diff --git a/frb/scripts/pzdm_mag.py b/frb/scripts/pzdm_mag.py
index 41fd322e..7b332779 100644
--- a/frb/scripts/pzdm_mag.py
+++ b/frb/scripts/pzdm_mag.py
@@ -114,7 +114,8 @@ def main(pargs):
     # Load f_mL
     f_mL = frb_gal_u.load_f_mL()
     # m_r(L*)
-    m_r_Lstar_min = float(f_mL(z_min))
+    z_min_capped = max([z_min,0.02])  # Capped at 0.02
+    m_r_Lstar_min = float(f_mL(z_min_capped))
     m_r_Lstar_max = float(f_mL(z_max))
 
     frac_Lstar_min = 10**(-0.4*(mag_corr-m_r_Lstar_min))