Tryptophan has been legal OTC for a long time now, Gym. And it was always available by prescription -- it was only prohibited for OTC use because of one tainted batch. But you can buy it in any supplement store now. However, tryptophan doesn't pass the blood brain barrier very well, and it's very likely most of it will end up increasing serotonin in the stomach or blood vessels rather than the brain. 5-HTP, a metabolite of tryptophan, is much more likely to pass that barrier and get to the brain. However, it will only increase serotonin if your body deems itself deficient in serotonin; otherwise, it'll just pass right back out. I also don't think serotonin will do anything about your thyroid or adrenal diseases. It might make you feel better, which is great, but serotonin isn't involved with those glands. I don't know if you're hyper or hypo thyroid, or if you have an autoimmune disease, or what your problems are with your adrenals, too low or too high, or what meds you're on. There are natural means of getting at these directly. I also don't know if your depression has anything to do with those problems or is separate from them. I would suggest you see a naturopath or a psychiatrist who practices integrated medicine who can help you navigate the difficult interactions of diet, meds, herbs, amino acids, etc.
Taking L-tryptophan is a great way to naturally increase your body’s production of serotonin. It’s an essential amino acid that is a precursor of serotonin. Although
L-tryptophan is perfectly safe, it has become wrapped up in so much red tape that you won’t be able to get a prescription for it. There are several food sources of L-tryptophan that you should incorporate into your diet: raw milk, sunflower seeds, bananas, turkey, nuts, and corn. You may also want to try ordering it from BIOS Biochemicals,
an on-line source that doesn’t require a prescription. Take 500 mg a day in divided doses.
I have thyroid and adrenal disease and thought this might help with those as well.