Glossary

Consistently following a treatment or supplement schedule as planned.

Any undesirable experience associated with the use of a medical product or treatment.

A substance that binds to a receptor and activates it, producing a biological response.

Alpha-melanocyte-stimulating hormone, a peptide hormone involved in skin pigmentation, inflammation, and appetite.

An organic molecule that serves as a building block for peptides and proteins. There are 20 standard amino acids used by the human body.

AMP-activated protein kinase, a cellular energy sensor that activates catabolic pathways (fat burning, glucose uptake) and inhibits anabolic pathways when cellular energy is low.

A peptide hormone co-secreted with insulin from pancreatic beta cells that slows gastric emptying, promotes satiety, and suppresses glucagon release.

A compound structurally similar to another but differing in composition, often designed to improve specific properties.

The formation of new blood vessels from existing ones, important for wound healing and tissue growth.

A substance that binds to a receptor and blocks or dampens its biological response.

A biologic molecule that combines a monoclonal antibody with a peptide agonist or antagonist, leveraging the antibody's long circulating half-life and the peptide's receptor-modulating activity. MariTide (maridebart cafraglutide) is a prominent example: an anti-GIPR antibody conjugated to a GLP-1 receptor agonist peptide, enabling once-monthly or less frequent dosing for obesity treatment.

A class of short peptides (typically 12–50 amino acids) produced by virtually all living organisms as part of innate immunity. AMPs kill bacteria, fungi, and viruses through mechanisms like membrane disruption, which makes resistance development difficult. AI-designed AMPs are now entering early clinical phases as alternatives to conventional antibiotics for multidrug-resistant infections.

A substance that inhibits oxidation and neutralizes free radicals, protecting cells from damage.

The body's process of cleaning out damaged cells and regenerating new ones.

Brain-Derived Neurotrophic Factor, a protein that supports the growth and survival of neurons.

A pharmacological phenomenon where a ligand preferentially activates one intracellular signaling pathway over another at the same receptor. In the GLP-1 context, ecnoglutide is a cAMP-biased GLP-1 RA, meaning it favors cAMP-mediated signaling over beta-arrestin recruitment, which may improve efficacy while reducing GI side effects.

The proportion of a substance that enters the bloodstream and is available to have an active effect when introduced into the body.

The gradual decline in physiological function that occurs over time, distinct from chronological age.

A measurable indicator of a biological state or condition, used to assess health, disease, or treatment response.

The proportions of fat, muscle, bone, and water in the body.

An FDA program designed to expedite the development and review of drugs intended to treat serious conditions where preliminary clinical evidence shows the drug may offer substantial improvement over existing therapies. Pemvidutide received this designation for MASH in January 2026. The designation provides intensive FDA guidance, organizational commitment, and eligibility for rolling review.

A phospholipid found almost exclusively in the inner mitochondrial membrane, essential for proper electron transport chain function and ATP production.

Relating to both the cardiovascular system (heart, blood vessels) and metabolic processes (blood sugar regulation, lipid metabolism, energy balance). Cardiometabolic disease encompasses conditions where cardiovascular risk and metabolic dysfunction overlap, including type 2 diabetes, obesity, dyslipidemia, and metabolic syndrome.

A large, randomized clinical trial specifically designed to evaluate whether a drug reduces the risk of major adverse cardiovascular events (MACE) — typically defined as heart attack, stroke, or cardiovascular death. The FDA requires CVOTs for diabetes and obesity drugs to confirm cardiovascular safety or demonstrate benefit.

A document from a laboratory confirming that a product meets its stated specifications for identity, purity, and potency.

The body's internal 24-hour clock that regulates sleep-wake cycles, hormone release, and other biological processes.

A research study conducted with human participants to evaluate the safety and effectiveness of a treatment.

An observational study that follows a group of people over time to see how certain factors affect outcomes.

The most abundant protein in the body, providing structure to skin, bones, tendons, and connective tissue.

The degree to which a person follows a prescribed treatment plan or research protocol.

The practice of creating customized medications by combining, mixing, or altering ingredients to meet individual needs.

A condition or factor that makes a particular treatment or procedure inadvisable.

Small proteins released by cells that have a specific effect on cell-to-cell communication and immune responses.

The deepest stage of non-REM sleep, characterized by slow brain waves and important for physical restoration.

The relationship between the amount of a substance administered and the magnitude of the resulting effect.

A study design where neither the participants nor the researchers know who is receiving the treatment vs. placebo.

