I think gelatin and aspirin can serve you well. Gelatin I like a lot before going to sleep, you sleep deep, plus it is more balanced than pure glycine, more of a food, less of a supplement
Aspirin has a definite anti-stress effect. The effect is most prominent when you are actually feeling stressed. When I used to get heat waves from cortisol when I was trying to sleep, 500mg aspirin would help drop my (stress) temps so I can actually fall asleep.
Adding glycine is one of the best things one could do for health. And with the right powder you should absolutely feel a calming effect with 1-3 grams.
Besides that it boosts your mood throughout the day, increases mental clarity and decreases water retention. At least that's my experience. I think it's a very powerful anti-cortisol/anti-serotonin substance, and it's natural and therefore safe.
There is a podcast Chris Masterjohn did on Glycine and he believes the best form is from hyrdolized collagen. I have pure glycine, gelatin and collagen but I usually only use the collagen and gelatin. He mentioned pure glycine powder doesn't absorb as good as the other two.