Silk is naturally temperature-regulating and low-friction, which is why many people choose it for both cooling comfort and hair/skin benefits. It feels cool quickly but performance varies by momme weight and weave quality.
For pillowcases, 22-momme is the mainstream benchmark, while 25-momme is thicker and often more durable. Compare Slip Pure Silk Pillowcase, Blissy Silk Pillowcase, and Fishers Finery 25-Momme Silk Pillowcase.
Silk is not always the best value for strong night-sweat management, so also review moisture-wicking fundamentals, bamboo alternatives, best cooling pillows and pillowcases, and choosing a cooling pillow setup.
If you buy silk, follow washing cooling bedding carefully to avoid finish damage and loss of smooth hand feel.