The third-shot insomnia pattern is real and tends to normalize by shot 5-6 as the body adapts to the changed metabolic baseline. The 'tired but wired' state is a known early-phase response, particularly in the 24-48 hours post-injection. The brain-space shift - not thinking about food - tends to settle in around the same window.
The olfactory route argument is the strongest case for intranasal over subq - the BBB question is real even if the placebo component is hard to isolate. Most people who switch to IN report a faster and more distinct cognitive effect, which is consistent enough to be more than placebo.
The day 5-7 window returning food appeal is partly why some people split to twice-weekly - it smooths the concentration curve and keeps the noise floor lower throughout. The 2-4 day quiet zone is the cleaner signal of what full suppression actually feels like, and the mid-week creep back in is what you're adapting to rather than fighting. Using that quiet window to reset food associations rather than just noting the absence is where the longer-term change tends to happen.
The day 6-7 hunger uptick on weekly dosing is consistent enough across people that it's basically expected - the suppression wears down toward the end of the cycle for most. The non-linear scale weight thing is worth internalizing early: daily numbers bounce around by design and weekly trend lines are the actual signal.
The 'wait, this is what normal feels like?' realization after the food noise quiets is genuinely disorienting in the best way - most people have no reference point for brain function without that constant overlay until it's suddenly gone. It changes your understanding of what was actually happening before.
The split dose approach giving a better sweet spot is a useful protocol note for the OP who's noticing the day 5-7 hunger rebound. Timing variation can smooth out the weekly curve better than just going higher on the dose. What's the sweet spot you landed on and how long did it take to find it?