Below is a summary of the scientific literature on each ingredient in the Zen1 formula.
Geniposide has historically been a relatively seldom studied iridoid glycoside, until quite recently.* It is extracted from the fruits of Gardenia jasminoides.* Gardenia jasminoides has been used as a dietary supplement in China for hundreds of years, for a variety of purposes, including mood support (Ye et al., 2018).* Recent preliminary studies indicate that geniposide may indeed play a role in helping to support a positive mood, although knowledge regarding the mechanism is limited and further research is needed (Cai et al., 2015, Zhao et al., 2018, Zhang et al., 2019, Sun et al., 2020, Yuan et al., 2020).* This is a research area of keen interest to certain companies and Zenstra does not wish to comment further on geniposide at this time. Further research may possibly be found online by searching for the term "geniposide mood," or by reading any of the aforementioned studies which can be found in the below reference list.
5-HTP (5-hydroxytryptophan) is a compound that our body synthesizes from the amino acid tryptophan, which is found in seeds, eggs, salmon and turkey.* Our bodies use 5-HTP to make serotonin.* Serotonin is thought to play a role in mood, appetite and autonomic functions.* 5-HTP may help to support a positive mood.* It may also potentially help to reduce sugar cravings (Ceci et al., 1989, Cangiano et al., 1998, Cangiano et al., 1991, Cangiano et al., 1992, Rondanelli et al., 2012).*
Polygala tenuifolia also known as Yuan Zhi, is a root traditionally consumed in Asia to support memory, calmness and sleep.*
Evidence suggest it may support healthy memory (Lee et al., 2009). Evidence also suggests that Polygala tenuifolia may help to support a positive mood (Lee et al., 2009, Hu et al., 2009, Yao et al., 2010, Hu et al., 2010, Hu et al., 2011).*
Research suggests that a saponin from polygala interacts with N-methyl-D-aspartic acid and its receptors, to promote a good mood (Jin et al., 2014).*
Additionally, polygala tenuifolia may help support calmness (Yao et al., 2010) and improve both REM and NREM sleep (Cao et al., 2016).*
Bacopa monnieri is an adaptogenic herb which has been shown to help maintain memory and support a calm mood (Rai et al., 2003, Bhattacharya and Ghosal, 1998). Research suggests it reduces cortisol, a hormone linked to stress (Benson et al., 2014).*
One 12-week study observed that taking Bacopa monnieri daily significantly improved the speed of processing visual information, learning rate, and memory (Stough et al., 2001).* Another study found that it increased dendritic length and branching (Vollala, Upadhya and Nayak, 2011).* Dendrites are parts of nerve cells in the brain that are closely linked to learning and memory.
Two other studies found that taking Bacopa monnieri daily significantly improved calmness and happiness scores in adults over 12 weeks (Stough et al., 2001, Calabrese et al., 2011).*
Gotu kola (Centella asiatica), known as the “herb of longevity,” has been traditionally used in Asia to support calmness, a positive mood, brain health, skin health, as well as liver and kidney health (Jana et al., 2010, Wattanathorn et al., 2008, Gray et al., 2016, Bylka et al., 2013).*
A 2013 review concluded that gotu kola can help maintain a calm, relaxed state (Sarris, McIntyre and Camfield, 2013).* Another 2016 study found that gotu kola promoted calmness in male mice that were sleep deprived for 72 hours (Chanana and Kumar, 2016).* A separate study looked at the cognitive enhancing effects of gotu kola on mice showed that it improved both learning and memory formation (Gray et al., 2016).*
Another 2016 study found that gotu kola Gotu Kola may support a healthy, positive mood.* The participants were asked to take gotu kola for 60 days. They self-reported decreased stress, improved calmness, and a positive mood (Lokanathan et al., 2016).*
A 2017 study suggested it may help support restful sleep, as well as liver and kidney health (Cauffield and Forbes, 2017).*
Phosphatidylserine is a compound similar to a dietary fat which is highly prevalent in human brain tissue.* It is vital for cognitive function and is synthesized naturally in our brains.*
Phosphatidylserine is thought to help regulate mood and memory.* In a 2015 study of people over the age of 65, the participants took a supplement containing phosphatidylserine and the omega-3 fatty acids DHA and EPA three times daily for 12 weeks. At the study's end, scores on a mood scale had markedly improved (Komori, 2015).*
It can also support memory. In a 2010 study published in the Journal of Clinical Biochemistry and Nutrition, 78 elderly people were given either phosphatidylserine or a placebo for six months.* Participants with relatively low memory scores at the start of the study were found to have experienced a significant improvement in memory (Kato-Kataoka et al., 2010).*
Schisandra chinensis (five flavour fruit) is a vine which bears purple-red berries described as amalgamating all five tastes: sweet, sour, salty, bitter and spicy. In Chinese tradition, Schisandra is considered beneficial to qi, the life force or energy inherent in all living things.* It’s thought to have a positive impact on several meridians, or pathways, in the body, including the heart, lungs, and kidneys.*
Schisandra berry is categorized as an adaptogen, as it helps the body adapt to both physical and chemical stress (Guan et al., 2011).
It supports healthy energy levels by promoting neural ATP synthesis, as well as brain function, relaxation and blood circulation (Lam and Ko, 2012, Park et al., 2013, Huang et al., 2007, Tsi and Tan, 2008).
Schisandrin C, a component of Schisandra, appears to support healthy brain function (Park et al., 2013).* A compound called deoxyschizandrin, found in Schisandra, is theorised to support cognition and memory (Hu et al., 2012). A double-blind, placebo-controlled, randomised study found that Schisandra helps maintain attention, cognition, and accuracy of people under stress (Aslanyan et al., 2010).*
Its calmness and relaxation promoting properties have been shown to be beneficial for sleep (Huang et al., 2007).* Schisandra is effective in helping the body control adrenaline and serotonin changes caused by stress (Chen et al., 2011).* Evidence suggests schisandra affords a broad spectrum stress protective effect (Panossian and Wikman, 2008).*
Taking a daily dose of about 130mg of Schisandra has shown an approximately 9% improvement in blood circulation in healthy adults (Tsi and Tan, 2008).* It has been shown to increase nitric oxide, which could lead to improvements in physical performance (Panossian et al., 1999).*
Among numerous other benefits, Schisandra also supports the liver and increases anti-oxidant response (Pu et al., 2012).* It has been found to stimulate antioxidant enzymes, particularly SOD and glutathione peroxidase (Nowak et al., 2019). Glutathione also helps protect the brain from memory impairment.*
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