diff --git a/Library/Homebrew/cask_dependent.rb b/Library/Homebrew/cask_dependent.rb
index 01bd0a7f19ff4..9c7127bd166b4 100644
--- a/Library/Homebrew/cask_dependent.rb
+++ b/Library/Homebrew/cask_dependent.rb
@@ -32,7 +32,7 @@ def full_name
 
   sig { returns(T::Array[Dependency]) }
   def runtime_dependencies
-    deps.flat_map { |dep| [dep, *dep.to_formula.runtime_dependencies] }.uniq
+    deps.flat_map { |dep| [dep, *dep.to_installed_formula.runtime_dependencies] }.uniq
   end
 
   sig { returns(T::Array[Dependency]) }
diff --git a/Library/Homebrew/cleanup.rb b/Library/Homebrew/cleanup.rb
index c48f2320fe2be..a30364d64399a 100644
--- a/Library/Homebrew/cleanup.rb
+++ b/Library/Homebrew/cleanup.rb
@@ -722,7 +722,7 @@ def self.autoremove(dry_run: false)
       # Remove formulae listed in HOMEBREW_NO_CLEANUP_FORMULAE and their dependencies.
       if Homebrew::EnvConfig.no_cleanup_formulae.present?
         formulae -= formulae.select { skip_clean_formula?(_1) }
-                            .flat_map { |f| [f, *f.runtime_formula_dependencies] }
+                            .flat_map { |f| [f, *f.installed_runtime_formula_dependencies] }
       end
       casks = Cask::Caskroom.casks
 
diff --git a/Library/Homebrew/cmd/install.rb b/Library/Homebrew/cmd/install.rb
index 5f187843c50c8..167e5072eb9f2 100644
--- a/Library/Homebrew/cmd/install.rb
+++ b/Library/Homebrew/cmd/install.rb
@@ -229,7 +229,6 @@ def run
               dep_names = CaskDependent.new(cask)
                                        .runtime_dependencies
                                        .reject(&:installed?)
-                                       .map(&:to_formula)
                                        .map(&:name)
               next if dep_names.blank?
 
diff --git a/Library/Homebrew/cmd/leaves.rb b/Library/Homebrew/cmd/leaves.rb
index 9ac093f6d4c2d..ec13935950417 100644
--- a/Library/Homebrew/cmd/leaves.rb
+++ b/Library/Homebrew/cmd/leaves.rb
@@ -24,9 +24,9 @@ class Leaves < AbstractCommand
 
       sig { override.void }
       def run
-        leaves_list = Formula.installed - Formula.installed.flat_map(&:runtime_formula_dependencies)
+        leaves_list = Formula.installed - Formula.installed.flat_map(&:installed_runtime_formula_dependencies)
         casks_runtime_dependencies = Cask::Caskroom.casks.flat_map do |cask|
-          CaskDependent.new(cask).runtime_dependencies.map(&:to_formula)
+          CaskDependent.new(cask).runtime_dependencies.map(&:to_installed_formula)
         end
         leaves_list -= casks_runtime_dependencies
         leaves_list.select! { installed_on_request?(_1) } if args.installed_on_request?
diff --git a/Library/Homebrew/dependency.rb b/Library/Homebrew/dependency.rb
index c766e750a2be2..d30df2342e657 100644
--- a/Library/Homebrew/dependency.rb
+++ b/Library/Homebrew/dependency.rb
@@ -36,8 +36,12 @@ def hash
     [name, tags].hash
   end
 
-  def to_formula(prefer_stub: false)
-    formula = Formulary.factory(name, warn: false, prefer_stub:)
+  def to_installed_formula
+    Formulary.from_installed(name)
+  end
+
+  def to_formula
+    formula = Formulary.factory(name, warn: false)
     formula.build = BuildOptions.new(options, formula.options)
     formula
   end
@@ -45,7 +49,7 @@ def to_formula(prefer_stub: false)
   sig { params(minimum_version: T.nilable(Version), minimum_revision: T.nilable(Integer)).returns(T::Boolean) }
   def installed?(minimum_version: nil, minimum_revision: nil)
     formula = begin
-      to_formula(prefer_stub: true)
+      to_installed_formula
     rescue FormulaUnavailableError
       nil
     end
@@ -86,7 +90,7 @@ def satisfied?(inherited_options = [], minimum_version: nil, minimum_revision: n
   end
 
