Supplement Glossary
122 essential terms and definitions for understanding dietary supplements, from adaptogens to withanolides.
A
Adaptogen
A class of herbs and mushrooms that help the body resist and adapt to physical, chemical, and biological stressors by modulating the hypothalamic-pituitary-adrenal (HPA) axis. Examples include ashwagandha, rhodiola, and holy basil.
Amino Acid
Organic compounds that serve as the building blocks of proteins. There are 20 standard amino acids, 9 of which are essential (must be obtained from diet). Supplements like BCAAs, L-theanine, and NAC are amino acid-based.
AMPK
AMP-activated protein kinase — an enzyme often called the 'metabolic master switch.' It regulates cellular energy balance and is activated by exercise, caloric restriction, and certain supplements like berberine and resveratrol.
AMPK
AMP-activated protein kinase — a cellular energy sensor enzyme that plays a key role in metabolism. When activated, AMPK increases fat burning, glucose uptake, and mitochondrial biogenesis. Berberine, metformin, and exercise all activate AMPK.
Anabolic
Relating to the metabolic process of building complex molecules from simpler ones, typically involving muscle tissue growth. Anabolic supplements aim to promote muscle protein synthesis. Examples include creatine, HMB, and protein supplements.
Antioxidant
A molecule that inhibits the oxidation of other molecules, protecting cells from damage caused by free radicals. Common antioxidant supplements include vitamin C, vitamin E, CoQ10, NAC, and alpha-lipoic acid.
Antioxidant
A substance that inhibits oxidation and neutralizes free radicals, protecting cells from oxidative damage. Common antioxidant supplements include vitamin C, vitamin E, glutathione, astaxanthin, and CoQ10. The body also produces endogenous antioxidants like superoxide dismutase (SOD).
ATP
Adenosine triphosphate — the primary energy currency of cells. Creatine supplementation increases phosphocreatine stores, which are used to rapidly regenerate ATP during high-intensity exercise.
Autophagy
The cellular process of recycling damaged or dysfunctional components. Autophagy declines with age and is implicated in aging and disease. Fasting, exercise, spermidine, and resveratrol can stimulate autophagy. Nobel Prize in Physiology awarded for autophagy research in 2016.
B
BCAA
Branched-Chain Amino Acids — leucine, isoleucine, and valine. These essential amino acids are popular in sports nutrition for muscle protein synthesis, though whole protein sources (like whey) are generally more effective.
Beta-Glucan
A type of soluble fiber found in the cell walls of mushrooms, yeast, and grains. Beta-glucans from medicinal mushrooms (like Lion's Mane and Reishi) have potent immunomodulating properties.
Beta-Glucan
A type of soluble fiber found in oats, barley, and medicinal mushrooms. Beta-glucans from mushrooms (1,3/1,6-beta-glucans) are potent immune modulators that activate macrophages, NK cells, and dendritic cells. Different from cereal beta-glucans which primarily lower cholesterol.
Bioavailability
The proportion of a supplement that enters the circulation and is available for use by the body. Factors affecting bioavailability include the chemical form, delivery method, and whether it's taken with food. For example, curcumin has ~1% bioavailability alone but 2,000% more with piperine.
Biotin
Also known as vitamin B7, biotin is a water-soluble B vitamin essential for metabolism of fats, carbohydrates, and proteins. Commonly supplemented for hair, skin, and nail health, though evidence for benefits in non-deficient individuals is limited.
Biotin
Vitamin B7, also known as vitamin H. Essential for fatty acid synthesis, gluconeogenesis, and amino acid metabolism. Commonly supplemented for hair, skin, and nail health, though evidence is strongest for those with actual deficiency. Can interfere with lab tests — stop 48 hours before blood work.
Branched-Chain Amino Acids (BCAAs)
Three essential amino acids — leucine, isoleucine, and valine — that have a branched molecular structure. Leucine is the primary driver of muscle protein synthesis. BCAAs are popular in sports nutrition but may be unnecessary if protein intake is adequate.
C
Carnosine
A dipeptide (beta-alanine + histidine) concentrated in skeletal muscle that acts as an intracellular pH buffer during high-intensity exercise. Beta-alanine supplementation increases muscle carnosine levels.
