The use of substances to enhance cognitive performance, also known as "nootropics," has a long history dating back to ancient civilizations.
In ancient Greece, philosophers and scholars used various herbs and plants to boost their mental abilities and improve their memory.
In the Middle Ages, alchemists sought to create elixirs and potions that would enhance the mind and body.
In the 20th century, the term "nootropic" was coined by Romanian psychologist and chemist Dr. Corneliu E. Giurgea to describe substances that could enhance memory and cognitive function without causing any negative side effects.
In the decades that followed, a variety of nootropic substances were developed and studied for their potential benefits on the brain.
Stimulants, on the other hand, have been used for centuries to promote alertness and wakefulness.
Some of the earliest known stimulants include caffeine, which is found in coffee, tea, and chocolate, and nicotine, which is found in tobacco.
Other stimulants, such as amphetamines, were developed in the early 20th century and used to treat conditions such as narcolepsy and ADHD.
The comparison between nootropics and stimulants is a critical discussion for individuals seeking to enhance focus and concentration.
Nootropics, known as "smart drugs," aim to offer cognitive enhancement with minimal side effects, while stimulants are recognized for their energizing effects.
This blog explores the differences between these categories, providing insights into their mechanisms, effects, and applications for cognitive improvement.
If you're looking to start taking Nootropics as a supplement, you can learn more about our Mood & Wellbeing Nootropic Supplement at nooroots. If you have any questions after reading this post, you can either visit our support resources or simply contact us via our online form.
Contents
- An Overview of Nootropics vs. Stimulants
- Are Nootropics Stimulants?
- The Effects of Nootropics on Focus and Concentration
- Synthetic Nootropics for Focus and Concentration
- Common Stimulant Substances
- Risks of Taking Synthetic Nootropics for Focus and Concentration
- Comparison of Nootropics And Stimulants for Focus And Concentration
Sharpening the mind: A look at Nootropics vs. Stimulants for Improved Focus and Concentration
An Overview of Nootropics vs. Stimulants
What are Nootropics and How Do They Work?
Nootropics, also known as "smart drugs" or cognitive enhancers, encompass a vast group of neurotropic substances.
These drugs have the unique ability to enhance memory, restore impaired cognitive function, stimulate wakefulness, improve learning and information reproduction, and bolster the body's resistance to adverse factors.
Notably, the first nootropic discovered was Piracetam, which demonstrated memory improvement without sedative effects.
Nootropics can be classified based on their action on brain metabolism, neurotransmitter systems (including cholinergic, glutamatergic, and GABAergic systems), cerebral vasodilation, neuropeptides and their analogues, antioxidants, and membrane protectors.
The main effect of these drugs is to enhance learning, memory, and higher cortical functions.
They differ significantly from other psychotropic drugs in their spectrum of pharmacological effects, which may include psychostimulating, anti-asthenic, adaptogenic, anxiolytic, antihypoxic, neuroprotective actions, and effects on cerebral circulation.
Nootropics are known for their low toxicity, minor side effects, and lack of addiction potential, making them a safe option for cognitive enhancement.
What are Stimulants and How Do They Work?
Stimulants are substances that increase alertness, attention, and energy by enhancing the activity of certain neurotransmitters in the brain, such as dopamine and norepinephrine.
These drugs can be prescribed for medical conditions like Attention Deficit Hyperactivity Disorder (ADHD) and narcolepsy, where they help to reduce symptoms and improve focus and wakefulness.
Common stimulants include methylphenidate, atomoxetine, and modafinil, among others.
The mechanism of action for stimulants involves the blockade of neurotransmitter reuptake or the increase of neurotransmitter release, which leads to an amplification of signaling in the brain.
This heightened neurotransmitter activity results in increased concentration, energy, and alertness. However, unlike nootropics, the use of stimulants can be associated with a higher risk of side effects, dependency, and withdrawal symptoms.
Stimulants are powerful and effective in treating specific disorders but require careful management and monitoring to mitigate potential risks.
Understanding the differences between these two types of cognitive enhancers is crucial for choosing the most appropriate intervention based on individual needs and health conditions.
Are Nootropics Stimulants?
Nootropic drugs are characterized by their low toxicity, minor side effects, and lack of causing speech and motor excitement, anxiety, the development of addiction, or depletion of the body’s functional capabilities.
