Supplement Glossary

Plain-English definitions for the terms you'll encounter when reading supplement labels, clinical studies, and ingredient guides. Every term explained clearly, no jargon required.

Adaptogen

A class of herbs and mushrooms believed to help the body resist physical, chemical, and biological stress. Common examples include ashwagandha, rhodiola, and lion's mane. The scientific evidence varies widely by compound.

Amino Acids

The building blocks of protein. There are 20 standard amino acids; 9 are "essential," meaning the body cannot synthesize them and must obtain them from food or supplements. Key for muscle repair, neurotransmitter production, and enzyme function.

Allulose

A rare naturally occurring sugar found in small amounts in figs and raisins. It has only 0.4 kcal/g (vs 4 for regular sugar), is not significantly metabolized, and has a glycemic index near zero. Unlike erythritol, allulose can caramelize.

Antioxidant

A molecule that neutralizes free radicals — unstable compounds that can damage cells and DNA. Vitamins C and E, polyphenols, and certain mineral cofactors (selenium, zinc) act as antioxidants. High-dose supplementation is not always beneficial; context matters.

BCAA (Branched-Chain Amino Acids)

Three essential amino acids — leucine, isoleucine, and valine — that are metabolized primarily in muscle rather than the liver. BCAAs are often marketed for muscle protein synthesis; however, if total protein intake is already sufficient, isolated BCAA supplements offer limited additional benefit.

Beta-Alanine

A non-essential amino acid that combines with histidine to form carnosine in muscle tissue. Carnosine buffers acid accumulation during high-intensity exercise, delaying fatigue. The most common side effect is a harmless tingling sensation called paresthesia.

Bioavailability

The proportion of a nutrient or compound that enters systemic circulation in an active form after administration. A supplement with high bioavailability is absorbed more efficiently. Factors include food co-ingestion, formulation, gut health, and individual metabolism.

Botanical Extract

A concentrated preparation derived from a plant material — leaves, roots, seeds, or bark — using solvents such as water, ethanol, or CO2. Standardized extracts guarantee a minimum percentage of the active compound (e.g., "standardized to 1% eurycomanone" for tongkat ali).

Certificate of Analysis (COA)

A document issued by an accredited laboratory that verifies the identity, purity, and potency of a supplement ingredient or finished product. A COA should include heavy metal testing, microbial limits, and active compound concentrations. WHYZ provides a COA for every batch.

Collagen Peptides

Short chains of amino acids derived from hydrolyzed collagen. They are rich in glycine, proline, and hydroxyproline, which serve as raw materials for the body's own collagen synthesis. Clinical trials support benefits for skin elasticity and joint comfort. Learn more at our collagen page.

Creatine HCl (Hydrochloride)

A form of creatine bonded to hydrochloric acid, increasing its solubility in water. Some manufacturers claim lower doses are needed, but head-to-head research comparing creatine monohydrate to creatine HCl at equivalent doses shows no significant performance advantage.

Creatine Monohydrate

The most studied form of creatine supplementation, with over 1,000 peer-reviewed trials supporting its safety and efficacy for strength, power, and potentially cognitive function. The standard dose is 3–5g daily. See our full creatine guide.

D-Chiro-Inositol

An isomer of inositol that mediates insulin signaling in cells. It is particularly researched for PCOS (polycystic ovary syndrome), where D-chiro-inositol combined with myo-inositol in a 1:40 ratio has shown benefits for hormone balance and ovarian function.

DRI (Dietary Reference Intake)

An umbrella term for reference values established by the National Academies of Sciences for nutrient intake planning. Includes the RDA (Recommended Dietary Allowance), AI (Adequate Intake), UL (Tolerable Upper Intake Level), and EAR (Estimated Average Requirement).

DHT (Dihydrotestosterone)

A potent androgen derived from testosterone via the enzyme 5-alpha reductase. DHT plays a role in male pattern baldness, prostate development, and libido. Some supplements (like saw palmetto) are marketed as DHT blockers, though evidence is mixed.

Dosage

The amount of a substance administered at one time or over a specified period. Effective dosages are established through clinical trials and can vary significantly by compound, individual body weight, and health goals. More is not always better.

E-E-A-T (Experience, Expertise, Authoritativeness, Trustworthiness)

Google's quality framework for evaluating health and wellness content. High E-E-A-T content is written by credentialed experts, cites peer-reviewed research (PMIDs), and is transparent about claims. WHYZ's Learn content is developed by the WHYZ Editorial Team with references to published studies.

Ergogenic Aid

Any substance, technique, or device designed to enhance athletic performance. Ergogenic aids include nutritional supplements (creatine, caffeine, beta-alanine), physical techniques (altitude training), and pharmacological agents. Regulatory status varies.