   def missing_options(inherited_options)
-    formula = to_formula(prefer_stub: true)
+    formula = to_installed_formula
     required = options
     required |= inherited_options
     required &= formula.options.to_a
diff --git a/Library/Homebrew/diagnostic.rb b/Library/Homebrew/diagnostic.rb
index b00517b55784f..7d0cf4daef7d5 100644
--- a/Library/Homebrew/diagnostic.rb
+++ b/Library/Homebrew/diagnostic.rb
@@ -21,7 +21,7 @@ module Diagnostic
 
     sig {
       params(formulae: T::Array[Formula], hide: T::Array[String], _block: T.nilable(
-        T.proc.params(formula_name: String, missing_dependencies: T::Array[Formula]).void,
+        T.proc.params(formula_name: String, missing_dependencies: T::Array[Dependency]).void,
       )).returns(T::Hash[String, T::Array[String]])
     }
     def self.missing_deps(formulae, hide = [], &_block)
diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index 33560d6e040e4..f6473e8776057 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -2322,7 +2322,7 @@ def self.installed_formula_names
   sig { returns(T::Array[Formula]) }
   def self.installed
     Formula.cache[:installed] ||= racks.flat_map do |rack|
-      Formulary.from_rack(rack)
+      Formulary.from_installed(rack.basename.to_s)
     rescue
       []
     end.uniq(&:name)
@@ -2478,23 +2478,28 @@ def any_installed_version
   # @api internal
   sig { params(read_from_tab: T::Boolean, undeclared: T::Boolean).returns(T::Array[Dependency]) }
   def runtime_dependencies(read_from_tab: true, undeclared: true)
-    deps = if read_from_tab && undeclared &&
-              (tab_deps = any_installed_keg&.runtime_dependencies)
-      tab_deps.filter_map do |d|
-        full_name = d["full_name"]
-        next unless full_name
+    cache_key = "#{full_name}-#{read_from_tab}-#{undeclared}"
+
+    Formula.cache[:runtime_dependencies] ||= {}
+    Formula.cache[:runtime_dependencies][cache_key] ||= begin
+      deps = if read_from_tab && undeclared &&
+                (tab_deps = any_installed_keg&.runtime_dependencies)
+        tab_deps.filter_map do |d|
+          full_name = d["full_name"]
+          next unless full_name
 
-        Dependency.new full_name
+          Dependency.new full_name
+        end
       end
+      begin
+        deps ||= declared_runtime_dependencies unless undeclared
+        deps ||= (declared_runtime_dependencies | undeclared_runtime_dependencies)
+      rescue FormulaUnavailableError
+        onoe "Could not get runtime dependencies from #{path}!"
+        deps ||= []
+      end
+      deps
     end
-    begin
-      deps ||= declared_runtime_dependencies unless undeclared
-      deps ||= (declared_runtime_dependencies | undeclared_runtime_dependencies)
-    rescue FormulaUnavailableError
-      onoe "Could not get runtime dependencies from #{path}!"
-      deps ||= []
-    end
-    deps
   end
 
   # Returns a list of {Formula} objects that are required at runtime.
@@ -2513,6 +2518,22 @@ def runtime_formula_dependencies(read_from_tab: true, undeclared: true)
     end
   end
 
