A
Adaptogen
A term used in herbal medicine to describe substances claimed to help the body adapt to stress. The concept originated in Soviet research in the 1940s-60s. While used commercially, "adaptogen" is not a recognized pharmacological classification in Western medicine, and regulatory bodies do not accept adaptogenic claims.
Adverse Event
Any undesirable experience associated with the use of a medical product or intervention in a patient. In clinical trials, adverse events are documented regardless of whether they are believed to be caused by the intervention being studied.
B
Bioavailability
The proportion of a substance that enters systemic circulation when introduced into the body and is available for physiological activity. Bioavailability is influenced by factors including route of administration, molecular properties, and individual physiological differences.
Blinding (Clinical Trials)
A methodology in clinical research where participants, researchers, or both are unaware of which treatment arm participants are assigned to. Single-blind studies conceal allocation from participants; double-blind studies conceal it from both participants and researchers.
C
Cohort Study
An observational study that follows a group of people over time to determine how certain factors affect outcomes. Unlike randomized controlled trials, cohort studies do not involve intervention by researchers.
Cytokine
Small proteins released by cells that have specific effects on cell-to-cell interactions and communication. Cytokines include interleukins, interferons, and tumor necrosis factors, among others. They play roles in immune response and inflammation.
D
Double-Blind Study
A clinical trial design in which neither the participants nor the researchers know which participants are receiving the active treatment versus placebo. This methodology reduces bias in outcome assessment.
Dose-Response Relationship
The relationship between the amount of a substance administered and the magnitude of the resulting effect. Establishing a dose-response relationship is one criterion used to evaluate whether an association between an exposure and an outcome is causal.
E
Efficacy
The ability of an intervention to produce a desired effect under ideal, controlled conditions (such as a clinical trial). Efficacy differs from effectiveness, which measures performance in real-world conditions.
Epidemiology
The study of how diseases and health conditions are distributed in populations, and the factors that influence or determine this distribution. Epidemiological studies inform public health decisions and identify risk factors.
F
First-Pass Metabolism
The phenomenon by which a substance is metabolized at a specific location in the body (typically the liver) before reaching systemic circulation. This can significantly reduce the bioavailability of orally administered substances.
H
Half-Life
The time required for the concentration of a substance in the body to decrease by half. Half-life is influenced by metabolism, excretion, and other pharmacokinetic factors.
Homeostasis
The tendency of biological systems to maintain internal stability while adjusting to changing external conditions. Many physiological processes work to maintain homeostatic balance.
I
Inflammation
A biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Acute inflammation is a protective response; chronic inflammation has been associated with various disease states in research literature.
In Vitro
Latin for "in glass." Refers to studies performed outside a living organism, such as in a test tube or cell culture. In vitro findings do not necessarily translate to in vivo (living organism) effects.
M
Meta-Analysis
A statistical technique that combines results from multiple studies to arrive at a pooled estimate of effect. Meta-analyses are considered high-quality evidence when conducted properly on comparable studies.
Mechanism of Action
The specific biochemical interaction through which a substance produces its pharmacological effect. Understanding mechanism of action is important for predicting effects, interactions, and adverse events.
P
Placebo
An inactive treatment or substance that has no therapeutic effect. In clinical trials, placebos are used as controls to distinguish between effects caused by an intervention and effects caused by expectation or other factors.
Pharmacokinetics
The study of how the body absorbs, distributes, metabolizes, and excretes drugs. Often summarized as "what the body does to the drug," in contrast to pharmacodynamics (what the drug does to the body).
Peer Review
The evaluation of scientific work by others working in the same field. Peer-reviewed publications have undergone scrutiny by experts before publication, though peer review does not guarantee accuracy.
R
Randomized Controlled Trial (RCT)
A study design in which participants are randomly assigned to receive either the intervention being tested or a control (often placebo). RCTs are considered the gold standard for evaluating the efficacy of interventions.
S
Statistical Significance
A determination that a result is unlikely to have occurred by chance alone. Conventionally, a p-value below 0.05 is considered statistically significant. Statistical significance does not necessarily imply clinical significance or practical importance.
Systematic Review
A comprehensive review of published literature on a specific topic, conducted using a rigorous methodology to identify, evaluate, and synthesize all relevant studies. Often accompanied by meta-analysis.