I started this thread thinking that we might benefit from an idea used in Rytary: using tartaric acid to increase the absorption of levodopa. But, while doing due diligence, I came across reports in this forum of problems with tartaric acid. So, perhaps for some people, this explains why they do badly on Rytary.

Rytary contains four components: one immediate release levodopa/carbidopa, two extended release levodopa/carbidopa, while according to Mittur et al. [1]:

"the fourth component does not contain levodopa or carbidopa but includes tartaric acid as a functional excipient serving as an acidifying agent designed to facilitate the absorption of levodopa".

This seems to run counter to the experience of Deangreen [2] on this forum:

"About 2 weeks ago I consumed a few glasses of tamarind juice and the next morning had the worst case of PD symptoms in 7 years, ... So, my question is if there are certain foods that can "assault the brain" and the PD progresses as we get older and that we cannot repair the damage (heal) like we used to. Tamarinds are very high in tartaric acid."

And in the same thread Niggs writes [2]:

"I've recently started drinking copious amounts of hibiscus tea, just because I like it and need to up my fluid intake. I've not had a dramatic crash as you describe but have certainly noticed a decline in the effectiveness of the meds and had started to wonder about it's contents.....15-30% citric,malic and tartaric acid."

Lurkingforacure writes [3]:

"tartaric acid....this blocks a cell's ability to use glucose normally and forces the cell to anaerobically produce energy. Energy created in this bad way is 20% as much as the cell could normally produce if tartaric acid were not blocking function".

References:

[1] "Pharmacokinetics of Rytary, An Extended-Release Capsule Formulation of Carbidopa-Levodopa"
Aravind Mittur, Suneel Gupta, Nishit B. Modi
Clinical Pharmacokinetics, Feb 2017
Pharmacokinetics of Rytary(R), An Extended-Release Capsule Formulation of Carbidopa–Levodopa | SpringerLink

[2] 2016
Foods that aggravate symptoms...tamarind

[3] 2014
How can we identify the cause?

John

it might be a slow release and fast release tartaric acid?