noun
hair tonic; hair growth tonic
A product applied to the scalp to promote hair growth or prevent hair loss.
彼は毎日養毛剤を使っている。
He uses hair tonic every day.
育毛剤 is a more common term for hair growth products, while 養毛剤 is a less frequent synonym often used in product names.
Compound of 養 (nourish), 毛 (hair), and 剤 (preparation, medicine).