Can someone explain how this substance, is well known, used as a biological reagent, has been used in experiments, and there are scientific papers written about it.

If you are a lab you can order it online, from chemical suppliers - it's not that expensive and not that mysterious. I am not saying it might not be used for getting high or rejuvenation or etc. I am not saying that it is not abused - but there are a number of logical conclusions here that do not stack up.

1.) If it's so fantastic, then street dealers and black market narcos would be supplying it - at least the low grade chemical form of it - you would have been offered it in the bathrooms of your local nightclub. Meth cooks and E cooks would be figuring out how to brew it up.

It doesn't make sense that's such a secret and yet also quite commonly known about and available.

2.) Has anyone bothered to order some and try it out ? It is stated to stop capillary decade amongst other things, so it has some rejuvenation properties - ok - here is some factual progress on the topic. It is also stated to stop fatigue and give alot of energy.... I mean rockstars all do coke because jetlagged on date 100 of the world tour - they need to blow the roof off the stadium just the same and WTF else can you do in that situation ? you need a bump - politicians the same...

so if Adrenochrome is the rich man's cocaine - how has it been kept such a big secret ?

https://pubmed.ncbi.nlm.nih.gov/14089791/ https://pubs.acs.org/doi/10.1021/ie500037x https://pubmed.ncbi.nlm.nih.gov/14975514/

there is a list of a dozen or so vendors on this page

https://pubchem.ncbi.nlm.nih.gov/compound/Adrenochrome don't come with speculation that you need "the real thing" or nonsense like - the pure chemical is not the same - in that case there must be other ingredients in fresh blood. i notice this was shut down lately...

https://www.tmc.edu/news/2019/03/fda-cracks-down-on-companies-claiming-young-blood-as-the-fountain-of-youth/