Reap what you sow. Butter London’s nail fertilizer harnesses Horsetail, a powerful herb rich in nutrients, high in silica, and proven to grow nails. Results so effective, you will use it as your base coat too. This nail rejuvenator is one of our ALL TIME favourite products! This product is 3 Free, and when used properly, the results are really quite staggering! Apply one coat every day for 7 days, then remove and begin again. Use for one month.