New scientific publication by Dr. Jerusa Oliveira, founder of NexusBioTox, questions whether the basic science on glutathione truly supports its widespread therapeutic use
Glutathione (GSH) is, without exaggeration, one of the most studied molecules in redox biochemistry. Present in virtually every cell in the body, it plays a role in cellular detoxification, mitochondrial function, and the signaling of inflammatory processes. It’s no wonder it has become a darling of the nutraceutical and "antioxidant" supplement market.
But does the science actually support everything that is promised about it?
That was the question guiding the systematic review and scientometric mapping published by our founder, Dr. Jerusa Oliveira, co-authored with researchers from institutions such as the Federal University of Alagoas (UFAL), Federal University of Goiás (UFG), Federal University of Uberlândia (UFU), and the Scientific Committee of Central Injectáveis. The work was published in the international journal Biomedicine & Pharmacotherapy (Elsevier), open access.
What the Study Did
The team analyzed more than two decades of scientific literature (2004–2025), following PRISMA guidelines for systematic reviews, combined with scientometric mapping via VOSviewer. In total, 98 records were identified across databases such as PubMed, Scopus, and ScienceDirect, resulting in 22 studies analyzed in depth — including preclinical models, in vitro studies, and clinical trials.
The goal was not simply to summarize "what is already known" about glutathione, but to map exactly where the disconnect lies between basic research and real clinical application.
Key Findings
1. Strong mechanism, but clinical efficacy still uncertain
Glutathione plays biologically well-established roles: it is a cofactor for essential antioxidant enzymes, regulates programmed cell death (including ferroptosis), and participates in the detoxification of xenobiotics. However, much of the available evidence comes from preclinical studies or surrogate biomarkers — not from clinical outcomes validated in patients.
2. Oral bioavailability remains the main obstacle
Conventional oral administration of glutathione undergoes significant degradation in the gastrointestinal tract, which limits its systemic absorption. This helps explain why so many clinical studies show inconsistent results.
3. New formulations improve pharmacokinetic parameters — but that is not the same as therapeutic efficacy
Liposomal, sublingual, and intranasal formulations have shown the ability to increase glutathione absorption and plasma levels. Even so, the review is emphatic: improving biochemical biomarkers does not automatically translate into improving clinically meaningful outcomes for patients.
4. The "reversive stress" paradox
One of the most interesting points in the study is its warning about excessive antioxidant supplementation. In excess, glutathione can suppress necessary physiological signaling by reactive species, creating an opposite imbalance — so-called reversive stress — which can also be harmful.
5. Glutathione as a central "hub" across multiple research areas
Network analysis revealed glutathione as a highly connected node, associated with topics as diverse as Autism Spectrum Disorder (ASD), HIV, aging, and cardiorenal syndrome — reinforcing its multifunctional biological relevance, even where direct therapeutic evidence is still limited.
Why This Matters for Those Developing Products and Therapies
This kind of critical review is exactly what guides NexusBioTox's day-to-day work: separating mechanistic promise from real evidence, something essential for pharmaceutical, agrochemical, cosmetic, and nanotechnology companies that need to make development decisions based on robust data — not just favorable biomarkers or market trends.
The study’s central message is not that glutathione "does not work." It is that science still needs well-designed, randomized clinical trials with patient-centered outcomes before established therapeutic efficacy can be claimed. Until then, what we have is a solid mechanistic foundation — and a real translational gap that the scientific community still needs to close.
Full article (open access): Carnib, B.L., et al. "Glutathione in redox homeostasis: Bridging molecular mechanisms, bioavailability constraints, and translational challenges in systemic therapeutics." Biomedicine & Pharmacotherapy, 203 (2026), 119817. DOI: 10.1016/j.biopha.2026.119817
NexusBioTox is a Brazilian deeptech and CRO specialized in preclinical toxicological testing using alternative models (zebrafish, Drosophila, Artemia salina), with OECD-certified methodologies. Incubated at UFAL and Porto Digital, it serves clients in the pharmaceutical, agrochemical, cosmetic, and nanotechnology sectors.
