There have been discussions in the forum about Lithium which does seem to have some merit as part of the WNT pathway.
I have just got some test results in.
Earlier this year I started on 1mg Lithium and after a month or so the steady state serum rate was below 50 microMole/Litre. That, however, was below the lower limit of the blood test I was using. Ideally I think it needs to be somewhere around 25-50 mcmol/L. There is not a lot of research on this, but there is some.
I increased it to 5mg and have just got a result of 100 mcmol/L. I will, therefore, be reducing to probably an average of 2.5mg a day.
Obviously not everyone will be affected exactly the same way by Lithium supplementation, but I have not seen any reports as to what dosage results in what serum concentration so thought it would be helpful to post this.
There is more research on the serum levels required for mental health effects
The minimum there is 600 mcmol/L and to get better effects 1,200mcmol/L. However, I would think that at a higher concentration it would be excreted faster as well.
This paper looks at nephrotoxicity
The serum levels there are generallly 600 mcmol/L or higher.
Obviously a question that is important to me is whether there is any sign of nephrotoxicity from lithium. Sadly the only way I can check this is by using the quite variable creatinine figure and I had to move labs between the comparable figures. However, the creatinine figure just before I increased dosage from 1mg to 5mg was 73 mcmol/L and 5 weeks later (the last I have for the year) was 75mcmol/L. From that I cannot say reliably that there was no effect, but I can say there is no substantial effect. I still intend dropping back the dosage, but it is useful to know for me that it does not seem to be doing any harm. That may not apply, of course, for anyone else.
Edit 15/1/23 - I have now redone my Lithium dosage and am taking 5mg 3 times a week. This should average 2 1/7.