diff --git a/cth/incl/cth/constants.hpp b/cth/incl/cth/constants.hpp
index 451a7d3..843df57 100644
--- a/cth/incl/cth/constants.hpp
+++ b/cth/incl/cth/constants.hpp
@@ -34,14 +34,12 @@
 #define CTH_DEBUG_INLINE_IMPL(code) { code }
 
 #define CTH_RELEASE_NOEXCEPT noexcept(false)
-#define CTH_RELEASE_CONSTEXPR
 #else
 #define CTH_DEBUG_IMPL = default;
 #define CTH_DEBUG_INLINE_IMPL(code) \
         {}
 
 #define CTH_RELEASE_NOEXCEPT noexcept(true)
-#define CTH_RELEASE_CONSTEXPR constexpr
 #endif
 #include <cstdint>
 
diff --git a/cth/incl/cth/ptr/not_null.hpp b/cth/incl/cth/ptr/not_null.hpp
index 3a1c5e8..50c3eb7 100644
--- a/cth/incl/cth/ptr/not_null.hpp
+++ b/cth/incl/cth/ptr/not_null.hpp
@@ -40,12 +40,12 @@ class not_null {
     static constexpr bool NOEXCEPT_CHECK_VAL = COMPILATION_MODE != CompilationMode::DEBUG;
     static constexpr bool RELEASE_VAL_NOEXCEPT = NOEXCEPT_ASSIGN && NOEXCEPT_MOVE_CTOR;
 
-    static CTH_RELEASE_CONSTEXPR void checkVal(T const& obj) noexcept(NOEXCEPT_CHECK_VAL) {
+    static constexpr void checkVal(T const& obj) noexcept(NOEXCEPT_CHECK_VAL) {
         CTH_CRITICAL(obj == Null, "obj must not be Null") {}
     }
 
 public:
-    CTH_RELEASE_CONSTEXPR not_null(T obj) noexcept(NOEXCEPT_MOVE_CTOR && NOEXCEPT_CHECK_VAL) :
+    constexpr not_null(T obj) noexcept(NOEXCEPT_MOVE_CTOR && NOEXCEPT_CHECK_VAL) :
         _obj{std::move(obj)} { not_null::checkVal(_obj); }
 
     template<class U> requires(std::convertible_to<U, T> && !std::same_as<U, T>)
diff --git a/cth/tests/src/pointers/not_null_test.cpp b/cth/tests/src/pointers/not_null_test.cpp
index 2538624..2fd432d 100644
--- a/cth/tests/src/pointers/not_null_test.cpp
+++ b/cth/tests/src/pointers/not_null_test.cpp
@@ -14,6 +14,14 @@ struct TestStruct {
 auto const data = std::make_unique<TestStruct>(EXAMPLE_NUMBER); // NOLINT(cert-err58-cpp)
 
 
+CTH_TEST(not_null, constexpr) {
+    static_assert([] {
+        not_null<int const*> const ptr{&EXAMPLE_NUMBER};
+        not_null<int const*> const copy{ptr};
+        return *copy;
+    }() == EXAMPLE_NUMBER);
+}
+
 CTH_TEST(not_null, comparison) {
     int a = EXAMPLE_NUMBER;
     int b = EXAMPLE_NUMBER;