The most complete glossary of bodybuilding, fitness, and supplement related nutritional terms and definitions. This is by no means a complete list, and is a work in progress. This information is for educational purposes only, and is not intended to replace any health care professionals. It is a compilation of many sources, mixed in with our opinions.

• ECA Stack
  A thermagenic supplement blend of Ephedra, Caffeine and Aspirin that is popular among fitness and bodybuilding cultures. It is said that these three ingredients give a synergistic effect together which give better results than any one on its own.
• Echincea
  Herb with immune protective properties, shown to have some benefit protecting against colds and flu. It can be used as a preventive measure to protect the body against the natural stress the immune system suffers in heavy training.
• Egg protein
  Source of protein with high Protein Efficiency Ratio, usually in egg white form (albumin) when used in protein powder to avoid cholesterol in egg yolk. Egg protein is the standard by which all other proteins are measured because of its very high ration of indispensable amino acids (also called essential amino acids because they must be supplied to the body from food or supplements) to dispensable amino acids.
• Ephedra / Ephedrine
  The active ingredient in the Oriental herb Ma Huang (Ephedra sinensis); this chemical has been proven to be both a powerful energizer and weight loss aid. Ephedrine is a powerful thermogenic agent: It releases norepinephrine, a brain neurotransmitter than exerts a stimulating effect. This same neurotransmitter signals the sympathetic nervous system, which is called into play during a 'fight or flight' response. Body temperature rises and promotes the breakdown of fat cells for fuel. Use ephedrine for short periods only. Cycling ephedrine can help you avoid side effects as well as improve results of your hard training. Ephedrine, taken with caffeine, can increase each other's ability to induce lipolysis (fat burning). Ephedrine acts at your body's nerve junctions, changing the release and activity of norepinephrine as well as acting on your beta-2 adrenergic receptors.
• Ergogenic aids
  Any nutrients that improve athletic performance.
• Essential Fatty Acids (EFA)
  They include Linoleic Acid, Omega-3 Fatty Acids, and Monounsaturated fats. These are considered the 'good' fats. They cannot be made by the body and must be supplied by our diet. You need approxiamately 2% of your daily calories as EFA's. By consuming plenty of EFAs, you supply your body with the appropriate precursors to form cell membranes and regulatory eicosanoids.
• Fat
  Macronutrient that is a source for long term energy and energy storage (as adipose tissue); necessary for absorption and transport of fat-soluble vitamins and constituant of hormones and cell membranes. One gram of fat equals nine calories. There are 455 grams in one pound. So nine calories times 455 grams equals 4,025 calories per pound of fat. So, technically, you need to lose 4,025 calories to lose one pound of fat.
• Fiber
  The more insoluble the fiber is (fiber that does not dissolve in water), the better it is for you. Insoluble fiber reduces the risk of colon cancer and high blood pressure. Fruit fiber seems to be more beneficial then vegetable or cereal fibers, probably because fruits are loaded with Pectin, an insoluble fiber. As a rule, the higher the insolubility, the fewer the calories. Corn bran is the best, followed by wheat bran, and then oat bran. It is best to eat fiber after you work out to avoid intestinal discomfort.
• Flavonoids
  A group of compounds widely distributed in plants which have a characteristic molecular structure. They have been found to have many beneficial activities, such as anti-inflammatory and anti-carcinogenic properties.
• Flaxseed Oil
  Flaxseed is an excellent source of the omega-3 fatty acid alpha-linolenic acid (an EFA). Supplementing with flaxseed oil has been shown to lower cholesterol, decrease heart disease, increase satiety and improve cell integrity.
• Free Radicals
  Free radicals are highly reactive molecules in the body which can destroy tissues by oxidizing cell membrane lipids and damaging DNA, the body's genetic material. Free redicals are produced through the body's normal process of metabolizing the air we breath and the food we eat, as well as exposure to tabacco smoke, excess sunlight and environmental pollutants. Antioxidants work in the body by neutralizing free radicals before the can do significant harm.
• Gamma Butyrolactone (GBL)
  A related product to GHB (Gamma hydroxybutyrate).
• Gamma Hydroxybutyrate (GHB)
  GHB is a simple carbohydrate fond naturally in every cell of the human body. GHB is both a metabolite of and a precursor to an amino acid called GABA (Gamma Aminobutyric Acid). The FDA has labeled GHB has a 'date-rape' drug, and wants to ban it from the market. GHB itself does not cause a person to remain conscious, engage in sex and then forget what they did. The problems occur when you take GHB with high levels of alcohol, since both alcohol and GHB are metabolized by the same enzyme in the body.
