diff --git a/src/cosmopower.cpp b/src/cosmopower.cpp
index a7a90fb..620b61a 100644
--- a/src/cosmopower.cpp
+++ b/src/cosmopower.cpp
@@ -90,7 +90,7 @@ static double powC(double q, double alpha_c)
 
 static double T_tilde_0(double q, double alpha_c, double beta_c)
 {
-  static const double c_E = 2.718282; //M_E;
+  static const double c_E = M_E;
   double a = log(c_E + 1.8 * beta_c * q);
   return a / ( a  + powC(q, alpha_c) * q * q);
 }