Norditropin simplexx 45iu contains a biosynthetic human growth hormone called somatropin which is identical to the growth hormone produced naturally in the body. Children need growth hormone to help them grow, but adults also need it for their general health. Norditropin simplexx 45iu comes as a solution in a cartridge ready for you to inject after you have put it in the matching NordiPen® injection pen.