See 20-hydroxyecdysone.

An ecdysteroid shown to have modest, growth-promoting and muscle-building effects in animal experiments. 20-hydroxyecdysone (or plant extracts standardized for 20-hydroxyecdysone) is non-toxic, and used in a variety of bodybuilding supplements, but whether it actually helps increase muscle mass and strength in humans is unknown.  A small, 2006 study on resistance-trained males taking a standardized, Polypodium vulgare/Suma root extract showed no effect at the dose administered.

Supplements containing 20-hydroxyecdysone (CAS 5289-74-7) use a variety of synonyms, including 20-beta-hydroxyecdysterone, beta-ecdysterone, beta-ecdysone, 20-hydroxy-ecdysterone, 20-beta-hydroxy ecdysone,  hydroxyecdysone, ecdysterone, and ecdisten.

Ecdysteroids are steroid compounds found in insects and a number of plants (phytoecdysteroids).  According to an extensive review, “the metabolic fate of ecdysteroids in mammals, including humans, is only poorly known.” They appear to be non-toxic and—according to Eastern European/Soviet research, may have modest growth-promoting effects in animals. Recent research suggests ecdysterones can increase protein synthesis in human and animal muscle cells and affect muscle fiber size in rats, but more work will need to be done before they can be given an unequivocal “thumbs up” for building muscle or strength in humans.

Most commercial ecdysteroid supplements use standardized extracts from Cyanotis vaga or Rhaponticum carthamoides.

Ecdysteroids are frequently referred to as “ecdysterones,” although this is term is not widely used in the scientific literature.

See Theophylline.

Also known as dimethylxanthine.  Theophylline is a metabolite of caffeine that’s also found naturally in tea.  Although it’s less well-known or used in supplements, theophylline – which is used therapeutically as a bronchodilator - has effects on thermogenesis and exercise performance similar to caffeine.

A source of gamma linolenic acid (GLA) used in supplements.  Borage oil has a higher percentage of GLA than evening primrose oil (23% – 24%).  High quality oil should be used, however, as it may contain traces of hepatotoxic pyrrolizidine alkaloids.

A source of gamma linolenic acid (GLA) used in supplements (evening primrose oil is approx. 10% GLA).  It’s used therapeutically to treat eczema. Evening primrose oil is also touted as an alternative treatment for a number of other conditions, such as arthritis, multiple sclerosis, diabetic neuropathy, PMS and menopause – but evidence of its effectiveness for these conditions is mixed and inconclusive.

An omega-6 fatty acid found in evening primrose, borage, hemp and black currant seed oil.  GLA is also formed naturally in the body from linoleic acid (LA).  Unlike (LA-derived) arachidonic acid (AA), however, GLA has anti-inflammatory activity.  In the body, GLA is converted to dihomogamma-linolenic acid (DGLA) which competes with arachidonic acid and interferes with the formation of pro-inflammatory eicosanoids from it.  In addition, DGLA-derived eicosanoids, such as PGE₁, also have anti-inflammatory effects.

An omega-3 essential fatty acid found in sources such as flax, hemp, perilla and chia seeds/oils.  Alpha-linolenic acid is a precursor to the essential metabolites EPA and DHA, although conversion is often limited and inefficient, due to factors such as gender and competition with (omega-6) linoleic acid – which is often oversupplied in the diet.

A source of pre-formed, omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which play important physiological roles.  Fish oil (either in supplement or food form, such as from fatty fish) has a variety of therapeutic and health benefits, particularly w/respect to preventing cardiovascular disease. Fish oil – in combination with exercise – can also enhance fat loss.

See the Fish Oil review for more information.