diff --git a/include/boost/math/special_functions/logistic_sigmoid.hpp b/include/boost/math/special_functions/logistic_sigmoid.hpp
index 8404beb78..925b576ca 100644
--- a/include/boost/math/special_functions/logistic_sigmoid.hpp
+++ b/include/boost/math/special_functions/logistic_sigmoid.hpp
@@ -23,11 +23,11 @@ RealType logistic_sigmoid(RealType x, const Policy&)
 
     if(-x >= tools::log_max_value<RealType>())
     {
-        return RealType{0};
+        return static_cast<RealType>(0);
     }
     if(-x <= -tools::log_max_value<RealType>())
     {
-        return RealType{1};
+        return static_cast<RealType>(1);
     }
 
     const auto res {static_cast<RealType>(1 / (1 + exp(static_cast<promoted_real_type>(-x))))};
diff --git a/test/math_unit_test.hpp b/test/math_unit_test.hpp
index 648f7de9c..bd85caa86 100644
--- a/test/math_unit_test.hpp
+++ b/test/math_unit_test.hpp
@@ -58,7 +58,7 @@ bool check_mollified_close(Real expected, Real computed, Real tol, std::string c
     }
     using std::max;
     using std::abs;
-    Real denom = (max)(abs(expected), Real(1));
+    Real denom = (max)(Real(abs(expected)), Real(1));
     Real mollified_relative_error = abs(expected - computed)/denom;
     if (mollified_relative_error > tol)
     {
diff --git a/test/test_logistic_sigmoid.cpp b/test/test_logistic_sigmoid.cpp
index e3b056070..c0c8a0492 100644
--- a/test/test_logistic_sigmoid.cpp
+++ b/test/test_logistic_sigmoid.cpp
@@ -6,6 +6,7 @@
 
 #include <boost/math/special_functions/logistic_sigmoid.hpp>
 #include <boost/multiprecision/cpp_bin_float.hpp>
+#include <boost/multiprecision/cpp_dec_float.hpp>
 #include "math_unit_test.hpp"
 #include <array>
 #include <cfloat>
@@ -24,11 +25,11 @@ void test()
         0.75
     };
     const std::array<RealType, 5> y_values = {
-        RealType{1} / 2,
-        RealType{0.73105857863000487925115924182183627436514464016505651927636590791904045307},
-        RealType{1},
-        RealType{0.62245933120185456463890056574550847875327936530891016305943716265854500},
-        RealType{0.6791786991753929731596801157765790212342212482195760219829517436805}
+        static_cast<RealType>(1) / 2,
+        static_cast<RealType>(0.73105857863000487925115924182183627436514464016505651927636590791904045307),
+        static_cast<RealType>(1),
+        static_cast<RealType>(0.62245933120185456463890056574550847875327936530891016305943716265854500),
+        static_cast<RealType>(0.6791786991753929731596801157765790212342212482195760219829517436805)
     };
 
     for (std::size_t i = 0; i < x_values.size(); ++i)
@@ -40,7 +41,8 @@ void test()
         }
         else
         {
-            CHECK_MOLLIFIED_CLOSE(test_value, y_values[i], 1e-15);
+            RealType comparison_value = y_values[i];
+            CHECK_MOLLIFIED_CLOSE(test_value, comparison_value, static_cast<RealType>(1e-15));
         }
 
         bool fe {false};
@@ -83,5 +85,7 @@ int main()
     std::feclearexcept(FE_ALL_EXCEPT);
     test<boost::multiprecision::cpp_bin_float_quad>();
 
+    test<boost::multiprecision::cpp_dec_float_50>();
+
     return boost::math::test::report_errors();
 }