I make no health claims whatsoever about any product listed here. Nothing listed here will cure or heal cancer or any other condition. Fenbendazole is a veterinary medication and is not for human consumption. I list the products, including brand names where applicable, because that is what I took — not because I recommend that you use them. Your health care providers can determine if there are any supplements appropriate for you.
Supplements I Refused to Take
There were two supplements I made a deliberate decision to avoid — glutathione and GABA. Both have research suggesting they may support cancer cell survival or tumor growth. I want to share my reasoning — not to tell you what to do, but because I believe you deserve to know what I found.
Glutathione
Supplemental glutathione — not the same as what your body makes
Glutathione is a powerful antioxidant naturally produced by the body, and it is widely marketed as a health supplement. The problem is that many cancer cells — particularly aggressive ones — hijack glutathione to protect themselves from oxidative stress, which is one of the mechanisms by which chemotherapy and some immunotherapies destroy tumors.
My personal concern: I was on Keytruda® (pembrolizumab), an immunotherapy that works in part by generating an immune-mediated oxidative environment around tumor cells. Supplementing with a potent antioxidant like glutathione felt directly counterproductive to me. I chose not to take it.
⚠ Important: NAC is NOT the same as supplemental glutathione
I did take NAC (N-Acetyl Cysteine), which is a precursor to glutathione. This is a critical distinction. NAC helps your body produce its own glutathione naturally — and that endogenous (internally made) glutathione is beneficial and protective. This is very different from taking glutathione as a direct supplement.
NAC works by providing the raw sulfur-containing building block (cysteine) that your liver uses to synthesize glutathione through its own regulated pathways. Your body produces only what it needs — it does not flood the system with pre-formed glutathione.
Similarly, I took MSM (Methylsulfonylmethane), an organic sulfur compound that supports the body's internal glutathione production through natural sulfur pathways. Again — supporting your body's own production is not the same as supplementing with pre-formed glutathione. I wanted the liver-support benefit of healthy glutathione metabolism without handing cancer cells a ready-made antioxidant shield.
Research — Supplemental Glutathione & Cancer Cell Protection
- Traverso et al. (2013) — Oxidative Medicine and Cellular Longevity
High intracellular glutathione is associated with multidrug resistance in several cancer types, including lung cancer. Elevated glutathione levels allow cancer cells to neutralize the oxidative damage that chemotherapy and immunotherapy depend on to kill them.
- Lv et al. (2021) — Frontiers in Oncology
Tumor cells upregulate glutathione synthesis to evade reactive oxygen species (ROS)-based cancer therapies. The review specifically notes that supplementing exogenous (pre-formed) glutathione could theoretically reinforce this protective mechanism — effectively helping the tumor defend itself.
- Kang et al. (2019) — Nature Communications
Elevated glutathione levels in cancer cells promote resistance to ferroptosis — a form of programmed cell death that relies on oxidative stress. Glutathione essentially acts as a shield that prevents this cancer-killing mechanism from working.
- Tew (1994) — Cancer Research
One of the foundational studies linking high intracellular glutathione to multidrug resistance in cancer. Established the mechanism by which cancer cells use glutathione to survive chemotherapy.
GABA
Gamma-Aminobutyric Acid
GABA is commonly sold as a calming supplement for anxiety and sleep. What many people don't know is that GABA receptors are expressed in several types of cancer cells, and emerging research suggests GABA signaling may promote tumor growth and proliferation in certain cancers — including non-small cell lung cancer, the exact type I had.
Given that I had NSCLC Stage 4 and found studies specifically linking GABA to NSCLC cell proliferation, this was an easy decision for me. I avoided it entirely.
Research — GABA Signaling & Cancer
- Bhatt et al. (2020) — Nature Medicine
GABA produced by tumor-infiltrating cells suppressed anti-tumor immune responses, essentially helping the tumor hide from the immune system. This was particularly alarming to me given that I was relying on Keytruda® to activate my immune system against the cancer.
- Schuller et al. (2008) — Cancer Letters
GABA receptor activation promoted the proliferation and migration of non-small cell lung cancer (NSCLC) cells — the exact cancer type I had. This study was one of the most direct pieces of evidence I found and made the decision straightforward for me.
- Schuller et al. (2012) — The Journal of Pharmacology and Experimental Therapeutics
GABA stimulated the growth of lung adenocarcinoma cells through a beta-adrenergic signaling pathway. Another direct link between GABA supplementation and lung cancer cell growth.
- Jiang et al. (2019) — Oncogene
GABAergic signaling has been linked to tumor angiogenesis — the formation of new blood vessels that feed tumors — in colorectal and pancreatic cancers. New blood vessel formation is how tumors grow and spread.
I share all of this not to frighten you or to tell you what to do. I share it because when I was sick and desperate and researching everything I could find, I wished someone had laid this out plainly for me. The supplement industry is enormous and largely unregulated, and many products that are marketed as health-supporting may not be appropriate for people with active cancer — especially those on immunotherapy or chemotherapy.
Do your research. Talk to your doctor. Be your own advocate.