somewhat similar to an aging theory is "bioidenticalism" where if you cause a system to be identical to a younger version, the person is as well as feels younger.
I read about research where the measured the reactivity to dopamine as well as serotonin amongst the brains of tweens to teens to twentysomethings. apparently the young teenagers had greater sensitivity to dopamine, oxytocin, as well as serotonin, thus their sensitivity, rather than the amount, was then described as being linked to teenage values, which were described as ease of emotional affiliation as well as a higher preference at taking risks. Now having actually tried being a teenager I think theres more to the teenage mind than that. The study did present the opportunity of upregulating the responsiveness to neurotransmitters rather than the amount of the actual neurotransmitters to duplicate young mind.
Thus a person could measure their receptor affinities at various ages, then use some drug or activity, or genetics to duplicate their receptors responsiveness to recreate young mind.
Note how different this is than simply upping the amount of an activating chemical.
ever so slightly amusingly, pre teens or teens could try an "adult receptor activation profile" drug to see if growing up was right for them. (results may vary, ask a physician if aging is right for you, side effects may include sudden death)