Catabolic
Relating to the metabolic process of breaking down complex molecules into simpler ones, often releasing energy. Cortisol is a catabolic hormone that can break down muscle tissue. Anti-catabolic supplements aim to prevent muscle breakdown during fasting or intense exercise.
Certificate of Analysis (COA)
A document from a laboratory that confirms the identity, purity, potency, and composition of a supplement product. Reputable brands publish COAs on their websites or provide them upon request. A COA should come from an independent third-party lab.
cGMP
Current Good Manufacturing Practices — FDA regulations that ensure dietary supplements are produced consistently and meet quality standards. Covers facility design, equipment maintenance, production processes, and quality control testing.
Chelated Mineral
A mineral that has been bound to an amino acid or organic acid to improve absorption. Examples include magnesium glycinate (bound to glycine) and zinc picolinate (bound to picolinic acid). Chelated forms are generally better absorbed than inorganic forms.
Chelated Mineral
A mineral that has been bonded to an organic molecule (usually an amino acid) to improve absorption. Examples include magnesium glycinate (bonded to glycine), zinc picolinate (bonded to picolinic acid), and iron bisglycinate. Generally better absorbed than oxide or carbonate forms.
Choline
An essential nutrient required for cell membrane structure, neurotransmitter synthesis (acetylcholine), and methylation. Most Americans don't get enough from diet alone. Alpha-GPC and CDP-Choline are the most bioavailable supplemental forms.
Circadian Rhythm
The body's internal 24-hour clock that regulates sleep-wake cycles, hormone release, and metabolism. Supplement timing can affect circadian rhythm — melatonin and magnesium support sleep when taken in the evening, while B vitamins and vitamin D are best taken in the morning.
COA (Certificate of Analysis)
A document from a third-party laboratory that verifies the identity, purity, potency, and contaminant levels of a supplement. Reputable brands make COAs available to consumers upon request or on their website.
Cofactor
A non-protein chemical compound that is required for an enzyme to function. Many vitamins and minerals serve as cofactors — for example, magnesium is a cofactor for over 600 enzymatic reactions in the body.
Collagen
The most abundant protein in the human body, providing structural support to skin, bones, tendons, and cartilage. Hydrolyzed collagen peptides are the most common supplemental form, broken down into smaller, absorbable peptides.
Cortisol
The body's primary stress hormone, produced by the adrenal glands. Chronically elevated cortisol can lead to weight gain, immune suppression, and muscle breakdown. Adaptogens like ashwagandha help modulate cortisol levels.
Cortisol
The primary stress hormone produced by the adrenal glands. Chronically elevated cortisol contributes to muscle breakdown, fat storage (especially abdominal), immune suppression, and poor sleep. Adaptogens like ashwagandha and rhodiola help modulate cortisol levels.
Curcuminoid
The active compounds in turmeric, with curcumin being the most studied. Curcuminoids have potent anti-inflammatory and antioxidant properties but very poor bioavailability without enhancement technologies like piperine or phytosome formulations.
Curcuminoid
The active compounds in turmeric, with curcumin being the most studied. Curcuminoids have potent anti-inflammatory and antioxidant properties but very poor bioavailability (2-3%). Enhanced forms like Meriva (phospholipid complex), Longvida, and C3 Complex with piperine dramatically improve absorption.
Cytokine
Small signaling proteins released by immune cells that regulate inflammation and immune responses. Pro-inflammatory cytokines (IL-6, TNF-alpha) drive inflammation, while anti-inflammatory cytokines (IL-10) resolve it. Many supplements (omega-3, curcumin, vitamin D) work by modulating cytokine balance.
D
DHA
Docosahexaenoic acid — an omega-3 fatty acid that is a major structural component of the brain (making up ~25% of brain fat) and retina. Critical for brain development and cognitive function throughout life.
DHA
Docosahexaenoic acid — an omega-3 fatty acid critical for brain structure and function. DHA makes up 40% of polyunsaturated fatty acids in the brain. Important for cognitive development, memory, and mood. Found in fatty fish, fish oil, and algae oil (vegan source).
DSHEA
Dietary Supplement Health and Education Act of 1994 — the federal law that defines dietary supplements and establishes the regulatory framework. Under DSHEA, supplements do not require FDA approval before marketing, but manufacturers are responsible for safety.
