The runner's high is largely endocannabinoid, not endorphin

For decades the post-run euphoria was blamed on endorphins — but endorphins barely cross the blood-brain barrier. Animal and human studies point instead to anandamide surging after sustained exercise. Your ECS, the same system THC hijacks, is the body's own reward for endurance.

What "moderate evidence" means here:
Consistent human data with real limitations — direction is clear, magnitude is not.