do whatever you want, but some advice - don't get sucked into debating yet another person with zero references or personal experience, especially over someone else's theory. "my presentation of what my infallible expert said to discredit someone else's infallible expert"
it would be different if Rassman was presenting his clinical experience personally.
it is not clear what a one off vasoconstriction would do.
Hair Loss and Scalp Cooling (mascc.org)
Chemotherapy-induced hair loss is a common and distressing side effect of cancer therapy and presents a major supportive care challenge. Scalp cooling has been shown to be effective for preventing hair loss for many patients. Although the mechanism for its effect is not certain, it is hypothesized that cooling of the scalp causes cutaneous vasoconstriction, which reduces blood flow to the hair follicles thereby as well as the uptake of chemotherapeutic agents.
ongoing vasoconstriction might be detrimental
Subcutaneous blood flow in early male pattern baldness - PubMed (nih.gov)
A reduced nutritive blood flow to the hair follicles might be a significant event in the pathogenesis of early male pattern baldness.
I've experimented/ing with nitrites/trates and PDE5 inhibitors, until i get full coverage band boy hair, i'm not claiming how or if anything works...
but i'm open to novel approaches if op has something coherent to share...