Dual Extraction
A processing method for medicinal mushrooms that uses both hot water extraction (to pull out beta-glucans) and alcohol extraction (to pull out triterpenes and other alcohol-soluble compounds). Considered the gold standard for mushroom supplements.
E
Ecdysteroid
A class of steroid hormones found in insects and some plants. Turkesterone and ecdysterone are ecdysteroids marketed for muscle building. While they can bind to estrogen receptor beta, human evidence for muscle-building effects is very limited.
Electrolyte
Minerals that carry an electric charge when dissolved in water, essential for nerve signaling, muscle contraction, and fluid balance. Key electrolytes: sodium, potassium, magnesium, calcium, chloride, and phosphate. Supplementation is important during exercise, fasting, and low-carb diets.
Elemental Amount
The actual amount of a mineral available for absorption, as opposed to the total weight of the mineral compound. For example, magnesium glycinate 500mg may contain only 70mg of elemental magnesium.
Emulsification
The process of mixing two immiscible liquids (like oil and water) into a stable mixture. In supplements, emulsification improves the absorption of fat-soluble nutrients like CoQ10, curcumin, and vitamin D. Liposomal and micellar formulations use emulsification technology.
Enteric Coating
A polymer coating on tablets or capsules that prevents dissolution in the stomach, allowing the supplement to pass to the small intestine before releasing. Used for ingredients that are degraded by stomach acid or cause GI irritation.
Enteric Coating
A special coating on tablets or capsules that prevents dissolution in the stomach acid but dissolves in the alkaline environment of the small intestine. Used for supplements that are stomach-irritating (like iron) or that need to reach the intestines intact (like certain probiotics).
EPA
Eicosapentaenoic acid — an omega-3 fatty acid with potent anti-inflammatory properties. EPA is particularly important for cardiovascular health, mood regulation, and reducing inflammatory markers.
EPA
Eicosapentaenoic acid — an omega-3 fatty acid with potent anti-inflammatory properties. EPA is particularly important for cardiovascular health, mood regulation, and reducing inflammation. Higher EPA ratios are preferred for depression and inflammation, while DHA is preferred for brain structure.
Ergogenic Aid
Any substance or technique that enhances physical performance, endurance, or recovery. Evidence-based ergogenic supplements include creatine, caffeine, beta-alanine, and citrulline.
Ergogenic Aid
Any substance, technique, or device that enhances energy production, use, or recovery to improve athletic performance. Ergogenic supplements include creatine, caffeine, beta-alanine, citrulline, and nitrate. The term comes from Greek 'ergon' (work) and 'gennan' (to produce).
Essential Amino Acid (EAA)
One of nine amino acids that the body cannot synthesize and must obtain from diet: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Complete proteins contain all nine EAAs. EAA supplements may be superior to BCAAs for muscle protein synthesis.
Essential Nutrient
A nutrient that the body cannot synthesize in sufficient quantities and must be obtained from diet or supplementation. Includes essential amino acids, essential fatty acids, vitamins, and minerals.
F
Fat-Soluble Vitamin
Vitamins that dissolve in fat and can be stored in the body's fatty tissue and liver. Includes vitamins A, D, E, and K. These should be taken with a fat-containing meal for optimal absorption and can accumulate to toxic levels at very high doses.
Flavonoid
A large class of plant polyphenols with antioxidant and anti-inflammatory properties. Subclasses include flavonols (quercetin), flavones (apigenin, luteolin), isoflavones (genistein), flavanones (hesperidin), and anthocyanins (from berries). Over 6,000 flavonoids have been identified.
Free Radical
An unstable molecule with an unpaired electron that can damage cells, proteins, and DNA through oxidation. Free radical damage (oxidative stress) is implicated in aging, cancer, and cardiovascular disease. Antioxidants neutralize free radicals.
Free Radical
An unstable molecule with an unpaired electron that can damage cells, proteins, and DNA through oxidation. Free radicals are produced during normal metabolism, exercise, and exposure to pollution, UV radiation, and toxins. Antioxidants neutralize free radicals by donating electrons.
