Plant hormones of the auxin class are hypothesized to be evolved as chemical signals of decay that plants started using as root development hormone. When tryptophan decays losing the amino group it goes into auxin. When it decays losing it's acid group it becomes tryptamine. Tryptamine only needs hydroxylation to become serotonin, so a free radical is enough.

https://www.youtube.com/watch?v=_wY1sDHFpcI

This would mean that one of the most common decay products of an amino acid when combined with an environment of ROS has evolved as the stress adaptation signal in animals. Even fungus actively avoids serotonin, even when they use it internally in manufacturing a stress adaptation (anti-ROS) compound, melatonin. But it's never free, only an intermediate step in the machinery.

For those that have been on T3 without prescriptions for a while or done so in the past, how long have you been on it and what's the quality, effectiveness and reliability of the T3 that you source online? I have poor conversion issues and plan on going on external T3 for a year or so to keep T3 in the high end of range constantly and try to fix the persistent metabolic issues I sustained after a diet many years ago. I will go to the doctors again and try to get it with a prescription but since it's difficult to get it prescribed if you're in range (albeit not close to optimal) I'll absolutely try and get it online as well. I want to get people's experiences that have done this long term and if it has been reliable for you for months/years or if there are quality or delivery issues etc.? Also how much T3 a day do you take to keep T3 at the higher end of the range? I plan on building up to 50mcg a day.

How could i M18 benefit from it . I read that it is beneficial for testosterone and a precursor to it but i also read some bad things about it. I am mainly asking for gym progress and sleep maybe idk.

How does one measure one’s own serotonin levels?