diff --git a/docs/dev-tools/backends/pipx.md b/docs/dev-tools/backends/pipx.md
index a06d767043..e33cbc2df8 100644
--- a/docs/dev-tools/backends/pipx.md
+++ b/docs/dev-tools/backends/pipx.md
@@ -27,6 +27,11 @@ This relies on having `uv` (recommended) or `pipx` installed.
 
 If you have `uv` installed, mise will use `uv tool install` under the hood and you don't need to install `pipx` to run the commands containing "pipx:".
 
+When [`install_before`](/configuration/settings.html#install_before) is set and mise installs a
+`pipx:` tool through uv, mise passes uv's `--exclude-newer` flag so transitive Python dependencies
+are resolved only from releases uploaded before that timestamp. This only applies to the uv install
+path; the `pipx` fallback does not receive a transitive release-age cutoff.
+
 In case you need `pipx` for other reasons, you can install it with or without mise.
 Here is how to install `pipx` with mise:
 
diff --git a/docs/dev-tools/mise-lock.md b/docs/dev-tools/mise-lock.md
index 5d272c2ec5..47cd2316a9 100644
--- a/docs/dev-tools/mise-lock.md
+++ b/docs/dev-tools/mise-lock.md
@@ -360,6 +360,10 @@ install_before = "7d"  # only resolve to versions released more than 7 days ago
 
 This pairs well with lockfiles — use `install_before` to avoid picking up brand-new releases, and lockfiles to pin the exact versions you've vetted.
 
+Some package-manager backends also forward this cutoff into transitive dependency resolution during
+install. This includes `npm:` tools and `pipx:` tools installed through uv. The `pipx` fallback path
+does not receive a transitive release-age cutoff.
+
 ## See Also
 
 - [Configuration Settings](/configuration/settings) - All available settings
diff --git a/docs/tips-and-tricks.md b/docs/tips-and-tricks.md
index 6635e3f22c..ebe491f263 100644
--- a/docs/tips-and-tricks.md
+++ b/docs/tips-and-tricks.md
@@ -180,9 +180,10 @@ install_before = "7d"  # only install versions released more than 7 days ago
 
 Supports relative durations (`7d`, `6m`, `1y`) and absolute dates (`2024-06-01`). For most backends, this only affects fuzzy version resolution (e.g., `node@20` or `latest`) — explicitly pinned versions like `node@22.5.0` bypass the filter.
 
-For `npm:` tools, the same cutoff is also forwarded to transitive dependency resolution during
-install. Refer to the [npm backend docs](/dev-tools/backends/npm.html) for package-manager support
-details.
+For `npm:` tools and `pipx:` tools installed through uv, the same cutoff is also forwarded to
+transitive dependency resolution during install. Refer to the
+[npm backend docs](/dev-tools/backends/npm.html) and [pipx backend docs](/dev-tools/backends/pipx.html)
+for package-manager support details.
 
 You can also set `install_before` per-tool to override the global setting:
 
diff --git a/settings.toml b/settings.toml
index 4b27381a50..67f8228821 100644
--- a/settings.toml
+++ b/settings.toml
@@ -1037,6 +1037,10 @@ like `node@20` or `latest`. Explicitly pinned versions like `node@22.5.0` are no
 allowing you to selectively use newer versions for specific tools while keeping others behind the
 cutoff date.
 
+Some package-manager backends also forward the cutoff to transitive dependency resolution during
+install. This includes `npm:` tools and `pipx:` tools installed through uv. The `pipx` fallback path
+does not receive a transitive release-age cutoff.
+
 Can be overridden with the `--before` CLI flag or per-tool with the `install_before` tool option.
 
 ```toml
diff --git a/src/backend/pipx.rs b/src/backend/pipx.rs
index d8b0766b8d..b5e5191003 100644
--- a/src/backend/pipx.rs
+++ b/src/backend/pipx.rs
@@ -18,8 +18,10 @@ use async_trait::async_trait;
 use eyre::{Result, eyre};
 use indexmap::IndexMap;
 use itertools::Itertools;
+use jiff::Timestamp;
 use regex::Regex;
 use std::collections::BTreeMap;
+use std::ffi::OsString;
 use std::path::{Path, PathBuf};
 use std::str::FromStr;
 use std::{fmt::Debug, sync::Arc};
@@ -229,6 +231,7 @@ impl Backend for PIPXBackend {
                 ctx.pr.as_ref(),
             )
             .await?;
+            cmd = cmd.args(Self::uv_exclude_newer_args(ctx.before_date));
             if let Some(args) = tv.request.options().get("uvx_args") {
                 cmd = cmd.args(shell_words::split(args)?);
             }
@@ -288,6 +291,13 @@ pub fn install_time_option_keys() -> Vec<String> {
 }
 
 impl PIPXBackend {
+    fn uv_exclude_newer_args(before_date: Option<Timestamp>) -> Vec<OsString> {
+        match before_date {
+            Some(before_date) => vec!["--exclude-newer".into(), before_date.to_string().into()],
+            None => vec![],
+        }
+    }
+
     pub fn from_arg(ba: BackendArg) -> Self {
         Self {
             latest_version_cache: CacheManagerBuilder::new(
@@ -640,3 +650,32 @@ fn fix_venv_python_symlink(install_path: &Path, pkg_name: &str) -> Result<()> {
 fn fix_venv_python_symlink(_install_path: &Path, _pkg_name: &str) -> Result<()> {
     Ok(())
 }
+
+#[cfg(test)]
+mod tests {
+    use super::PIPXBackend;
+    use pretty_assertions::assert_eq;
+    use std::ffi::OsString;
+
+    #[test]
+    fn test_uv_exclude_newer_args_with_cutoff() {
+        let before_date = "2024-01-02T03:04:05Z".parse().unwrap();
+        let args = PIPXBackend::uv_exclude_newer_args(Some(before_date));
+
+        assert_eq!(
+            args,
+            vec![
+                OsString::from("--exclude-newer"),
+                OsString::from("2024-01-02T03:04:05Z"),
+            ]
+        );
+    }
+
+    #[test]
+    fn test_uv_exclude_newer_args_without_cutoff() {
+        assert_eq!(
+            PIPXBackend::uv_exclude_newer_args(None),
+            Vec::<OsString>::new()
+        );
+    }
+}