Clinical Studies

Bacopa Monnieri

A randomized, double-blind, placebo-controlled trial conducted in otherwise healthy persons over the age of 55. Bacopa monnieri significantly improved verbal learning, memory acquisition, and delayed recall as measured by the AVLT.  [Source]

A randomized, double-blind, placebo-controlled clinical trial conducted in persons over 65 years of age, with no signs of dementia. Bacopa monnieri daily for 12 weeks showed significant improvements in attention (less likely to pay attention to irrelevant information), working memory, and less anxiety and depression. [Source]

Bacopa monnieri over 90 days in healthy persons aged 18-60 with no history of mental ailments showed an increase in working memory, as well as precision of rapid identification. [Source

A double-blind, placebo-controlled study, with healthy subjects between the ages of 18-60. Bacopa monnieri daily for 12 weeks, with testing occurring at 5 and 12 weeks into the study as well as baseline, show improved speed of learning, memory capacity. Effects were greater over 12 weeks relative to 5 weeks. [Source]

A randomized, double-blind, placebo-controlled clinical trial. Bacopa monnieri had the potential for enhancing cognitive performance in older people (average age of 73) when taken daily. Bacopa monnieri participants had enhanced AVLT delayed word recall memory scores relative to placebo. Stroop results were similarly significant. The effects occurred after 6 weeks and 12 weeks of supplementation. [Source]

Phosphatidylserine (PS)

A double-blind, placebo-controlled trial evaluated the effect of six months of PS supplementation in 494 elderly patients with cognitive impairment. This study found that phosphatidylserine produced significant improvement in behavioral and cognitive function after three and six months. [Source]

In elderly persons without dementia but with memory complaints given phosphatidylserine (complexed with DHA, a fatty acid) for 15 weeks, supplementation was associated with improvements in memory and learning processes as well as time taken to complete tasks. Oddly, persons with higher baseline cognition were more likely to respond to treatment. [Source]

A double-blind cross-over study of phosphatidylserine vs. placebo in patients with early dementia of the Alzheimer type. Phosphatidylserine (PS) daily for 8 weeks showed signs of improved well-being compared to those who took a placebo. [Source]

 A study of 70 people who showed signs of developing Alzheimer’s Disease were given PS twice a day. This study found that mental function improved in these patients after eight and sixteen weeks. [Source] 

A clinical study with 10 elderly women who had depressive disorders were treated with PS for 30 days, following 15 days of being treated with a placebo. The researchers concluded that the PS supplement lead to an improvement of depressive symptoms, memory and behavior in all 10 women. [Source] 

Rhodiola Rosea

Rhodiola twice daily for 4 weeks in persons with life and work-related stress was greatly able to reduce dysfunction and fatigue associated with stress in a time-dependent manner. Significant improvements were noted in social and work function secondary to reduced fatigue and improved mood. [Source]

A multicenter, non-randomized, open-label, single-arm trial with twenty days of rhodiola supplementation during examination periods for students was able to improve neuromotoric fitness (accuracy of maze drawing test), fatigue, and well- being relative to placebo. Exam scores were 8.4% higher in the rhodiola group relative to placebo. [Source] 

A double-blind, placebo controlled cross-over study in otherwise healthy physicians, given supplementation of rhodiola for 2 weeks showed significant anti-fatigue effects as assessed by a total fatigue index and improved performance on work-related tasks by approximately 20%. [Source]

In military cadets performing regular military night duties, 5 days of supplementation of rhodiola was able to significantly reduce total fatigue and improve well-being when measured 2 hours after supplement ingestion and again at the end of the trial. Capacity for mental work significantly increased relative to placebo. [Source]

Ginkgo Biloba

A double-blind, randomized, placebo controlled trial including 400 patients aged 50 years or above with Alzheimer's disease (AD) or vascular dementia showed that supplementation of ginkgo biloba daily for a period of 24 weeks was associated with significant improvements in cognition as assessed by SKT (3.2-point improvement while placebo experienced a 1.3-point decrement). [Source]

A randomized, double-blind, placebo-controlled, multi-center study, over a period of 24 weeks in persons already diagnosed with Alzheimer's and/or dementia noted that supplementation was associated with more instances of memory and cognitive improvement than placebo. [Source]

 A double blind, placebo controlled trial over the course of 3 months in elderly persons experiencing cognitive decline but not diagnosed with dementia or other neurodegenerative diseases. Gingko biloba supplementation showed noted improvements in cognition and reaction time relative to placebo. [Source]

A multi-center, double-blind, randomized, placebo-controlled, with mild to moderate dementia supplementation over a period of 24 weeks. Gingko biloba supplementation was associated with improvements on symptoms of dementia as assessed by SKT and NPI. [Source] [Source]

Standardized gingko biloba appears to be equally effective as Donepezil in reducing cognitive impairment associated with Alzheimer's, although combination therapy was more effective than either in isolation. [Source

A study of 59 patients with age-related mild cognitive impairment of the non-Alzheimer type. Supplementation of ginkgo biloba appears to be effective in improving memory formation and improving general cognition as assessed by SF-12. [Source]


A study where participants experienced conditions of physical or psychological stress showed that l-theanine not only reduced anxiety but also attenuated the blood-pressure increase in high-stress-response adults. [Source]

A double blind study showed that l-theanine was able to promote relaxation as assessed by the tranquil-troubled subscale of the VAMS (self-report survey). [Source]

A double-blind, placebo controlled study. Subjects given a mental arithmetic task after l-theanine or placebo showed that the increase in anxiety, stress, and heart rate that occurred in placebo was attenuated with l-theanine. The increase in salivary IgA concentration was approximately halved. [Source]

L-theanine has been consumed for thousands of years. More studies are currently ongoing to look beyond the anti-anxiety properties of l-theanine to examine its neuroprotective properties. This is because excessive glutamate stimulation in the brain (excitotoxicity), has a role in the development of long-term neurodegenerative disorders. Therefore, l-theanine’s blocking of glutamate make it a promising neuroprotective and preventative against neurodegenerative disorders.

Vitamins B6, B9 and B12

Homocysteine is a risk factor for Alzheimer’s. Homocysteine-lowering treatment with B vitamins slows the rate of brain atrophy in mild cognitive impairment. B vitamins appear to slow cognitive and clinical decline in people with MCI, in particular in those with elevated homocysteine. [Source]

According to the NIH, B9 (folic acid) deficiency is associated with depression and dementia. In elderly people it may be related to aging, poor diet, malabsorption, drugs, or increased demand or be unexplained. Folic acid has particular effects on mood and cognitive and social function. Impaired folate metabolism may result in a pattern of cognitive dysfunction that resembles aging. Folic acid is important in the nervous system at all ages, but in elderly people deficiency contributes to aging brain processes, increases the risk of Alzheimer's disease and vascular dementia. [Source]

Between 10 to 30 percent of people over 50 years old produce too little stomach acid, leading to decreased absorption of B12 from food. The percentage of people with this problem increases with advancing age. [Source]