They are known to combine well with drugs from other groups.
The spectrum of pharmacological effects of various nootropics may include a psycho-stimulating effect, which influences intellectual and motor retardation, apathy, and mental inertia, among other effects such as anti-asthenic (influence on mental and physical asthenia, lethargy, weakness, and exhaustion), adaptogenic (increased tolerance to various extreme exogenous factors), anxiolytic (influence on emotional lability, irritability, and anxiety), anti-hypoxic neuroprotective action, and the ability to improve cerebral circulation.
This broad spectrum of effects underlines the primary function of nootropics, which is to impact learning and memory processes positively, improve impaired higher cortical functions, and address mental retardation without necessarily acting as traditional stimulants.
Unlike stimulants that primarily act by increasing the overall activity of the central nervous system (CNS) and can lead to addiction and other side effects, nootropics offer a more targeted approach to enhancing cognitive function, with a focus on improving specific cognitive processes rather than inducing a generalized stimulating effect.
This distinction is crucial in understanding the role of nootropics in cognitive enhancement compared to stimulants.
The Effects of Nootropics on Focus and Concentration
The pursuit of enhanced focus and concentration has led to the exploration of various natural and synthetic substances.
Among these, nootropics have gained popularity for their potential cognitive benefits without the harsh side effects often associated with stimulants.
Here, we explore several common nootropic substances, their origins, mechanisms of action, and potential benefits for cognitive enhancement.
Common Nootropic Substances
- Guarana Seed
- Origin: Guarana (Paullinia cupana) is a plant native to the Amazon basin and known for its large seeds rich in caffeine.
- What It Is: Guarana seeds are a natural source of caffeine, offering stimulant effects.
- Mechanism of Action: The high caffeine content in guarana seeds acts as a central nervous system stimulant, blocking adenosine receptors, which can increase alertness and reduce fatigue.
- Benefits: Guarana may enhance focus, attention, and memory, particularly in tasks requiring sustained mental effort.
- L-Theanine
- Origin: Found predominantly in green tea leaves, L-Theanine is an amino acid known for its calming effects.
- What It Is: A natural compound that promotes relaxation without sedation.
- Mechanism of Action: It modulates aspects of brain function in humans, possibly by increasing serotonin, dopamine, GABA, and glycine levels in specific brain areas.
- Benefits: L-Theanine can improve focus and attention, especially when combined with caffeine, by promoting a state of relaxed alertness.
- Acetyl-L-Carnitine (ALCAR)
- Origin: ALCAR is a naturally occurring amino acid derivative found in the body and in red meats.
- What It Is: A supplement that supports mitochondrial function and energy production.
- Mechanism of Action: It assists in the transport of fatty acids into mitochondria for energy production and exhibits neuroprotective properties.
- Benefits: ALCAR may improve mental energy, focus, and memory, as well as reduce cognitive decline in the elderly.
- Ginkgo Biloba
- Origin: Ginkgo biloba, one of the oldest living tree species, has been used in traditional Chinese medicine for centuries.
- What It Is: An extract made from the leaves of the ginkgo tree, known for its antioxidant properties.
- Mechanism of Action: Ginkgo improves cerebral blood flow and has neuroprotective effects, possibly by modulating neurotransmitter systems.
- Benefits: It may enhance cognitive function, including focus, memory, and processing speed in healthy individuals.
- Rhodiola Rosea
- Origin: A herb that grows in cold, mountainous regions of Europe and Asia, used historically to combat fatigue.
- What It Is: An adaptogen that helps the body resist physical and mental stress.
- Mechanism of Action: It enhances neurotransmitter systems and has neuroprotective effects, improving stress resistance.
- Benefits: Rhodiola Rosea can improve attention, cognitive function, and mental performance under stress or fatigue.
- Bacopa Monnieri
- Origin: A perennial herb from wetlands across the globe, used in Ayurvedic medicine.
- What It Is: An adaptogenic herb that supports brain health.
- Mechanism of Action: It enhances synaptic communication by modulating the growth of nerve endings and neurotransmitter levels, including acetylcholine.
- Benefits: Bacopa monnieri is known to improve memory formation and reduce anxiety, leading to better focus and cognition over time.
