Adrenaline and Caffeine. The worst substances in existence.
Highly deadly and poisonous to literally every life form in existence. No wonder, that hostile forces use it as tipping for their weapons, ammo, knives, etc.
They are feared. They are Powerful.
Until they fight their first human on a spaceship by a raid.
The attackers didn't know that it makes them stronger and near invincible.
The human didn't know, that they mean Add/Caffeine with "deadly poison".
The crew is afraid and doesn't know how to cope with a human, who is (even hours after the encounter) still hyped up and full of caffeine and rest adrenaline.
That day everyone learned something new.
The earliest accepted Humans in the Galactic Alliance were the Britanians. Everyone knows that. However, the earliest known Humans, out on the Edge where all things of dubious legality happen, go much, much further back. Back to the days where Humans would just... randomly turn up, and were far less understood by Alliance citizens. Back to the days when the Gen'rathi terrorised the space lanes.
They were fearsome warriors, the first to weaponise synthetic caffeine and adrenaline together to create a lethal, concentrated poison that could cause a cogniscent's heart to explode in less than half a minute. The colloquial term for it was Three Seconds Left. The Gen'rathi thought they had the ultimate weapon of terror and destruction... until they chanced to stab a Human.
The Human, there to protect the Hemidact crew from dangers untold and hardships unnumbered, pulled the spearpoint out of their arm and, in the same motion, used it to stab the offending attacker. The other three Gen'rathi attempted to slash or stab with their envenomed weapons, but it was already too late. They were so used to merely scratching their prey that creating serious wounds was beyond them, even in the relatively more delicate Hemidacts. Scratching at a Human seemed to be a tremendously bad idea - worse than naming a vessel "Titanic".