Fruiting Body
The above-ground, visible part of a mushroom — the cap and stem. For medicinal mushrooms, fruiting body extracts are generally preferred over mycelium-on-grain products because they contain higher concentrations of active compounds.
Fulvic Acid
A naturally occurring organic acid found in soil, compost, and shilajit. Fulvic acid is a potent chelator that can improve mineral absorption and has antioxidant properties. It's the primary active component in shilajit supplements. Research is still emerging.
G
GABA
Gamma-aminobutyric acid — the primary inhibitory neurotransmitter in the brain. GABA reduces neuronal excitability and promotes relaxation. Oral GABA supplements may not cross the blood-brain barrier effectively, though some forms (PharmaGABA) show stress-reducing effects in studies.
Ginsenoside
The primary active compounds in ginseng (Panax ginseng and Panax quinquefolius). Over 100 ginsenosides have been identified, with Rg1, Rb1, and Rg3 being the most studied. They have adaptogenic, anti-inflammatory, neuroprotective, and immune-modulating properties.
Glutathione
The body's most important endogenous antioxidant, present in every cell. Essential for detoxification, immune function, and protection against oxidative stress. NAC (N-Acetyl Cysteine) is the most effective oral supplement for raising glutathione levels.
Glutathione
The body's master antioxidant, a tripeptide made from glutamine, cysteine, and glycine. Glutathione is critical for detoxification, immune function, and cellular protection. Oral glutathione has poor bioavailability — liposomal glutathione or NAC (a precursor) are more effective supplementation strategies.
Glycemic Index
A measure of how quickly a food raises blood sugar levels on a scale of 0-100. Low GI foods (<55) cause gradual blood sugar rises, while high GI foods (>70) cause rapid spikes. Supplements like berberine, chromium, and alpha-lipoic acid can help moderate glycemic response.
Glycinate
A chelated form of a mineral bound to the amino acid glycine. Magnesium glycinate is one of the most popular and well-absorbed forms of magnesium, prized for its calming effects and minimal GI side effects.
GMP
Good Manufacturing Practices — quality assurance standards for the production of supplements and pharmaceuticals. See cGMP (Current Good Manufacturing Practices) for the FDA's updated requirements.
GMP (Good Manufacturing Practice)
A set of regulations enforced by the FDA that ensure supplements are produced consistently and meet quality standards. GMP covers facility cleanliness, equipment maintenance, staff training, record-keeping, and quality control testing. All supplement manufacturers must follow GMP.
H
Half-Life
The time it takes for the concentration of a substance in the blood to decrease by half. Important for determining dosing frequency — supplements with short half-lives (like berberine, ~4 hours) need to be taken multiple times daily.
Hericenone
A class of compounds found in the fruiting body of Lion's Mane mushroom that can cross the blood-brain barrier and stimulate Nerve Growth Factor (NGF) synthesis. One of the key reasons Lion's Mane is valued for cognitive health.
HMB
Beta-hydroxy beta-methylbutyrate — a metabolite of the amino acid leucine. HMB reduces muscle protein breakdown (anti-catabolic) and is most effective for preventing muscle loss during periods of inactivity, caloric restriction, or in older adults. Typical dose: 3g daily.
Hormesis
A biological phenomenon where a low dose of a stressor produces a beneficial adaptive response, while a high dose is harmful. Examples: exercise stress builds muscle, cold exposure improves resilience, and small amounts of plant toxins (polyphenols) activate protective pathways. Many supplement benefits work through hormesis.
HPA Axis
Hypothalamic-Pituitary-Adrenal axis — the body's central stress response system. Adaptogens work primarily by modulating the HPA axis, helping the body maintain homeostasis under stress.
Hydrolyzed
A process where proteins are broken down into smaller peptides using water and enzymes. Hydrolyzed collagen (collagen peptides) and hydrolyzed whey protein are more easily absorbed than their intact forms.
I
Immunomodulator
A substance that modifies the immune response, either by stimulating or suppressing it. Many medicinal mushrooms (reishi, turkey tail) and supplements (vitamin D, zinc) have immunomodulating properties.
Insulin Sensitivity
The degree to which cells respond to insulin's signal to absorb glucose from the blood. Higher sensitivity means cells respond efficiently, requiring less insulin. Supplements that improve insulin sensitivity include berberine, magnesium, alpha-lipoic acid, chromium, and cinnamon extract.
