Stay warm with slim and supportive women's thermal underwear. These styles are designed to trap heat and keep you cosy. Opt for breathable materials like natural silk, or choose technical fabrics with a stretchy fit for snugness. Smooth options will sit neatly under other layers. Pick from practical designs in neutral and dark tones, such as long-sleeved tops for cold seasons or a camisole when there's a nip in the air.