Lion's Mane extract produced significantly faster performance on the Stroop task, a standard measure of cognitive processing speed, 60 minutes after consumption in healthy young adults. Study: Saitsu Y, et al. Improvement of cognitive functions by oral intake of Hericium erinaceus. Biomedical Research. 2019. Link: https://pubmed.ncbi.nlm.nih.gov/30612505/
Cognitive improvement over 12 weeks (2019) A double-blind, placebo-controlled trial published in Biomedical Research followed 31 healthy adults over age 50 for 12 weeks. Participants taking 3.2 grams of Lion's Mane daily showed significant improvements in cognitive function scores compared to the placebo group. Link: https://pubmed.ncbi.nlm.nih.gov/30612505/
Nerve Growth Factor stimulation Preclinical research has consistently shown that hericenones and erinacines from Lion's Mane promote NGF synthesis in nerve cells, providing the biological mechanism behind the cognitive effects observed in human trials. Study: Kawagishi H, et al. Erinacines A, B and C, strong stimulators of nerve growth factor (NGF)-synthesis, from the mycelia of Hericium erinaceum. Tetrahedron Letters. 1994. Link: https://www.sciencedirect.com/science/article/abs/pii/S0040403901809849
Mood and stress reduction A 28-day follow-up in a 2023 study observed a trend toward reduced subjective stress scores in participants taking Lion's Mane daily compared to placebo. Study: Docherty S, et al. The Acute and Chronic Effects of Lion's Mane Mushroom Supplementation on Cognitive Function. Nutrients. 2023. Link: https://www.mdpi.com/2072-6643/15/22/4842
Cordyceps Mushroom (Cordyceps militaris)
Cordyceps contains active compounds including cordycepin and adenosine that have been studied for their role in supporting ATP production and oxygen utilization at the cellular level. Multiple human trials have demonstrated improvements in aerobic capacity, endurance, and exercise performance.
Key studies:
Meta-analysis of 14 randomized controlled trials (2025) A systematic review and meta-analysis published in Frontiers in Nutrition analyzed 14 randomized controlled trials involving 528 athletes. The analysis found that Cordyceps supplementation significantly improved endurance performance, ventilatory threshold, and VO2peak, all key markers of aerobic capacity. Study: Frontiers in Nutrition, 2025. Link: https://www.frontiersin.org/journals/nutrition
Endurance and oxygen uptake in recreationally active adults (2017) A study published in the Journal of Dietary Supplements followed 28 recreationally active adults over three weeks of Cordyceps militaris supplementation. Results showed significant improvements in time-to-exhaustion during high-intensity cycling and improvements in maximal oxygen uptake. Study: Hirsch KR, et al. Cordyceps militaris Improves Tolerance to High-Intensity Exercise After Acute and Chronic Supplementation. Journal of Dietary Supplements. 2017. Link: https://pubmed.ncbi.nlm.nih.gov/27736063/
Lactate threshold improvements in older adults A study on 20 healthy older adults found that after 12 weeks of Cordyceps supplementation, their lactate threshold increased by 10.5% and ventilatory threshold increased by 8.5% compared to no change in the control group. Study: Ko KM, et al. Supplementation of Cordyceps sinensis and Rhodiola rosea improves physical performance. Journal of Alternative and Complementary Medicine. 2010.
ATP and cellular energy production Preclinical research suggests Cordyceps supports the production of adenosine triphosphate, the primary energy currency of cells, which may explain the consistent endurance improvements observed in human trials. Study: Guo YR, et al. Cordyceps sinensis and its effects on adenosine and adenosine triphosphate. Evidence-Based Complementary and Alternative Medicine. 2010.
Vitamin B12 (Cobalamin)
Vitamin B12 is an essential nutrient involved in energy metabolism, red blood cell production, nervous system function, and the synthesis of dopamine and serotonin. Deficiency is associated with fatigue, cognitive decline, mood changes, and neurological symptoms.
Key studies and sources:
B12 and energy metabolism B12 is a required cofactor in the methylmalonic acid pathway, which is essential for converting food into cellular energy. The National Institutes of Health Office of Dietary Supplements provides a comprehensive review of B12's role in energy metabolism. Source: National Institutes of Health. Vitamin B12 Fact Sheet for Health Professionals. Link: https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/
B12 and neurotransmitter production B12 is required for the synthesis of S-adenosylmethionine, a methyl donor involved in the production of dopamine and serotonin. Deficiency has been linked to depressive symptoms and mood disturbances. Study: Coppen A, Bolander-Gouaille C. Treatment of depression: time to consider folic acid and vitamin B12. Journal of Psychopharmacology. 2005. Link: https://pubmed.ncbi.nlm.nih.gov/15671130/
B12 deficiency prevalence Research suggests B12 deficiency affects a significant portion of the population, particularly vegans, vegetarians, people over 50, and people taking certain medications including metformin and proton pump inhibitors. Study: Allen LH. How common is vitamin B-12 deficiency? American Journal of Clinical Nutrition. 2009. Link: https://pubmed.ncbi.nlm.nih.gov/19116335/
Natural Caffeine from Green Tea
Green tea has powered focused mornings for centuries, and its leaves naturally carry L-theanine, the amino acid most often credited with tea's calm, steady reputation. Natural caffeine from green tea absorbs more gradually than synthetic caffeine anhydrous and produces a smoother, more sustained energy effect.
Key studies:
Caffeine and cognitive performance A comprehensive review published in Neuroscience and Biobehavioral Reviews found that caffeine reliably improves alertness, attention, and reaction time at doses between 40 and 300mg in healthy adults. Study: Einother SJ, Giesbrecht T. Caffeine as an attention enhancer: reviewing existing assumptions. Psychopharmacology. 2013. Link: https://pubmed.ncbi.nlm.nih.gov/23108971/
Caffeine dose and anxiety risk A 2024 meta-analysis published in Frontiers in Psychology found that high-dose caffeine intake of 400mg or more per day had a highly significant association with increased anxiety risk in healthy adults. Lower doses showed a more moderate association. Study: Frontiers in Psychology. Caffeine consumption and anxiety: a meta-analysis. 2024. Link: https://www.frontiersin.org/journals/psychology
L-theanine and the calm energy pairing Green tea leaves naturally contain L-theanine, an amino acid long associated with the calm, focused quality of a tea lift. It is a big part of why green tea has a different reputation than coffee even at similar caffeine doses. Josie's caffeine is extracted from green tea into a clear sparkling base, which also means none of coffee's teeth-staining tannins come along for the ride.
Natural vs synthetic caffeine absorption Research suggests that natural caffeine sources containing accompanying plant compounds like polyphenols and tannins produce a slower absorption curve and more gradual energy onset compared to isolated synthetic caffeine anhydrous.
Why This Matters
Most energy drinks do not publish their science. They list ingredients on a label and rely on marketing to fill in the rest. Josie is built differently. Every ingredient was chosen because peer-reviewed human research supports its use, the mechanism of action is understood, and the safety profile is established.
65mg of natural caffeine from green tea. Lion's Mane for focus. Cordyceps for endurance. Vitamin B12 for mood and energy metabolism. Zero sugar, zero calories, nothing artificial.
That is the formula. That is the science. That is Josie.
Shop Josie at drinkjosie.com/collections/josie-beverages.
