diff --git a/include/mimalloc-atomic.h b/include/mimalloc-atomic.h
index 86deaf76..722b6ad6 100644
--- a/include/mimalloc-atomic.h
+++ b/include/mimalloc-atomic.h
@@ -223,11 +223,11 @@ static inline uintptr_t mi_atomic_or(volatile _Atomic(uintptr_t)* p, uintptr_t x
 }
 static inline bool mi_atomic_cas_weak(volatile _Atomic(uintptr_t)* p, uintptr_t desired, uintptr_t expected) {
   MI_USING_STD
-  return atomic_compare_exchange_weak_explicit(p, &expected, desired, memory_order_acq_rel, memory_order_relaxed);
+  return atomic_compare_exchange_weak_explicit(p, &expected, desired, memory_order_acq_rel, memory_order_acquire);
 }
 static inline bool mi_atomic_cas_strong(volatile _Atomic(uintptr_t)* p, uintptr_t desired, uintptr_t expected) {
   MI_USING_STD
-  return atomic_compare_exchange_strong_explicit(p, &expected, desired, memory_order_acq_rel, memory_order_relaxed);
+  return atomic_compare_exchange_strong_explicit(p, &expected, desired, memory_order_acq_rel, memory_order_acquire);
 }
 static inline uintptr_t mi_atomic_exchange(volatile _Atomic(uintptr_t)* p, uintptr_t exchange) {
   MI_USING_STD