Isoflavone
A type of flavonoid found primarily in soybeans and red clover. Isoflavones (genistein, daidzein) are phytoestrogens that can weakly bind to estrogen receptors. They may help with menopausal symptoms and bone health, but effects on breast cancer risk are debated.
K
Ketone
Molecules produced by the liver from fatty acids during fasting, low-carb diets, or intense exercise. Ketones (beta-hydroxybutyrate, acetoacetate, acetone) serve as alternative fuel for the brain and muscles. Exogenous ketone supplements can raise blood ketone levels without dietary restriction.
L
Lipid Peroxidation
The oxidative degradation of lipids (fats) in cell membranes by free radicals, leading to cell damage. A key marker of oxidative stress. Antioxidants like vitamin E, astaxanthin, and CoQ10 are particularly effective at preventing lipid peroxidation due to their fat-soluble nature.
Liposomal
A delivery technology where the active ingredient is encapsulated in tiny fat-based vesicles (liposomes) that improve absorption. Liposomal vitamin C and liposomal glutathione are common examples of this technology.
Liposomal
A delivery technology where active ingredients are encapsulated in tiny phospholipid spheres (liposomes) that mimic cell membranes. Liposomal delivery dramatically improves absorption of poorly bioavailable nutrients like vitamin C, glutathione, and curcumin by protecting them through digestion.
Loading Phase
A period of higher-dose supplementation to rapidly saturate tissue stores, followed by a lower maintenance dose. Most commonly associated with creatine (20g/day for 5-7 days, then 5g/day maintenance), though loading is optional.
M
Methylation
A biochemical process where a methyl group (CH3) is added to a molecule. Critical for DNA repair, detoxification, neurotransmitter production, and energy metabolism. Key nutrients for methylation include folate (as methylfolate), B12, and choline.
Methylation
A biochemical process where a methyl group (CH3) is added to a molecule, affecting gene expression, detoxification, neurotransmitter production, and homocysteine metabolism. Key methylation nutrients: folate (as methylfolate), B12 (as methylcobalamin), B6, betaine (TMG), and SAMe. MTHFR gene variants can impair methylation.
Microbiome
The community of trillions of microorganisms (bacteria, fungi, viruses) living in and on the human body, primarily in the gut. The gut microbiome influences digestion, immunity, mood, and metabolism. Probiotics and prebiotics support microbiome health.
Mitochondria
The 'powerhouses' of cells — organelles responsible for producing 95% of the body's energy (ATP) through oxidative phosphorylation. CoQ10, PQQ, and L-carnitine are supplements that support mitochondrial function.
Mitochondria
The 'powerhouses' of cells that produce ATP (energy) through oxidative phosphorylation. Mitochondrial function declines with age, contributing to fatigue and disease. Supplements supporting mitochondria include CoQ10, PQQ, NMN/NR (NAD+ precursors), alpha-lipoic acid, and acetyl-L-carnitine.
Mitophagy
The selective autophagy (recycling) of damaged mitochondria. Mitophagy is essential for maintaining healthy mitochondrial populations and declines with age. Urolithin A (from pomegranate) and spermidine are being studied for their ability to stimulate mitophagy.
mTOR
Mechanistic target of rapamycin — a protein kinase that regulates cell growth, protein synthesis, and metabolism. mTOR activation promotes muscle growth (anabolic), while mTOR inhibition promotes autophagy and longevity. Leucine and insulin activate mTOR; fasting and rapamycin inhibit it.
Mycelium
The underground root-like network of a fungus. Some mushroom supplements use mycelium grown on grain, which is controversial because these products often contain significant amounts of starch filler from the grain substrate.
N
NAD+
Nicotinamide adenine dinucleotide — a coenzyme found in all living cells that is essential for energy metabolism, DNA repair, and cellular signaling. NAD+ levels decline with age, contributing to aging and disease. NMN and NR are precursors that can boost NAD+ levels.
NGF
Nerve Growth Factor — a protein essential for the growth, maintenance, and survival of neurons. Lion's Mane mushroom is the only known natural compound that stimulates NGF synthesis through its hericenone and erinacine compounds.
