noun
desiccant; moisture absorbent
A substance or product used to absorb moisture from the air, often placed in packaging, closets, or rooms to prevent humidity damage.
この調湿剤は押し入れの湿気を取ってくれます。
This moisture absorbent removes humidity from the closet.
食品の包装に調湿剤が入っている。
A desiccant is included in the food packaging.
除湿剤 is a more common word for household dehumidifying products, often referring to disposable moisture absorbers. 調湿剤 can imply a reusable or regulating function.
Compound of 調湿 (humidity control) and 剤 (agent, preparation).