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Liposomal vs Reduced vs S-Acetyl Glutathione: What the Head-to-Head Studies Show

Adrian XH
Published Author, Certificate: Medical Research

Last updated

S-acetyl glutathione is sold as the form that survives your gut. Europe’s food safety agency went through the main human study of it. Not one plasma sample held a measurable trace of S-acetyl glutathione.1,2

What showed up was plain glutathione, at about the levels you’d get from swallowing the plain kind.2

Every other form has the same gap between the label and the lab. Only six studies have compared two forms of glutathione head to head. Every one was run, paid for or co-written by a company selling one of the forms.

One dose of 300 mg liposomal raised blood glutathione about as much as 500 mg plain. S-acetyl gave slightly more in plasma and slightly less in red cells, and a sublingual tablet beat a swallowed capsule on one measure. The only six-month placebo win belongs to plain reduced glutathione, the cheapest form on the shelf.3,1,4,5

Liposomal vs reduced vs S-acetyl glutathione compared

Evidence. Placebo: compared against a dummy pill. Small trials: a few dozen people or fewer. One dose study: blood measured for hours after a single dose.

Glutathione forms compared by what they are, the best human evidence, price per gram and the main catch
FormWhat it isBest human evidencePer gramThe catch
1ReducedL-glutathione, SetriaThe plain moleculePlacebo, 6 monthsUp 30 to 35% at 1,000 mg a day.5$0.37 to $2.11A 4-week trial found nothing.6
2LiposomalGlutathione inside phospholipid bubblesSmall trialsOne dose of 300 mg matched 500 mg plain.3$1.67 to $27.22Bile and gut enzymes can break liposomes open.7
3S-acetylGlutathione with an acetyl cap on its sulfurOne dose studyPlasma a bit higher, red cells a bit lower than plain.1$3.17 to $10.83No S-acetyl reached the blood. No human safety trials.2
4Sublingual, lozenge, filmPlain glutathione dissolved in the mouthSmall trialsBeat a swallowed capsule on one ratio in 20 adults.4$3.06 to $33.33The main trial was co-written by the maker.
5Oxidized (GSSG)Two glutathione molecules joinedOne skin trialSame skin results as reduced at 250 mg.8Not pricedNo blood data.
6GGCThe building block one step before glutathioneOne dose studyImmune-cell glutathione up 53% in 90 minutes.9$3.56 to $5.42Back near baseline by 5 hours.
7NACA form of cysteine, the scarcest building blockMixedRaised glutathione only in people who started low.10$0.32Several placebo trials found no rise.
8IVGlutathione injected into a veinClears fastHalf-life about 14 minutes.11Clinic priceFDA alert on supplement-grade IV glutathione.12

Per gram is list price divided by grams of the active ingredient, across the products we priced.

Is L-glutathione the same as reduced glutathione?

Yes. L-glutathione, reduced glutathione and GSH are one molecule. The FDA’s substance registry files “L-glutathione reduced” and “reduced L-glutathione” under the same entry as plain glutathione.13

Setria is a brand of that same molecule, made by yeast fermentation.14 Plain glutathione also has an FDA “no questions” letter on its safety as a food ingredient (GRAS), at up to 742.5 mg a serving.15 So if one bottle says L-glutathione and another says reduced glutathione, the only thing left to compare is price. And “Setria vs liposomal” is really plain vs wrapped, since some liposomal products put Setria inside the wrapper.16

Liposomal is a wrapper around that same molecule. S-acetyl adds a small chemical cap to the sulfur, the part that does the antioxidant work. Oxidized glutathione, or GSSG, is different again. It’s two glutathione molecules joined at the sulfur, with twice the weight.2,17

Every head-to-head study of glutathione forms

Human studies that compared two or more forms of glutathione in the same trial
StudyComparedWhat happenedWho is behind it
1Solnier 2026314 healthy adultsLiposomal 300 mg, plain 500 mg and micellar 300 mg, one dose eachPeak rise in whole-blood glutathione: 45.5 liposomal vs 42.8 µg/mL plain. About equal.Run by ISURA. Co-written by the owner of the micellar brand.
2Fanelli 2018117 healthy adultsS-acetyl 3.5 g vs plain 3.5 g, one dose eachPlasma peak 0.74 vs 0.47 µM, higher with S-acetyl. Red cells 64.5 vs 68.5 µM, slightly higher with plain.Co-written by an employee of the S-acetyl maker, which supplied the product.
3Schmitt 2015420 adults with metabolic syndromeSublingual 450 mg, swallowed 450 mg and NAC 200 mg a day, 3 weeks eachRatio of active to oxidized glutathione: up 9.4 sublingual, up 7.4 NAC, down 6.9 swallowed.Two of four authors worked for the sublingual maker.
4Weschawalit 2017857 womenReduced 250 mg vs oxidized 250 mg vs placebo, 12 weeksNeither form beat placebo on the main skin-darkness measure. No difference between the two forms.Paid for by Kyowa, which makes both forms.
5Jung 202618healthy adultsMouth-dissolving film vs tablet, one 300 mg dose, then 100 mg a day for 4 weeksPlasma glutathione higher with the film at 4 and 6 hours. Total exposure only trended higher.Co-authors from Bio360 and Esther Formula, which sells glutathione strips.
6Prasad 20261912 healthy adultsLipoDuo liposomal 1 g vs plain 1 g, one dose, 6 people per groupPeak plasma glutathione about 6 times plain.Every author works for the maker.

