I haven't evaluated it for synergistic effects, but IIRC Melissa does have some effects on GABA-transaminase inhibition, as well as on neuronal nicotinic ACh receptors.
As for valerian, IMO one would need to use a LOT for an excessive time, to wind up in trouble in terms of GABAa receptors. I find that it produces a natural, although extremely rapid tachyphylaxis. I tend to use it only occasionally, but when I do, a couple of boxes of high dose extract tablets, for its powerful oneirogenic effects. To this effect at least, it becomes near impossible to do so three nights in a row (or days for those who sleep during the daytime usually), night 1-full effects, night/sleep period 2 in a row, very much weakened. Night/sleep cycle 3 in a row, tachyphylaxis to the effect has set in and its almost impossible to push past. Wonderful herb, even if it does smell like somebody soaked a pair of old gym socks in pentanoic and propionic acid then shit out a swallowed vomit smoothie into said old sweaty sock, before farting into it a few times, following through a bit.
I would be somewhat impressed if a man could physically manage to swallow abusive level doses for long at all without coughing up their spleen in a chunky butyric acid flavoured soup afterwards. Valerian stinks like Theresa May's policies, and is about as pleasant as her face is fuck ugly.
For Melissa, its best grown and use fresh picked. I find its lovely used to make a cup of lady grey tea, with a bit of grated lime zest, using a hot infusion made from several handfuls of freshly picked flowering young balm tops, a little splash of lime juice, and used to make the tea, lady grey having a lovely citrusy flavour, and it helps calm the caffeine edge.
I'm not best to evaluate the GABA-T inhibition of balm vodka though, I take chlormethiazole, and sometimes nitrazepam with it, plus opiods, so alcohol has a great deal of potentiation and synergism from the chlormethiazole, its one to be fucking careful with alcohol, especially taking benzos like nitraz.
But I can tell you one thing-It IS fucking tasty stuff, some great quality vodka distilled from the herb, it makes a most admirable liquor, especially with a few drops of diethyl ether equivalent added to a bottle so that much would be in every shot. Distill the vodka from the chopped, bruised balm with a little ether in it, then add a little more EtOEt to the distillate, gives it a lovely sweetness. Some added flavour can be given by adding fresh lime peels, bruised, and a little lemon slice and lime slice during the distillation.
I'd like to experiment more with herb and fruit blends during the distillation stage. Let it sit and stew for several days in the bottle, with the little bit of diethyl ether, THEN distill, after the flavours have all percolated into the vodka, adding a bit more ether for flavour after. Makes it lovely and sweet and aromatic, heady.
GRRR, this fucking cloudflare shite, its making it REALLY difficult to post and especially to PM.