If your doctor looks at the clinical studies, he/she should be able to derive enough info from those, or else by contacting Dr Jill Smith at Penn State. If your doctor agrees to try you on Naltrexone, but at a lower dose than those used in the trials, demand the 4.5 mg. I don't know why, or how, the researchers behind it derived that 'magical' number, but they did. From my crude understanding of how it works, 4.5 mg triggers a rebound effect. If you opt for less, then you can probably anticipate minimal or no rebound effect. Likewise, if you took 50mg Naltrexone, it would prevent any rebound from taking place. I've heard of people (either their idea or their doctors) opting for lower doses... 3.0 mg and 1.5mg. I've never heard of any studies using those dosages, or of any one having success at those dosages. If one is fearful of some reaction... well, an allergic reaction should occur just as easily at 1.5, 3.0 or 4.5 mg... As for a toxic reaction, that should occur sooner at a higher dose... thus the earlier warned, the less potential for any long term issues. This is just guesswork on my part, I have no medical training to back it up... but I've experienced both allergic and toxic reactions, (not from LDN ever), and this was how they occured. Just in case you face opposition to the standard 4.5 mg dose. I mean, if you can get LDN, I'm sure you want to have the very best shot at making it work for you, right? Once you have the prescription, then find a pharmacy that is familiar with compounding it. If they have that experience, then you've really nothing to worry about regarding capsule type or filler (unless you are sensitive to certain things... like lactose to name one). All the best.