Ingredient Watch: Glycocyamine
Glycocyamine is an ingredient that some companies add to their creatine-containing supplements. Because glycocyamine is the immediate precursor for creatine synthesis, it represents an additional pathway for increasing creatine storage in muscle tissue. It also has hypoglycemic effects, and may be able to enhance creatine uptake in muscle without a sugar-mediated insulin spike.
Glycocyamine, however, has a dark side, and there have been warnings posted on various boards about avoiding supplements that include it. In higher amounts, glycocyamine can cause:
- an increase in plasma homocysteine levels – which is a risk factor for cardiovascular disease. The process of converting glycocyamine to creatine imposes a high “methylation demand.” S-adenosylmethionine (SAM) is the methyl donor for the reaction, and homocysteine is one of the end products. Homocysteine can degrade protein function; and can inactivate the enzyme (DDAH) responsible for the breakdown of another potentially harmful compound (asymmetric dimethylarginine).
- seizures: glycocyamine accumulates in the brains of patients with GAMT deficiency. This is a genetic disorder that prevents the conversion of glycocyamine to creatine. Epileptic seizures are a symptom of the disorder, and can be corrected by measures that reduce glycocyamine levels. This symptom may be related to glycocyamine’s ability to generate free radicals.
In addition, glycocyamine competes with creatine for the same transporters, which would negate any benefits from co-administration.
Personally, I feel the dangers are being exaggerated: only small amounts are used in bodybuilding supplements – it’s mostly “label decoration.” I have a hard time seeing how it could be harmful at that level. In older experiments, glycocyamine has been fed to both rats and chicks at low concentrations with no apparent harm, nor have any problems been reported from the use of glycocyamine-containing supplements. Nonetheless, there’s no apparent advantage to including it, and little to be lost by removing it.
All things considered, regular creatine formulas get the job done, and are still the best choice.
