I’ve just started taking LDN this week. I keep reading about increasing gradually until you find your sweet spot.
How do I know what that is?
Will I get bad symptoms if I go above my omptimal level?
If eg your thyroid isn’t drastically bad, does that mean you’ll likely need less?
If you have theee autoimmune diseases, does that mean you’ll likely need more?
Thank you so much, any help much appreciated.
The answer to your main question is different for each of us. The general rule is to increase slowly (I usually recommend 4-6 weeks at each dose level), then stay at the one that you did the best. If you go above the "sweet spot" you will most likely not feel as good as you did on a lower dose. Some people struggle with each raise in dose for up to a week, others don't, hence the advise of 4-6 weeks.
Using myself as an example, 4.5 works great for pain, not so good for my depression & anxiety. 3 mg gives me good pain relief, still not good for the other stuff. 2.25 is okay for pain relief and doesn't spike depression or anxiety. I deal with Fibromyalgia, arthritis, gout, bursitis, TMJ, IBS, depression & anxiety and low performing thyroid. All my issues except the bursitis are better. This took me several years to figure out, with the help of my doctor (who thought 4.5mg was the best dose, it took some educating).
Thyroid...most likely you will have to adjust meds if you take them. You should stay in contact with your doctor, especially in the first months. It's not unusual for LDN to first help the Thyroid issues. However, the severity of your issue doesn't always relate to the amount of LDN that helps. Caution, (if I hadn't said this to you yet) those with Thyroid issues do much better overall if they start low - 1mg to 1.5 mg.
Having more than one autoimmune diseases doesn't mean you'll have to take more LDN, it could mean it will take longer for some issues to benefit. Patience will be key 
Michelle
Thank you very much Michelle. I do have thyroid issues and read to start at 1mg, which fortunately I did.
I also have my GP monitoring my thyroid bloods. He suggested every 4 weeks, does this sound about right please?
I don’t know whether it’s coincidence, but I have felt amazing from day 1 on LDN. It’s only been a week, but I’ve slept better, had energy and all my brain fog has gone! I haven’t felt this good in over a decade. I’m hoping it is LDN that’s working already. Wish I’d found it sooner!
It's great to hear you're getting benefits so soon. Yes, some patients do respond that fast!
Your doctor sounds wonderful, testing at a month is a good idea. However, if you find yourself having Thyroid symptoms (racing pulse, fast heartbeat, etc) call him up and let them know. He may reduce your Thyroid meds or do testing at that point.
Michelle
LDN and thyroid 
ldn
LDN and insomnia 
Taking Tramadol with LDN for ME/ CFS and Fibromyalgia.