diff --git a/postprocessor.py b/postprocessor.py
index e6a986d..3f15ad3 100644
--- a/postprocessor.py
+++ b/postprocessor.py
@@ -926,7 +926,7 @@ class PostProcessor(HDF5Container):
         mask_fit = (
             (centers > self.pp_params.pdf.xmin_fit)
             & (centers < self.pp_params.pdf.xmax_fit)
-            & (values > 0)
+            & (values > self.pp_params.pdf.fit_cut * np.max(values))
         )
         (slope, origin, correlation, _, stderr) = linregress(
             centers[mask_fit], np.log10(values[mask_fit])