diff --git a/Library/Homebrew/cmd/shellenv.sh b/Library/Homebrew/cmd/shellenv.sh
index 326807d67a..11c1f11852 100644
--- a/Library/Homebrew/cmd/shellenv.sh
+++ b/Library/Homebrew/cmd/shellenv.sh
@@ -15,31 +15,31 @@ homebrew-shellenv() {
       echo "set -gx HOMEBREW_PREFIX \"${HOMEBREW_PREFIX}\";"
       echo "set -gx HOMEBREW_CELLAR \"${HOMEBREW_CELLAR}\";"
       echo "set -gx HOMEBREW_REPOSITORY \"${HOMEBREW_REPOSITORY}\";"
-      [[ -n "${HOMEBREW_SHELLENV_SET}" ]] && return
+      [[ ":${HOMEBREW_SHELLENV_SET}:" == *":${HOMEBREW_PREFIX}:"* ]] && return
       echo "set -q PATH; or set PATH ''; set -gx PATH \"${HOMEBREW_PREFIX}/bin\" \"${HOMEBREW_PREFIX}/sbin\" \$PATH;"
       echo "set -q MANPATH; or set MANPATH ''; set -gx MANPATH \"${HOMEBREW_PREFIX}/share/man\" \$MANPATH;"
       echo "set -q INFOPATH; or set INFOPATH ''; set -gx INFOPATH \"${HOMEBREW_PREFIX}/share/info\" \$INFOPATH;"
-      echo "set -gx HOMEBREW_SHELLENV_SET 1;"
+      echo "set -q HOMEBREW_SHELLENV_SET; or set HOMEBREW_SHELLENV_SET ''; set -gx HOMEBREW_SHELLENV_SET \"${HOMEBREW_PREFIX}\" \$HOMEBREW_SHELLENV_SET;"
       ;;
     csh | -csh | tcsh | -tcsh)
       echo "setenv HOMEBREW_PREFIX ${HOMEBREW_PREFIX};"
       echo "setenv HOMEBREW_CELLAR ${HOMEBREW_CELLAR};"
       echo "setenv HOMEBREW_REPOSITORY ${HOMEBREW_REPOSITORY};"
-      [[ -n "${HOMEBREW_SHELLENV_SET}" ]] && return
+      [[ ":${HOMEBREW_SHELLENV_SET}:" == *":${HOMEBREW_PREFIX}:"* ]] && return
       echo "setenv PATH ${HOMEBREW_PREFIX}/bin:${HOMEBREW_PREFIX}/sbin:\$PATH;"
       echo "setenv MANPATH ${HOMEBREW_PREFIX}/share/man\`[ \${?MANPATH} == 1 ] && echo \":\${MANPATH}\"\`:;"
       echo "setenv INFOPATH ${HOMEBREW_PREFIX}/share/info\`[ \${?INFOPATH} == 1 ] && echo \":\${INFOPATH}\"\`;"
-      echo "setenv HOMEBREW_SHELLENV_SET 1;"
+      echo "setenv HOMEBREW_SHELLENV_SET ${HOMEBREW_PREFIX}\`[ \${?HOMEBREW_SHELLENV_SET} == 1 ] && echo \":\${HOMEBREW_SHELLENV_SET}\"\`;"
       ;;
     *)
       echo "export HOMEBREW_PREFIX=\"${HOMEBREW_PREFIX}\";"
       echo "export HOMEBREW_CELLAR=\"${HOMEBREW_CELLAR}\";"
       echo "export HOMEBREW_REPOSITORY=\"${HOMEBREW_REPOSITORY}\";"
-      [[ -n "${HOMEBREW_SHELLENV_SET}" ]] && return
+      [[ ":${HOMEBREW_SHELLENV_SET}:" == *":${HOMEBREW_PREFIX}:"* ]] && return
       echo "export PATH=\"${HOMEBREW_PREFIX}/bin:${HOMEBREW_PREFIX}/sbin\${PATH+:\$PATH}\";"
       echo "export MANPATH=\"${HOMEBREW_PREFIX}/share/man\${MANPATH+:\$MANPATH}:\";"
       echo "export INFOPATH=\"${HOMEBREW_PREFIX}/share/info:\${INFOPATH:-}\";"
-      echo "export HOMEBREW_SHELLENV_SET=1;"
+      echo "export HOMEBREW_SHELLENV_SET=\"${HOMEBREW_PREFIX}\${HOMEBREW_SHELLENV_SET+:\$HOMEBREW_SHELLENV_SET}\";"
       ;;
   esac
 }
diff --git a/Library/Homebrew/env_config.rb b/Library/Homebrew/env_config.rb
index ed7519c930..95a5422055 100644
--- a/Library/Homebrew/env_config.rb
+++ b/Library/Homebrew/env_config.rb
@@ -306,8 +306,8 @@ module Homebrew
         boolean:     true,
       },
       HOMEBREW_SHELLENV_SET:                  {
-        description: "If set, `brew shellenv` skips export statements for paths.",
-        boolean:     true,
+        description: "A colon separated list of brew prefixes. If it is set and contains the current brew prefix, " \
+                     "`brew shellenv` skips export statements for paths.",
       },
       all_proxy:                              {
         description: "Use this SOCKS5 proxy for `curl`(1), `git`(1) and `svn`(1) when downloading through Homebrew.",
diff --git a/docs/Manpage.md b/docs/Manpage.md
index 5ab46f5a5a..3d2cb825df 100644
--- a/docs/Manpage.md
+++ b/docs/Manpage.md
@@ -2089,7 +2089,7 @@ example, run `export HOMEBREW_NO_INSECURE_REDIRECT=1` rather than just
   <br>If set, verbose output will print a `.` no more than once a minute. This can be useful to avoid long-running Homebrew commands being killed due to no output.
 
 - `HOMEBREW_SHELLENV_SET`
-  <br>If set, `brew shellenv` skips export statements for paths.
+  <br>A colon separated list of brew prefixes. If it is set and contains the current brew prefix, `brew shellenv` skips export statements for paths.
 
 - `all_proxy`
   <br>Use this SOCKS5 proxy for `curl`(1), `git`(1) and `svn`(1) when downloading through Homebrew.
diff --git a/manpages/brew.1 b/manpages/brew.1
index 04f46b8958..acecd9fab0 100644
--- a/manpages/brew.1
+++ b/manpages/brew.1
@@ -1,7 +1,7 @@
 .\" generated with Ronn/v0.7.3
 .\" http://github.com/rtomayko/ronn/tree/0.7.3
 .
-.TH "BREW" "1" "July 2021" "Homebrew" "brew"
+.TH "BREW" "1" "August 2021" "Homebrew" "brew"
 .
 .SH "NAME"
 \fBbrew\fR \- The Missing Package Manager for macOS (or Linux)
@@ -3043,7 +3043,7 @@ If set, verbose output will print a \fB\.\fR no more than once a minute\. This c
 \fBHOMEBREW_SHELLENV_SET\fR
 .
 .br
-If set, \fBbrew shellenv\fR skips export statements for paths\.
+A colon separated list of brew prefixes\. If it is set and contains the current brew prefix, \fBbrew shellenv\fR skips export statements for paths\.
 .
 .TP
 \fBall_proxy\fR