Heart/Performance/Weight

Betaine

Methyl donor compound that lowers homocysteine and may modestly support liver and exercise markers in adults.

score

evidence

Caution

risk

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Use with caution

This supplement may interact with medications, medical conditions or sensitive populations. Review safety before use.

Overview

Forms

Safety

Stack

Quick Take

Mostly worth considering for elevated homocysteine; outside that, benefits are modest and fairly niche.

Betaine, usually sold as trimethylglycine (TMG), is a naturally occurring methyl-donor compound found in beets, spinach, wheat bran, quinoa, and shellfish. It helps recycle homocysteine back to methionine and also acts as a cell osmolyte. The best-supported use is lowering homocysteine, while evidence for exercise performance, body composition, and liver markers is weaker. It tends to help adults with elevated homocysteine or low methyl-donor intake most.

Potential benefits

Lowers homocysteine

May improve power output

May improve body composition

May improve liver fat markers

Protocol

Amount

1.5-3 g

Frequency

Once daily or split into 2 doses

When

With meals to reduce GI upset; consistency matters more than timing.

Onset Time

2-4 weeks for homocysteine; 2-6 weeks for exercise effects

Who Should Consider

Adults with elevated homocysteine

People with low folate or B12 intake

Adults eating low-plant, high-methionine diets

Resistance trainers seeking a small edge

Adults with fatty liver under clinician guidance

Food Sources

Wheat bran or wheat germ (~200-500 mg per serving)
Cooked spinach (~300-600 mg per cup)
Beets (~100-200 mg per cup)
Cooked quinoa (~100-200 mg per cup)
Shrimp or shellfish (~100-200 mg per 100 g)

How It Works

Betaine donates a methyl group through the BHMT pathway, converting homocysteine to methionine and supporting methylation reactions. It also acts as an osmolyte, helping cells maintain fluid balance under metabolic stress.

Updated 5/19/2026