What is glutathione?

What it is

Glutathione is a peptide, a short chain of amino acids, made of three: glutamate, cysteine and glycine. Nearly every cell makes it to defend against oxidative stress, the damage done by reactive forms of oxygen. The name usually means reduced glutathione. Oxidized glutathione, two molecules joined together, is the form left after glutathione neutralizes an oxidant.^1,2

Glutathione is sold in the United States as a dietary supplement. In 2022, FDA staff found medical spas across the country offering glutathione injections and infusions for skin lightening.²

How it works

Inside cells, enzymes use glutathione to neutralize hydrogen peroxide and other harmful by-products of normal metabolism, and to inactivate drugs, pollutants and other foreign chemicals.^1,2

An enzyme in the gut and liver (gamma-glutamyl transferase) breaks swallowed glutathione apart. In a 1992 study of 7 healthy volunteers, a single large swallowed dose did not raise blood glutathione over the next four and a half hours. Levels in red blood cells did not change over 4 weeks in a 2011 trial of 40 adults but rose over 6 months in a 2015 trial of 54 adults. They fell back within a month of stopping.^3,4,5

Given into a vein, it leaves the blood quickly: in a study of 10 healthy volunteers, its level halved about every 15 minutes.²

A 2014 trial report and a 2016 review describe how glutathione might lighten skin, based on lab studies. It may block tyrosinase, an enzyme needed to make the pigment melanin, and shift pigment cells toward red melanin rather than brown.^6,7

How it is taken

Trials have given glutathione into a vein (intravenously, or IV), by mouth, as an inhaled mist, as a nasal spray and on the skin. Compounders have prepared it for injection into a muscle or under the skin and as suppositories, the FDA’s 2022 review found.^{8,5,9,10,6,11,2}

What the research in people shows

In 2022, FDA staff reviewed the evidence for glutathione in 24 proposed uses and found no information or too little evidence that it works for any. Some evidence may support skin lightening, they said, but no specific group or dose had been established.²

The largest randomized trials of glutathione, in which people were assigned by chance, tested it in China to prevent kidney injury from the X-ray dye used in heart procedures. None reduced kidney injury. One, a 2015 trial of 825 people, compared IV glutathione with a placebo, a dummy infusion. Two others, of 505 people aged 75 or older (2015) and 396 older people with diabetes (2020), used no placebo.^12,13,14

A 2019 Cochrane systematic review, which gathers all trials meeting rules set in advance, pooled the two inhaled trials, with 258 people. Lung function was probably better than with placebo at three months; at six, results differed by measure. The reviewers concluded that inhaled and oral glutathione appear to improve lung function, but that intensive antibiotic and other treatments make any effect hard to judge.¹⁹

Several small trials in the 1990s and 2000s reported less nerve damage when IV glutathione was given with the platinum cancer drugs cisplatin or oxaliplatin; the FDA’s review called the results mixed. A 1997 randomized trial of 151 women with ovarian cancer also reported fewer nerve symptoms with glutathione.^2,20

A 2026 systematic review of 25 randomized trials of glutathione and related compounds found that none clearly reduced nerve damage. It linked glutathione to fewer severe cases but called this preliminary. The American Society of Clinical Oncology’s 2020 guideline does not recommend any medicine for preventing this nerve damage.^21,22

Skin-lightening trials

A 2012 Thai trial gave 60 medical students glutathione capsules or a placebo for 4 weeks. Pigment readings from a light-based meter fell at all six measured sites with glutathione, but by more than with placebo at only two. FDA staff noted the trial did not show whether the readings matched changes visible to the eye.^23,2

A 2017 trial by the same group gave 60 women capsules of reduced glutathione, oxidized glutathione or a placebo for 12 weeks. Pigment readings tended to be lower with both forms, but the differences could have been due to chance. The company that supplied the capsules paid for the trial.^24,2

A 2014 trial had 30 women apply oxidized glutathione lotion to one side of the face and a placebo lotion to the other for 10 weeks. Pigment readings were lower on the treated side. Three of the four authors worked for the company that made the oxidized glutathione. A 2021 trial of 46 people over 8 weeks reported more lightening with glutathione on the skin and by mouth together than with placebo.^6,11

A 2025 systematic review of 10 years of studies found only one placebo-controlled trial of IV glutathione for skin lightening. In that 2016 trial, 50 women received an IV product containing glutathione, vitamin C and collagen, or salt water, for 6 weeks, and 32 finished. Lightening was not clearly more common with the product, and it faded after treatment stopped, FDA staff reported.^25,2

The 2025 review rated swallowed and skin-applied glutathione as moderately effective for lightening but called both unsustainable. It judged side effects minimal for skin-applied forms and substantial for swallowed ones, and said IV glutathione should not be used, citing side effects and lack of effect. The FDA’s review found no data that lightening from glutathione helps treat any skin disease, such as melasma, which causes patches on the face.^25,2,26

Side effects and risks

FDA staff listed anaphylaxis, a life-threatening allergic reaction, along with liver injury and severe wheezing as serious safety issues with glutathione. In FDA adverse event reports from 2000 through 2021, they found 17 cases linked to glutathione, 15 in the United States. Seven described anaphylaxis or other allergic reactions, five of them after IV use. In one US case, a woman had anaphylaxis during an infusion and again when given glutathione 10 days later, the second time needing CPR.²

Inhaling glutathione can narrow the airways of people with asthma. In a 1997 trial, 8 people with mild asthma inhaled glutathione or a placebo a week apart. On average glutathione narrowed their airways, severely in one person, and it caused cough in four and breathlessness in three.^27,2

