The paper presents a novel constrained constant modulus (CMA) approach for the blind suppression of multiuser interference in multi-carrier code division multiple access (MC-CDMA) systems. In this paper, we put forward a novel receiver, which combines CMA blind adaptive multiuser detection with Invasive weed optimization (IWO) for MC-CDMA interference suppression over multipath fading channel. To work around potentially computational intractability, the proposed scheme exploits heuristics in consideration of both global and local exploration the step size of the CMA. The computer simulation results show that compared with the various CMA developed previously, the proposed IWO method obtains the most desirable bit error rate performance with low computational complexity.