This article is a bit old (like the other comment about missing year tag says). I think there's newer news that AKG, an easy to get and cheap supplement, has anti-aging effects with no known issues. https://www.science.org/content/article/bodybuilding-supplem...
The actual paper is here [1]. And it’s not quite as conclusive in mammals yet. But it sounds like there is a clinical trial to actually study the supplement, which is a welcome thing in the anti-aging world. I’m happy to read that this work came out of the Buck Institute in Novato, which is a solid research institution. It’s also a beautiful campus. Disclaimer: I was there for a short stint as a postdoc a while back…
But there is no citation for this statement. Any idea where to read about how these levels change naturally?