L-Methionine
Also known as: methionine, DL-methionine
An essential sulfur-containing amino acid that starts every protein chain and is the precursor to S-adenosylmethionine, the body's main methyl donor, as well as cysteine and glutathione. It appears in liver-support, lipotropic, and hair-and-nail formulas, usually at modest doses. Supplemental methionine has little outcome research in healthy adults, and excess intake raises homocysteine, so formulators keep doses low and balance it with B vitamins.
Research summary
Precursor to S-adenosylmethionine for methylation reactions and to cysteine for glutathione synthesis.
Dosage
Daily amounts, of compound.
| Lowest studied | Typical range | Highest studied | Upper limit |
|---|---|---|---|
| — | 500–1,000 mg | — | — |
500–1,000 mg/day is the consumer range, often with choline and inositol in lipotropic blends. A review of human methionine tolerance concluded that intakes of about 100 mg/kg as a single load cause transient homocysteine rises without lasting harm in healthy adults, but there is no established benefit dose. Pair with folate, B6, and B12 to support homocysteine remethylation.
Source material: fermentation-derived or synthetic
Format suitability
- Capsule
- Powder
- Tablet
- Softgel
- Gummy
- Liquid
Distinct sulfur odor and bitter taste; capsules preferred.
Formulation notes
Combined with choline and inositol in lipotropic formulas and with biotin in hair products. Keep away from high-dose formulas that already raise homocysteine load without B-vitamin cofactors.
Sources
Related ingredients
Collagen Peptides (Bovine, Type I/III)
ProteinEnzymatically hydrolyzed collagen from bovine hide or bone, delivering short peptides rich in glycine, proline, and hydroxyproline.
Typical: 2.5–15 g
Zinc Gluconate
MineralThe most common zinc salt in multivitamins, lozenges, and immune products, containing about 14.3% elemental zinc.
Typical: 10–25 mg
Zinc Picolinate
MineralZinc chelated with picolinic acid, a tryptophan metabolite that is proposed to aid mineral transport across the gut wall.
Typical: 10–25 mg
Saw Palmetto Berry Extract
BotanicalA lipid-sterol extract of saw palmetto berries, standardized to fatty acids, that is the most widely used botanical in men's prostate and urinary-comfort products.
Typical: 320 mg
Biotin
VitaminBiotin is a water-soluble B vitamin that serves as the cofactor for five carboxylase enzymes in fatty acid, glucose, and amino acid metabolism.
Typical: 300–5,000 mcg