diff --git a/Formula/c/cp2k.rb b/Formula/c/cp2k.rb
index 35da18eee0b2c..4df716640eb7a 100644
--- a/Formula/c/cp2k.rb
+++ b/Formula/c/cp2k.rb
@@ -4,6 +4,7 @@ class Cp2k < Formula
   url "https://github.com/cp2k/cp2k/releases/download/v2025.1/cp2k-2025.1.tar.bz2"
   sha256 "65c8ad5488897b0f995919b9fa77f2aba4b61677ba1e3c19bb093d5c08a8ce1d"
   license "GPL-2.0-or-later"
+  revision 1
 
   livecheck do
     url :stable
@@ -32,8 +33,8 @@ class Cp2k < Formula
   depends_on "openblas"
   depends_on "scalapack"
 
-  fails_with :clang do
-    cause "needs OpenMP support for C/C++ and Fortran"
+  on_macos do
+    depends_on "libomp"
   end
 
   resource "libint" do
@@ -58,12 +59,12 @@ def install
       ENV.prepend_path "PKG_CONFIG_PATH", libexec/"lib/pkgconfig"
     end
 
-    # TODO: Add workaround to link to LLVM OpenMP (libomp) with gfortran after migrating OpenBLAS
+    # Workaround to link to LLVM OpenMP (libomp) with gfortran
     omp_args = []
-    # if OS.mac?
-    #   omp_args << "-DOpenMP_Fortran_LIB_NAMES=omp"
-    #   omp_args << "-DOpenMP_omp_LIBRARY=#{Formula["libomp"].opt_lib}/libomp.dylib"
-    # end
+    if OS.mac?
+      omp_args << "-DOpenMP_Fortran_LIB_NAMES=omp"
+      omp_args << "-DOpenMP_omp_LIBRARY=#{Formula["libomp"].opt_lib}/libomp.dylib"
+    end
 
     # TODO: Remove dbcsr build along with corresponding CMAKE_PREFIX_PATH
     # and add -DCP2K_BUILD_DBCSR=ON once `cp2k` build supports this option.
@@ -85,9 +86,7 @@ def install
     # Avoid trying to access /proc/self/statm on macOS
     ENV.append "FFLAGS", "-D__NO_STATM_ACCESS" if OS.mac?
 
-    # Set -lstdc++ to allow gfortran to link libint
     cp2k_cmake_args = %W[
-      -DCMAKE_SHARED_LINKER_FLAGS=-lstdc++
       -DCMAKE_INSTALL_RPATH=#{rpath};#{rpath(target: libexec/"lib")}
       -DCP2K_BLAS_VENDOR=OpenBLAS
       -DCP2K_USE_LIBINT2=ON
diff --git a/Formula/d/dynare.rb b/Formula/d/dynare.rb
index 93180f65d96b4..fa823bc897510 100644
--- a/Formula/d/dynare.rb
+++ b/Formula/d/dynare.rb
@@ -4,7 +4,7 @@ class Dynare < Formula
   url "https://www.dynare.org/release/source/dynare-6.4.tar.xz"
   sha256 "9865e2e7f6b3705155538d5fb1fb0b01bc9decf07250b3b054d3555d651c3843"
   license "GPL-3.0-or-later"
-  revision 1
+  revision 2
   head "https://git.dynare.org/Dynare/dynare.git", branch: "master"
 
   livecheck do
@@ -37,6 +37,10 @@ class Dynare < Formula
   depends_on "openblas"
   depends_on "suite-sparse"
 
+  on_macos do
+    depends_on "libomp"
+  end
+
   fails_with :clang do
     cause <<~EOS
       GCC is the only compiler supported by upstream
@@ -72,6 +76,12 @@ def install
     ENV.append_path "LIBRARY_PATH", Formula["suite-sparse"].opt_lib
     ENV.append_path "LIBRARY_PATH", buildpath/"slicot/lib"
 
