diff --git a/grayskull/strategy/py_base.py b/grayskull/strategy/py_base.py
index de128c80..61d09da7 100644
--- a/grayskull/strategy/py_base.py
+++ b/grayskull/strategy/py_base.py
@@ -696,18 +696,30 @@ def download_sdist_pkg(sdist_url: str, dest: str, name: str | None = None):
 
 def merge_deps_toml_setup(setup_deps: list, toml_deps: list) -> list:
     re_split = re.compile(r"\s+|>|=|<|~|!")
-    all_deps = defaultdict(list)
-    for dep in toml_deps + setup_deps:
-        if dep.strip():
-            dep_name = re_split.split(dep)[0]
-            if dep_name not in all_deps:
-                if dep_name.replace("_", "-") in all_deps:
-                    dep_name = dep_name.replace("_", "-")
-                elif dep_name.replace("-", "_") in all_deps:
-                    dep_name = dep_name.replace("-", "_")
-            all_deps[dep_name].append(dep)
-
-    return [deps[0] for deps in all_deps.values()]
+    # drop any empty deps
+    setup_deps = [dep for dep in setup_deps if dep.strip()]
+    toml_deps = [dep for dep in toml_deps if dep.strip()]
+
+    # get dep names
+    toml_dep_names = [re_split.split(dep)[0] for dep in toml_deps]
+    setup_dep_names = [re_split.split(dep)[0] for dep in setup_deps]
+
+    # prefer toml over setup; only add setup deps if not found in toml
+    merged_deps = toml_deps
+    for dep_name, dep in zip(setup_dep_names, setup_deps):
+        if not dep_name.strip():
+            continue
+        alternatives = [
+            dep_name,
+            dep_name.replace("_", "-"),
+            dep_name.replace("-", "_"),
+        ]
+        found = any([alternative in toml_dep_names for alternative in alternatives])
+        # only add the setup dep if no alternative name was found
+        if not found:
+            merged_deps.append(dep)
+
+    return merged_deps
 
 
 def merge_setup_toml_metadata(setup_metadata: dict, pyproject_metadata: dict) -> dict:
diff --git a/grayskull/strategy/pypi.py b/grayskull/strategy/pypi.py
index c1cddcc6..cd8ea780 100644
--- a/grayskull/strategy/pypi.py
+++ b/grayskull/strategy/pypi.py
@@ -185,18 +185,16 @@ def merge_requires_dist(pypi_metadata: dict, sdist_metadata: dict) -> list:
     :param sdist_metadata: sdist metadata
     :return: list with all requirements
     """
-    all_deps = sdist_metadata.get("install_requires") or []
-    all_deps += pypi_metadata.get("requires_dist") or []
 
-    re_search = re.compile(r";\s*extra")
-    all_deps = [pkg for pkg in all_deps if not re_search.search(pkg)]
-    current_pkg = pypi_metadata.get("name", "")
-
-    requires_dist = []
-    pypi_deps_name = set()
-    with progressbar_with_status(len(all_deps)) as bar:
-        for pos, sdist_pkg in enumerate(all_deps, 1):
-            match_deps = RE_DEPS_NAME.match(sdist_pkg)
+    def _get_pkg_names(deps, current_pkg, bar, pos):
+        """
+        Get pkg names for each dep, dropping deps where no pkg name is found
+        """
+        new_deps = []
+        pkg_names = []
+        for dep in deps:
+            pos += 1
+            match_deps = RE_DEPS_NAME.match(dep)
             if not match_deps:
                 bar.update(pos)
                 continue
@@ -205,11 +203,32 @@ def merge_requires_dist(pypi_metadata: dict, sdist_metadata: dict) -> list:
             bar.update(pos, pkg_name=pkg_name)
             if current_pkg and current_pkg == pkg_name:
                 continue
-            if pkg_name in pypi_deps_name:
-                continue
+            new_deps.append(dep.replace(match_deps, pkg_name))
+            pkg_names.append(pkg_name)
+        return pkg_names, new_deps
+
+    sdist_deps = sdist_metadata.get("install_requires") or []
+    pypi_deps = pypi_metadata.get("requires_dist") or []
+
+    re_search = re.compile(r";\s*extra")
+    sdist_deps = [pkg for pkg in sdist_deps if not re_search.search(pkg)]
+    pypi_deps = [pkg for pkg in pypi_deps if not re_search.search(pkg)]
+    current_pkg = pypi_metadata.get("name", "")
+
+    count = len(sdist_deps) + len(pypi_deps)
+    # progress bar here because calling normalize_pkg_name() on each package
+    # takes awhile
+    with progressbar_with_status(count) as bar:
+        pos = 0
+        sdist_pkgs, sdist_deps = _get_pkg_names(sdist_deps, current_pkg, bar, pos)
+        pypi_pkgs, pypi_deps = _get_pkg_names(pypi_deps, current_pkg, bar, pos)
+
+    # prefer sdist over pypi; only add pypi deps if not found in sdist
+    requires_dist = sdist_deps
+    for pkg_name, dep in zip(pypi_pkgs, pypi_deps):
+        if pkg_name not in sdist_pkgs:
+            requires_dist.append(dep)
 
