Glutathione: evidence, FDA status and research

It is sold as an antioxidant booster, for skin lightening drips and for detox. One small trial showed slight lightening at two skin sites, and trials for other uses failed.

Sold for

Glutathione is sold as a master antioxidant, for skin whitening by intravenous drip, for detox and for Parkinson's disease.

Studies say

Oral glutathione does raise body stores and produced a modest, site-specific lightening in one small trial, while inhaled glutathione failed in cystic fibrosis and intravenous glutathione showed no clear benefit in a Parkinson's pilot, so the grade is B for the skin claim and lower for the others.

Why grade B. For skin lightening, the use glutathione is most often sold for, there is one randomised placebo-controlled trial of oral glutathione in 60 healthy students that found a small drop in melanin index at two of six skin sites. The larger trials in hand were for other purposes: a 153-patient inhaled trial in cystic fibrosis that missed its primary endpoint, a 54-adult trial showing oral glutathione raises blood levels, and a 21-patient Parkinson's pilot. No trial of intravenous glutathione for skin exists. ²⁵⁴³

FDA. Glutathione is not approved by the FDA as a drug for any indication. Oral glutathione is sold as a dietary supplement, intravenous and inhaled forms are made by compounding pharmacies, and glutathione sits in Category 1 of the FDA's list of nominated compounding substances, meaning it may be compounded while the agency evaluates it. ¹

Written from 5 cited sources. Last refreshed 2026-10-27. Not physician reviewed.

What this means for you

What people take it for: Skin lightening, detox and general health
Can a US doctor prescribe it?: No. It is not approved as a drug, though pharmacies may make it up.
Properly tested in people?: Partly: some human trials, with gaps. The skin trial had 60 students.

Evidence checklist

Randomised controlled trial One placebo-controlled skin trial, 60 studentsyes
Human study over 100 people 153-patient cystic fibrosis trial; skin trial 60yes
More than one research group Article does not say who ran the trialsno information
Clinical outcomes, not surrogate markers Melanin index, not a clinical outcomeno
Human safety data beyond case reports Oral and inhaled tolerated; IV not studiedyes

Drawn from the cited studies below. A dash means the sources give no information.

What it is

Glutathione is a tripeptide of glutamate, cysteine and glycine. Every cell makes it. It is the most abundant small-molecule antioxidant inside cells. There it neutralises reactive oxygen species and helps the liver clear drugs. As it does this work, its reduced form (GSH) turns into an oxidised form (GSSG). The ratio of the two is a common measure of oxidative stress. ⁴

Three supplement routes exist. Oral capsules are sold over the counter. Wellness clinics offer drips into a vein, mostly for skin lightening. Researchers have studied nebulised glutathione for lung disease. For years people assumed that gut enzymes destroyed oral glutathione before absorption. ⁴⁵

How it works

For skin, the proposed mechanism has two parts. Glutathione blocks tyrosinase, the enzyme that starts melanin making. This shifts melanin production from the dark eumelanin to the lighter pheomelanin. It also scavenges the free radicals that stimulate melanocytes. Cell studies describe this well. The open question is whether glutathione by mouth or by vein reaches skin cells at levels that matter. ²

In the lungs, glutathione is the major antioxidant in the airway lining fluid. Cystic fibrosis depletes it. That is why researchers tested inhaled replacement. ⁵

What human research shows

Richie and colleagues randomised 54 non-smoking adults to oral glutathione at two doses or placebo for six months. In the higher-dose group, blood glutathione rose 30 to 35% in red cells, plasma and lymphocytes. The ratio of oxidised to reduced forms fell. Natural killer cell activity doubled. All of it returned to baseline a month after stopping. ⁴

In the skin trial, 60 medical students took oral glutathione or placebo for four weeks. Melanin index fell at all six measured sites in the glutathione group. But the difference from placebo was significant at only two. These were the right side of the face and the sun-exposed left forearm. ²

Griese and colleagues randomised 153 people with cystic fibrosis to inhaled glutathione or placebo for six months. Sputum glutathione rose. Yet lung function was no different between groups at the end. There were no fewer exacerbations and no better quality of life. In Parkinson's disease, Hauser's pilot randomised 21 patients. They got glutathione by vein or placebo over four weeks. The drug was well tolerated. Motor scores did not change by a significant amount. ⁵³

Study	Model	Finding
Richie 2015, oral absorption	Humans, n=54, randomised double-blind placebo-controlled, 6 months	Oral glutathione raised blood and tissue glutathione 30 to 35% and lowered the oxidised-to-reduced ratio; levels fell back after a one-month washout. ⁴
Arjinpathana 2012, skin lightening	Humans, n=60 healthy students, randomised double-blind placebo-controlled, 4 weeks	Melanin index fell at all sites but was significantly lower than placebo at only two of six. ²
Griese 2013, cystic fibrosis	Humans, n=153, randomised double-blind placebo-controlled, 6 months inhaled	No difference in lung function, exacerbations or quality of life despite confirmed delivery to the airways. ⁵
Hauser 2009, Parkinson's	Humans, n=21, randomised double-blind placebo-controlled pilot, 4 weeks intravenous	Well tolerated; no statistically significant improvement in motor scores versus placebo. ³

Safety

Oral glutathione was well tolerated in the six-month trial. In cystic fibrosis, inhaled glutathione caused about as many side effects as placebo. The concerns lie with the intravenous route. It is compounded, not made under drug approval. The skin trial authors note that the long-term safety of glutathione for lightening has not been established. ⁴⁵²

Questions for your clinician

Is there any trial of the intravenous form for skin?
What is known about long-term use for skin lightening?
Who makes the compounded version, and how is it tested?

Questions people ask

Is glutathione FDA-approved?

No. It is sold as a dietary supplement by mouth. Pharmacies compound it for intravenous or inhaled use. The FDA lists it in Category 1 of nominated compounding substances. That permits compounding while the agency decides whether to add it to the approved bulk substances list. ¹

Does oral glutathione get absorbed?

Yes, according to a six-month randomised trial in 54 adults. Blood and cell glutathione rose with supplements and fell back after stopping. Earlier small studies had suggested otherwise. That is why many clinics still say only the intravenous route works. ⁴

Does glutathione lighten skin?

Modestly. One four-week trial gave oral glutathione to 60 students. Melanin index dropped at two of six sites compared with placebo. The cited literature has no controlled trial of intravenous glutathione for skin lightening. So the drip clinics are working from the oral data and from mechanism. ²

Does glutathione help Parkinson's disease?

A pilot gave intravenous glutathione to 21 patients. It found the drug safe over four weeks. It showed no significant benefit on motor scores against placebo. The authors called for larger trials. Those trials have not changed the picture. ³

Citations

FDA: bulk drug substances nominated for use in compounding under section 503A, category list fda.gov
Arjinpathana 2012, Journal of Dermatological Treatment: glutathione as an oral whitening agent, randomised placebo-controlled study doi.org
Hauser 2009, Movement Disorders: randomised double-blind pilot of intravenous glutathione in Parkinson's disease doi.org
Richie 2015, European Journal of Nutrition: randomised controlled trial of oral glutathione on body stores pubmed.ncbi.nlm.nih.gov
Griese 2013, American Journal of Respiratory and Critical Care Medicine: inhaled glutathione in cystic fibrosis, randomised trial pubmed.ncbi.nlm.nih.gov