With some substances there could be a "tipping" point depending on the substance, the dosage and the patient's stage of cancer where the substance may have a higher chance of having a negative effect instead of positive. It usually relates to ROS levels. Adequate levels of ROS are important for cancer cell homeostasis involved in the development of cellular processes such as proliferation, differentiation, migration, and cell death. In contrast, high levels of ROS are harmful to cancer cells and ultimately lead to cell death. This article gets into the nitty gritty:
"Roles of Reactive Oxygen Species in Biological Behaviors of Prostate Cancer"
ncbi.nlm.nih.gov/pmc/articl...
There's also implications of drugs affecting the Adrogen Receptors.
So on many substances, the question of what's the right dosage has never really been answered? Or more importantly, how wide is the "safe" dose range may be unknown? Patients have to try to make semi-informed guesses based on not a very large body of evidence especially long-term.
There's quite a lot of substances discussed on this forum. Probably 7 of the top 12 or so are statins, metformin, sulforaphane, melatonin, lycopene, modified citrus pectin, vitamin E, and vitamin D.
But which of these carries the least risk of being counterproductive in the most common dosage range based on the limited knowledge we have to date on them?
Based on reading and discussions, it seems statins, Metformin, and vitamin D all have a low chance of being counter-productive? Whereas there's a body of evidence Vitamin E in all sorts of cancers can be counterproductive if I recall.
Is Melatonin a good example of one that too much, too early (or too late) could be counterproductive since it can be anti-ROS up to a point then pro-ROS?
Do some substances, pre-CRPC, accelerate time to CRPC instead of slow it?
What other supplements do people consider based on the latest information they've gathered and/or personal experience (or advice from their MO) as having a low-risk of being potentially counterproductive and/or not just a plain waste of money (excluding in the context of actively receiving chemo or radiotherapy?)
Personally, I can only come up with statins, Vitamin D, and high-quality sulforaphane supplements. The question also arises, does synergy of adding other substances raise or lower the risk of negative versus positive effects? Seems plausible combining too many things that raise or lower ROS? I guess no one really knows but interested in other's current opinions.