None ran longer than 12 weeks. Only one measured something you could see in a mirror, and on its main measure neither form beat placebo. The rest measured blood for a few hours or weeks.

Reduced glutathione: the cheap form with the best trial

The strongest trial of any oral glutathione used plain capsules. In 54 adults over six months, 1,000 mg a day raised glutathione in red cells, plasma and lymphocytes by 30 to 35% against placebo. A month after stopping, it was back to baseline.5

The rest of the record is shakier. A 4-week trial of 1,000 mg a day found no change.6 When 7 people swallowed 3 grams at once, plasma glutathione did not rise.20 In another, the extra glutathione showed up bound to blood proteins rather than free in plasma.21

It’s also the cheapest form by far. Nutricost’s 500 mg capsules work out to $0.37 a gram, and Healthy Origins’ Setria capsules to $0.67.22,14 Thorne’s sustained-release version costs $5.14 a gram. No human study of a sustained-release glutathione turned up.23

Liposomal glutathione: small rises, no clear edge

In the best-known liposomal trial, 12 adults on 500 or 1,000 mg a day saw blood glutathione rise up to 40% by week 2. There was no placebo group, and the maker paid for it.24 In 18 adults with type 2 diabetes, a placebo-controlled trial found reduced glutathione rose in red cells only.25

In the one head-to-head not run by a liposomal maker, 300 mg liposomal and 500 mg plain raised whole-blood glutathione about equally after one dose.3 The only study claiming a big win, about 6 times plain, had 6 people per group and was written by the maker’s own staff.19 Our liposomal glutathione guide covers every liposomal trial, and our ranking of the best liposomal glutathione scores ten brands.

S-acetyl glutathione: what the human data show

The pitch for S-acetyl is that the acetyl cap protects it in the gut, and your cells take it off. One study has compared it with plain glutathione in people.

Eighteen healthy adults took a single 3.5 g dose of S-acetyl and, on another day, 3.5 g of plain glutathione. That’s about 12 times the 300 mg daily limit EFSA later set. Seventeen finished. S-acetyl glutathione was “not quantifiable in any plasma sample.” Plasma glutathione peaked a little higher after S-acetyl, and red-cell glutathione a little higher after plain.1

Results varied wildly from person to person, so any “x times better” figure from this study means little.2 One co-author worked for Gnosis, the S-acetyl maker, which made the test product. The paper still lists no competing interests.1

The EU food safety agency (EFSA) reviewed that study and said the glutathione profile from S-acetyl “did not substantially differ” from plain. It cleared S-acetyl at up to 300 mg a day for adults, about 270 mg for ages 14 to 17 and 190 mg for ages 10 to 13. Pregnancy and breastfeeding are excluded. That limit comes from a rise in liver weight in rats, and EFSA noted that no human safety study of S-acetyl exists.2

The only longer human study gave about 100 mg a day inside a multi-ingredient capsule to 10 people with mild Alzheimer’s, with no placebo. It can’t tell you what the S-acetyl did.26 And unlike plain glutathione, S-acetyl has no FDA GRAS notice on file in the US.15

Labels go further than the data. Nootropics Depot sells “Superior Bioavailability vs Regular” and backs it with a veterinary journal paper.27 S-acetyl capsules run $3.17 a gram from California Gold Nutrition to $10.83 from Seeking Health.28,29 And a gram of S-acetyl isn’t a gram of glutathione, since about 12% of its weight is the cap.2

Sublingual, lozenge and film glutathione

These dissolve in your mouth, so some glutathione can cross the lining of your cheek and skip the gut. The best trial gave 20 adults with metabolic syndrome 450 mg a day of sublingual or swallowed glutathione, or 200 mg of NAC, for 3 weeks each. Sublingual improved the active-to-oxidized ratio most, NAC came close, and swallowed glutathione went backward. Two of the four authors worked for the sublingual maker.4

Terry Naturally’s slow-melt tablet advertises a “230% improvement” from “a human published study” it doesn’t name.30 Its chart shows 21 days on 150 mg tablets, the same design as that trial. If that’s the study, the 230% is measured against swallowed glutathione that got worse, and NAC nearly matched it.4

In 16 men, sublingual glutathione lowered LDL cholesterol against placebo but did not improve blood vessel function.31 A cheek tablet raised blood glutathione within 30 to 60 minutes in 15 people, with no comparison group.32 A daily lozenge lightened skin in 30 Filipino women over 8 weeks, also with no comparison group.33 Prices run from $3.06 a gram for Source Naturals’ 50 mg lozenges to $33.33 for Seeking Health’s 25 mg S-acetyl lozenges.34,29

Reduced vs oxidized glutathione

Labels sell reduced glutathione as the “active” form. In the one trial that compared 250 mg of each against placebo for 12 weeks, reduced and oxidized did the same for skin, and neither beat placebo on the main measure for the whole group.8 Our page on liposomal glutathione benefits grades the skin trials.

