Are silk thermals good?
Silk is very fine because it feels smooth on the skin and so this can work really well as a base layer especially between clothing heavier (and scratchier) clothing.
Silk is ideal for winter to combat the dangers of cold dry air. As a base layer, silk worn directly against the skin creates a near-frictionless shield. This initial layer of fabric provides a hypo-allergenic barrier against the cold and your other clothing.
The texture of silk allows it to glide over the skin rather than drag across like many other fabrics tend to do. Wearing a layer of silk is highly recommended for people who suffer from skin conditions such as eczema.