Not what you had in mind, but the only supp I've run across that you have to "cycle" on/off because the body develops tolerance was pramacetam which I took ages ago.
I do not believe there is any feedback inhibition for melatonin. Also, I personally have not experienced any lessening of effects from the 1 mg I've taken on and off, mostly on for years.
What evidence do you have that NAC induces tolerance?
PS You are lucking living in NZ. Great place. Hope the volcanoes stay quiet.
From what I've experienced and understand, with any hormone with which we supplement, this can down-regulate the body's natural production of it.
1. What you read is based on the fact that there are feedback loops so that e.g. if you take certain hormones the body senses that and makes less. As far as I know these feedback loops do not exist for melatonin. Don't believe me, research it for yourself.
NB: melatonin is a hormone, not a man made sleeping pill. Having said that, if it doesn't work for you, don't take it.
2. Re: glutathione:
A. You'll need someone with more biochemistry than I to address feedback and glutathione.
B. From Josh Mitteldorf (Cracking the Aging Code):
https://joshmitteldo...og.com/2017/07/ [scroll down]
title of this blog entry is
Mitochondria in Aging, II: Remedies
Gutathione / NAC
I’ve never heard anyone say a bad word about glutathione. It’s the antioxidant with no downside. Genetic modifications that upregulate glutathione have increased lifespan in worms, flies and mice.
For a long while, it has been assumed that you can’t eat glutathione, because it doesn’t survive digestion. Some researchers at Penn State disagree, finding impressive increases in tissue and blood levels when people were supplemented with up to 1 g per day raw glutathione. Liposomal glutathione is an oral delivery form that gets around the digestion problem, especially when taken with methyl donors like SAMe....
For the future, we might hope to do better. Less than 20% of the cell’s glutathione actually makes its way to the mitochondria, where it is most needed.
Edited by Benko, 01 September 2017 - 11:00 PM.