Erythritol

A sugar alcohol naturally found in fermented foods, produced commercially via yeast fermentation. It provides approximately 0.2 kcal/g, has a GI of ~0, and does not cause the GI distress associated with sorbitol or maltitol. A 2023 Nature Medicine study flagged a potential cardiovascular association at high doses — ongoing research continues.

Essential Amino Acids (EAAs)

The nine amino acids the human body cannot synthesize: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Complete proteins (meat, dairy, soy, quinoa) provide all nine; incomplete proteins (most plants) lack at least one.

Fulvic Acid

A humic substance found in soil, compost, and some mineral deposits. It is present in shilajit and marketed for nutrient absorption and mitochondrial support. Research is preliminary; clinical trials in humans are limited.

GMP (Good Manufacturing Practice)

A system of quality controls mandated by the FDA for dietary supplement manufacturers. GMP-certified facilities follow strict protocols for ingredient identity testing, contamination prevention, and documentation. Look for "NSF GMP" or "USP GMP" certification on product labels.

GRAS (Generally Recognized as Safe)

An FDA designation indicating that a food ingredient is considered safe by qualified experts based on scientific evidence and common use. Both monk fruit extract and high-purity stevia (Reb A) carry GRAS status in the United States.

Glycemic Index (GI)

A scale from 0 to 100 that ranks how quickly a carbohydrate raises blood glucose levels compared to pure glucose (GI = 100). Foods with GI > 70 are considered high-glycemic; below 55 is low. Table sugar has a GI of ~65; monk fruit and stevia have a GI of 0.

Half-Life

The time it takes for the concentration of a substance in the body to decrease by 50%. Understanding a compound's half-life helps determine optimal dosing frequency. For example, NMN has a short half-life of roughly 2–3 hours, while creatine's intramuscular phosphocreatine stores have a much longer effective window.

Hydrolyzed

Broken down into smaller components via the addition of water, typically using enzymes or acids. Hydrolyzed collagen (collagen peptides) is more bioavailable than intact collagen because the long protein chains are pre-digested into short peptides that absorb more efficiently.

Inositol

A carbocyclic sugar that serves as a cell-signaling molecule and membrane component. The most studied forms are myo-inositol (metabolic and ovarian health) and D-chiro-inositol (insulin signaling). See our full inositol guide.

Isolate

A highly purified form of a macronutrient, typically protein. Whey protein isolate contains ≥90% protein by weight (vs. ~80% for concentrate) with minimal fat and lactose. Isolates are preferred by those with lactose sensitivity or who want maximum protein per calorie.

Lion's Mane

A medicinal mushroom (Hericium erinaceus) containing hericenones and erinacines, which may stimulate Nerve Growth Factor (NGF) synthesis. Preliminary human trials suggest benefits for mild cognitive impairment. Evidence is promising but early-stage.

Loading Phase

A strategy used with creatine supplementation involving 20g/day (split into 4 doses) for 5–7 days to rapidly saturate muscle phosphocreatine stores. After loading, a maintenance dose of 3–5g/day sustains saturation. Skipping the loading phase achieves the same result in ~4 weeks.

Micronized

A process that reduces particle size to microscopic levels, improving solubility and mixability. Micronized creatine monohydrate dissolves more easily in water and may cause less gastrointestinal discomfort than standard creatine powder.

Mogroside

The antioxidant triterpene glycoside compounds responsible for monk fruit's sweetness. Mogroside V is the most abundant and most studied; it is approximately 250× sweeter than sugar. Mogrosides are not metabolized for energy and have zero impact on blood glucose.

MOQ (Minimum Order Quantity)

The smallest quantity a supplier is willing to produce or sell in a single order. Relevant in supplement manufacturing; bulk ingredient MOQs typically range from 1–25 kg for specialty extracts. Not generally relevant for end-consumer supplements.

Myo-Inositol

The most abundant naturally occurring form of inositol, found in high concentrations in fruits, beans, grains, and nuts. It is the primary form used in clinical PCOS research (typically 2–4g/day) and is the primary form in WHYZ Inositol. See our inositol guide.

NAD+ (Nicotinamide Adenine Dinucleotide)

A coenzyme found in every cell, essential for energy metabolism and DNA repair. NAD+ levels decline with age. NMN and NR are precursors that the body converts to NAD+. Active research is investigating whether raising NAD+ slows aging-related cellular decline.

NMN (Nicotinamide Mononucleotide)

A direct precursor to NAD+ that has shown promise in animal aging studies. Human clinical trials are underway but still limited. See our full NMN guide for a current evidence review.

