I've been studying Metformin (not Berberine, yet). My conclusion reading all the latest studies, especially the large meta-studies, is that evidence is weak on Metformin having a significant positive effect BY ITSELF.
There appears to be significant evidence it has a positive effect when used synergistically.
1. Time to biochemical recurrence or distant metastases appears to be lengthened when combined with a statin.
ncbi.nlm.nih.gov/pmc/articl....
pubmed.ncbi.nlm.nih.gov/320...
....on and on if you search around.
2. It definitely appears to mitigate the metabolic syndrome side effect of ADT. Seems like taking it during ADT is a no brainer?
3. Definitely appears to have a radiosensitizing effect during radiotherapy. Has anyone only used Metformin during RT to avoid ADT side effects or is the benefit of taking both together higher enough to really want to do both during RT?
The downside of it is that it is counter productive to the health benefits in general you get from exercise. Although that appears to be at a doses of => 1,700 mg a day. You can always go off it around the time you do exercise if you aren't diabetic.
pubmed.ncbi.nlm.nih.gov/315...
I'm wondering if maybe a low dose, like 500mg a day (2X 250 or 500 extended release) on an indefinite basis has only the potential to help. Or would that dose be too low to make any significant difference (in someone that is non-diabetic?)
I know with Metformin you probably want to occasionally take a B12 supplement for good measure.
What's the skinny on Berberine? What's the downside?