Glutathione: Reference Overview and Reconstitution Notes

Published by the ✔ Medically reviewed by Bryan Le, PharmD, RPhEditorial standards

Glutathione research image

What it is

Glutathione is a tripeptide made of glutamate, cysteine and glycine that the body produces endogenously. It functions as a primary intracellular antioxidant, cycling between reduced (GSH) and oxidised (GSSG) forms, with the GSH:GSSG ratio used in research as a marker of oxidative stress.

Quick answer: An endogenous tripeptide — glutamate, cysteine, glycine — central to cellular redox balance. Oral forms are sold as dietary supplements; injectable glutathione is not FDA-approved for the uses it is commonly marketed for.

In this article

  1. What it is
  2. Research context
  3. Status
  4. Reconstitution and handling
  5. Status in sport
  6. Related reading
  7. Frequently asked questions
  8. What the community gets wrong
For research and educational reference only. Preppin Peppers sells laboratory hardware and materials (reconstitution pens, cartridges, and bacteriostatic water); it does not sell peptides or any substance for consumption. This is educational content, not medical, health, veterinary, dosing, or compounding advice, has not been evaluated by the FDA, and is not intended to diagnose, treat, cure, or prevent any condition, or for human or animal use. Comply with the laws that apply to you and consult a licensed professional for any health decision.

What it is

Chemical structure of Glutathione
The chemical structure of Glutathione.

Glutathione is a tripeptide the body makes for itself, built from glutamate, cysteine and glycine. It is one of the main intracellular antioxidants, cycling between a reduced form (GSH) and an oxidised form (GSSG); the ratio between the two is a widely used marker of oxidative stress in research.

Research context

Grouped under longevity and anti-aging research, where it is discussed in relation to oxidative stress, mitochondrial function and cellular aging. It also appears in detoxification research, because glutathione conjugation is one route by which cells process reactive compounds.

Worth separating clearly: glutathione as endogenous biochemistry is very well characterised. Glutathione as an administered compound — particularly the injectable skin-lightening use it is heavily marketed for — is not, and the FDA has warned about unapproved injectable products in that space.

Status

  • Regulatory status: Oral glutathione is sold in the United States as a dietary supplement. Injectable glutathione is not FDA-approved, and the FDA has issued warnings about unapproved injectable products marketed for skin lightening.
  • Sport status: Not specifically listed on the WADA Prohibited List.

Reconstitution and handling

Reconstitution follows the standard math: concentration equals the milligrams in the vial divided by the millilitres of bacteriostatic water added. There is no single correct concentration — it depends on solubility and how large a draw is wanted. If a mix does not go fully clear, add more water. The reconstitution calculator shows concentration, draw size and portions per vial for any volume.

Refrigerate reconstituted vials at 2–8 °C, keep them out of light, wipe stoppers with alcohol before each puncture, and label with the mix date. Discard anything cloudy, discoloured, or with floaters.

Status in sport

Glutathione is not named on the WADA Prohibited List. Verify against the current year’s list, since classification can change.

Reminder: research and educational reference only. Preppin Peppers sells hardware and materials, not peptides. Not medical, dosing, or health advice, not evaluated by the FDA, and not intended for human or animal use.

Frequently asked questions

Is glutathione a peptide?

Yes. It is a tripeptide built from glutamate, cysteine and glycine, and the body produces it endogenously.

Is injectable glutathione FDA-approved?

No. Oral glutathione is sold as a dietary supplement in the United States, but injectable glutathione is not FDA-approved, and the FDA has warned about unapproved injectable products marketed for skin lightening.

What is the GSH/GSSG ratio?

Glutathione cycles between a reduced form (GSH) and an oxidised form (GSSG). The ratio between them is a common laboratory marker of oxidative stress.

What the research community gets wrong about Glutathione

  • Endogenous does not mean administered is understood. Glutathione’s role inside the cell is well characterised. That says little about what administering it does, which is a separate and much weaker literature.
  • Vendor labels are not assays. Identity and purity come from a certificate of analysis on the batch in front of you, not from the name printed on a vial.
  • A reconstituted vial does not stay good forever. Compounds in solution break down over time, and rough handling (shaking hard enough to foam) can damage them. Note the reconstitution date and store as your protocol calls for.

Sources

Macro of Glutathione lyophilized powder
Close detail of the lyophilized powder.
  1. PubChem Compound Summary: Glutathione
  2. StatPearls — Biochemistry, Glutathione (NCBI Bookshelf)
  3. Bacteriostatic Water for Injection, USP — FDA/DailyMed label (0.9% benzyl alcohol)
  4. Sigma-Aldrich (Merck) — Handling and Storage Guidelines for Peptides and Proteins

✔ Reviewed by Bryan Le, PharmD, RPh

Bryan is a licensed pharmacist (Doctor of Pharmacy, Registered Pharmacist). Reconstituting lyophilized preparations is core pharmacy practice, so he reviews The Lab’s content for technical accuracy and to keep it within a research-and-education scope, with no medical or dosing advice. View profile on LinkedIn.
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