+    # Workaround to unofficially link to LLVM OpenMP (libomp) with GCC
+    if OS.mac?
+      inreplace "meson.build", "openmp_dep = dependency('openmp')",
+                               "openmp_dep = declare_dependency(compile_args : '-fopenmp', link_args : '-lomp')"
+    end
+
     system "meson", "setup", "build", "-Dbuild_for=octave", *std_meson_args
     system "meson", "compile", "-C", "build", "--verbose"
     system "meson", "install", "-C", "build"
diff --git a/Formula/f/fftw.rb b/Formula/f/fftw.rb
index 7978d812029dc..876b4a79c5d9b 100644
--- a/Formula/f/fftw.rb
+++ b/Formula/f/fftw.rb
@@ -4,7 +4,7 @@ class Fftw < Formula
   url "https://fftw.org/fftw-3.3.10.tar.gz"
   sha256 "56c932549852cddcfafdab3820b0200c7742675be92179e59e6215b340e26467"
   license all_of: ["GPL-2.0-or-later", "BSD-2-Clause"]
-  revision 2
+  revision 3
 
   livecheck do
     url :homepage
@@ -27,11 +27,9 @@ class Fftw < Formula
   depends_on "open-mpi"
 
   on_macos do
-    depends_on "gcc"
+    depends_on "libomp"
   end
 
-  fails_with :clang
-
   # Fix the cmake config file when configured with autotools, upstream pr ref, https://github.com/FFTW/fftw3/pull/338
   patch do
     url "https://github.com/FFTW/fftw3/commit/394fa85ab5f8914b82b3404844444c53f5c7f095.patch?full_index=1"
@@ -41,6 +39,11 @@ class Fftw < Formula
   def install
     ENV.runtime_cpu_detection
 
+    if OS.mac?
+      ENV["OPENMP_CFLAGS"] = "-Xpreprocessor -fopenmp"
+      ENV.append "LIBS", "-lomp"
+    end
+
     args = [
       "--enable-shared",
       "--disable-debug",
diff --git a/Formula/g/gromacs.rb b/Formula/g/gromacs.rb
index 3dafa5a4ec080..ee3dc60a4e0ab 100644
--- a/Formula/g/gromacs.rb
+++ b/Formula/g/gromacs.rb
@@ -4,6 +4,7 @@ class Gromacs < Formula
   url "https://ftp.gromacs.org/pub/gromacs/gromacs-2025.3.tar.gz"
   sha256 "8bdfca0268f3f10a7ca3c06e59b62f73ea02420c67211c0ff3912f32d7833c65"
   license "LGPL-2.1-or-later"
+  revision 1
 
   livecheck do
     url "https://ftp.gromacs.org/pub/gromacs/"
@@ -23,31 +24,25 @@ class Gromacs < Formula
   depends_on "cmake" => :build
   depends_on "pkgconf" => :build
   depends_on "fftw"
-  depends_on "gcc" # for OpenMP
   depends_on "lmfit"
+  depends_on "muparser"
   depends_on "openblas"
 
   uses_from_macos "zlib"
 
   on_macos do
-    conflicts_with "muparser", because: "gromacs ships its own copy of muparser"
+    depends_on "libomp"
   end
 
-  on_linux do
-    depends_on "muparser"
-  end
-
-  fails_with :clang
-
   def install
     # Non-executable GMXRC files should be installed in DATADIR
     inreplace "scripts/CMakeLists.txt", "CMAKE_INSTALL_BINDIR",
                                         "CMAKE_INSTALL_DATADIR"
 
