Comment · Tue, December 12, 2017
5-HTP does or doesn't cross the blood barrier effectively?
Original post in this thread
gruberexn · 16 points
I was having this argument with a friend where I would quote the MDMA Supplementation Guide that says the following statement:
5-HTP can pass your blood brain barrier, while 5-HT cannot. This means that when you supplement 5-HTP, you want to make sure it gets converted to 5-HT in your brain and not your periphery. The enzyme that converts 5-HTP to 5-HT is aromatic L-amino acid decarboxylase.
But, researching further, I found this paper:
5-HTP efficacy and contraindications
Which states the following:
* In central nervous system disease states associated with synaptic serotonin dysfunction, synaptic serotonin levels in the brain must be increased to induce optimal outcomes.
Serotonin does not cross the blood–brain barrier.
* 5-HTP freely crosses the blood–brain barrier.
* 5-HTP is freely converted to serotonin without biochemical feedback inhibition.
* When infinitely high amounts of 5-HTP are administered, it is theoretically possible to achieve infinitely high levels of serotonin. One limiting factor is the availability of the enzyme…
What they were answering
Direct reply to the original post — see the thread post above.
u/MisterYouAreSoDumb
5-HTP passes the blood brain barrier just fine. However, you also have a ton of aromatic L-amino acid decarboxylase enzyme in your periphery. That converts 5-HTP to serotonin. Too much serotonin in your periphery is bad, as it causes stomach problems and is correlated with increased risk of heart problems. You're also wasting the 5-HTP for what you are using it for. Remember, peripheral serotonin cannot pass the BBB. You want 5-HTP to pass the BBB THEN convert to serotonin. So taking EGCG is meant to inhibit aromatic L-amino acid decarboxylase in the periphery, allowing the 5-HTP to pass the BBB, then convert to serotonin in the brain.