This site states this specific window directly across several sections: the brand frames 30-90 days, not an overnight change.
Rather than a vague "give it time" instruction, this site names a specific range — worth planning your own evaluation, and your reorder timing, around that stated window rather than judging within the first few days.
Since this site's own corrected math puts a single bottle at 15 actual days, worth planning bottle count around both the corrected supply figures and this 30-90 day evaluation window together.