- Citicoline
- Origin: A naturally occurring brain chemical that is broken down into choline and cytidine upon ingestion.
- What It Is: A supplement that supports brain health and cognitive function.
- Mechanism of Action: Citicoline increases phosphatidylcholine synthesis, essential for brain function, and enhances neurotransmitter levels, including acetylcholine.
- Benefits: It has been shown to improve focus, cognitive speed, and attention, making it beneficial for cognitive enhancement.
- N-Acetyl L-Tyrosine (NALT)
- Origin: Tyrosine is a non-essential amino acid found in many high-protein foods; NALT is its acetylated form.
- What It Is: A supplement that enhances cognitive function under stress.
- Mechanism of Action: NALT serves as a precursor for dopamine and norepinephrine, neurotransmitters involved in cognitive alertness and focus.
- Benefits: NALT can improve cognitive flexibility, reduce stress, and enhance performance in mentally demanding tasks.
Each of these nootropic substances offers unique benefits for enhancing focus, concentration, and overall cognitive function.
Unlike stimulants, which may cause jitteriness or dependency, nootropics generally support brain health and cognitive performance with minimal side effects, making them an appealing option for those looking to improve their mental acuity naturally.
Synthetic Nootropics for Focus and Concentration
In the pursuit of improved cognitive abilities, synthetic nootropics serve as tools to enhance focus, concentration, and brain function.
These compounds, developed in laboratories, provide specific mechanisms of action with effects on mental sharpness and energy.
Beginning with piracetam, which established the foundation for further advancements, to newer compounds like modafinil and armodafinil, synthetic nootropics have become essential for those aiming to improve cognitive performance.
Substances such as stimulants and cognitive enhancers, including Adderall/Ritalin, Noopept, and Phenylpiracetam, act through diverse neurochemical pathways to improve focus, memory, and attention, proving their worth in clinical applications and daily life.
- Piracetam
- Origin: Derived from gamma-aminobutyric acid (GABA) and acetamide.
- What it is: A cyclic derivative of GABA, known as a nootropic compound.
- Mechanism of Action: Modulates ion channels (Ca2+ and K+), enhancing neuronal excitability. It enhances acetylcholine function via muscarinic receptors and affects NMDA receptors, increasing cell membrane permeability and oxygen consumption in the brain, linked to ATP metabolism.
- Benefits: Improves interhemispheric transmission, glucose metabolism, and brain function in conditions like hypoxia, alcohol withdrawal symptoms, post-traumatic cognitive dysfunction, and developmental dyslexia. Has been tested for Alzheimer's disease treatment with varying results.
- Modafinil
- Origin: Synthetic; developed in the 1970s as a treatment for narcolepsy.
- What is it: A wakefulness-promoting agent used to treat sleep disorders and off-label for cognitive enhancement.
- Mechanism of action: Increases dopamine levels by inhibiting dopamine reuptake. Also affects other neurotransmitters like norepinephrine, serotonin, and orexin systems, enhancing alertness and cognitive functions.
- Benefits: Improves alertness, cognitive function, and wakefulness in individuals with sleep disorders; may enhance attention and memory in healthy individuals.
- Adderall/Ritalin (Amphetamine/Dextroamphetamine & Methylphenidate)
- Origin: Synthetically developed compounds.
- What it is: Central nervous system stimulants used primarily for Attention Deficit Hyperactivity Disorder (ADHD).
- Mechanism of Action: Increase dopamine and norepinephrine levels in the brain by inhibiting their reuptake. This action improves attention, focus, and control over impulses.
- Benefits: Clinically proven to improve attention span, focus, and behavior in individuals with ADHD. Their effectiveness in enhancing cognitive function in healthy individuals is debated and associated with potential risks and side effects.
- Noopept
- Origin: Synthetically developed peptide.
- What it is: A potent nootropic that is considered similar to piracetam but with significantly higher potency.
- Mechanism of Action: Enhances brain-derived neurotrophic factor (BDNF) levels, improves synaptic plasticity, and enhances memory and learning processes.
- Benefits: Has been shown to improve cognitive function, memory, and learning capabilities in various conditions, including cognitive impairment after brain injuries.
- Phenylpiracetam
- Origin: Derived from piracetam with an added phenyl group.
