noun
hair growth formula; hair growth agent
A product or preparation intended to stimulate hair growth, often used in medical or cosmetic contexts.
新しい発毛剤を試してみることにした。
I decided to try a new hair growth formula.
この発毛剤は医師の処方が必要です。
This hair growth agent requires a doctor's prescription.
Compound of 発毛 (hatsumou, 'hair growth') + 剤 (zai, 'agent, preparation').