Glutathione

Origin and structure

Glutathione is a tripeptide made of three amino acids: glutamate, cysteine and glycine. The link between glutamate and cysteine is unusual: it runs from the side chain of glutamate (a so-called gamma bond) instead of from its backbone, which protects it from most protein-digesting enzymes. The thiol group of cysteine, a sulphur atom carrying a hydrogen, is the reactive part. Glutathione exists in a reduced form, GSH, which does the antioxidant work, and an oxidised form, GSSG, in which two molecules are joined.

Cells make their own glutathione in two enzyme steps, and the supply of cysteine largely sets how much they can make. The body also breaks it down: the enzyme gamma-glutamyl transferase, present among other places in the gut wall and the liver, splits it into its building blocks. That is the main reason researchers have long doubted whether glutathione taken by mouth reaches the blood intact.

As a product it comes in capsules, liposomal liquids, creams and lotions, and as powder for injection. TAD, one of the Italian brands, contains glutathione sodium: 646 mg of the salt equals 600 mg of glutathione. Research-grade glutathione is the same molecule, sold in vials for laboratory work.

How it works

Glutathione is the cell's main buffer against oxidation. Glutathione peroxidases, most of which contain selenium, use it to neutralise hydrogen peroxide and lipid peroxides; the oxidised GSSG that results is turned back into GSH by glutathione reductase. Glutathione S-transferases attach it to reactive chemicals, including breakdown products of drugs, so that the body can excrete them. Low glutathione has been linked to many diseases, but that link alone does not show that adding glutathione helps.

The Italian medicines rest on a specific idea: nerve damage from cisplatin is thought to come from platinum building up in the sensory nerve ganglia next to the spinal cord, and glutathione given just before the chemotherapy is meant to limit that build-up. Glutathione given into a vein leaves the blood quickly: in healthy volunteers its plasma half-life was about 14 minutes.

The skin-lightening idea comes from pigment chemistry. In laboratory work glutathione inhibits tyrosinase, the enzyme that starts melanin production, and steers pigment cells from dark eumelanin towards lighter pheomelanin. Whether enough glutathione from a capsule, a cream or a drip reaches the pigment cells in the skin to do this is exactly what the human studies have struggled to show.

Is glutathione approved?

Not by the EMA or the FDA. Injectable glutathione is a prescription medicine in Italy, for one narrow indication, and glutathione is sold as a food supplement in the EU and the US.

In the Netherlands no medicine in the CBG's register contains glutathione as its active substance; it appears only as an inactive ingredient in a few biological medicines. The registered Dutch medicine that works by raising glutathione is acetylcysteine (NAC): Fluimucil 200 mg/ml for intravenous infusion is the prescription antidote for paracetamol overdose, and according to its product information it works mainly by supplying the building block for glutathione, so that cells keep enough to neutralise NAPQI, the toxic breakdown product of paracetamol.

Research-grade glutathione, sold in vials for laboratory use, is neither a medicine nor a food supplement. It has no marketing authorisation, is not made under a medicines licence and may not be used in people.

• Italy: the medicines agency AIFA has authorised several brands of injectable glutathione, among them TAD (authorised in 1989) and Tationil. They are prescription-only, the 600 mg vials are not reimbursed, and their only indication is preventing neuropathy caused by chemotherapy with cisplatin or related platinum drugs.
• EU food law: according to EFSA, glutathione is an ingredient of a range of food supplements on the EU market. A chemically modified form, S-acetyl glutathione, is treated as a novel food; in 2026 EFSA judged it safe under the proposed conditions of use, which is a step towards an EU authorisation, not the authorisation itself.
• US: glutathione is not an FDA-approved drug. It is sold as a dietary supplement and since 2009 it has been regarded as generally recognised as safe (GRAS) as a food ingredient, as EFSA also notes. Pharmacies compound injectable glutathione, and the FDA has warned them twice, in 2019 and on 27 August 2026, not to use dietary-supplement-grade glutathione to make injections. The FDA has approved no injectable product for skin whitening or lightening.

What the research shows

Most glutathione studies are small and short. Apart from cancer chemotherapy, no use has been tested in a large trial, and several of the better-designed trials were negative. The main results:

• Uptake by mouth: in 7 healthy volunteers a single large dose did not raise glutathione in the blood over the next 4.5 hours (Witschi 1992). In a six-month randomised, placebo-controlled trial in 54 non-smoking adults, levels in red blood cells, plasma and lymphocytes rose by 30 to 35% on the higher of two doses and fell back to baseline within a month of stopping; the activity of natural killer cells, a type of immune cell, more than doubled at three months on that dose (Richie 2015). Neither study tested a health outcome.
• Skin colour: a 2019 systematic review found only four studies in healthy volunteers, three of them placebo-controlled. Oral glutathione and a lotion of oxidised glutathione lightened sun-exposed skin, but not sun-protected skin, and the authors judged the evidence inconclusive because of the quality of the studies and inconsistent results.
• Nerve damage from chemotherapy: the Italian label cites trials in ovarian, gastric and colorectal cancer in which glutathione infused before cisplatin or oxaliplatin reduced nerve and kidney damage. A placebo-controlled phase 3 trial, the American study N08CA in 185 patients receiving paclitaxel and carboplatin, found no protection against neuropathy, and two other measures favoured placebo (Leal 2014).
• Parkinson's disease: a 2021 meta-analysis that also searched Chinese databases pooled 7 randomised trials with 450 participants. It found a small improvement in motor scores (standardised mean difference −0.48, 95% CI −0.88 to −0.08), no difference in the scores for mood, thinking and daily living, and no more side effects than in the control groups.
• Cystic fibrosis: in a randomised trial of 153 patients aged 8 and older, inhaled glutathione for six months reached the lungs but did not improve lung function (FEV1) compared with placebo, nor reduce flare-ups, improve quality of life or lower markers of oxidative damage (Griese 2013).

Skin-lightening drips and injections: the warnings

Injectable glutathione is sold online and through spas and clinics with promises of a lighter, more even skin. Neither the Italian labels nor any EMA or FDA approval covers that use. The FDA has warned that injectable skin-whitening products are unapproved new drugs that may be unsafe, because buyers cannot know what is in them or how they were made. In September 2017 a US federal judge ordered a New Jersey company whose injectable whitening products contained glutathione, vitamin C, collagen and even human placenta to stop selling them and recall some of them.

The best-documented harm comes from product quality rather than from glutathione itself. After a first warning in 2019, the FDA reported on 27 August 2026 that at least 30 patients had fever, chills, pain, dizziness and signs of shock or sepsis-like symptoms, some needing hospital care, after intravenous glutathione that several compounding pharmacies had made from one lot of dietary-supplement-grade powder. The symptoms fit contamination with endotoxin, a fever-causing fragment of bacteria, and two pharmacies in Texas recalled their glutathione injections.

In the controlled trials glutathione itself was well tolerated: in the cystic fibrosis trial and the Parkinson's meta-analysis side effects were about as common as in the placebo or control groups, and the skin studies reported only non-serious events. The Italian label lists very rare skin rashes after intramuscular injection, soreness at the injection site, and the fever, vein inflammation and infection risks that come with any injection. The skin studies were short, so they say nothing about the safety of repeated courses over years.

Frequently asked questions

Does glutathione lighten the skin?

Possibly a little, but the evidence is thin. A 2019 systematic review found only four small studies in healthy volunteers; oral glutathione and a lotion of oxidised glutathione lightened sun-exposed skin but not sun-protected skin, and the authors called the evidence inconclusive. No glutathione product is approved for skin lightening by the EMA or the FDA, and the FDA has warned that injectable skin-whitening products are unapproved and may be unsafe.

Does glutathione work if you swallow it?

It is partly broken down in the gut wall and liver, and in 7 healthy volunteers a single large dose did not measurably raise glutathione in the blood. Taken daily for months it can raise body stores: in a six-month trial in 54 adults, levels in blood cells and plasma rose by 30 to 35% on the higher dose and fell back within a month of stopping. Whether higher levels improve health in people who are not deficient has not been shown.

Is glutathione legal in the Netherlands?

As a food-supplement ingredient it is on sale: according to EFSA, glutathione is used in a range of supplements on the EU market. As a medicine it does not exist in the Netherlands; no product in the CBG's register has it as its active substance, and the nearest medicine is acetylcysteine, the prescription antidote for paracetamol poisoning. Injectable glutathione is a prescription medicine in Italy. Research-grade glutathione is neither a medicine nor a supplement and may not be used in people.

Is glutathione banned in sport?

The substance is not: glutathione is not on the WADA Prohibited List for 2026. The method can be. Under rule M2.2, intravenous infusions or injections of more than 100 mL in total within 12 hours are prohibited at all times, unless they are legitimately received during hospital treatment, surgery or clinical investigations. A glutathione drip of more than 100 mL outside those settings is therefore a prohibited method for athletes who are tested.

Are glutathione drips and injections safe?

In controlled trials glutathione itself caused few problems. The documented harm comes from the products: on 27 August 2026 the FDA reported at least 30 patients with fever, chills and shock- or sepsis-like reactions, some admitted to hospital, after intravenous glutathione that pharmacies had made from supplement-grade powder contaminated with endotoxin, after a similar warning in 2019. No injectable glutathione is approved for skin lightening or 'detox' by the EMA or the FDA; the Italian medicines are licensed only to prevent nerve damage from chemotherapy.

Storage and handling

Store according to product-label instructions and batch handling notes. Lyophilized research peptides are commonly kept dry, protected from light, and handled with clean laboratory technique.

References

Checked against these sources on 28 October 2026.

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