-            pypi_deps_name.add(pkg_name)
-            requires_dist.append(sdist_pkg.replace(match_deps, pkg_name))
     return requires_dist
 
 
@@ -322,8 +341,13 @@ def get_pypi_metadata(config: Configuration) -> PypiMetadata:
 def get_run_req_from_requires_dist(requires_dist: list, config: Configuration) -> list:
     """Get the run requirements looking for the `requires_dist` key
     present in the metadata"""
+    re_selector = re.compile(r"\s+#\s+\[.*\]", re.DOTALL)
     run_req = []
     for req in requires_dist:
+        if re_selector.search(req):
+            # if there's already a selector, make sure we're arch
+            config.is_arch = True
+
         list_raw_requirements = req.split(";")
         selector = ""
         if len(list_raw_requirements) > 1:
diff --git a/grayskull/utils.py b/grayskull/utils.py
index 88242e47..dcd7f5d1 100644
--- a/grayskull/utils.py
+++ b/grayskull/utils.py
@@ -128,7 +128,7 @@ def rm_duplicated_deps(all_requirements: list | set | None) -> list | None:
     # and underscores converted to dashes. The value is the requirement itself,
     # as it should be added.
     # (This is order-preserving since dicts are ordered by first insertion.)
-    new_reqs: dict[str, str] = {}
+    new_reqs: dict[tuple[str, str], str] = {}
     re_split = re.compile(r"\s+(|>|=|<|~|!|#)+")
     for dep in all_requirements:
         if dep.strip().startswith(("{{", "<{")):
@@ -136,6 +136,12 @@ def rm_duplicated_deps(all_requirements: list | set | None) -> list | None:
             continue
         dep_name, *constrains = re_split.split(dep.strip())
         dep_name = dep_name.strip()
+
+        if "#" in dep:
+            selector = dep.split("#")[-1]
+        else:
+            selector = ""
+
         constrains = [
             c.strip()
             for c in constrains
@@ -143,17 +149,20 @@ def rm_duplicated_deps(all_requirements: list | set | None) -> list | None:
         ]
         canonicalized = dep_name.replace("_", "-").lower()
         constrains.insert(0, dep_name)
-        if canonicalized in new_reqs:
+        # a canonicalized dependency is only redundant if it also has the same
+        # selector as a pervious dependency
+        key = (canonicalized, selector)
+        if key in new_reqs:
             # In order to break ties deterministically, we prioritize the requirement
             # which is alphanumerically lowest. This happens to prioritize the "-"
             # character over "_".
             # Example: given "importlib_metadata" and "importlib-metadata", we will
             # keep "importlib-metadata" because it is alphabetically lower.
-            previous_req = new_reqs[canonicalized]
+            previous_req = new_reqs[key]
             if len(dep) > len(previous_req) or "-" in dep_name:
-                new_reqs[canonicalized] = " ".join(constrains)
+                new_reqs[key] = " ".join(constrains)
         else:
-            new_reqs[canonicalized] = " ".join(constrains)
+            new_reqs[key] = " ".join(constrains)
     return [re.sub(r"\s+(#)", "  \\1", v.strip()) for v in new_reqs.values()]
 
