I recently learned that hydrogen sulfide (H2S) – previously thought to be simply a toxic rotten-egg-smelling gas – is an endogenous redox regulator of the human immune system and mitochondria! Dilek et al. (2020). Hydrogen Sulfide: An endogenous regulator of the immune system.
H2S is a gasotransmitter – a tiny, gaseous molecule that can hold a positive/negative/neutral charge acts as an information carrier within and between cells. The other two known gasotransmitters are nitric oxide (NO, which was a Nobel Prize discovery of 1998) and carbon monoxide (CO).
H2S is used as a metabolic charge carrier for primordial thermophilic bacteria that thrive in oceanic geothermal environments. Apparently this mechanism is all conserved in the eukaryotic cell, which inherited ancient archaebacterial programs through the mitochondrial DNA.
Low plasma H2S levels are strongly correlated with poor outcomes in COVID, hence there is a rationale for replenishment as a therapeutif strategy, e.g. Bourgonje et al. (2021). N-acetylcysteine and Hydrogen Sulfide in Coronavirus Disease 2019.
N-acetylcysteine (NAC) is a sulfur-containing pro-drug of the amino acid cysteine, which gives nutritional precursors for redox metabolism (including H2S, and the master antioxidant, glutathione). Here’s a review on NAC: Schwalfenberg (2021). N-Acetylcysteine: A Review of Clinical Usefulness (an Old Drug with New Tricks).
I believe that many clinical trials are using insufficient amounts, way lower than recommended here: Shi & Puyo (2020). N-Acetylcysteine to Combat COVID-19: An Evidence Review. Another confouding element is that it doesn’t work if given too late in the game. An ounce of prevention… Furthermore, NAC is dirt cheap and not patentable, so funding for trials may be lacking.
Oddly, the FDA has recently attempted to ban NAC for over-the-counter use; even though it has been on the market for decades, they are claiming a loophole that long ago it was once briefly used as a prescription drug. This has resulted in Amazon pulling all products containing NAC, preemptively (Shame on you, Jeff Bezos)! Fortunately, it is available elsewhere, and I have stocked up. Actually, I’ve had NAC in my medicine cabinet for over a decade. I recommend that you might look into doing the same. It breaks up mucus, is good for the lungs, inflammation, and much more.