Yes you can regain the muscle mass, i mean if body builders can gain more muscle mass through the use of amino acids, why shouldn't we ?
Amino acid supplementation is best, especially L-Glutamine. It also helps restore intestinal health. www.ncbi.nlm.nih.gov/pubmed/25811544www.livestrong.com/article/542549-what-does-l-glutamine-do-in-the-body/
I use a powder supplement from the German clinic, it contains
It is awesome, also tastes good. I used to take it with almond milk but recently because my stomach is much better i switched to organic cow milk (or goat milk when i can find it).
Buhner also recommends L-arginine 5000 mg daily in divided doses (don't use it if you have active herpes, chicken pox, or shingles) - it's on the front page on his website buhnerhealinglyme.com
But you need large amounts, several grams per day. 500mg a day will maybe help your intestines but not build muscle... When you take several grams, it is usually a good idea to take it with food. If you take small amunts 500-1000mgr you can take on empty stomach.