Betaine, from food and supplements, supports two body functions: passing methyl tags cells need and helping cells cope with stress. Its most reliable effect is lowering homocysteine, a blood marker linked to heart and brain aging. Strength and body-composition help is modest and mixed; aging, liver, and mood roles stay unproven. Higher doses raise cholesterol — a real trade-off. (Full Review)

Protocol

Dose

0.5–6 g/day

0.5–2 g longevity/methylation; 2.5 g ergogenic; 3–6 g homocysteine

Frequency

Split, twice daily

e.g. 1.25 g twice daily; once-daily adequate (~14 h half-life)

Timing

Flexible

Near training, or with largest meal to reduce GI upset

Time to effect

Homocysteine

Days–weeks

Begins to fall within days to a few weeks

Performance / body composition

2–6 weeks

Ergogenic and body-composition effects, if they occur

Liver effects

Months

Where present, take months

Benefits

High: Homocysteine reduction

Medium: Muscular power and strength

Low: Body composition with resistance training; thermoregulation and cellular hydration; liver fat reduction

Speculative: Epigenetic aging and methylation capacity; mood and depression support; homocysteine buffering during NAD+ precursor use

Contraindications

Pregnancy or breastfeeding

Established high LDL (>160 mg/dL), familial hypercholesterolemia, or atherosclerotic cardiovascular disease

Significant kidney impairment

Known trimethylaminuria (high doses)

Key Interactions

Homocysteine-lowering cofactors (folate, vitamin B6, vitamin B12)

SAMe

Choline supplements and lecithin

Nicotinamide-based NAD+ precursors (nicotinamide riboside, nicotinamide mononucleotide)

Antifolate drugs (methotrexate, trimethoprim, sulfasalazine)

Lipid-lowering therapy (statins such as atorvastatin, rosuvastatin; ezetimibe)

Risk & Side Effects

High: Elevated LDL and total cholesterol

Medium: Gastrointestinal distress

Low: Body odor; cerebral edema with hypermethioninemia

Speculative: Trimethylamine N-oxide elevation

Monitoring

Marker	Target	Why
Homocysteine	<7–8 µmol/L	Primary target; tracks betaine's core benefit
LDL cholesterol	<100 mg/dL (lower if high cardiovascular risk)	Detects betaine's main adverse effect early
Total cholesterol	<200 mg/dL	Confirms the direction of the lipid response
Vitamin B12 & folate	B12 >500 pg/mL; folate mid-to-upper range	Cofactors for the parallel homocysteine pathway
Methionine	Within normal reference range	Safety check at high therapeutic doses
ALT	<25 U/L (men), <20 U/L (women)	Tracks liver-fat context where relevant

Cadence: Recheck homocysteine and a lipid panel at about 8–12 weeks after starting or changing dose, then every 6–12 months once stable.

Qualitative Assessment

Training performance and recovery
Heat and exercise tolerance
Energy and general well-being
Absence of bothersome side effects (stomach upset, body odor)

Betaine for Health & Longevity

Protocol

Benefits

Risk & Side Effects

Monitoring

Qualitative Assessment