Final answer:
Dehydrated skin lacks water, and while oil or sebum helps in retaining moisture, it is the hydration from water that dehydrated skin needs.
Step-by-step explanation:
Dehydrated skin primarily lacks water. While sebum, which is the oil produced by the sebaceous glands, plays a crucial role in moisturizing the skin and inhibiting water loss, dehydrated skin is specifically in need of hydration or moisture, which refers to water, rather than oils or lipids. The sebaceous glands are associated with hair follicles and secrete sebum, a mixture of lipids that help lubricate and waterproof the skin and hair, thereby preventing excessive water loss and keeping the skin moisturized.
But when the skin lacks water, it becomes dehydrated, often leading to a feeling of tightness and the appearance of dryness. Dehydrated skin lacks water. When the skin does not receive an adequate amount of water, it becomes dry, flaky, and may feel tight or itchy. Drinking enough water and using moisturizers can help hydrate the skin and prevent dehydration.