Nootropic
A substance that enhances cognitive function, including memory, focus, creativity, and motivation. Can be natural (Lion's Mane, Bacopa, Alpha-GPC) or synthetic (racetams, modafinil). The term was coined by Romanian psychologist Corneliu Giurgea in 1972.
Nootropic
A substance that enhances cognitive function, including memory, creativity, motivation, and attention. The term was coined in 1972 by Corneliu Giurgea. Nootropics range from well-studied (caffeine, creatine, omega-3) to experimental (racetams, peptides). Also called 'smart drugs' or 'cognitive enhancers.'
NSF International
An independent organization that tests and certifies supplements for quality, purity, and label accuracy. NSF Certified for Sport is the gold standard for athletes, testing for over 270 banned substances.
O
Omega-6 to Omega-3 Ratio
The dietary balance between pro-inflammatory omega-6 fatty acids and anti-inflammatory omega-3 fatty acids. The modern Western diet has a ratio of 15-20:1, while the optimal ratio is thought to be 1-4:1. Supplementing with omega-3 fish oil helps improve this ratio.
Oxidative Stress
An imbalance between free radical production and the body's antioxidant defenses, leading to cellular damage. Chronic oxidative stress contributes to aging, cardiovascular disease, neurodegeneration, and cancer.
Oxidative Stress
An imbalance between free radical production and the body's antioxidant defenses. Chronic oxidative stress damages DNA, proteins, and lipids, contributing to aging, cancer, cardiovascular disease, and neurodegeneration. Both excessive and insufficient antioxidant supplementation can be problematic.
P
Paresthesia
A tingling or prickling sensation, commonly experienced with beta-alanine supplementation. The tingling is harmless and temporary (15-30 minutes), caused by beta-alanine activating sensory neurons in the skin.
Peptide
A short chain of amino acids (typically 2-50). Collagen peptides, BPC-157, and glutathione are examples of peptide-based supplements. Peptides are smaller than proteins and often better absorbed.
Peptide
A short chain of amino acids (2-50 amino acids) linked by peptide bonds. Bioactive peptides from collagen, whey, and casein have specific biological activities. Collagen peptides support skin and joints, while whey peptides may have immune-modulating effects.
Phytochemical
Biologically active chemical compounds produced by plants. Includes polyphenols, carotenoids, glucosinolates, and terpenes. Phytochemicals are not essential nutrients but have significant health benefits including antioxidant, anti-inflammatory, and anti-cancer properties.
Phytosome
A delivery technology where a plant extract is complexed with phospholipids to improve absorption. Curcumin phytosome (Meriva) has 29x better absorption than standard curcumin.
Piperine
The active compound in black pepper that enhances the bioavailability of many supplements by inhibiting drug-metabolizing enzymes in the gut and liver. Most notably, piperine increases curcumin absorption by 2,000%. BioPerine is the patented form.
Polyphenol
A large family of plant compounds with antioxidant properties. Major subgroups include flavonoids, phenolic acids, stilbenes (resveratrol), and lignans. Found abundantly in berries, tea, coffee, dark chocolate, and olive oil. Over 8,000 polyphenols have been identified.
Prebiotic
Non-digestible fibers that feed beneficial gut bacteria. Common prebiotics include inulin, FOS (fructooligosaccharides), and GOS (galactooligosaccharides). Prebiotics and probiotics work synergistically for gut health.
Prebiotic
Non-digestible food components (typically fibers) that selectively feed beneficial gut bacteria. Common prebiotics include inulin, FOS (fructooligosaccharides), GOS (galactooligosaccharides), and resistant starch. Prebiotics complement probiotics by nourishing the bacteria you're trying to establish.
Probiotic
Live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. Common probiotic strains include Lactobacillus and Bifidobacterium species. CFU (Colony Forming Units) indicates the number of viable organisms.
Proprietary Blend
A supplement label practice where multiple ingredients are listed under a single 'blend' with only the total weight disclosed, not individual amounts. Generally considered a red flag because it hides ingredient dosages from consumers.
R
RDA
Recommended Dietary Allowance — the average daily intake level sufficient to meet the nutrient requirements of 97-98% of healthy individuals. Note that RDAs represent minimum amounts to prevent deficiency, not necessarily optimal amounts for health.