In the 2016 IV skin trial, 9 of the 25 women given the product stopped because of severe side effects, FDA staff reported. Eight stopped for abnormal liver tests and one for anaphylaxis. Every woman given the product reported side effects, and none given salt water did.²

Two of 60 women in the 2017 capsule trial stopped because of raised liver test results, which returned to normal within a few weeks. The paper did not say which group they were in. A Japanese case report described liver injury in a man with Parkinson disease after five months of IV glutathione alongside other medicines; it resolved after they were stopped.^24,2

The Philippines’ drug regulator has reported thyroid problems, kidney problems and severe, potentially fatal skin reactions after IV glutathione. FDA staff, who relayed these reports, said it is unclear whether glutathione itself or other factors, such as other ingredients, caused particular IV reactions.²

The FDA has warned that injectable skin lighteners, including products containing glutathione, are potentially unsafe and ineffective, and may contain unknown harmful ingredients or contaminants. The warning was first issued in 2015 and last revised in 2018.^26,28

The FDA’s review linked swallowed glutathione mainly to stomach and gut side effects. In the 6-month 2015 trial, no serious side effects were reported, and minor ones were about as common with placebo.^2,5

A 2009 trial of 27 people with colorectal cancer found IV glutathione lowered the overall blood levels of the cancer drug oxaliplatin. The authors concluded that this did not impair the drug, but FDA staff said it may affect how well the drug works. Higher glutathione levels are often linked to cancer cells resisting chemotherapy, they added.^29,2

FDA status

No glutathione drug is FDA-approved for any use. An approved eye irrigation solution contains oxidized glutathione, which the FDA treats as a different substance. Nor does glutathione have an official US Pharmacopeia quality standard as a drug ingredient (a drug monograph).^2,30,46

State-licensed pharmacies compound under section 503A of federal law. They may use a raw ingredient (a bulk drug substance) that has such a monograph or is part of an FDA-approved drug. An ingredient that is neither must be on the FDA’s list of extra permitted ingredients, the 503A bulks list. Glutathione meets none of these.^31,32,30

FDA staff reviewed glutathione for that list and in May 2022 recommended against adding it, citing serious safety issues, especially with injected and inhaled forms, and too little evidence that it works. On June 8, 2022, the FDA’s Pharmacy Compounding Advisory Committee, a panel of outside advisers, voted 8 to 5, with 1 abstention, for adding it. Yes voters cited patient access and the ingredient’s stability; no voters cited too little evidence that it works.^2,30

The FDA has not decided. Its list of nominated substances, updated May 14, 2026, places glutathione in Category 1, under evaluation. Until it decides, the FDA says it does not intend to act against compounding with Category 1 substances when the conditions in its guidance are met. It can remove a substance from Category 1, for example over safety risks.^33,31

Outsourcing facilities, FDA-registered compounders of sterile drugs under section 503B, follow separate lists. The FDA’s 503B list, updated March 21, 2025, also places glutathione in Category 1, with a similar policy of not acting when set conditions are met.^34,35,36

In October 2026, HHS, the FDA’s parent department, published a draft policy saying it does not intend to take enforcement action against 503A compounding with six named peptides under set conditions. Glutathione is not one of the six.^37,38

The FDA does not approve dietary supplements before they are sold. A supplement must be swallowed, so injected, inhaled and skin products are not supplements.³⁹

Problems with compounded injections

In 2019 the FDA reported seven patients at one clinic who fell ill within minutes of compounded IV glutathione, one needing hospital care. FDA testing found too much bacterial endotoxin, a toxic fragment of bacteria, in the powder used, which was labeled as a dietary supplement.⁴⁰

On August 27, 2026, the FDA reported at least 30 patients with reactions after IV glutathione, alone or mixed with other ingredients. Symptoms included fever, chills, pain, dizziness, signs of shock and symptoms resembling sepsis, a life-threatening response to infection, and some patients were hospitalized. The FDA said these fit too much endotoxin, which can also cause low blood pressure and death, though not all such effects had been reported. The pharmacies involved had all used one lot of glutathione labeled dietary supplement grade.⁴¹

Four Texas pharmacies recalled glutathione injections for high endotoxin levels between July and October 2026, FDA enforcement records show. The FDA put three of the four recalls in Class I, its most serious class, for products with a reasonable probability of causing serious harm or death. One recalled product was made for injection under the skin; its pharmacy reported two patients who needed emergency care after it was given into a vein.^42,43,44,45

The CDC reported in September 2026 that over 25 people in at least four states had become sick after glutathione injections into a vein, under the skin or into a muscle. At least three, all given it into a vein, were hospitalized, and one needed intensive care for shock and abnormal blood clotting. So far, every linked injection had been made by a compounding pharmacy from glutathione intended for dietary supplements.⁴⁶

The FDA says compounders should not use supplement-grade ingredients in injectable drugs or rely on testing alone, and advises clinicians to ask their compounders where the glutathione comes from.⁴¹

What isn’t known

The long-term safety of IV glutathione is unknown: a 2016 review found no study of its long-term safety, for any purpose. The IV trials described here lasted from a single dose to 6 weeks, or a course of chemotherapy, and the longest swallowed and inhaled trials ran 6 and 12 months.^{7,12,2,15,5,16}

The 2016 review also warned that shifting skin pigment from brown toward red melanin might make skin more prone to sun damage and skin cancer. It based this on a lab study of pigment cells, not on studies of people taking glutathione.⁷

The FDA’s 2022 review found compounders preparing glutathione for injection under the skin but described no study of that route in people. It found too few animal studies to judge the effects of repeated doses or of exposure during pregnancy and development.²

Questions to ask a clinician