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Glutathione

Studied for skin lightening, oral, skin lightening, topical and raising body glutathione stores. A three-amino-acid antioxidant the body makes in every cell, identified over a century ago. Sold since the 2000s as an intravenous, oral and topical skin-lightening product.

categorylongevity
clinical evidencemixed human
community adoptionmoderate
uses graded5
sources13
last reviewed24 Aug 2026
compound file

The answer, first. A three-amino-acid antioxidant the body makes in every cell, identified over a century ago. Sold since the 2000s as an intravenous, oral and topical skin-lightening product. The strongest evidence is for skin lightening, oral, graded C — small or open-label human only.

Five small randomised trials report a lower melanin index against placebo 1.

The Thai trial, 60 students on 500 mg daily for four weeks, reached significance at two of six measured sites 2. The other use — skin lightening, intravenous — grades D or E: a claim the human trials have already tested and not supported.

What it is used for

Every use graded on its own evidence, not the compound as a whole. 5 outcomes, ranked by what the human record supports.

#outcome · human · animal · gradewhat the best evidence actually shows
01Skin lightening, oral5 randomised trials · mechanism onlygrade CFive small randomised trials report a lower melanin index against placebo 1. The Thai trial, 60 students on 500 mg daily for four weeks, reached significance at two of six measured sites 2.
02Skin lightening, topicalrandomised trials, pooled · mechanism onlygrade CTopical 0.5% glutathione beat 0.1% and placebo in the pooled review 1. A double-blind trial found topical plus oral better than either alone 3. All small, all short, all reversible.
03Raising body glutathione stores1 randomised trial, n=54 · supportinggrade CSix months of oral glutathione at 1,000 mg daily raised erythrocyte, plasma and lymphocyte stores 30 to 35% in 54 adults 4. Stores returned to baseline after a month off. A single 3 g oral dose does nothing to plasma 5.
04Wrinkles and skin elasticity1 randomised trial, n=60 · nonegrade CIn 60 Thai women on 250 mg daily for twelve weeks, wrinkles fell significantly at some sites and elasticity trended upward 6. One trial, surrogate instruments, three months.
05Skin lightening, intravenous1 controlled study, n=32 · mechanism onlygrade EThe route that sells has the thinnest file. A 2025 systematic review found one placebo-controlled intravenous study, 37.5% versus 18.7% responders, not significant at P=0.054, and calls the route contraindicated 1.
gradewhat it means
ARegulatory approval, or multiple adequately-powered trials agreeing with each other
BAt least one well-powered human randomised trial, with the direction replicated
CSmall or open-label human trials only
DAnimal or mechanism data only, with no controlled human outcome
EA claim the human trials have already killed

How it works

The proposed mechanism, in three steps. A mechanism is a reason to run a trial, never a substitute for one.

1targetInhibits tyrosinase directly and chelates its copper site, the rate-limiting step in melanin synthesis 7.
2signalIt also shifts melanocytes away from eumelanin toward the lighter pheomelanin pathway 7.
3effectMelanin index falls in small trials. The effect reverses when dosing stops, and no trial has followed it past six months 1.

What it does not do

Claims the current record does not support. Worth knowing before you set expectations.

not supported by the evidence

How it is used

What published protocols administered, and what the community reports doing. Descriptive on both counts, and never a recommendation.

routeIntravenous infusion is what clinics sell. Oral capsules and topical creams carry the published trials. Intramuscular injection also circulates.
formatLyophilised powder in vials for intravenous drips. Capsules, buccal lozenges and 0.5% topical preparations elsewhere.
published dosesThe trials dosed orally: 500 mg daily for four weeks 2, 250 mg daily for twelve weeks 6, 250 or 1,000 mg daily for six months 4. A buccal lozenge ran eight weeks 9. The pharmacokinetic study infused 2 g per square metre intravenously 10. No published trial sets an intravenous lightening schedule.
human pharmacokineticsIntravenous half-life 14.1 minutes in ten healthy volunteers 10. A single 3 g oral dose does not raise plasma glutathione 5.
reported conventionsAs reported on skin-lightening forums and clinic menus, 2012-2026: intravenous courses of roughly 600 to 2,400 mg. Once or twice weekly for six to twelve weeks, usually with vitamin C in the same bag. Then a monthly maintenance drip. Convention, not guidance.
commonly paired withNAD+

This site does not publish protocols to follow. The doses above are what studies administered or what users report, stated as facts about the literature and the market. How protocols are structured, mixing and storage and the reconstitution calculator cover the arithmetic.

What to expect

Where a trial measured it, the trial. Where only the community reports it, that is said out loud.

onsetThe buccal lozenge trial recorded lower melanin indices from two weeks 9. The four-week oral trial measured at four weeks 2 and the twelve-week trial at twelve 6. No trial has measured how fast an intravenous course changes skin colour.
most common reportA small drop in measured melanin index, larger on sun-exposed sites than covered ones, and detected by instruments before it is visible 2.
adverse effectsThe oral and topical trials report good tolerability with no serious events 269. For the intravenous route the record is regulatory rather than statistical: liver, kidney and neurological toxicity, Stevens-Johnson syndrome, and infection risk from non-sterile administration 8. Anaphylaxis and hepatotoxicity appear in the review literature 11.
the stop signalThe Philippine FDA directs anyone experiencing side effects to seek medical attention and report it 8. The trial literature sets no stop rule, and the reviews note that the effect reverses when dosing ends 112.