S
Salidroside
One of the primary active compounds in Rhodiola Rosea, responsible for many of its adaptogenic and neuroprotective effects. Quality Rhodiola extracts are standardized to contain at least 1% salidroside.
Senolytic
A compound that selectively destroys senescent (zombie) cells — old, damaged cells that refuse to die and secrete inflammatory molecules. Senolytics are a hot area of longevity research. Quercetin + dasatinib and fisetin are the most studied senolytic combinations.
SHBG
Sex hormone-binding globulin — a protein that binds to testosterone and estrogen, making them inactive. High SHBG reduces free (active) testosterone. Supplements like tongkat ali, stinging nettle root, and boron may help lower SHBG levels, increasing free testosterone.
Sirtuin
A family of proteins (SIRT1-7) involved in cellular regulation, DNA repair, and longevity. Sirtuins are activated by NAD+, caloric restriction, and certain compounds like resveratrol. They play a role in the proposed mechanisms of several longevity supplements.
Stacking
The practice of combining multiple supplements to achieve synergistic or complementary effects. Common stacks include: sleep (magnesium + glycine + L-theanine), performance (creatine + caffeine + beta-alanine), and longevity (NMN + resveratrol + spermidine). Proper stacking considers timing, interactions, and individual needs.
Standardized Extract
An extract that has been processed to contain a guaranteed minimum percentage of specific active compounds. This ensures consistency between batches and allows meaningful comparison between products.
Sublingual
A method of administration where the supplement is placed under the tongue and absorbed directly into the bloodstream through the mucous membranes. Bypasses the digestive system, providing faster absorption. Common for B12 and some hormones.
Synergy
When two or more supplements work together to produce an effect greater than the sum of their individual effects. Examples: Vitamin D + K2, Curcumin + Piperine, Vitamin C + Iron, Creatine + Beta-Alanine.
T
Telomere
Protective caps at the ends of chromosomes that shorten with each cell division and with age. Shorter telomeres are associated with aging and disease. Some supplements (astragalus/TA-65, omega-3, vitamin D) may help maintain telomere length, though evidence is still emerging.
Terpene
A large class of organic compounds produced by plants and some insects. In supplement context, triterpenes from medicinal mushrooms (like ganoderic acids from Reishi) have anti-inflammatory and immune-modulating properties.
Thermogenic
A substance that increases heat production in the body, typically by boosting metabolic rate. Thermogenic supplements include caffeine, green tea extract (EGCG), capsaicin, and grains of paradise. They may modestly increase calorie burning by 3-8% but are not magic weight loss solutions.
Third-Party Testing
Independent laboratory testing of supplements by organizations not affiliated with the manufacturer. Verifies that products contain what the label claims and are free from contaminants like heavy metals, pesticides, and microbes.
Tolerable Upper Intake Level (UL)
The maximum daily intake of a nutrient that is unlikely to cause adverse health effects. Exceeding the UL increases the risk of toxicity. For example, the UL for vitamin D is 4,000 IU/day (though many experts consider higher doses safe with monitoring).
U
Ubiquinol
The reduced (active) form of Coenzyme Q10 (CoQ10). Better absorbed than ubiquinone (the oxidized form), especially in older adults. Recommended for those over 40 and statin users.
USP
United States Pharmacopeia — a nonprofit organization that sets quality standards for medicines and supplements. USP Verified supplements have been tested for identity, strength, purity, and manufacturing quality.
W
Water-Soluble Vitamin
Vitamins that dissolve in water and are not stored in the body in significant amounts. Includes B vitamins and vitamin C. Excess amounts are excreted in urine, making toxicity rare (with some exceptions like B6).
Withanolide
The primary active compounds in ashwagandha (Withania somnifera). Withanolides are responsible for ashwagandha's adaptogenic, anti-inflammatory, and neuroprotective effects. KSM-66 is standardized to 5% withanolides.
X
Xenobiotic
A foreign chemical substance found within an organism that is not normally produced or expected to be present. Includes drugs, pesticides, and environmental pollutants. The liver detoxifies xenobiotics through Phase I (CYP450 enzymes) and Phase II (conjugation) pathways. Supplements like milk thistle and NAC support these pathways.