L-Glutathione

Graded C: small human trials (IV, intranasal and oral) exist, but none shows a clear clinical benefit; it is not approved in the US.

Strengths: 600 mg
Also known as: Glutathione, GSH, Reduced glutathione, γ-L-glutamyl-L-cysteinyl-glycine
Molecule: Tripeptide (3 amino acids, unusual γ-linkage)
Formula: C10H17N3O6S
Mol. weight: 307.32 g/mol
CAS: 70-18-8
Sequence: γ-Glu-Cys-Gly

Origin

The same molecule as the catalog's Glutathione listing. The 'L-' simply names the natural form; all biological glutathione is built from L-amino acids. This listing is a smaller 600 mg vial with published purity certificates.

How it works

Cells make glutathione from glutamate, cysteine and glycine. Its cysteine thiol neutralizes reactive oxygen species, regenerates other antioxidants and tags toxins for removal. Lab work suggests it inhibits tyrosinase and shifts melanin toward a lighter form.

What the research shows

An IV pilot in 21 Parkinson's patients showed a non-significant advantage over placebo, and an intranasal trial in 45 patients was no better than placebo. A 6-month oral trial raised blood glutathione 17 to 35%, falling back after stopping. Small oral and topical trials reported lighter skin, but a 2019 systematic review rated the evidence inconclusive, and no trial has tested IV glutathione for skin lightening. Full background is in the Glutathione entry.

Key studies

Hauser et al., Movement Disorders 2009 IV pilot in Parkinson's; non-significant difference from placebo.
Mischley et al., J Parkinson's Disease 2017 Intranasal glutathione not better than placebo.
Richie et al., Eur J Nutrition 2015 Oral glutathione modestly raised blood levels over 6 months.
Dilokthornsakul et al., J Cosmet Dermatol 2019 Skin-lightening evidence rated inconclusive.

Safety findings

Oral and topical forms were well tolerated in trials, and the IV pilot had no adverse-event withdrawals. In 2019 FDA linked reactions in 7 patients, one hospitalization and a suspected bloodstream infection to IV glutathione compounded from supplement-grade powder with high endotoxin levels. A purity certificate does not show sterility or endotoxin testing.

Regulatory status

No FDA-approved glutathione drug exists; oral glutathione has GRAS status. It is in FDA's 503A Category 1 (under evaluation) as of May 2026. Not on the WADA list, though WADA's method rules (M2.2) restrict large-volume IV infusions outside hospital settings. Status as of October 2026.

Catalog notes

Offered in 600 mg. Lot LGLU600-0528 has a certificate (99.9% purity, COA4841, June 17, 2026), and a 1,500 mg certificate also filed here (lot GLU1500-0803, 99.76%, COA7597) likely belongs to the 1,500 mg Glutathione listing. Follow the storage stated on the label and certificate.