Is it normal for ADHD meds to reduce appetite only some days?

Yes, this variability is very typical. Stimulant medications can suppress appetite, but the effect is influenced by sleep, stress, hormone cycles, activity level, and dose timing. Some days hunger cues are clearly reduced, and other days they return more normally. This does not mean the medication is inconsistent or failing. It reflects how the nervous system responds differently day to day. Planning nutrition proactively, rather than relying solely on hunger cues, is often helpful.