     # Avoid superenv shim reference
-    gcc = Formula["gcc"]
-    cc = gcc.opt_bin/"gcc-#{gcc.any_installed_version.major}"
-    cxx = gcc.opt_bin/"g++-#{gcc.any_installed_version.major}"
+    cc = DevelopmentTools.locate(ENV.cc)
+    cxx = DevelopmentTools.locate(ENV.cxx)
+
     inreplace "src/gromacs/gromacs-hints.in.cmake" do |s|
       s.gsub! "@CMAKE_LINKER@", "/usr/bin/ld"
       s.gsub! "@CMAKE_C_COMPILER@", cc
@@ -75,15 +70,9 @@ def install
       -DGMX_INSTALL_LEGACY_API=ON
       -DGMX_EXTERNAL_ZLIB=ON
       -DGMX_USE_LMFIT=EXTERNAL
+      -DGMX_USE_MUPARSER=EXTERNAL
       -DGMX_SIMD=#{gmx_simd}
     ]
-    args << if OS.mac?
-      # Use bundled `muparser` as brew formula is linked to libc++ on macOS but we need libstdc++.
-      # TODO: Try switching `gromacs` and its dependency tree to use Apple Clang + `libomp`
-      "-DFETCHCONTENT_SOURCE_DIR_MUPARSER=#{buildpath}/src/external/muparser"
-    else
-      "-DGMX_USE_MUPARSER=EXTERNAL"
-    end
 
     system "cmake", "-S", ".", "-B", "build", *std_cmake_args, *args
     system "cmake", "--build", "build"
diff --git a/Formula/m/muparser.rb b/Formula/m/muparser.rb
index 25bee26685eb9..303b9991f9883 100644
--- a/Formula/m/muparser.rb
+++ b/Formula/m/muparser.rb
@@ -4,7 +4,7 @@ class Muparser < Formula
   url "https://github.com/beltoforion/muparser/archive/refs/tags/v2.3.5.tar.gz"
   sha256 "20b43cc68c655665db83711906f01b20c51909368973116dfc8d7b3c4ddb5dd4"
   license "BSD-2-Clause"
-  revision 1
+  revision 2
   head "https://github.com/beltoforion/muparser.git", branch: "master"
 
   bottle do
@@ -20,13 +20,13 @@ class Muparser < Formula
   depends_on "cmake" => :build
 
   on_macos do
-    conflicts_with "gromacs", because: "gromacs ships its own copy of muparser"
+    depends_on "libomp"
   end
 
   def install
     ENV.cxx11 if OS.linux?
 
-    system "cmake", "-S", ".", "-B", "build", "-DENABLE_OPENMP=#{OS.mac? ? "OFF" : "ON"}", *std_cmake_args
+    system "cmake", "-S", ".", "-B", "build", "-DENABLE_OPENMP=ON", *std_cmake_args
     system "cmake", "--build", "build"
     system "cmake", "--install", "build"
   end
diff --git a/Formula/n/nwchem.rb b/Formula/n/nwchem.rb
index f3a3e0b9d3fee..4cbcb423c9865 100644
--- a/Formula/n/nwchem.rb
+++ b/Formula/n/nwchem.rb
@@ -5,7 +5,7 @@ class Nwchem < Formula
   version "7.2.3"
   sha256 "7788e6af9be8681e6384b8df4df5ac57d010b2c7aa50842d735c562d92f94c25"
   license "ECL-2.0"
-  revision 1
+  revision 2
 
   livecheck do
     url :stable
@@ -36,6 +36,10 @@ class Nwchem < Formula
 
   uses_from_macos "libxcrypt"
 
+  on_macos do
+    depends_on "libomp"
+  end
+
   # fix download url in build_dftd3a.sh, upstream pr ref, https://github.com/nwchemgit/nwchem/pull/1054
   patch do
     url "https://github.com/nwchemgit/nwchem/commit/65ce7726d9fa418f7c01665bebfc1e2181f15adf.patch?full_index=1"
@@ -46,6 +50,9 @@ def install
     pkgshare.install "QA"
 
     cd "src" do
+      # Workaround to link to LLVM OpenMP (libomp) with gfortran
+      inreplace "config/makefile.h", /(\bLDOPTIONS *\+= *)-fopenmp$/, "\\1-lomp" if OS.mac?
+
       (prefix/"etc").mkdir
       (prefix/"etc/nwchemrc").write <<~EOS
         nwchem_basis_library #{pkgshare}/libraries/
diff --git a/Formula/o/openblas.rb b/Formula/o/openblas.rb
index e1e58948a4322..3f7de066bde78 100644
--- a/Formula/o/openblas.rb
+++ b/Formula/o/openblas.rb
@@ -9,6 +9,7 @@ class Openblas < Formula
   # 3. interface/{gemmt.c,sbgemmt.c} is BSD-2-Clause
   # 4. relapack/ is MIT but license is omitted as it is not enabled
   license all_of: ["BSD-3-Clause", "BSD-2-Clause-Views", "BSD-3-Clause-Open-MPI", "BSD-2-Clause"]
+  revision 1
   head "https://github.com/OpenMathLib/OpenBLAS.git", branch: "develop"
 
   livecheck do
@@ -28,10 +29,27 @@ class Openblas < Formula
 
   keg_only :shadowed_by_macos, "macOS provides BLAS in Accelerate.framework"
 
