Subcutaneous Glutathione: What Human Evidence Shows

What does the human research show about subcutaneous glutathione?

We found no published human study that measures glutathione pharmacokinetics after a subcutaneous injection or compares subcutaneous with intramuscular glutathione. The human pharmacokinetic studies located for this review used intravenous glutathione. Those results cannot establish how a subcutaneous dose is absorbed, its dose, or a route-specific injection technique.

This distinction matters because injection guidance for a vaccine, insulin, or another medicine is not evidence for a glutathione product. A technique that is appropriate for one formulation does not establish the dose, needle, volume, or absorption of another.

What the human pharmacokinetic studies measured

Study	Route and participants	What it can answer
Hong et al., 2005	Intravenous glutathione in seven healthy male volunteers; the study measured glutathione and metabolite concentrations in blood.	Reports blood-level changes after IV administration. It did not study subcutaneous or intramuscular injection.
Aebi et al., 1991	Intravenous glutathione in 10 healthy volunteers.	Reports plasma kinetics after IV infusion. It does not establish absorption after an injection under the skin.
Human subcutaneous glutathione	No direct pharmacokinetic study located for this review.	Absorption rate, peak concentration, bioavailability, and duration after subcutaneous injection remain unestablished by these studies.

Why route matters when reading glutathione studies

Intravenous administration places a substance directly into the circulation. Subcutaneous administration requires absorption from tissue. Oral administration introduces a further route-specific set of absorption and metabolism questions. A result from one route cannot be converted into an absorption curve or dose recommendation for another.

For that reason, numerical claims about subcutaneous glutathione onset, bioavailability, injection angle, volume limits, or superiority over intramuscular administration need direct evidence for the formulation and route. We did not locate such evidence in the human studies reviewed here.

What a useful subcutaneous study would need to report

A route-specific study would identify the formulation and concentration, describe the administered amount and injection method, collect timed blood samples, and report pharmacokinetic outcomes such as peak concentration and exposure. A head-to-head route comparison would also need a comparator arm. Without those measurements, IV or oral research cannot fill the subcutaneous evidence gap.

Human research

• Hong et al., Pharmacokinetics of glutathione and its metabolites in normal subjects, 2005
• Aebi et al., High-dose intravenous glutathione in man: pharmacokinetics and effects on cyst(e)ine in plasma and urine, 1991

FDA safety history for compounded glutathione (as of September 5, 2026)

Compounded glutathione is not FDA-approved for any indication. On June 7, 2019, FDA published an alert after adverse events in 8 patients who received injectables compounded with L-glutathione powder labeled as a dietary supplement (from the supplier Letco); FDA's point was that ingredients not intended for sterile compounding can contain endotoxins, and it later issued a reminder to compounders not to use dietary-supplement-grade glutathione in injectables. Since then, compounded glutathione 200 mg/mL multi-dose vials have been recalled for elevated endotoxin levels, including a nationwide recall by Optimal Balance Pharmacy and a similar recall by Victory Medical Center Pharmacy. Glutathione does appear on FDA's list of bulk drug substances nominated for use by 503B outsourcing facilities (updated March 21, 2025), which is a nomination status, not an approval. If you inject compounded glutathione, ask the pharmacy whether it uses pharmaceutical-grade (not dietary-supplement-grade) glutathione and tests for endotoxin.

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Platform Disclaimer. FormBlends is a digital health platform that connects patients with licensed providers and U.S.-based pharmacies. We do not manufacture, prescribe, or dispense medication directly. All clinical decisions are made by independent licensed providers.

Compounded Medication Notice. Compounded glutathione is not FDA-approved. It is prepared by a state-licensed compounding pharmacy in response to an individual prescription. Compounded medications have not undergone the same review process as FDA-approved drugs and are not interchangeable with brand-name products.

Results Disclaimer. Individual results vary. Glutathione outcomes depend on dose, frequency, baseline oxidative stress levels, diet, concurrent medications, and individual response to treatment. Statements about absorption rates and pharmacokinetics reference published clinical trial data, which may differ from real-world results.

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