35 key terms every nootropics enthusiast should know
A
Acetylcholine
A neurotransmitter essential for memory formation, learning, and attention. Many nootropics - including Alpha-GPC, Citicoline, and Huperzine-A - work by increasing acetylcholine levels or activity in the brain.
Acetylcholinesterase Inhibitor
A substance that blocks the enzyme acetylcholinesterase, which normally breaks down acetylcholine. By slowing this breakdown, more acetylcholine remains available in synapses. Huperzine-A and Galantamine are well-known examples.
Adaptogen
A natural substance that helps the body resist and adapt to physical, chemical, and biological stressors. Adaptogens typically modulate the HPA axis and cortisol response. Examples include Ashwagandha, Rhodiola Rosea, and Holy Basil. See our Adaptogens Guide for more.
A protein that supports the survival of existing neurons and encourages the growth of new neurons and synapses. Higher BDNF levels are linked to better memory, learning, and mood. Lion's Mane, exercise, and Bacopa Monnieri are known to increase BDNF.
Bioavailability
The proportion of a substance that enters the bloodstream and reaches its target site after ingestion. A compound with low bioavailability may need to be paired with an enhancer - for example, Curcumin is often taken with Piperine to improve absorption by up to 2,000%.
C
Cerebral Blood Flow
The supply of blood to the brain at any given moment. Increased cerebral blood flow delivers more oxygen and glucose to neurons, supporting cognitive function. Nootropics that improve blood flow include Ginkgo Biloba, Vinpocetine, and Pine Bark Extract.
Cholinergic
Relating to or acting on the neurotransmitter acetylcholine. Cholinergic nootropics either supply choline (the precursor), increase acetylcholine release, or inhibit its breakdown. Examples: Alpha-GPC, Citicoline, Choline.
Cognitive Enhancement
The use of any means - supplements, drugs, techniques, or technologies - to improve cognitive functions such as memory, attention, creativity, or executive function beyond a person's baseline. This is the central goal of nootropic use.
Cycling
The practice of taking a nootropic for a set period and then pausing for a break before resuming. Cycling helps prevent tolerance buildup and maintains effectiveness. Common patterns include 5 days on / 2 off, or 4 weeks on / 1 week off.
CYP Enzymes
Cytochrome P450 enzymes - a family of liver enzymes responsible for metabolising the majority of drugs and supplements. Some nootropics (notably St. John's Wort) strongly induce or inhibit CYP enzymes, leading to significant interactions with other substances.
D
Dopaminergic
Relating to or acting on the neurotransmitter dopamine, which governs motivation, reward, pleasure, and motor control. Dopaminergic nootropics include Mucuna Pruriens (contains L-DOPA), L-Tyrosine, and Sulbutiamine.
E
Excitotoxicity
Neuronal damage or death caused by excessive stimulation from neurotransmitters such as glutamate. When glutamate receptors are over-activated, calcium floods into cells and triggers destructive pathways. Several neuroprotective nootropics (e.g. Magnesium, Memantine) work partly by guarding against excitotoxicity.
G
GABAergic
Relating to or acting on gamma-aminobutyric acid (GABA), the brain's primary inhibitory neurotransmitter. GABAergic substances promote relaxation, reduce anxiety, and support sleep. Examples include GABA, Phenibut, Kava, and Magnolia Bark.
Glutamatergic
Relating to or acting on glutamate, the brain's primary excitatory neurotransmitter. Glutamate is vital for learning and synaptic plasticity. Racetams such as Piracetam and Aniracetam modulate glutamate receptors (particularly AMPA receptors) to enhance cognition.
H
Half-Life
The time it takes for the concentration of a substance in the body to reduce by half. Half-life determines how long a nootropic's effects last and how often it needs to be dosed. For example, Caffeine has a half-life of roughly 5 hours, while Modafinil lasts 12-15 hours.
HPA Axis
The hypothalamic-pituitary-adrenal axis - a neuroendocrine system that controls the body's stress response, immune function, and energy regulation. Chronic HPA axis activation leads to elevated cortisol and cognitive impairment. Adaptogens like Ashwagandha help normalise HPA axis function.
M
MAO Inhibitor
A substance that inhibits monoamine oxidase, an enzyme that breaks down neurotransmitters like serotonin, dopamine, and norepinephrine. MAO inhibition increases the availability of these neurotransmitters. Selegiline (MAO-B selective) is a notable example. Combining MAO inhibitors with serotonergic compounds is dangerous.
Mitochondrial Support
Actions that improve the function or number of mitochondria - the energy-producing organelles in every cell. The brain consumes roughly 20% of the body's energy, making mitochondrial health critical for cognition. CoQ10, PQQ, Creatine, and ALCAR are key mitochondrial supporters.
N
Neurogenesis
The process of generating new neurons in the brain. Once thought impossible in adults, neurogenesis has been confirmed in regions like the hippocampus (critical for memory). Lion's Mane stimulates neurogenesis via nerve growth factor (NGF) production.
Neuroprotection
The preservation of neuronal structure and function, particularly against damage from oxidative stress, inflammation, toxins, or ageing. Many nootropics offer neuroprotective benefits, including NAC, Resveratrol, and Alpha Lipoic Acid.
