As many of you are aware the BCAA compete for transport into the brain (and other cells maybe??) with tryptophan, tyrosine, and phenylalanine. So, if you raise the ratio of BCAA to the other acids less tryptophan will get into the brain/cells and thus less serotonin will be produced. There have been many studies testing this idea and at this point it has been pretty well established that it works.
The problem with this approach is that BCAAs will also deplete tyrosine, which is the amino acid from which dopamine is synthesized. So, the question scientists have been trying to answer is whether BCAA can be used to deplete serotonin only but leave dopamine unchanged. The reason for these tests is that in theory reducing serotonin and raising dopamine will have a positive effect on physical (and maybe) performance.
So, the attached study recently came out and it confirmed that one can reduce serotonin BUT keep dopamine intact (maybe even increase it a little) by ingesting a BCAA combo in the dosage 19mg/kg:12mg/kg:12mg/kg (leucine:isoleucine:valine) AND adding tyrosine at the dosage of 14mg/kg. To me this amounts to about taking 3500mg of BCAA and 1500mg tyrosine (Dinkov, 2020).
Remember these rules:
Low Dopamine = Low Libido.
Low Serotonin = High Libido.
High Dopamine = High Libido.
High Serotonin = Low Libido.
To ramp up Dopamine production, checkout this drug from Russia:
https://www.ergogenichealth.com.au/product/bromantane

For more neurotransmitter hacks - Checkout this FREE sleep masterclass:
https://www.ergogenichealth.com.au/masterclass/sleep