Has anyone come across that recent Nature paper claiming supplementation with GSH rescues cancer cell survival and growth when cystine is low? The details went over my head so I could not tell whether the delivery method like liposomal, reduced, oral or injectable made any difference. An AI conversion put the mouse dose at roughly thirteen thousand milligrams daily for a seventy kilogram person. Anyone have a clearer breakdown or other studies on this?
Glutathione supplementation and cancer concerns
Summary
Does glutathione supplementation feed cancer cells or pose risks for people with or at risk of cancer?
The thread discusses a Nature study showing extracellular glutathione can supply cysteine that supports tumor growth when cystine is limited. Participants note that while this raises caution for anyone with active cancer, glutathione and NAC remain beneficial for healthy individuals dealing with oxidative stress or aging-related conditions. Oral NAC is viewed as a steadier way to raise levels without the extracellular spikes seen with direct glutathione injections. Overall the group treats the findings as a reason for caution rather than a blanket ban on the supplement.
What this discussion establishes- Extracellular glutathione can act as a cysteine reservoir that tumors exploit under certain conditions.
- High-dose equivalents used in mouse studies are unlikely to match typical human intake.
- Oral NAC raises intracellular glutathione more gradually and may carry lower risk than injections.
- Low glutathione is linked to several age-related diseases, creating a trade-off for supplementation decisions.
- Cancer cells can use many nutrients, so context of active disease versus general health matters.
Whether NAC and glutathione carry meaningfully different risks around extracellular cysteine supply when tumors are present.
Still openHow relevant the mouse findings are to normal human doses and long-term supplementation in people without active cancer.
Nothing here is advice.
9 replies · 6 people
At first glance glutathione looks like other antioxidant supplements that may not be wise for cancer patients. The new wrinkle here is that it can serve as a nutrient source for breast cancer and likely other types as well. A write-up on the work also flags taurine as a possible fuel for leukemia. That is enough to make someone pause if they have known genetic risks, though cancer biology is complex and simple claims like glutathione feeds tumors would be overstated, similar to the sugar argument. On the other side, low glutathione levels link to several aging-related conditions including Parkinson's, COPD, liver disease, Alzheimer's, macular degeneration and heart disease.
Thanks for the details and the clear take on what the studies actually show. I try to view these reports with some skepticism and look for ways the results might be oversimplified or overstated, especially since the doses used in the lab seem far higher than anything a person would normally take. Still, it helps to know the possible downsides of any supplement.
Oral NAC is the more usual way people raise glutathione and is often considered more effective for longer-term use than direct injections. Because oral NAC does not cause the same sharp rise in levels, it might carry less risk overall. Higher NAC doses can still raise hematocrit though, which is a concern for anyone already on TRT.
Cancer cells grab whatever nutrients they can. If someone has active cancer or a past history, supplementing is probably not a good idea. Healthy people will get the same amino acids from food anyway, so adding the supplement is not a problem.
↳ replying to @ClearWillow37
Roughly one in three people will develop some form of cancer, so researchers stay cautious even about things like milk raising IGF-1. Still, there are larger risks to focus on such as workplace carcinogen exposure or long-term HGH use.
↳ replying to @SharpCinder28
That is not quite right. The issue is not about spiking levels, and NAC supplies cysteine just as readily. The paper itself notes that NAC rescued the cancer cells equally well. The whole setup shows glutathione acting as a cysteine store when the experiment deliberately limited it to slow tumor growth. Cysteine becomes conditionally essential during rapid cell growth like cancer. The study focused on glutathione in the environment around an active tumor that had been transplanted into mice. In normal conditions glutathione supports oxidative balance, detoxification and liver health, and supplementation has shown benefits. In short, if cancer is already present glutathione can help by giving it cysteine, but without active disease the molecule is clearly helpful.
The key word in the paper title is extracellular. Oral NAC supports the cell's own production inside, whereas an injection floods the outside space and can bypass normal controls, as seen with skin-lightening effects from prolonged high-dose use in some regions. That suggests injections might be better suited to short-term or acute situations. Similar points apply to other approaches.
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