LCF is supposed to help you build new mitochondria and restore the mitochondria you already have (see
@Deltrus post above). So maybe if you don't have mitochondrial problems it won't help you. Not sure, just thinking out loud about why someone might not get a reaction from it.
But I can say beyond a doubt that it really helped me with exertion tolerance and exercise tolerance, after I was able to get stabilized with it. The sides (overstimulation, anxiety, insomnia, etc.) were kind of hard to get through but after stopping and starting a few times over the course of about half a year or more I was able to tolerate it.
ALCAR never did anything for me until I'd been on Freddd's protocol for a while. Now it seems to kind of overstimulate me, but I have some choline/liver problems and it's supposed to work more on the neurological/nervous system. That's all related. IIRC ALCAR can pass the blood-brain barrier, whereas LCF does not do that.
@Gretel: I'm a Freddd's protocol success story, and consider LCF a foundation of my recovery. I plan never to be without it. I take 1000mg/day, every day. I tend not to stop things that I know work for me, but rather add new things I think might help on top of them. FMN/B2 has been a help, as well.
I experienced a "classic" Freddd recovery following the protocol pretty much as he laid out (upping folate doses when adverse symptoms appeared, adding in co-factors when symptoms dictated, etc.). I also had some old symptoms return before I got entirely stabilized on Freddd's protocol, including gastric/gut issues (still ongoing, although better with the addition of gut therapeutics), some immune issues (mostly eczema, resolved) and some unwanted behavioral/psych issues (thankfully also resolved).
I highly recommend LCF, within the caveat of understanding the sides might be more than some people can tolerate, even with very low and slow titration. It's quite a powerful substance. But if you've already had a positive response from it, even a little one, I'm confident in speculating that it might work well for you, especially if you can find the right approach for using it. For whatever that's worth. Good luck!