What it is
Glutathione is a short chain of amino acids (a peptide). It has just three: glutamate, cysteine and glycine. Nearly every cell makes its own supply. It is the most common antioxidant the body makes. An antioxidant helps protect cells from damage.
Its cysteine part holds a sulfur atom. This sulfur lets it calm down harmful, reactive forms of oxygen. It also helps liver enzymes mark some drugs and toxins so the body can remove them. Doing this work uses it up (it becomes oxidized). Enzymes then recycle it back to its working form.
The body does not need glutathione from food. It builds its own from amino acids in food. Glutathione is sold as a supplement taken by mouth. In the Philippines and other parts of Asia, it is also offered as a drip into a vein or as a shot to lighten skin. Neither the US FDA nor the Philippine FDA has approved glutathione shots for skin lightening.
Glutathione (γ-L-glutamyl-L-cysteinylglycine; C10H17N3O6S, 307.33 g/mol) has an isopeptide bond between the γ-carboxyl of glutamate and cysteine, which protects it from most peptidases. It is synthesized in two ATP-dependent steps by glutamate–cysteine ligase (rate-limiting and feedback-inhibited by glutathione) and glutathione synthetase, reaching millimolar intracellular concentrations, mostly as reduced GSH. Glutathione peroxidases use GSH to reduce hydrogen peroxide and lipid hydroperoxides, forming glutathione disulfide (GSSG), which glutathione reductase regenerates with NADPH; the GSH:GSSG ratio is a standard redox marker. Glutathione S-transferases conjugate GSH to electrophiles, including the acetaminophen metabolite NAPQI, for excretion through the mercapturic acid pathway.
Extracellular glutathione is degraded by membrane γ-glutamyltransferase, and plasma concentrations are low (6.2 µmol/L at baseline in Witschi et al., 1992). Its antioxidant and conjugation roles are enzymatic rather than receptor-mediated. The proposed skin-lightening mechanism, drawn mainly from in-vitro work, is inhibition of tyrosinase and a shift from dark eumelanin toward lighter pheomelanin; human evidence for this is limited.
Who made it and when
In 1888, the French scientist J. de Rey-Pailhade found a substance in yeast. It turned sulfur into hydrogen sulfide. He named it “philothion”. That is Greek for “sulfur-loving”.
In 1921, the British scientist Frederick Gowland Hopkins pulled the substance out on its own. He named it glutathione. He thought it was made of two amino acids. Others disagreed. In 1929, Hopkins found it has three. Edward Kendall in the US found the same thing on his own. In 1935, chemists made it from scratch in the lab. This confirmed its structure.
Glutathione is a natural molecule, so no company owns it. Some countries allow glutathione shots as a medicine. The Philippines is one of them. The United States does not. In the US, a different form of glutathione (the oxidized form) is only one ingredient in an approved rinse used during eye surgery.
De Rey-Pailhade (1888) described philothion in yeast extracts as a substance that reduces sulfur to hydrogen sulfide. Hopkins (Biochem J 1921, “On an autoxidisable constituent of the cell”) isolated it, provisionally named it glutathione, and proposed a glutamyl-cysteine dipeptide. In 1929 Hopkins (“On glutathione: a reinvestigation”, J Biol Chem) and, independently, Edward C. Kendall revised this to a tripeptide of glutamate, cysteine and glycine, and Harington and Mead reported its synthesis in 1935 (“Synthesis of glutathione”, Biochem J).
The Philippine FDA states that injectable glutathione is approved there as an adjunct treatment in cisplatin chemotherapy. In the US, the oxidized dimer glutathione disulfide (0.184 mg/mL) is one of eight listed active ingredients of BSS PLUS (Alcon; NDA 018469, approved 1981-10-28), an intraocular irrigating solution for eye surgery. Renovion’s ARINA-1, a nebulized combination of reduced glutathione and ascorbic acid, is in an FDA-regulated phase 3 trial (NCT05654922), following a phase 1 study in bilateral lung transplant recipients (NCT03226431) and a phase 2a study in non-cystic fibrosis bronchiectasis (NCT05495243). It is the only active late-stage US program containing glutathione identified for this article. No patent is listed.
What the data say
Taken by mouth: An early study gave one large dose by mouth. It did not raise glutathione in the blood. The gut and liver broke it down first.
A 2015 trial lasted six months and included 54 adults. Daily supplements did raise glutathione stored in blood cells. At the higher dose, levels went up by about a third. But levels fell back within a month of stopping. A separate four-week trial found no change.
