Start with the label. Look for 100 percent silk (or “silk”), and ideally a clear quality or origin note such as mulberry, plus a momme weight, especially if you are buying a silk pillowcase.

Also consider price and feel. Real silk is supple and feels dry smooth and luxurious rather than plastic like. The sheen of silk is usually subtler and deeper than polyester. You can do a simple rub test: silk warms up quickly in your hand and typically does not feel static.

Be cautious with burn tests. They are risky and can damage the product. Buy from reputable sellers, check return policies, and watch out for terms like “silky” or “satin,” which often do not mean real silk.