- What it is: A potent stimulant and nootropic compound.
- Mechanism of Action: Similar to piracetam, but the phenyl group increases its potency and provides stimulant properties, enhancing physical performance.
- Benefits: Improves cognitive function, memory, and has potential benefits in enhancing physical performance.
- Armodafinil
- Origin: R-enantiomer of modafinil, providing a longer half-life.
- What it is: A wakefulness-promoting agent used for sleep disorders.
- Mechanism of Action: Similar to modafinil, armodafinil increases dopamine levels by inhibiting its reuptake, enhancing alertness and cognitive functions.
- Benefits: Improves focus, cognitive function, and wakefulness with a longer duration of action compared to modafinil.
- Origin: Synthetically developed derivative of vitamin B1 (thiamine).
- What it is: A nootropic compound designed to surpass the blood-brain barrier more efficiently than thiamine, increasing thiamine levels in the brain.
- Mechanism of Action: Enhances cholinergic, dopaminergic, and glutamatergic neurotransmission, promoting improved cognitive function, energy levels, and mood. It specifically targets the increase of thiamine triphosphate (TTP) in the brain, which is crucial for enhancing neural efficiency and cognitive capabilities.
- Benefits: Known for boosting memory, attention span, and energy. Sulbutiamine improves cognitive function, reduces fatigue, and enhances both physical and mental endurance. It is beneficial for individuals seeking to enhance learning capacity, memory recall, and overall mental alertness without the typical stimulant side effects.
- Sunifiram
- Origin: Synthetically created compound, structurally similar to Piracetam but with significantly higher potency.
- What it is: A potent nootropic known for its cognitive-enhancing effects, despite being relatively new and less researched.
- Mechanism of Action: Acts on glutamatergic and cholinergic systems to enhance synaptic plasticity, crucial for learning and memory. It increases the release of acetylcholine, a neurotransmitter directly linked to learning and memory processes, and modulates glutamate receptors to improve cognitive functions.
- Benefits: Demonstrates significant potential in enhancing memory, learning, attention, and overall cognitive abilities. Sunifiram is noted for its ability to improve focus and learning efficiency with minimal side effects, making it a strong candidate for enhancing cognitive performance and studying its applicability in treating cognitive impairments and neurodegenerative conditions.
Common Stimulant Substances
Stimulant substances are known for their ability to enhance focus, concentration, and information processing in the brain.
Here's an overview of common stimulants and their effects:
- Caffeine
- Origin: Naturally found in coffee beans, tea leaves, cocoa beans, and kola nuts.
- What is it: A central nervous system stimulant known for its wakefulness-promoting effects.
- Mechanism of action: Blocks adenosine receptors in the brain, reducing tiredness and increasing alertness.
- Benefits: Improves focus, alertness, and concentration; enhances cognitive performance and reduces the perception of effort during physical activity.
- Amphetamines (Example: d-amphetamine)
- Origin: Synthetic origin; first synthesized in the late 19th century.
- What is it: A class of potent stimulant drugs used both recreationally and as prescription medication.
- Mechanism of action: Increases the activity of neurotransmitters (dopamine and norepinephrine) in the brain.
- Benefits: Enhances focus, energy, and alertness; used in the treatment of ADHD to improve attention and control behavior.
- Nicotine
- Origin: Found in high concentrations in the leaves of the tobacco plant (Nicotiana tabacum) and other related species.
- What is it: A plant alkaloid known for its stimulant and relaxant effects.
- Mechanism of action: Downregulates the expression of nicotinic receptors, affecting neurotransmitter release.
- Benefits: Associated with improvement of learning and memory indices in healthy cohorts and mitigation of memory impairment in ageing.
- Prescription Stimulants (General overview)
- Origin: Various, both synthetic and natural derivatives.
- What is it: Medications prescribed to treat ADHD, narcolepsy, and other conditions.
- Mechanism of action: Increase neurotransmitter activity in the brain, enhancing focus, attention, and alertness.
- Benefits: Improves attention span, focus, and behavior control in individuals with ADHD; enhances wakefulness in those with sleep disorders.
- Cocaine
- Origin: Derived from the coca plant (Erythroxylon coca), which is native to South America. Cocaine has been used for thousands of years in its native context for its stimulant properties.
