辣椒的辣味主要来自辣椒素。

The spiciness of chili peppers mainly comes from ___capsaicin.

这种药膏含有辣椒素，可以有效缓解肌肉疼痛。

This ointment contains ___capsaicin, which can effectively relieve muscle pain.

辣椒中的辣椒素含量越高，吃起来就越辣。

The higher the ___capsaicin content in peppers, the spicier they taste.