1. Cotton Fabric: The lining of the shirt is often made from a lightweight cotton fabric, matching the main fabric of the shirt for consistency and comfort.

2. Reinforcement: This cotton lining serves to reinforce the collar and cuffs, providing structure and durability to these areas that undergo frequent wear and tear.

3. Breathability: Cotton is a breathable material, allowing air to circulate and preventing overheating, ensuring comfort even during extended wear.

4. Softness: The cotton lining enhances comfort by providing a soft touch against the skin, reducing irritation or discomfort around the neck and wrists.

5. Moisture Absorption: Cotton has excellent moisture-wicking properties, helping to absorb sweat and moisture, keeping you feeling fresh and dry throughout the day.

6. Subtle Detailing: While primarily functional, the cotton lining may also feature subtle detailing or a contrasting color, adding a touch of sophistication when visible at the collar or cuffs.

Overall, the cotton lining of an M&S Mens Formal Full-Sleeved Shirt contributes to both the comfort and durability of the garment, ensuring a polished appearance and ease of wear for formal occasions.