Trimethylglycine (TMG), also known as betaine anhydrous, is a compound consisting of the amino acid glycine with three methyl groups attached. TMG is naturally produced in the body and consumed through diet, but many people use supplements to support specific health goals, such as enhancing athletic performance or promoting cardiovascular function. A common question regarding TMG supplementation is whether it negatively impacts cholesterol levels. This investigation clarifies the relationship between TMG consumption and changes in lipid profiles based on current scientific evidence.
TMG’s Effect on Cholesterol: The Current Research
The answer to whether TMG raises cholesterol is complex, as research findings are inconsistent and appear to be dose-dependent. Some clinical studies suggest that TMG supplementation may slightly increase total cholesterol and low-density lipoprotein (LDL) cholesterol. This potential increase in lipids is a concern because it could counteract the other cardiovascular benefits TMG offers.
A detailed analysis of combined data from multiple placebo-controlled trials indicated a clear effect at higher dosages. Supplementing with 6 grams of betaine daily for six weeks consistently increased both total cholesterol and the LDL fraction, while also raising triglyceride concentrations. Specifically, this 6 g/day dosage resulted in an average increase of LDL cholesterol by 0.36 mmol/l and triglycerides by 0.14 mmol/l.
The impact on high-density lipoprotein (HDL) cholesterol generally appears neutral across most studies. However, the ratio of total cholesterol to HDL cholesterol did increase, suggesting a less favorable lipid profile overall at the higher dose. Doses lower than 6 grams per day also showed a trend toward increased LDL cholesterol, but these changes were not consistently statistically significant in the analyzed trials.
The overall picture is complicated by studies focusing on specific populations, which sometimes report a favorable effect on lipids. For instance, in individuals with hypercholesterolemia or nonalcoholic fatty liver disease, TMG supplementation (3 to 6 grams daily) has been associated with reductions in total and LDL cholesterol. This suggests that the individual’s metabolic context may influence the outcome on their lipid profile. Research indicates that the risk of cholesterol elevation is tied to the amount consumed, making lipid monitoring advisable when using higher supplement doses.
The Primary Function of TMG: Homocysteine Metabolism
The main reason Trimethylglycine is taken as a supplement is its central involvement in the body’s methylation processes. TMG functions as a methyl donor, meaning it can donate one of its three methyl groups to other molecules. This action is a fundamental part of the one-carbon metabolism cycle, which supports numerous cellular functions.
The most recognized role of TMG is its participation in converting the amino acid homocysteine back into methionine. This biochemical reaction is catalyzed by the liver enzyme betaine-homocysteine methyltransferase (BHMT). By donating a methyl group, TMG effectively recycles homocysteine, preventing its accumulation in the bloodstream.
Elevated levels of homocysteine are a marker for potential cardiovascular issues. When homocysteine levels rise, it can be detrimental to the lining of blood vessels. TMG supplementation is a reliable way to lower these plasma homocysteine concentrations, supporting cardiovascular health.
The conversion of homocysteine to methionine also generates S-adenosylmethionine (SAMe) as an indirect byproduct. SAMe serves as a universal methyl donor involved in the synthesis of neurotransmitters and the regulation of gene expression. TMG’s action thus provides a dual benefit: reducing a potential risk factor while supporting the production of an important metabolic compound.
Sourcing TMG: Diet vs. Supplements and Dosage
Trimethylglycine is naturally present in a variety of foods, with some sources providing substantial amounts. Vegetables like beets and spinach are among the richest dietary sources, along with certain whole grains and wheat bran. The body can also synthesize TMG internally from the nutrient choline, found in foods such as eggs and soybeans.
For individuals seeking therapeutic effects, the amounts obtained through diet are often insufficient, which is why TMG is widely available as a supplement. Dosages used in research vary depending on the intended goal. For general wellness or maintenance, a lower dose, often around 500 to 800 milligrams per day, is common.
Athletes frequently use TMG to support performance, with typical research dosages ranging from 2.5 to 3 grams daily. When the primary goal is to significantly lower elevated homocysteine levels, studies have employed a higher intake, generally 4 to 6 grams per day, split into multiple doses. While TMG is considered safe, the potential for lipid changes at the 6-gram level highlights the importance of matching the dosage to a specific, monitored goal.