• Garcinia Cambogia
  Fruit from India that contains Hydroxicitric Acid (-HCA), an organic acid influencing carbohydrate and fat metabolism
• Garlic
  Can be called the 'Stinking Rose'. Studies show that garlic may lower blood cholesterol levels, lower elevated blood pressure and offer a hedge against the onset of several types of cancer. Some studies show that garlic has enhanced fat breakdown coupled with an increasd amount of brown adipose tissue (BAT), a type of specialized fat that is known to convert fat calories into heat, thereby disspating excess calories.
• Genistein
  A compound thought to protect you against cancer. It is found in soy based food products. It surpresses the production of stress proteins in cells, proteins that otherwise help cancer cells survive destruction by the immune system.
• Ginkgo Biloba
  A herb shown to enhance mental accuity. Some research has shown that Ginkgo Biloba increases cerebral blood flow to the brain. Also, boost brain levels of adenosine triphosphate and scavenge free radicals. Combined with ginger, gingko has also been shown too reduce stress induced anxiety.
• Ginseng
  A family of herbs with adaptogenic properties affecting energy. There are different ginsengs (Asian, American, Siberian). Some ginsengs have shown to have mental enhancing effects. Studies show that an individual ginseng component called ginsenoside Rb acts favorably in reversing memory deficits by increasing he secretion of acetychilone. Studies also suggest that ginseng extract improved learning and retention processes.
• Glucomannan
  A fiber derived from the Amorphophallus Konjac root, a perennial plant of the Araceae family. The root is low in protein, lipids (fats), calories and vitamins, but, because of its glucomannan content, it can provide many tangible bodybuilding and health advantages. Glucomannan can help mitigate insulin response to high glycemic corbohydrates, which might allow bodybuilders to add variety to low carb diets and still accrue the benefits of the regimens. Glucomannan may also help remove fat from the body.
• Glucosamine
  Organic compound found in cartilage and joint fluid; relieves joint pain and may help in healing some joint injuries. Glucosamine is a provider of the building blocks of joints.
• Glucose (monosaccharide)
  Type of sugar that circulates in the bloodstream, thus the term 'blood glucose levels' or 'blood sugar'. All carbohydrates, whether simple or complex, are eventually converted to glucose in the body. Glycogen is many units of glucose together.
• Glucose Tolerance Factor (GTF)
  GTF is thought to be a complex of chromium, nicotinic acid, and the amino acids glycine, cystein and glutamic acid (these aminos are components of gluthathione). GTF is thought to be synthesize by the liver. In many people, chromium is likely the deficient substrate for GTF formation. GTF is found in foods such as organ meats, whole gains, cheese, mushrooms and brewer's yeast.
• Glutamine
  An amino acid. Glutamine is the most abundant amino acid in muscle tissue. Studies are beginning to show that having extra glutamine in your body may be important to maximize muscle growth, by increasing growth hormone levels. Glutamine also is important to maintain proper health, and is shown to have anabolic and anticatabolic properties. During intense training, the signal for muscle breakdown (which is a bad thing) may be the release of skeletal muscle glutamine. That means that each time you train, your muscles release glutamine which in part triggers a catabolic state (a catabolic state is synonymous with muscle breakdown). By proving Glutamine, documented clinical studies have shown that Glutamine will have a significant impact on maintaining a positive nitrogen balance which is essential to muscular development and recovery.
• Glycemic Index
  The glycemic Index (GI) measures only the rise in blood sugar elicited by various foods and drinks. It is not like an index of factors like nutrient density or vitamin or fiber content. The GI can help you if you want to avoid a spike in blood sugar, and insulin. If measures how much a food affects your blood sugar.
• Glycerin
  Glycerin is a trihydric alcohol that is derived from animal fats and plants emollients. It is used in many protein bars to give the bar a soft texture and to make it easy to chew. Glycerin yields 4.32 calories per gram. Glycerin is a crystalline, viscous liquid formed when fat molecules split. It is half as sweet as sugar and is used to keep bars moist and to plasticize other foods such as fudge, gum, geltin, etc. The big question is if glycerin is a carb or is it a new 'category'. The reason that glycerin is not listed as a carbohydrate by some manufacturers is that glycerin does not effect blood glucose or insulin levels. However, the FDA states that glycerin is to be listed as a carbohydrate; thus the controversy.