+  # Returns a list of installed {Formula} objects that are required at runtime.
+  sig { params(read_from_tab: T::Boolean, undeclared: T::Boolean).returns(T::Array[Formula]) }
+  def installed_runtime_formula_dependencies(read_from_tab: true, undeclared: true)
+    cache_key = "#{full_name}-#{read_from_tab}-#{undeclared}"
+
+    Formula.cache[:installed_runtime_formula_dependencies] ||= {}
+    Formula.cache[:installed_runtime_formula_dependencies][cache_key] ||= runtime_dependencies(
+      read_from_tab:,
+      undeclared:,
+    ).filter_map do |d|
+      d.to_installed_formula
+    rescue FormulaUnavailableError
+      nil
+    end
+  end
+
   sig { returns(T::Array[Formula]) }
   def runtime_installed_formula_dependents
     # `any_installed_keg` and `runtime_dependencies` `select`s ensure
@@ -2523,7 +2544,7 @@ def runtime_installed_formula_dependents
                                                                                .select(&:any_installed_keg)
                                                                                .select(&:runtime_dependencies)
                                                                                .select do |f|
-      f.runtime_formula_dependencies.any? do |dep|
+      f.installed_runtime_formula_dependencies.any? do |dep|
         full_name == dep.full_name
       rescue
         name == dep.name
@@ -2533,10 +2554,10 @@ def runtime_installed_formula_dependents
 
   # Returns a list of formulae depended on by this formula that aren't
   # installed.
-  sig { params(hide: T::Array[String]).returns(T::Array[Formula]) }
+  sig { params(hide: T::Array[String]).returns(T::Array[Dependency]) }
   def missing_dependencies(hide: [])
-    runtime_formula_dependencies.select do |f|
-      hide.include?(f.name) || f.installed_prefixes.empty?
+    runtime_dependencies(read_from_tab: true, undeclared: true).select do |f|
+      hide.include?(f.name) || !f.installed?
     end
   # If we're still getting unavailable formulae at this stage the best we can
   # do is just return no results.
diff --git a/Library/Homebrew/formulary.rb b/Library/Homebrew/formulary.rb
index dcf95aeceea7f..7b223aab62194 100644
--- a/Library/Homebrew/formulary.rb
+++ b/Library/Homebrew/formulary.rb
@@ -551,7 +551,7 @@ def self.resolve(
     else
       rack = to_rack(name)
       alias_path = factory(name, force_bottle:, flags:, prefer_stub:).alias_path
-      f = from_rack(rack, *spec, alias_path:, force_bottle:, flags:)
+      f = from_rack(rack, *spec, alias_path:, force_bottle:, flags:, prefer_stub:)
     end
 
     # If this formula was installed with an alias that has since changed,
@@ -949,9 +949,15 @@ class FromKegLoader < FormulaLoader
     def self.try_new(ref, from: nil, warn: false)
       ref = ref.to_s
 
-      return unless (keg_formula = HOMEBREW_PREFIX/"opt/#{ref}/.brew/#{ref}.rb").file?
+      keg_directory = HOMEBREW_PREFIX/"opt/#{ref}"
+      return unless keg_directory.directory?
 
-      new(ref, keg_formula)
+      # The formula file in `.brew` will use the canonical name, whereas `ref` can be an alias.
+      # Use `Keg#name` to get the canonical name.
+      keg = Keg.new(keg_directory)
+      return unless (keg_formula = HOMEBREW_PREFIX/"opt/#{ref}/.brew/#{keg.name}.rb").file?
+
+      new(keg.name, keg_formula)
     end
   end
 
@@ -1067,7 +1073,12 @@ def klass(flags:, ignore_errors:)
 
     sig { overridable.params(flags: T::Array[String]).void }
     def load_from_api(flags:)
-      json_formula = Homebrew::API::Formula.all_formulae[name]
+      json_formula = if Homebrew::EnvConfig.use_internal_api?
+        Homebrew::API::Formula.formula_json(name)
+      else
+        Homebrew::API::Formula.all_formulae[name]
+      end
+
       raise FormulaUnavailableError, name if json_formula.nil?
 
       Formulary.load_formula_from_json!(name, json_formula, flags:)
@@ -1177,9 +1188,10 @@ def self.factory(
       alias_path:   T.any(NilClass, Pathname, String),
       force_bottle: T::Boolean,
       flags:        T::Array[String],
+      prefer_stub:  T::Boolean,
     ).returns(Formula)
   }
-  def self.from_rack(rack, spec = nil, alias_path: nil, force_bottle: false, flags: [])
+  def self.from_rack(rack, spec = nil, alias_path: nil, force_bottle: false, flags: [], prefer_stub: false)
     kegs = rack.directory? ? rack.subdirs.map { |d| