Improve is a chemical substance that improves a characters strength, HT, Extra Hits, gives him DR and some levels of Density Increase. It is yet not know how it really works on a body because all information about "Improve" where destroyed. It also gives different extends of power on different people. If a person drinks "Improve" it will actually improve him like described above, but the power-levels may differ from other characters who drank it. This is a GM descision.