Nootropic

A substance claimed to enhance cognitive function — memory, focus, creativity, or mental clarity. The term is loosely defined; compounds range from well-studied (caffeine + L-theanine) to heavily marketed but evidence-poor. Always evaluate the specific clinical evidence behind any nootropic claim.

Phycocyanin

A blue pigment-protein complex from spirulina (cyanobacteria). It acts as an antioxidant and has shown anti-inflammatory activity in cell and animal studies. It is the compound responsible for spirulina's distinctive blue-green color.

PMID (PubMed ID)

A unique numerical identifier assigned to publications indexed in PubMed, the National Library of Medicine's database of biomedical literature. When a supplement claim cites a PMID, you can verify it at pubmed.ncbi.nlm.nih.gov. WHYZ cites PMIDs for all major claims.

Prebiotics

Non-digestible food components (primarily fibers like inulin, FOS, and pectin) that feed beneficial gut bacteria. Prebiotics are the "food" for probiotics. Common dietary sources include garlic, onions, leeks, asparagus, and Jerusalem artichokes.

Probiotics

Live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. Common probiotic strains include Lactobacillus acidophilus and Bifidobacterium longum. Efficacy is strain- and condition-specific; not all probiotics are equivalent.

Reb A (Rebaudioside A)

The most abundant and most studied steviol glycoside in stevia leaf. It is approximately 200–300× sweeter than sugar and carries FDA GRAS status. Higher Reb A concentration generally means better taste with less bitterness. See our stevia guide.

RDA (Recommended Dietary Allowance)

The average daily dietary intake level sufficient to meet the nutrient requirement of nearly all (97–98%) healthy individuals of a particular life stage and sex. Established by the National Academies. Note: many supplements are dosed far above the RDA — more is not always better.

Steviol Glycosides

The family of sweet compounds found in stevia leaves, including stevioside, rebaudioside A (Reb A), rebaudioside C, and rebaudioside M (Reb M). The glycosides vary in sweetness intensity and aftertaste; Reb M is considered the cleanest tasting but is rarer and more expensive.

Sublingual

Administered under the tongue, where compounds absorb directly into the bloodstream through the sublingual mucosa, bypassing the digestive system. This route allows faster onset and higher bioavailability for some compounds. NMN sublingual lozenges are marketed using this rationale, though NMN capsules appear to raise plasma NMN levels effectively as well.

Superfoods

A marketing term (not a scientific or regulatory classification) for foods perceived to be especially nutrient-dense or health-promoting. Common "superfoods" include spirulina, moringa, acai, and chlorella. While many are genuinely nutritious, the label alone does not guarantee clinical efficacy.

Third-Party Testing

Independent laboratory verification of a supplement's label claims, purity, and absence of contaminants (heavy metals, pesticides, microbes, banned substances). Reputable certifiers include NSF International, Informed Sport, and USP. WHYZ provides third-party COAs for every production batch.

Tongkat Ali

An herbal extract from the root of Eurycoma longifolia, native to Southeast Asia. Clinical trials suggest it supports free testosterone levels, libido, and stress-related hormone balance at 200–400mg/day of standardized extract. See our full tongkat ali guide.

Type I Collagen

The most abundant collagen in the human body, found in skin, tendons, ligaments, corneas, and bone. Most bovine-sourced collagen peptides are primarily Type I (and Type III). Hydrolyzed Type I collagen is the most studied form for skin elasticity and joint support.

Type III Collagen

A fibrillar collagen found alongside Type I in skin, blood vessels, and internal organs. It provides elasticity and structure. Bovine collagen peptide products typically contain both Type I and Type III collagen. Marine collagen (from fish scales) is predominantly Type I.

USP (United States Pharmacopeia)

A non-profit standards-setting organization that establishes quality standards for medicines, foods, and dietary supplements. USP Verified supplements meet identity, strength, purity, and quality standards. USP verification is one of the most rigorous third-party seals in the supplement industry.

Vegan

In supplement context, a product free from all animal-derived ingredients. This includes gelatin (found in most capsules), dairy (whey, casein), eggs, honey, and animal-derived collagen. Vegan alternatives include plant-based capsules (hydroxypropyl methylcellulose / HPMC) and plant protein sources.

WHYZ

A supplement brand focused on single-ingredient, transparently labeled products for people who ask "why?" about everything in their stack. WHYZ products contain no fillers, no proprietary blends, and no artificial additives. Every batch is third-party tested and sold with a Certificate of Analysis.

Xylitol

A sugar alcohol naturally found in birch trees and many fruits and vegetables. It has ~40% fewer calories than sugar and a low glycemic index (~7–13). Commonly used in gum and dental products. Important warning: xylitol is highly toxic to dogs and cats; even small amounts can cause liver failure in canines.

Deep dives on every ingredient — full evidence grades, dosage ranges, and peer-reviewed citations.