 
@@ -168,6 +177,7 @@ def format_dependencies(all_dependencies: list, name: str) -> list:
     formatted_dependencies = []
     re_deps = re.compile(r"^\s*([\.a-zA-Z0-9_-]+)\s*(.*)\s*$", re.MULTILINE | re.DOTALL)
     re_remove_space = re.compile(r"([<>!=]+)\s+")
+    re_selector = re.compile(r"\s+#\s+\[.*\]", re.DOTALL)
     re_remove_tags = re.compile(r"\s*(\[.*\])", re.DOTALL)
     re_remove_comments = re.compile(r"\s+#.*", re.DOTALL)
     for req in all_dependencies:
@@ -184,6 +194,10 @@ def format_dependencies(all_dependencies: list, name: str) -> list:
             if len(match_req) > 1:
                 deps_name = " ".join(match_req)
         deps_name = re_remove_space.sub(r"\1", deps_name.strip())
+        if re_selector.search(deps_name):
+            # don't want to remove selectors
+            formatted_dependencies.append(deps_name)
+            continue
         deps_name = re_remove_tags.sub(r" ", deps_name.strip())
         deps_name = re_remove_comments.sub("", deps_name)
         formatted_dependencies.append(deps_name.strip())
diff --git a/tests/test_pypi.py b/tests/test_pypi.py
index b802e34d..94de9ffc 100644
--- a/tests/test_pypi.py
+++ b/tests/test_pypi.py
@@ -682,6 +682,119 @@ def test_merge_pypi_sdist_metadata():
     )
 
 
+def test_pypi_metadata_constraints_for_python_versions():
+    config = Configuration(name="apache-airflow-providers-trino", version="6.0.0")
+    pypi_metadata = get_pypi_metadata(config)
+    assert sorted(pypi_metadata["requires_dist"]) == sorted(
+        [
+            "apache-airflow-providers-common-sql>=1.20.0",
+            "apache-airflow>=2.9.0",
+            'pandas<2.2,>=1.5.3; python_version < "3.9"',
+            'pandas<2.2,>=2.1.2; python_version >= "3.9"',
+            "trino>=0.318.0",
+            'apache-airflow-providers-google; extra == "google"',
+            'apache-airflow-providers-openlineage; extra == "openlineage"',
+        ]
+    )
+
+    config = Configuration(name="databricks-sql-connector", version="3.7.0")
+    pypi_metadata = get_pypi_metadata(config)
+    assert sorted(pypi_metadata["requires_dist"]) == sorted(
+        [
+            'alembic<2.0.0,>=1.0.11; extra == "alembic"',
+            "lz4<5.0.0,>=4.0.2",
+            'numpy>=1.16.6; python_version >= "3.8" and python_version < "3.11"',
+            'numpy>=1.23.4; python_version >= "3.11"',
+            "oauthlib<4.0.0,>=3.1.0",
+            "openpyxl<4.0.0,>=3.0.10",
+            'pandas<2.3.0,>=1.2.5; python_version >= "3.8"',
+            "pyarrow>=14.0.1",
+            "requests<3.0.0,>=2.18.1",
+            'sqlalchemy>=2.0.21; extra == "sqlalchemy" or extra == "alembic"',
+            "thrift<0.21.0,>=0.16.0",
+            "urllib3>=1.26",
+        ]
+    )
+
+
+def test_sdist_metadata_from_toml_project_dependencies():
+    config = Configuration(name="apache-airflow-providers-trino", version="6.0.0")
+    pypi_metadata = get_pypi_metadata(config)
+    sdist_metadata = get_sdist_metadata(pypi_metadata["sdist_url"], config)
+    assert sorted(sdist_metadata["install_requires"]) == sorted(
+        [
+            "apache-airflow-providers-common-sql>=1.20.0",
+            "apache-airflow>=2.9.0",
+            'pandas>=1.5.3,<2.2;python_version<"3.9"',
+            'pandas>=2.1.2,<2.2;python_version>="3.9"',
+            "trino>=0.318.0",
+            "python ~=3.9",
+        ]
+    )
+
+
+def test_sdist_metadata_from_toml_poetry_dependencies():
+    config = Configuration(name="databricks-sql-connector", version="3.7.0")
+    pypi_metadata = get_pypi_metadata(config)
+    sdist_metadata = get_sdist_metadata(pypi_metadata["sdist_url"], config)
+    assert sorted(sdist_metadata["install_requires"]) == sorted(
+        [
+            "python >=3.8.0,<4.0.0",
+            "thrift >=0.16.0,<0.21.0",
+            "pandas >=1.2.5,<2.3.0  # [py>=38]",
+            "pyarrow >=14.0.1",
+            "lz4 >=4.0.2,<5.0.0",
+            "requests >=2.18.1,<3.0.0",
+            "oauthlib >=3.1.0,<4.0.0",
+            "numpy >=1.16.6  # [py>=38 and py<311]",
+            "numpy >=1.23.4  # [py>=311]",
+            "openpyxl >=3.0.10,<4.0.0",
+            "urllib3 >=1.26",
+        ]
+    )
+
+
+def test_merge_pypi_sdist_metadata_from_toml():
+    # tests merging pyproject.toml dependencies from poetry with pypi data,
+    # including multiple numpy constraints with python version selectors
+    config = Configuration(name="databricks-sql-connector", version="3.7.0")
+    pypi_metadata = get_pypi_metadata(config)
+    sdist_metadata = get_sdist_metadata(pypi_metadata["sdist_url"], config)
+    merged_data = merge_pypi_sdist_metadata(pypi_metadata, sdist_metadata, config)
+    assert sorted(merged_data["requires_dist"]) == sorted(
+        [
+            "python >=3.8.0,<4.0.0",
+            "thrift >=0.16.0,<0.21.0",
+            "pandas >=1.2.5,<2.3.0  # [py>=38]",
+            "pyarrow >=14.0.1",
+            "lz4 >=4.0.2,<5.0.0",
+            "requests >=2.18.1,<3.0.0",
+            "oauthlib >=3.1.0,<4.0.0",
+            "numpy >=1.16.6  # [py>=38 and py<311]",
+            "numpy >=1.23.4  # [py>=311]",
+            "openpyxl >=3.0.10,<4.0.0",
+            "urllib3 >=1.26",
+        ]
+    )
+
+    # tests merging pyproject.toml project dependencies with pypi data,
+    # including multiple pandas constraints with python version selectors
+    config = Configuration(name="apache-airflow-providers-trino", version="6.0.0")
+    pypi_metadata = get_pypi_metadata(config)
+    sdist_metadata = get_sdist_metadata(pypi_metadata["sdist_url"], config)
+    merged_data = merge_pypi_sdist_metadata(pypi_metadata, sdist_metadata, config)
+    assert sorted(merged_data["requires_dist"]) == sorted(
+        [
+            "apache-airflow-providers-common-sql>=1.20.0",
+            "apache-airflow>=2.9.0",
+            'pandas>=1.5.3,<2.2;python_version<"3.9"',
+            'pandas>=2.1.2,<2.2;python_version>="3.9"',
+            "trino>=0.318.0",
+            "python ~=3.9",
+        ]
+    )
+
+
 def test_update_requirements_with_pin():
     req = {
         "build": ["<{ compiler('c') }}"],
@@ -787,6 +900,55 @@ def test_run_requirements_sdist():
         ]
     )
 
