The kinetic properties of aqueous solutions of CTAB with pentanol and KBr are studied with a T-jump device. The transition range from spherical to cylindrical micelles is determined with a microcalorimeter, and the semidilute range with an Oswald viscometer. The kinetic results show that, for elongated micelles, the value of the relaxation time decreases when the salt or pentanol concentration increases. This variation indicates that the decrease of the potential barrier is larger than the increase of the endcap energy. The observed variation of the potential barrier with salt concentration obeys a scale law, as expected by the DLVO theory. Its variation with pentanol obeys to a linear law. At the transition from spherical to cylindrical micelles the variation of the relaxation time is essentially controlled by the growth in the width of the length distribution.