Semax is a heptapeptide that is considered to be an analog of the N-terminal fragment of adrenocorticotropin that has been shown to have various neuroprotective effects examined through several animal-based studies.
A study conducted by Levitskaya et. Al examined the effects Semax has on dopaminergic systems in the brain. White rats were given the neurotoxin MPTP in order to induce lesions on the dopaminergic centers. MPTP was given to the rats in 25 mg/kg doses and was shown to cause an increase in anxiety and a decrease in activity in the rats. Following the administration of the neurotoxin MPTP, the rats were given Semax intranasally at doses of 0.2 mg/kg. The study concluded that this dose of Semax greatly reduced the effects of the lesions caused by the neurotoxin. Overall, Semax acted in a protective manner against the lesions in the dopaminergic centers of the brain (https://link.springer.com/article/10.1023/B:NEAB.0000018752.59465.28).