New Era Comb K contains kali sulph, nat mur and silica. Silica is the best known tissue salt for brittle nails and lacklustre hair, nat mur is traditionally linked with fluid balance in the scalp and skin, and kali sulph is commonly used where skin and scalp renewal seem sluggish.
That makes New Era Comb K a hair-and-nails formula. It is usually chosen when nails split easily or hair seems dull, dry or lacking strength. Biotin is especially relevant here because biotin contributes to the maintenance of normal hair and normal skin.
Silica and biotin are the headline ingredients most buyers will recognise, but the tissue salt pairing matters too. Nat mur and kali sulph are often used in scalp and skin support, which helps explain why this product is aimed at both hair and nails rather than nails alone.