New Era No.11 Nat Sulph contains sodium sulphate as its single tissue salt, with biotin and lactose. In tissue salt use, nat sulph is traditionally linked with fluid balance, bilious digestion and sluggish, heavy states that can affect the digestive system or the body more generally.
That makes New Era No.11 Nat Sulph a more specific product than its name first suggests. It is often chosen when there is a tendency toward water retention, heaviness after rich foods, or a damp, sluggish state. Biotin is the added nutrient, but sodium sulphate is the main reason to choose this product.
Nat sulph is also one of the tissue salts traditionally used when symptoms seem worse in damp weather or after rich meals. If that pattern matters to you, it is a useful detail to know before buying.