• Glycogen
  It is a term for many units of glucose strung together. The body stores glycogen in two areas, the liver and the muscles. Only about 5 grams, or 20 calories worth of glucose flows in the blood. Liver stores about 75 to 100 grams, or 300 to 400 calories; an hour of aerobics can burn up half the liver glycogen content. The muscles store around 360 grams, or 1,440 calories. Carbohydrate loading is one technique used to increase muscle glycogen content. By not consuming enough carbohydrates, you deplete both liver and muscle glycogen reserves. While complex carbs are considered to be more desirable than simple carbs, simple carbs are more efficient after a workout for replacing muscle glycogen. Simple carbs are absorbed faster, and promote a greater insulin output. A carbohydrate drink with at least 50 grams of carb will do the trick.
• Glycogen (Muscle)
  Muscle glycogen is extremely important for bodybuilding, since it's the primary fuel that powers anaerobic training, such as lifting weights. Glycogen that's stored in a muscle is available only to that muscle because muscles lack a certain enzyme, glucose-6-phosphatase, that's needed to release glucose into the blood. Muscles can absorb glucose without insulin, which why exercise helps prevent diabetes.
• Glycogen (Liver)
  Liver glycogen is a fuel reserve that helps maintain blood glucose levels. This is important because the brain relies on a constant supply of glucose to function properly.
• Grape Seed Extract
  Source of proanthocyanadins, an important antioxidant.
• Green Tea
  Perhaps more notable, recent research has shown that green tea reduces the risk of developing stomach cancer by 50% and esophageal cancer by 6-%. No one knows for sure, but scientists think that polyphenols in green tea protect health by combating free radicals. The main constituents of green tea are polyphenols, caffeien, vitamins, minerals, amino acids and other nitrogenous compounds, it also contains small amounts of carbohydrates and lipids. Also, green tea contains polyphenols, theanine, and catechins. The greater the theanine content in green tea, the higher the price.
• Growth Hormone
  Known in the medical community as somatotropin. It is a powerful anabolic hormone that affects all systems of the body and plays an important role in muscle growth. It is a peptite hormone, which is composed of many amino acids (191 of them) linked together. It is rapidly metabolized by the liver and has a half-life in the blood of approxiamately 17 to 45 minutes. Because of this, detecting GH in a drug screen is very hard.
• Guarana
  Source of caffeine. Comes from the seed of a herb found in the Amazon, long popular among Brazilians for its stimulatory effects.
• Guggulsterone
  Guggulsterone is a ketosteroid specifically called Z-Guggulsterone. It's effect on the thyroid is that it increases the metabolic rate via stimulation of the tyroid gland. Studies indicate that Guggulsterone can result in higher levels of T4 (Thyroxine), one of the two main thyroid hormones. .
• Hydroxicitric Acid (HCA)
  Also known as Citrimax. Acid found in the fruit Garcinia Cambogia that affects fat and carbohydrate metabolism. Studies have shown it reduces the conversion of carbs into bodyfat. HCA competitively inhibits an enzyme kown as ATP-Citrate lyase (the major enzyme responsible for the production of fatty acid). When HCA blocks the production of fatty acids, a buildup of citrate occurs, which may cause the cell to inhibit glycolysis (breakdown of stored sugars).
• HMB
  See 'Beta-Hydroxy Beta-Methylbutyrate'
• HDL
  High Density Lipoprotein Cholesterol. Protects against cardiovascular disease. HDLs help to shuttle cholesterol out of the blood and back to the liver, where it's degraded into bile that then can be excreted from the body.
• Hypoglycemia
  A term meaning low blood sugar. It's a set of symptoms that point to irregularities in the way the body handles glucose, the sugar that circulates in the blood. Symptoms of hypoglycemia include sweating, trembling, anxiety, fast heartbeat, headache, hunger, weakness, mental confusion, and on occasion, seizures and coma. However, it occurs rarely because the body has a lot of backup systems preventing it.
• IGF-1
  Stands for Insulin-like growth factor. An important hormone for muscle growth. Naturally produced by the body in response to exercise and is necessary for normal physiological functioning. Excess of IGF-1 may be associated with an increased risk of breast cancer, and prostate cancer.
• Inositol
  An active factor in the B-Complex vitamins which help convert food to energy. With Choline, Inositol is active in the metabolism of fats.
• Insulin
  An anabolic hormone that's supposed to take the sugar and traansport it into the muscle. Insulin also promotes increased amino acid entry into muscle and increases muscle protein synthesis. Too much insulin can cause sugar to bypass muscle, and be stored as bodyfat.
