Disclaimer: If you try to do this for yourself, I won't take any responsibility at all. I'm not a doctor and can't give trustworthy medical advice to anyone. It worked for me but I can't tell by any chance is it going to work for you as well.
Background: Dimethyl fumarate was used as psoriasis treatment for over 40 years in Germany and Netherlands and had been proven as clinically safe (with some precaution measures). Around 2006 it was noticed that patients who had MS alongside with psoriasis have huge MS benefits as well while taking DMF. Same year, clinical trials for MS started in USA, patents were granted by 2008, and DMF became available as MS treatment, but at 36.000$ price tag due to patent which expires in 2028.
Reality: All you need to produce DIY analogue of this medicaton is lab-grade DMF and empty gastro-resistant capsules, size 1. Dosage should be ~250mg/pill and that's pretty much done by filling size 1 capsuless full. Exact dosage isn't a big deal. Other ingredients present in market pills (talcum, crystalline celulose etc) are fillers and aren't mandatory, however they can be added if one wants. Original info came from this guy, dr Juergen Erhardt, who practically saved my life:
Effects: Noone knows all mechanisms exactly but one of the basic ones is lowering your lymphocyte counts, that is, selective immunosupression. Also, prevents oxidative nerve damage to some extent.
Applicable for: Relapsing-Remiting MS (RRMS). Don't try for other MS types, ever.
Dosage: 250mg pill, twice a day, after a meal.
Interactions with food, drinks: None.
Interactions with medications: Don't combine with any other immunosupressant drugs. You can destroy your immunity if you do so.
Safety: Control your blood counts, liver and kidney function monthly and reduce dosage or discontinue treatment if lymphocyte count goes below 0.5 billion/liter or if there are signs of kidney or liver disfunction. Chances for all these issues are very low, 1-2%.
Common side effects: Gastric issues in first month of treatment (they cease afterwards, dairy products help alleviate those), ocassional skin flushing after taking medication (harmless and short lasting). That's it. Impressive, isn't it? :D
My case: Here's my blog, it's in Serbian but Google translate will do.