Approval and status

What regulators and sport bodies have actually said, separately from what the evidence shows.

approvalNot approved anywhere for skin lightening. Approved in the Philippines as an adjunct in cisplatin chemotherapy 8.
FDASold in the US as a supplement or a compounded injectable. No US approval for skin lightening by any route.
sport [WADA]Not a banned substance. Any infusion above 100 mL per 12 hours is.
sold asresearch chemical

Check the vial

The grade above describes a molecule studied under controlled conditions. It says nothing about the powder in a particular vial.

That gap is the one part of this market a reader can actually close. How to read a certificate of analysis covers the five measures in five minutes, and the 2026 audit grades vendors on the documents they publish against a rubric printed in full.

Questions we get

What is Glutathione used for?

Skin lightening, almost entirely. It is sold as an intravenous drip in clinics across Southeast Asia and increasingly elsewhere, and as capsules, lozenges and creams. A smaller market buys it as a general antioxidant or an anti-ageing supplement.

The published trial evidence sits almost entirely on the oral and topical routes, in small short studies from Thailand, the Philippines, Indonesia and India. The route people actually pay most for is the one with the least evidence.

How is Glutathione used?

Described rather than advised. The trials dosed it orally at 250 to 1,000 mg a day, for four weeks to six months. Topically at 0.5%, and as a buccal lozenge for eight weeks.

The one intravenous pharmacokinetic study infused 2 g per square metre. As reported on clinic menus and forums, intravenous courses run 600 to 2,400 mg once or twice weekly. Usually with vitamin C, then a monthly drip. Convention, not guidance.

How long does Glutathione take to work?

In the trials that measured it, weeks. The buccal lozenge study recorded lower melanin indices from two weeks. The oral trials measured at four and twelve weeks. Changes are instrument-measured before they are visible, and they are small.

Nobody has published a timeline for the intravenous route, and nobody has followed any route past six months. How long an effect lasts once dosing stops is unmeasured.

Is Glutathione an approved drug?

Not for skin lightening, anywhere. The Philippine FDA has approved injectable glutathione only as an adjunct in cisplatin chemotherapy. It has issued a public advisory against its use as a lightening agent.

The advisory names liver, kidney and nervous-system toxicity, Stevens-Johnson syndrome and infection risk. In the US it is sold as a supplement or compounded injectable. Our index grades it mixed human on clinical evidence and moderate on community adoption, rated separately on purpose.

Does intravenous Glutathione work better than oral?

That is the marketing claim and the evidence does not support it. Intravenous dosing produces the highest plasma concentrations. But the half-life is 14 minutes, and the one placebo-controlled intravenous study found a responder difference that did not reach significance.

The 2025 systematic review that located it concluded the intravenous route is contraindicated for lack of efficacy and for side effects. The oral and topical routes carry what modest evidence exists.

References

  1. Sarkar R, et al. Glutathione as a skin-lightening agent and in melasma: a systematic review. Int J Dermatol. 2025;64:992-1004. PMID 39444151
  2. Arjinpathana N, Asawanonda P. Glutathione as an oral whitening agent: a randomized, double-blind, placebo-controlled study. J Dermatolog Treat. 2012;23:97-102. PMID 20524875
  3. Wahab S, et al. Combination of topical and oral glutathione as a skin-whitening agent: a double-blind randomized controlled clinical trial. Int J Dermatol. 2021;60:1013-1018. PMID 33871071
  4. Richie JP Jr, et al. Randomized controlled trial of oral glutathione supplementation on body stores of glutathione. Eur J Nutr. 2015;54:251-63. PMID 24791752
  5. Witschi A, et al. The systemic availability of oral glutathione. Eur J Clin Pharmacol. 1992;43:667-9. PMID 1362956
  6. Weschawalit S, et al. Glutathione and its antiaging and antimelanogenic effects. Clin Cosmet Investig Dermatol. 2017;10:147-153. PMID 28490897
  7. Sonthalia S, Daulatabad D, Sarkar R. Glutathione as a skin whitening agent: Facts, myths, evidence and controversies. Indian J Dermatol Venereol Leprol. 2016;82:262-72. PMID 27088927
  8. FDA Philippines. Advisory No. 2019-182: Unsafe Use of Glutathione as Skin Lightening Agent. fda.gov.ph
  9. Handog EB, Datuin MS, Singzon IA. An open-label, single-arm trial of the safety and efficacy of a novel preparation of glutathione as a skin-lightening agent in Filipino women. Int J Dermatol. 2016;55:153-7. PMID 26148180
  10. Aebi S, Assereto R, Lauterburg BH. High-dose intravenous glutathione in man. Pharmacokinetics and effects on cyst[e]ine in plasma and urine. Eur J Clin Invest. 1991;21:103-10. PMID 1907548
  11. Alzahrani TF, et al. Exploring the Safety and Efficacy of Glutathione Supplementation for Skin Lightening: A Narrative Review. Cureus. 2025;17:e78045. PMID 40013212
  12. Dilokthornsakul W, et al. The clinical effect of glutathione on skin color and other related skin conditions: A systematic review. J Cosmet Dermatol. 2019;18:728-737. PMID 30895708
  13. Sitohang IBS, et al. Evaluating Oral Glutathione Plus Ascorbic Acid, Alpha-lipoic Acid, and Zinc Aspartate as a Skin-lightening Agent: An Indonesian Multicenter, Randomized, Controlled Trial. J Clin Aesthet Dermatol. 2021;14:E53-E58. PMID 34840651

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