• Inzitol
  Inzitol is the trade name for Pinitol, a form ogff sugar than researchers are studying for use in insulin-deficient conditions, such as diabetes mellitus type 1. Taking Inzitol can show an increase in both glucose uptake and glycogen storange.
• Ipriflavone
  One of many flavonoids, ipriflavone, formally known as 7-isopropoxyisoflavone, is synthesized from the soy isoflavone daidzein. It has anabolic effects that are especially pronounced in bone.
• Iron
  Mineral essential to oxygen transport in blood (via hemoglobin and myoglobin), enzyme production and immune support. A deficiency can cause the most common form of anemia. Teenagers need additional iron during their years of maximum growth; women need extra iron during the years they are menstruating and during pregnancy.
• Isoflavones
  Phytonutrient antioxidants, including genisteine and diadzein, that act as estrogen receptor protectors (minimize PMS, menopause side effects) and lower cholesterol levels.
• Isoleucine
  One of the three branched chain amino acids. They are called BCAA's because they structurally branch off another chain of atoms instead of forming a line. Studies have shown that BCAA's help to stimulate protein synthesis and inhibit its breakdown, so BCAA's have powerful anabolic and anticatabolic effects on the body. They may also potentiate the release of some anabolic hormones, such as growth hormone. Regular ingestion of BCAA's help to keep the body in a state of postive nitrogen balance. In this state, your body much more readily builds muscle and burns fat. Studies have shown that athletes taking extra BCAA's have shown a loss of more bodyfat than those not taking BCAA's.
• Kombucha
  A tea made from a fungus / yeast fermentation with high nutrient level used by people for immune protection, increase energy, and other postive effects. Sometimes called a Kombucha mushroom. It is two life forms, a yeast culture and bacteria living in symbiosis, from Manchuria.
• Kynoselen
  Also called Kyno, it is a veterinary drug, not an anabolic steroid. It is used to treat abnormal muscle conditions in animals. Some bodybuilder use it to increase muscle hardness. Main ingredient in Kynoselen is AMP, a substance formed during the process of creating energy. Concerns for bodybuilders is that life threatening heart problems can arise with its use.
• Lactoferrin
  It is a glycoprotein, which means its structure includes a carbohydrate attached to a simple protein. The single protein in lactoferrin contains 703 amino acids in a precise configuration. It appars to offer protectve benefits against a wide range of fungi and viruses.
• Lactose
  Sugar in milk which many people, especially adults, have an intollerance to (indigestion) to to a lack of the enzyme lactasein their bodies.
• Lecithin
  Dry powder source of phospholipids high in B-fatty acids.
• Leptin
  This protein was been portrayed as the way to a cure for obesity. Leptin was first described as an apiodocyte - derived signaling factor, which, after interaction with its receptors, induced a complex response, including control of bodyweight and energy expenditure. It could be quite a fat burner. Research shows that people who used high doses of leptin for six months lost weight, most of it bodyfat.
• Leucine
  One of the three branched chain amino acids. They are called BCAA's because they structurally branch off another chain of atoms instead of forming a line. Studies have shown that BCAA's help to stimulate protein synthesis and inhibit its breakdown, so BCAA's have powerful anabolic and anticatabolic effects on the body. They may also potentiate the release of some anabolic hormones, such as growth hormone. Regular ingestion of BCAA's help to keep the body in a state of postive nitrogen balance. In this state, your body much more readily builds muscle and burns fat. Studies have shown that athletes taking extra BCAA's have shown a loss of more bodyfat than those not taking BCAA's.Leucine appears to be the most important BCAA for athletes, as it can affect various anabolic hormones, and have an effect on preventing protein degradation. HMB is a metabolite of Leucine. Some experts have suggested that if you do not have Leucine in your body, you will not have muscle growth.
• Linoleic Acid
  An essential fatty acid (EFA) that your body cannot make itself. It is found in polyunsaturated oils such as safflower, sunflower, walnut oil, etc. This is considered a type of 'good' fat. You need approxiamately 2% of your daily calories as EFA's.
• Lipotropic nutrients
  Substances that prevent or curtail the buildup of fat in the liver, such as B-fatty acids and methionine.
• Lutein
  A carotenoid phytonutrient with antioxidant properties especially important to eye protection.
• Lycopene
  Most powerful of the carotenoid antioxidants; shown to be beneficial in prostate protection and treatment.

Compiled by Ron Avidan