Skin: A small trial included 60 Thai medical students. They took glutathione by mouth for four weeks. Their skin was slightly lighter at two of six spots tested. A 2018 review looked at glutathione given into a vein for skin lightening. It found the proof rested on just one poorly designed study.
Disease: A trial in 153 people with cystic fibrosis tested breathed-in glutathione. It did not help lung function. In Parkinson disease, small trials gave glutathione into a vein or through the nose. People handled it well. But it did not work better than a dummy treatment (placebo).
Bioavailability: Witschi et al. (Eur J Clin Pharmacol 1992) gave 7 volunteers about 3 g orally and found no significant rise in plasma glutathione over 270 minutes, attributed to gut and liver γ-glutamyltransferase. Richie et al. (Eur J Nutr 2015) randomized 54 non-smokers to 250 or 1,000 mg/day or placebo for 6 months; at 1,000 mg, GSH rose 30–35% in erythrocytes, plasma and lymphocytes and 260% in buccal cells, returning to baseline after a 1-month washout. Allen and Bradley (2011; 500 mg twice daily for 4 weeks; n=40) found no change in oxidative-stress markers or glutathione status.
Skin: Arjinpathana and Asawanonda (2012) reported that 500 mg/day orally for 4 weeks lowered the melanin index more than placebo at 2 of 6 sites (n=60). Sonthalia et al. (2018) called the IV evidence a single, dubiously designed study.
Disease: Griese et al. (NCT00506688; AJRCCM 2013) found no FEV1 difference with 646 mg inhaled twice daily for 6 months in CF (n=153). Hauser et al. (Mov Disord 2009; 1,400 mg IV three times weekly for 4 weeks; n=21) and Mischley et al. (NCT02424708; J Parkinsons Dis 2017; 100 or 200 mg intranasally three times daily; n=45) found no significant difference from placebo.
Regulatory picture
There are three separate things to know.
Approval: No FDA-approved drug uses the main form of glutathione (reduced glutathione) as its active ingredient. The oxidized form is one of eight ingredients in an approved rinse used during eye surgery. A breathed-in mix of glutathione and vitamin C is in a late-stage trial. The trial is in people who had a lung transplant. That is why this page lists glutathione as still being tested.
Compounding: In the US, glutathione drips are made by compounding pharmacies. These pharmacies mix their own drugs. The FDA keeps a list of bulk ingredients they may use. Glutathione is “under evaluation” for that list (Category 1). There is no final decision yet. In 2022, an FDA advisory group voted 8 to 5 to add it. That vote does not have to be followed. The FDA has not acted on it.
Safety warnings: In 2019, the FDA warned compounding pharmacies. Patients had reactions to shots made with contaminated glutathione powder. The FDA warned again in August 2026. At least 30 patients became ill after glutathione drips into a vein. These were made from a supplement-grade ingredient. The US FDA (2015) and the Philippine FDA (2019) have both said no skin-lightening shot is approved.
Approval: investigational. Reduced glutathione is not an active ingredient of any FDA-approved product (BSS PLUS contains the distinct disulfide), but ARINA-1 (Renovion; 150 mg/mL reduced glutathione with 88 mg/mL ascorbic acid, 4 mL nebulized twice daily) is in a recruiting, FDA-regulated phase 3 trial for bronchiolitis obliterans syndrome after bilateral lung transplant (NCT05654922).
Compounding: glutathione is in 503A Category 1 (FDA list updated 2026-05-14) and is not on the 503A bulks list in 21 CFR 216.23. The Pharmacy Compounding Advisory Committee reviewed it on 2022-06-08 and voted 8–5 with 1 abstention in favour of inclusion; the vote is non-binding and FDA had not completed rulemaking to add it as of the 2026-05-14 list, so compounding is recorded as unknown. On 2019-02-01 FDA warned against L-glutathione distributed by Letco Medical after seven patients reacted to an injectable compounded with it at 200 mg/mL, and on 2019-06-07 it reported that all FDA-tested samples contained excessive endotoxin, some up to five times the appropriate limit. In 2026, three Texas compounders recalled glutathione products for elevated endotoxin, CDC counted more than 25 cases in at least four states, and FDA’s 2026-08-27 alert cited at least 30 patients and a dietary-supplement-grade ingredient supplied by Medisca Inc.
Cosmetic use: FDA’s 2015 consumer update on injectable skin-lightening products, which followed a 2014 seizure of injectable glutathione kits, and Philippine FDA Advisory No. 2019-182 both state that no injectable skin-lightening product is approved.