+    # a more complex example with selectors
+    config = Configuration(name="apache-airflow-providers-trino", version="6.0.0")
+    recipe = GrayskullFactory.create_recipe("pypi", config)
+    assert "noarch" not in recipe["build"]
+    selectors = {
+        "python >=3.9,<4.dev0": None,
+        "apache-airflow-providers-common-sql >=1.20.0": None,
+        "apache-airflow >=2.9.0": None,
+        "pandas >=1.5.3,<2.2": "[py<39]",
+        "pandas >=2.1.2,<2.2": "[py>=39]",
+        "trino-python-client >=0.318.0": None,
+    }
+
+    for dep in recipe["requirements"]["run"]:
+        dep_str = str(dep)
+        assert dep_str in selectors
+        selector = selectors[dep_str]
+        if dep.inline_comment is None:
+            assert selector is None
+        else:
+            assert str(dep.inline_comment) == selector
+
+    # another example with selectors
+    config = Configuration(name="databricks-sql-connector", version="3.7.0")
+    recipe = GrayskullFactory.create_recipe("pypi", config)
+    assert "noarch" not in recipe["build"]
+    selectors = {
+        "python >=3.8.0,<4.0.0": None,
+        "thrift >=0.16.0,<0.21.0": None,
+        "pandas >=1.2.5,<2.3.0": "[py>=38]",
+        "pyarrow >=14.0.1": None,
+        "lz4 >=4.0.2,<5.0.0": None,
+        "requests >=2.18.1,<3.0.0": None,
+        "oauthlib >=3.1.0,<4.0.0": None,
+        "numpy >=1.16.6": "[py>=38 and py<311]",
+        "numpy >=1.23.4": "[py>=311]",
+        "openpyxl >=3.0.10,<4.0.0": None,
+        "urllib3 >=1.26": None,
+    }
+
+    for dep in recipe["requirements"]["run"]:
+        dep_str = str(dep)
+        assert dep_str in selectors
+        selector = selectors[dep_str]
+        if dep.inline_comment is None:
+            assert selector is None
+        else:
+            assert str(dep.inline_comment) == selector
+
 
 def test_format_host_requirements():
     assert sorted(format_dependencies(["setuptools>=40.0", "pkg2"], "pkg1")) == sorted(