Hi Aunt bean,
Of course I am a Parkinson’s patient.
I made fava bean tincture from beans but instead of putting them in the dark as I read later. I placed them in a clear jar and on the kitchen counter in the light (shady place) in sunny California.
Is the tincture still good or is the L-Dopa killed with light?
Tinctures always have better shelf life if kept away from light exposure. If you have started to use it and it was working , but losing it’s effect from being in the light awhile…you will know the l-dopa has been diminished. It would not make the tincture harmful, just less effective. You can not say the l-dopa would be killed since it is not a living substance, just an extract form a bean.
Next time do keep the extract inside a dark place while shaking for a month and place in a amber or dark blue bottle in a dark place for storage…or place a clear jar in a paper bag in the dark for storage. Hope this clarifies your question…