+  depends_on "pkgconf" => :test
   depends_on "gcc" # for gfortran
-  fails_with :clang
+
+  on_macos do
+    depends_on "libomp"
+  end
 
   def install
+    # Workaround to use Apple Clang and link to `libomp`
+    if ENV.compiler == :clang
+      inreplace "Makefile.system" do |s|
+        s.gsub! "+= -fopenmp", "+= -Xpreprocessor -fopenmp"
+        # Also add GCC path to pkgconfig file as we don't symlink libgfortran to HOMEBREW_PREFIX/lib
+        s.gsub! "+= -lgfortran", "+= -L#{Formula["gcc"].opt_lib}/gcc/current -lgfortran"
+      end
+      inreplace "Makefile.install" do |s|
+        s.gsub! ":= -fopenmp", ":= -I#{Formula["libomp"].opt_include} -Xpreprocessor -fopenmp"
+        s.gsub! "+= -lgomp", "+= -L#{Formula["libomp"].opt_lib} -lomp"
+      end
+    end
+
     ENV.runtime_cpu_detection
     ENV.deparallelize # build is parallel by default, but setting -j confuses it
 
@@ -61,6 +79,7 @@ def install
 
     lib.install_symlink shared_library("libopenblas") => shared_library("libblas")
     lib.install_symlink shared_library("libopenblas") => shared_library("liblapack")
+    pkgshare.install "cpp_thread_test"
   end
 
   test do
@@ -88,5 +107,24 @@ def install
     system ENV.cc, "test.c", "-I#{include}", "-L#{lib}", "-lopenblas",
                    "-o", "test"
     system "./test"
+
+    cp_r pkgshare/"cpp_thread_test/.", testpath
+    ENV.prepend_path "PKG_CONFIG_PATH", lib/"pkgconfig"
+    flags = shell_output("pkgconf --cflags --libs --static openblas").chomp.split
+    ["dgemm_thread_safety", "dgemv_thread_safety"].each do |test|
+      inreplace "#{test}.cpp", '"../cblas.h"', '"cblas.h"'
+      system ENV.cxx, "#{test}.cpp", "-o", test, *flags
+      system "./#{test}"
+    end
+
+    return unless OS.mac?
+
+    # Check linkage uses correct OpenMP
+    require "utils/linkage"
+    libopenblas = lib/shared_library("libopenblas")
+    libomp = Formula["libomp"].opt_lib/shared_library("libomp")
+    libgomp = Formula["gcc"].opt_lib/"gcc/current"/shared_library("libgomp")
+    assert Utils.binary_linked_to_library?(libopenblas, libomp), "No linkage with #{libomp.basename}!"
+    refute Utils.binary_linked_to_library?(libopenblas, libgomp), "Unwanted linkage with #{libgomp.basename}!"
   end
 end
diff --git a/Formula/p/pytorch.rb b/Formula/p/pytorch.rb
index 7caf7d2562667..ce52dbe56c7bb 100644
--- a/Formula/p/pytorch.rb
+++ b/Formula/p/pytorch.rb
@@ -6,7 +6,7 @@ class Pytorch < Formula
   url "https://github.com/pytorch/pytorch/releases/download/v2.8.0/pytorch-v2.8.0.tar.gz"
   sha256 "c70a2c9488f6f6e8af5982a10d1cc2c37b7df5e6506d839daa5d5e250953d7b5"
   license "BSD-3-Clause"
-  revision 2
+  revision 3
 
   livecheck do
     url :stable