An abnormal, unpleasant sensation on the skin — often described as burning, tingling, prickling, or numbness — that can occur spontaneously or in response to touch. In peptide research, dysesthesia has emerged as a notable side effect in clinical trials of triple agonist retatrutide, reported in up to 20.9% of participants on the highest dose.

How well a treatment works in real-world, everyday conditions as opposed to controlled clinical settings.

The ability of a treatment to produce the desired effect under ideal, controlled conditions (e.g., clinical trials).

The collection of glands that produce hormones regulating metabolism, growth, development, and other functions.

Originating from within the body, as opposed to being introduced externally.

A compound that reproduces some of the metabolic and physiological benefits of exercise without physical activity, typically by activating exercise-responsive signaling pathways like AMPK.

The process of physical and physiological restoration after exercise, including muscle repair and glycogen replenishment.

Originating from outside the body; introduced externally.

The network of proteins and molecules surrounding cells that provides structural and biochemical support.

The process by which the U.S. Food and Drug Administration reviews and authorizes a drug for sale and use.

A cell type that produces collagen and other components of the extracellular matrix, essential for tissue repair.

An unstable molecule that can damage cells and contribute to aging and disease.

The use of artificial intelligence models — particularly masked diffusion language models, transformer architectures, and graph neural networks — to computationally design novel peptide sequences optimized for specific properties such as binding affinity, solubility, membrane permeability, and metabolic stability. Unlike traditional screening, generative design creates new peptide candidates that may not exist in nature.

A hormone primarily produced by the stomach that stimulates appetite and growth hormone release.

A class of drugs that mimic the incretin hormone glucagon-like peptide-1 (GLP-1), stimulating insulin secretion, suppressing appetite, and slowing gastric emptying.

A hormone produced by the pituitary gland that stimulates growth, cell reproduction, and cell regeneration.

The time it takes for the concentration of a substance in the body to reduce by half.

A chemical messenger produced by glands that travels through the bloodstream to regulate body functions.

Insulin-like Growth Factor 1, a hormone similar in structure to insulin that mediates many of growth hormone's effects.

The body's defense mechanism against foreign substances, pathogens, or abnormal cells.

Studies or experiments conducted in a controlled environment outside a living organism, such as in test tubes or cell cultures.

Studies or experiments conducted within a living organism, such as animal models or human trials.

A group of gut hormones (including GLP-1 and GIP) released after eating that stimulate insulin secretion and regulate blood sugar levels.

The body's immune response to injury, infection, or irritation, characterized by redness, swelling, heat, and pain.

How effectively the body's cells respond to insulin and absorb glucose from the bloodstream.

Any molecule that binds to a specific receptor to produce a signal or effect.

A unique identifier assigned to a specific batch of a manufactured product.

A peptide whose backbone or side chains form a ring structure, conferring enhanced binding affinity, metabolic stability, and in some cases oral bioavailability compared to linear peptides.

The specific biochemical process through which a drug or compound produces its effect.

A group of peptide hormones that act through melanocortin receptors, involved in pigmentation, inflammation, and sexual function.

A hormone produced by the pineal gland that regulates sleep-wake cycles.

A statistical technique that combines results from multiple studies to identify patterns and draw stronger conclusions.

The sum of chemical reactions in the body that convert food into energy and building blocks for growth and repair.

A substance formed during metabolism; the breakdown product of a drug or compound in the body.

A class of small peptides encoded within the mitochondrial genome that function as systemic signaling molecules, regulating metabolism, stress responses, and cellular aging.

The brain's ability to reorganize itself by forming new neural connections throughout life.

Strategies and mechanisms that protect nerve cells from damage, degeneration, or death.

Nuclear Factor kappa-light-chain-enhancer of activated B cells, a protein complex that controls inflammation and immune response genes.

A small-molecule drug that activates a peptide receptor without being a peptide itself. Non-peptide agonists like orforglipron (Foundayo) and aleniglipron (GSBR-1290) offer advantages including oral bioavailability without absorption enhancers, room-temperature stability, and simpler manufacturing compared to peptide-based therapies.

The use of a medication for a purpose, population, or method not specified in its FDA-approved labeling.

An imbalance between free radicals and antioxidants in the body, contributing to cell damage and aging.

The evaluation of scientific work by independent experts in the same field before publication.

A short chain of amino acids linked by peptide bonds, typically fewer than 50 amino acids. Peptides are smaller than proteins and can act as signaling molecules in the body.

A therapeutic molecule that links a targeting peptide to a cytotoxic or bioactive payload via a cleavable or stable linker. The peptide component selectively binds receptors overexpressed on target cells (such as tumor cells), enabling precise drug delivery while minimizing off-target toxicity. PDCs are a lightweight alternative to antibody-drug conjugates (ADCs) with faster tissue penetration.