Precursors: NAC and gamma-glutamylcysteine

You can skip glutathione and give your cells the parts. NAC supplies cysteine, the building block your body runs short of first.35 It raised glutathione only in people who started low, and it costs about 32 cents a gram.10,36 Our liposomal glutathione vs NAC comparison has the full trial record.

Gamma-glutamylcysteine (GGC) is the step right before glutathione. One 2 g dose raised glutathione in immune cells by 53% within 90 minutes. Peaks reached about twice baseline at 2 g and three times at 4 g, around 3 hours in, and were back near baseline by 5 hours.9 The study had no placebo arm. Its two authors patented the GGC manufacturing process, which is licensed to the GGC maker, and Zarka later joined that company.9,37

The main US consumer brand, Continual-G, costs $3.56 to $5.42 a gram. Its comparison image says glutathione supplements have “No published evidence,” which the six-month plain trial contradicts.38,5 GGC’s GRAS status is self-affirmed. The FDA never reviewed it.37

IV, inhaled and nasal glutathione

IV glutathione skips the gut entirely, but it leaves the blood fast, with a half-life of about 14 minutes.11 The FDA warned compounders against making IV doses from supplement-grade powder after at least 30 people had adverse events.12 In Parkinson’s, neither IV nor nasal glutathione beat placebo.39,40

Inhaled glutathione has a clear harm in one group. In 8 people with mild asthma, nebulized glutathione cut lung function by 19%.41 If you have asthma, don’t inhale it.

What each form costs per gram and per serving

Per serving tells you more than per gram here. S-acetyl capsules usually hold 100 mg, while plain capsules hold 500 mg.28,22

Price per gram and per serving of glutathione supplements, by form
FormExample productPer gramPer serving
ReducedNutricost 500 mg capsules22$0.37$0.19
Reduced (Setria)Healthy Origins 500 mg capsules14$0.67$0.33
NACNOW 600 mg capsules36$0.32$0.19
LiposomalCodeage 1,000 mg capsules42$1.67$1.67
LiposomalReadiSorb liquid, 422.7 mg43$6.01$2.54
S-acetylCalifornia Gold Nutrition 100 mg28$3.17$0.32
S-acetylSeeking Health 100 mg29$10.83$1.08
LozengeSource Naturals 50 mg34$3.06$0.15
Sustained releaseThorne Glutathione-SR 175 mg23$5.14$0.90
GGCContinual-G powder, 415 mg38$3.56$1.48

List prices for one bottle. Per serving is one capsule, packet, teaspoon or lozenge as labeled. Per gram counts the active ingredient on the label, not what your body absorbs.

What is the best form of glutathione to take?

  • For the most evidence per dollar, plain reduced glutathione. The six-month trial used 250 and 1,000 mg a day.5
  • If you want liposomal, pick the bottle with a lab report and a fair price per gram. Our liposomal glutathione rankings show which brands post a lab report.
  • S-acetyl runs $3.17 to $10.83 a gram against $0.37 to $2.11 for most plain capsules, for a form whose one study found about the same result. EFSA’s limit is 300 mg a day for adults, and it excludes pregnancy.2
  • If you can’t swallow pills, a lozenge or sublingual tablet is a fair choice. The evidence is small and mostly maker-run.
  • If you are older or likely low, NAC has more trials than any glutathione form, and glycine plus NAC raised low glutathione in older adults.44 See our NAC comparison.
  • Never get IV glutathione made from supplement powder, and never inhale glutathione if you have asthma.12,41

FAQ

Is S-acetyl glutathione better than liposomal?

No trial has compared them. Each was compared with plain glutathione only in single-dose studies, and neither has a study showing it does more for your health.1,3

Is Setria liposomal?

No. Setria is plain reduced glutathione made by fermentation. Some liposomal products, like LivOn’s Lypo-Spheric, put Setria inside liposomes.14,16

Which form of glutathione is best absorbed?

No study has shown that one oral form gets more glutathione into your tissues than another. The head-to-heads measured blood for hours, and the differences were small or came from the maker.

Which form of glutathione is best for skin?

The skin trials used plain, oxidized or lozenge glutathione. No published trial has tested liposomal or S-acetyl glutathione on skin.8,33

So which glutathione form wins?

On the evidence, plain reduced glutathione. It has the only long placebo-controlled win, and it costs the least.5 Liposomal, S-acetyl and sublingual each have a small study showing a different curve on a blood test. None has shown it makes you healthier than the plain capsule.

So if a label promises a form that “absorbs” better, ask which study it means, how many people were in it, and who paid.

This article is for information and is not medical advice.

Sources

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