Melanin transfer in the epidermis: the pursuit of skin pigmentation control mechanisms
BPC-157 accelerates the healing of injured ligaments and tendons in animal models by promoting fibroblast migration and angiogenesis. Sikiric et al., Pharmacological Research 2
fat oxidation and body composition optimization
Studies show that supplemental melatonin changes the composition of the gut microbiome, reduces weight, decreases fatty liver, and decreases low-grade inflammation.[ref] Another animal study showed that melatonin not only changes the gut microbiome but also improves the intestinal barrier and increases gastrointestinal motility.[ref] Viral and parasitic infections: Cardiomyopathy, caused by a viral infection (Coxsackievirus B3), is prevented by supplemental melatonin.[ref] Quite a few parasitic infections show improvement with melatonin including malaria, toxoplasmosis, and trypanosomiasis.[ref] Pretreatment with melatonin decreases the damage to the lungs in RSV infection.[ref] Melatonin may even help with the Ebola virus.[ref] Migraines: A randomized placebo-controlled trial showed that melatonin (3mg/night) for 12 weeks was superior to placebo for migraine prevention

They are often discussed in nootropic and biohacking communities for goals such as focus, memory, mood, sleep, stress resilience, neuroprotection, and brain repair
Where can researchers find high-quality GHK-Cu for their studies