Betaine | Trimethylglycine | TMG | Glycine Betaine
Betaine was originally found in sugar beets (Beta vulgaris), which is the source of its name. Betaines are a group of structurally similar compounds. But because the first betaine discovered was trimethylglycine (the type of betaine found in sugar beets), betaine is commonly used as a synonym for trimethylglycine (TMG), though TMG is more specifically called glycine betaine (there can be non-glycine containing betaines but they are not typically used as dietary supplements). Betaine is an amino acid derivative (i.e., it falls into the protein category). It is found in some foods—in addition to beet roots, other good sources include quinoa, spinach, lamb and wheat brain. Betaine can also be made in the body from choline. This is thought to be a main metabolic fate of dietary choline. However, according to the National Institute of Health, most adults don’t get the recommended amount of choline in their diet, so relying on choline (which is also needed to produce phosphatidylcholine for cell membranes and the neurotransmitter acetylcholine) to make betaine can be akin to the saying “Robbing Peter to pay Paul.” Betaine is an important cofactor in methylation, a process that occurs in cells where methyl groups (-CH3) are donated for other processes in the body. These processes include (1) synthesizing neurotransmitters such as dopamine and serotonin, (2) making melatonin and CoQ10, (3) methylation of DNA for epigenetics, (4) remethylation of homocysteine  (which has a key role in cardiovascular health ), and (5) influencing S-Adenosyl Methionine (SAMe) and folate levels (since they are actively involved in methylation). Betaine is thought to be the source of up to 60% of the methyl groups required for the methylation of homocysteine . Strategies that boost NAD can decrease betaine [4,5] (NAD metabolites are methylated for elimination). Because of this, experts recommend supplementing betaine when strategies are used to boost NAD. Betaine has been largely used to support heart and liver function, but more recently has been receiving attention as a possible ergogenic (i.e., sports performance) and nootropic. Some biohackers use betaine to support sleep.
Betaine sourcing is focused on ensuring it is NON-GMO, gluten-free and vegan.
Betaine plays a central role in methylation and is involved in the synthesis of important neurotransmitters (dopamine and serotonin) and the neurohormone melatonin. It is also something which can be decreased when higher doses of niacin equivalent compounds are supplemented. For these reasons, it can play a role in a variety of different types of formulations. The dose of betaine used in a formulation will vary depending upon the purpose it is being used for. In general, Neurohacker Collective believes it’s prudent to supplement betaine (or a choline source) when niacin equivalents are used in amounts significantly greater than the daily value (DV) to ensure against unintended depletion. When used to ensure against depletion a general rule of thumb is that approximately 1 mg of betaine can be used for each mg of niacin equivalent supplemented. When used for supporting homocysteine metabolism, heart or liver health, as a nootropic or ergogenic (i.e., not simply to ensure against depletion), or for supporting sleep, higher doses are often used. Doses above 1500 mg a day may increase cholesterol levels, so, even in these other applications, Neurohacker Collective believes in using a more moderate dose of betaine, combined with other supportive nutrients.
Methylates homocysteine to produce the amino acid L-methionine 
Regulates the blood levels of homocysteine (a risk factor for cardiovascular disease) [6–8]
Balances the demand for methyl groups caused by the metabolism of niacin equivalents 
Supports the production of hepatic S-adenosylmethionine [10–12]
Balances the reduction in hepatic levels of S-adenosylmethionine (SAM) caused by the metabolism of niacin equivalents 
Protects from fat accumulation in the liver (hepatic steatosis) [10–12]
Supports resistance training performance [13–17]
Supports anabolic signaling 
Osmolyte—regulates cell hydration 
Choline—Supplementation with choline sources can increase betaine levels [20,21]
S-Adenosyl Methionine (SAMe)—Supplementation with betaine can increase SAMe levels 
Folic acid in regulating homocysteine levels 
Melatonin—appears to have synergies when combined for gut health [23,24]
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