The study of what a drug does to the body — its biological and physiological effects.

The study of how a drug is absorbed, distributed, metabolized, and excreted by the body.

An FDA advisory committee that evaluates whether specific bulk drug substances should be added to the 503A or 503B bulks lists, which determines whether compounding pharmacies can legally prepare and dispense those substances with a prescription. The PCAC reviews safety, clinical need, and manufacturing considerations for each nominated compound.

Clinical trials progress through phases: Phase 1 tests safety, Phase 2 tests effectiveness, Phase 3 confirms results in larger groups.

A small endocrine gland in the brain that produces melatonin and is involved in sleep regulation.

A small gland at the base of the brain that produces hormones controlling growth, metabolism, and reproduction.

An inactive treatment or substance used as a control in experiments to test the effectiveness of a real treatment.

The stage of research that occurs before human clinical trials, including laboratory and animal studies.

A pharmacologically inactive compound that is metabolized or chemically transformed in the body to release the active drug. In peptide therapeutics, prodrug platforms like Ascendis Pharma's TransCon technology use PEGylation or other carrier systems to extend the half-life of short-lived peptides (such as CNP, which has a natural half-life of ~2 minutes) into once-weekly or less frequent dosing.

A large, complex molecule made up of one or more long chains of amino acids. Proteins perform a vast array of functions within organisms.

Laboratory analysis to verify that a substance contains the stated compound at the stated concentration without contaminants.

A study in which participants are randomly assigned to either the treatment group or a control group.

A protein on or inside a cell that binds to a specific molecule (ligand), triggering a cellular response.

The method by which a substance is delivered into the body (e.g., oral, topical, subcutaneous).

A permeation enhancer (also known as SNAC or sodium N-[8-(2-hydroxybenzoyl)amino]caprylate) used in oral peptide formulations to improve intestinal absorption. It works by locally raising pH in the stomach, protecting peptides from enzymatic degradation and facilitating their transport across the gastric epithelium into the bloodstream.

A substance that promotes the secretion of another substance, such as a hormone.

The permanent arrest of cell division in response to stress, damage, or aging signals. Senescent cells accumulate with age and secrete inflammatory molecules (the SASP) that contribute to tissue dysfunction.

A class of compounds that selectively induce death (apoptosis) in senescent cells — aged, damaged cells that have stopped dividing but resist normal clearance. Senescent cells accumulate with age and secrete inflammatory factors (the SASP) that damage surrounding tissue. FOXO4-DRI is a senolytic peptide that disrupts the FOXO4-p53 interaction keeping senescent cells alive, allowing p53 to trigger apoptosis selectively.

The length of time a product remains usable and effective under recommended storage conditions.

An unintended effect of a treatment, which can be positive or negative.

The amount of time it takes to transition from full wakefulness to sleep.

The ability of a compound to maintain its chemical integrity and potency over time under specified conditions.

A peptide modified with a chemical 'staple' — typically a hydrocarbon bridge — that locks it into a helical shape, improving cell penetration, protease resistance, and target binding.

The environmental requirements (temperature, light, humidity) needed to maintain a product's stability and potency.

An individual's self-reported assessment of their overall quality of life, mood, and satisfaction.

The chemical process of building complex molecules from simpler ones, such as creating peptides from amino acids.

A comprehensive summary of all available research on a specific topic, using rigorous methods to minimize bias.

A type of white blood cell crucial for adaptive immunity, maturing in the thymus gland.

An enzyme that adds DNA to the ends of chromosomes (telomeres), potentially slowing cellular aging.

Protective caps at the ends of chromosomes that shorten with age and cell division.

Independent laboratory verification of a product's identity, purity, and potency by a lab not affiliated with the manufacturer.

A gland in the chest that produces T-cells and peptides important for immune function, most active before puberty.

A decrease in response to a substance after repeated use, requiring higher amounts to achieve the same effect.

The systematic recording of data points such as biomarkers, subjective effects, and timing related to a regimen.

A drug that simultaneously activates three distinct hormone receptors. In the metabolic space, retatrutide is the first triple agonist (targeting GIP, GLP-1, and glucagon receptors) to reach Phase 3 development. The glucagon receptor component adds energy expenditure and hepatic fat mobilization beyond what dual GLP-1/GIP agonists like tirzepatide provide.

A tetrapeptide naturally produced by the spleen that stimulates immune cell activity.

The maximum rate of oxygen consumption measured during exercise, indicating cardiovascular fitness.

A period during a study when a participant stops taking a treatment to eliminate its effects before starting a new phase.