This is the closest human-trial evidence anywhere in the class, and it was negative
Galeazzi, G.M
Some research shows that these medications possibly increase the progression of retinopathy or eye problems, while other studies show that they might have a beneficial effect (Dicembrini, 2017)
While combination therapy is theoretically possible, it is unnecessary

Additional Monitoring May Be Considered In Research Models Involving: Significant pigmentation variability or extensive freckling Large numbers of moles or atypical pigmentation-related findings UV-response variability and dermatological sensitivity Cardiovascular or significant cardiometabolic conditions Mood-related, psychiatric, or neuroendocrine conditions Neurological sensitivity or chronic migraines Hormonal or melanocortin-related research models Multiple concurrent melanocortin, neuroregulatory, or stimulant-related compounds Avoid or Carefully Evaluate in Research Models With: Known hypersensitivity to peptide compounds Active melanoma or suspicious pigmentation-related findings Severe uncontrolled cardiovascular disease Severe uncontrolled mood-related, psychiatric, or neurological conditions Active severe systemic illness Pregnancy or breastfeeding contexts Additional Research Considerations Because Melanotan II may influence melanocortin, pigmentation-related, and neuroendocrine signaling pathways, research protocols may warrant monitoring of: Pigmentation and melanogenesis-response variability Pigmentation variability involving freckles, moles, or existing pigmentation UV-response variability and dermatological sensitivity Appetite-, mood-, or neuroregulatory-response patterns Overall individual tolerance and pigmentation-response variability Combination protocols involving melanocortin-related, neuroregulatory, or pigmentation-focused compounds may further influence pigmentation and neuroendocrine response pathways

The only scheduling requirement is consistency in the day of the week