December 2015 in “Journal of Neurology and Stroke” A man had a stroke after getting a scalp injection for hair loss.
March 2025 in “Journal of Cosmetic Dermatology” Botulinum toxin type A may widen certain arteries, but more research is needed.
January 2019 in “Headache” Peripheral nerve blocks are a safe and effective way to treat various headaches and provide lasting pain relief.
December 1994 in “The American Journal of Cosmetic Surgery” Understanding the scalp's blood flow and using delay techniques can improve the success of hair restoration surgeries.
The conclusion is that closing scalp wounds is possible, but restoring hair without donor material is still a major challenge.