diff --git a/neutrinos/sneut5.H b/neutrinos/sneut5.H
index 6b066a2895..7fbe0171c9 100644
--- a/neutrinos/sneut5.H
+++ b/neutrinos/sneut5.H
@@ -347,7 +347,7 @@ void sneut5(const Real temp, const Real den,
     t9     = temp * 1.0e-9_rt;
     xl     = t9 * con1;
     xldt   = 1.0e-9_rt * con1;
-    xlp5   = sqrt(xl);
+    xlp5   = std::sqrt(xl);
     xl2    = xl*xl;
     xl3    = xl2*xl;
     xl4    = xl3*xl;