Neuroplasticity
The brain's ability to reorganise itself by forming new neural connections throughout life. Greater neuroplasticity means faster learning, better adaptation, and improved recovery from injury. Nootropics that enhance neuroplasticity include Noopept, Bacopa Monnieri, and Lion's Mane.
NGF (Nerve Growth Factor)
A protein that plays a vital role in the maintenance, survival, and regeneration of neurons. Like BDNF, higher NGF levels support cognitive health and repair. Lion's Mane is the most well-known NGF-boosting nootropic.
Nootropic
A substance taken to improve cognitive function - particularly memory, focus, creativity, motivation, or executive function - with minimal side effects. The term was coined in 1972 by Romanian chemist Corneliu Giurgea. See our What Are Nootropics? guide for a full explanation.
O
Oxidative Stress
An imbalance between free radicals (reactive oxygen species) and the body's ability to neutralise them with antioxidants. Chronic oxidative stress damages neurons and accelerates cognitive decline. Antioxidant nootropics like NAC, Astaxanthin, and Alpha Lipoic Acid help combat this.
P
Peptide Nootropic
A nootropic composed of short chains of amino acids (peptides). Peptide nootropics are typically administered nasally or by injection as they have poor oral bioavailability. Examples include Semax, Selank, BPC-157, and Cerebrolysin.
Prodrug
A biologically inactive compound that is converted into its active form after ingestion, typically by liver enzymes. Adrafinil is a classic example - it is metabolised into Modafinil in the liver.
R
Racetam
A family of synthetic nootropics that share a pyrrolidone nucleus. Racetams modulate neurotransmitter systems (particularly glutamate and acetylcholine) and are among the oldest and most studied nootropics. The family includes Piracetam, Aniracetam, Oxiracetam, Phenylpiracetam, and Pramiracetam.
S
Serotonergic
Relating to or acting on serotonin, a neurotransmitter involved in mood regulation, sleep, appetite, and social behaviour. Serotonergic nootropics include 5-HTP, L-Tryptophan, St. John's Wort, and Saffron.
Serotonin Syndrome
A potentially life-threatening condition caused by excessive serotonergic activity in the nervous system. Symptoms range from agitation and tremor to hyperthermia and seizures. It can occur when multiple serotonergic substances are combined - for example, 5-HTP with St. John's Wort or SSRIs. Always check interactions before combining serotonergic nootropics.
Stack
A combination of two or more nootropics taken together for synergistic or complementary effects. Stacking is a core practice in the nootropics community. A classic example is Caffeine + L-Theanine for focused alertness without jitters. See our Stacks Guide and Community Stacks.
Synergy
When two or more substances produce a combined effect greater than the sum of their individual effects. In nootropics, synergy is the goal of stacking. For example, Piracetam paired with Alpha-GPC is more effective than either alone.
T
Tolerance
A reduction in response to a substance after repeated use, requiring higher doses to achieve the same effect. Tolerance is common with stimulatory nootropics like Caffeine and Phenylpiracetam. Cycling is the primary strategy to prevent or reverse tolerance.
U
Upregulation
An increase in the number or sensitivity of receptors on a cell's surface, typically in response to reduced stimulation. Upregulation can make the brain more responsive to a particular neurotransmitter. For example, taking a break from dopaminergic substances may upregulate dopamine receptors, restoring sensitivity.
W
Wakefulness Agent
A substance that promotes wakefulness and alertness without the broad stimulatory effects of traditional stimulants. Modafinil and Adrafinil are the best-known wakefulness agents. Unlike amphetamines, they target specific brain regions involved in the sleep-wake cycle.
Frequently Asked Questions
A nootropic is a specific category of supplement (or drug) taken primarily to improve cognitive function - memory, focus, creativity, or mental energy. Regular supplements may target general health (e.g. vitamin D for bone health). The overlap occurs because some general supplements also have cognitive benefits.
Serotonergic means "acting on serotonin." A serotonergic nootropic either increases serotonin production, blocks its reuptake, or otherwise raises serotonin activity. This is important to understand because combining multiple serotonergic substances can risk serotonin syndrome - a serious medical emergency.
Cycling prevents tolerance - where your body becomes accustomed to a substance and it loses effectiveness. By taking scheduled breaks, you allow receptors to upregulate (become more sensitive again). Not all nootropics require cycling; adaptogens and many natural compounds can often be taken continuously.
Racetams are a family of synthetic compounds that share a common chemical structure. Piracetam, the first racetam, has been studied since the 1960s and has a strong safety profile. As a class, racetams are generally well-tolerated with mild side effects (headaches, which are often resolved by adding a choline source). However, they are not regulated as supplements in all countries.
Bioavailability determines how much of a supplement actually reaches your brain. A compound could be highly effective in laboratory studies but useless in practice if the body cannot absorb it. This is why formulation matters - liposomal delivery, pairing with absorption enhancers like Piperine, or choosing more bioavailable forms (e.g. Magnesium L-Threonate over Magnesium Oxide) can dramatically improve results.