- What is it: A strong stimulant drug used recreationally for its intense euphoric effects and medically for specific uses, such as local anesthesia for some surgical procedures.
- Mechanism of action: Cocaine works by blocking the reuptake of dopamine, serotonin, and norepinephrine into neurons. This action leads to an accumulation of these neurotransmitters in the brain, resulting in increased stimulation of the post-synaptic neurons and enhanced feelings of pleasure and euphoria.
- Benefits: While its recreational use is illegal and associated with numerous health risks, the increased levels of dopamine in the brain's reward circuit can temporarily boost mood, alertness, and energy, as well as enhance focus and concentration in the short term. However, these effects come at a high cost, including the risk of addiction and adverse health effects.
These stimulants, while beneficial for focus and concentration, come with varying degrees of side effects and potential for dependence.
It's important to use them responsibly and under medical supervision when used for therapeutic purposes.
Cocaine, unlike the other stimulants discussed, has a higher potential for abuse and addiction. Its effects on focus and concentration can be profound but are often overshadowed by the detrimental impact on an individual's physical and mental health.
The use of cocaine and similar substances for enhancing cognitive functions is strongly discouraged due to the significant risks involved.
Risks of Taking Synthetic Nootropics for Focus and Concentration
Among the myriad of options for cognitive enhancement, five synthetic nootropics stand out for their popularity and efficacy in improving focus and concentration:
- Phenylpiracetam
- Noopept
- Sunifiram
- Adrafinil
- Sulbutiamine
These nootropics have garnered attention for their potential to significantly enhance cognitive functions.
A key reason for their popularity is their perceived effectiveness and, for some, the availability without a prescription.
Understanding the Risks
While the benefits of synthetic nootropics can be appealing, it's crucial to consider the potential risks involved.
These risks can vary based on the specific substance and the individual's health profile. Key concerns include:
- Side Effects: Substances like Phenylpiracetam and Noopept may cause side effects ranging from headaches and nausea to dizziness. Although these effects are often mild and temporary, they can be disruptive and uncomfortable for the user.
- Drug Interactions: Nootropics such as Adrafinil and Sulbutiamine may interact with other medications, including antidepressants and blood pressure drugs. Such interactions can lead to adverse effects, underscoring the importance of consulting a healthcare professional before commencing use.
- Tolerance and Addiction: Certain nootropics, including Sunifiram and Adrafinil, have the potential to induce tolerance, necessitating higher doses to achieve the same cognitive enhancement effects. This escalation can lead to addiction and associated negative outcomes, impacting financial stability and social relationships.
- Legal and Regulatory Considerations: Phenylpiracetam and Noopept are not regulated by the FDA, meaning their safety and efficacy remain largely unverified. The lack of regulation poses risks, as the quality and composition of these nootropics may vary, leading to uncertainty about what users are ingesting.
Comparison of Nootropics And Stimulants for Focus And Concentration
While both categories aim to improve cognitive functions, their mechanisms, advantages, and considerations vary significantly.
Advantages and Disadvantages
Nootropics
Advantages:
- Safety and Tolerance: Generally well-tolerated, with minor side effects. They do not typically cause speech and motor excitement, anxiety, addiction, or depletion of the body’s functional capabilities.
- Cognitive Enhancement: Improve cognitive functions, especially in cases where there is damage or degeneration, without the immediate risk of overdose or severe side effects.
- Long-term Benefits: Designed for sustained improvement in cognitive functions, requiring continuous usage over time to achieve noticeable effects.
Disadvantages:
- Delayed Effects: Most nootropics show no immediate effects after a single dose, requiring an extended period of use to produce results.
- Variable Efficacy: The effectiveness can significantly vary between individuals, and the lack of immediate feedback may lead to inconsistency in use.
Stimulants
Advantages:
- Immediate Effects: Offer rapid improvements in focus, alertness, and energy, making them suitable for acute needs.
- Well-Researched: The effects of common stimulants like caffeine, amphetamines, and modafinil are well-documented, providing a predictable range of outcomes.
Disadvantages:
- Potential for Abuse: Some stimulants, particularly prescription ones, can lead to dependency and abuse.
- Side Effects: Can cause a range of side effects, including increased heart rate, insomnia, and anxiety. The risk of adverse effects increases with dosage and prolonged use.
Choosing Between Nootropics and Stimulants
Personal Health and Objectives:
- Individuals seeking a safe, long-term solution to enhance cognitive function without the risk of severe side effects might prefer nootropics. They are especially suited for sustained mental clarity, memory enhancement, and cognitive support.
- Those requiring immediate, short-term boosts in focus and alertness might opt for stimulants. They are beneficial for acute situations requiring heightened concentration, such as deadlines, exams, or demanding cognitive tasks.
Risk Tolerance:
- Users must consider their tolerance for side effects and the potential for dependency. Those with a low tolerance for risk may lean towards nootropics, given their safer profile and lower potential for abuse.
Regularity of Use:
- Nootropics are designed for regular, ongoing use and may be more suitable for individuals looking for cumulative cognitive benefits.
- Stimulants may be chosen for occasional use when immediate cognitive enhancement is needed.
Health Conditions:
- Pre-existing health conditions can influence the choice. For instance, individuals with cardiovascular issues may need to avoid certain stimulants. Similarly, conditions like anxiety might be exacerbated by stimulants, making nootropics a preferable option.
Conclusion
Nootropics and stimulants are both effective for improving focus and concentration, but they work in different ways and have different potential risks and benefits.
Nootropics are generally considered to be safe and well-tolerated, with few side effects, but they may not provide the same level of immediate and powerful effects as stimulants.
Stimulants can provide a quick boost in alertness and energy, but they can also have potential side effects and can be addictive if not used responsibly.
When choosing between nootropics and stimulants for improving focus and concentration, it is important to consider your personal needs and preferences, as well as the potential risks and benefits of each option.
If you are looking for a safe and natural way to improve cognitive function, nootropics may be the best choice for you. If you need a quick and powerful boost in focus and concentration, stimulants may be the way to go.
Whether the aim is to improve cognitive function for academic, professional, or personal development, it is essential to approach cognitive enhancement with an informed perspective, emphasizing safety, efficacy, and long-term well-being.
If you're looking to start taking Nootropics as a supplement, you can learn more about our Mood & Wellbeing Nootropic Supplement at nooroots.
Learn more about the vitamins, minerals and natural nootropic plant extracts we use to give your brain a daily boost
- A Beginner's Guide to Ashwagandha
- A Beginner's Guide to Ginkgo Biloba
- A Beginner's Guide to Organic Cacao
- A Beginner's Guide to Holy Basil
- A Beginner's Guide to Rhodiola Rosea
- A Beginner's Guide to Guarana
- A Beginner's Guide to L-Theanine
- A Beginner's Guide to L-Tyrosine
- A Beginner's Guide to Piperine
References
- Bloemendaal, M., Froböse, M. I., Wegman, J., Zandbelt, B. B., Van De Rest, O., Cools, R., & Aarts, E. (2018). Neuro-Cognitive effects of acute tyrosine administration on reactive and proactive response inhibition in healthy older adults. ENeuro, 5(2), ENEURO.0035-17.2018. https://doi.org/10.1523/eneuro.0035-17.2018
- Bruce, S. E., Werner, K., Preston, B. F., & Baker, L. (2014). Improvements in concentration, working memory and sustained attention following consumption of a natural citicoline–caffeine beverage. International Journal of Food Sciences and Nutrition, 65(8), 1003–1007. https://doi.org/10.3109/09637486.2014.940286
- Chan, B., Freeman, M., Ayers, C., Korthuis, P. T., Paynter, R., Kondo, K., & Kansagara, D. (2020). A systematic review and meta-analysis of medications for stimulant use disorders in patients with co-occurring opioid use disorders. Drug and Alcohol Dependence, 216, 108193. https://doi.org/10.1016/j.drugalcdep.2020.108193
- Chen, N., Yang, M., Zhou, M., Xiao, J., Guo, J., & He, L. (2017). L-carnitine for cognitive enhancement in people without cognitive impairment. The Cochrane Library, 2017(3). https://doi.org/10.1002/14651858.cd009374.pub3
- Dighriri, I. M., Alsubaie, A. M., Hakami, F. M., Hamithi, D., Alshekh, M. M., Khobrani, F. A., Dalak, F. E., Hakami, A. A., Alsueaadi, E. H., Alsaawi, L. S., Alshammari, S. F., Alqahtani, A. S., Alawi, I. A., Aljuaid, A. A., & Tawhari, M. Q. (2022). Effects of omega-3 polyunsaturated fatty acids on brain functions: a systematic review. Cureus. https://doi.org/10.7759/cureus.30091
- Dove Press. (2007, July 15). Mechanisms of modafinil: A review of current research. NDT. https://www.dovepress.com/articles.php?article_id=911
- Fang, Y., Qiu, Z., Hu, W., Yang, J., Yi, X., Huang, L., & Zhang, S. (2013). Effect of piracetam on the cognitive performance of patients undergoing coronary bypass surgery: A meta-analysis. Experimental and Therapeutic Medicine, 7(2), 429–434. https://doi.org/10.3892/etm.2013.1425
- Fillmore, M. T., Kelly, T. C., & Martin, C. A. (2005). Effects of d-amphetamine in human models of information processing and inhibitory control. Drug and Alcohol Dependence, 77(2), 151–159. https://doi.org/10.1016/j.drugalcdep.2004.07.013
- Hack, B., Penna, E. M., Talik, T., Chandrashekhar, R., & Millard‐Stafford, M. (2023). Effect of Guarana (Paullinia cupana) on Cognitive Performance: A Systematic Review and Meta-Analysis. Nutrients, 15(2), 434. https://doi.org/10.3390/nu15020434
- Humphreys, K. L., Eng, T., & Lee, S. S. (2013). Stimulant medication and substance use outcomes. JAMA Psychiatry, 70(7), 740. https://doi.org/10.1001/jamapsychiatry.2013.1273
- Li, I., Lee, L., Tsai-Teng, T., Chen, W., Chen, Y., Shiao, Y., & Chen, C. (2018). Neurohealth Properties ofHericium erinaceusMycelia Enriched with Erinacines. Behavioural Neurology, 2018, 1–10. https://doi.org/10.1155/2018/5802634
- Mereu, M., Bonci, A., Newman, A. H., & Tanda, G. (2013). The neurobiology of modafinil as an enhancer of cognitive performance and a potential treatment for substance use disorders. Psychopharmacology, 229(3), 415–434. https://doi.org/10.1007/s00213-013-3232-4
- Nobre, A. C., Rao, A., & Owen, G. (2008). L-theanine, a natural constituent in tea, and its effect on mental state. PubMed, 17 Suppl 1, 167–168. https://pubmed.ncbi.nlm.nih.gov/18296328
- Peth-Nui, T., Wattanathorn, J., Muchimapura, S., Tong-Un, T., Piyavhatkul, N., Rangseekajee, P., Ingkaninan, K., & Vittaya-Areekul, S. (2012). Effects of 12-WeekBacopa MonnieriConsumption on attention, cognitive processing, working memory, and functions of both cholinergic and monoaminergic systems in healthy elderly volunteers. Evidence-based Complementary and Alternative Medicine, 2012, 1–10. https://doi.org/10.1155/2012/606424
- Stojcheva, E. I., & Quintela, J. C. (2022). The Effectiveness of Rhodiola rosea L. Preparations in Alleviating Various Aspects of Life-Stress Symptoms and Stress-Induced Conditions—Encouraging Clinical Evidence. Molecules, 27(12), 3902. https://doi.org/10.3390/molecules27123902
- Stough, C., Clarke, J., Lloyd, J., & Nathan, P. J. (2001). Neuropsychological changes after 30-day Ginkgo biloba administration in healthy participants. The International Journal of Neuropsychopharmacology, 4(02). https://doi.org/10.1017/s1461145701002292
- Воронина, Т. А. (2023). Cognitive Impairment and nootropic Drugs: mechanism of action and spectrum of effects. Neurochemical Journal, 17(2), 180–188. https://doi.org/10.1134/s1819712423020198
- Vakhitova YV, Sadovnikov SV, Borisevich SS, Ostrovskaya RU, A Gudasheva T, Seredenin SB. Molecular Mechanism Underlying the Action of Substituted Pro-Gly Dipeptide Noopept. Acta Naturae. 2016 Jan-Mar;8(1):82-9. PMID: 27099787; PMCID: PMC4837574.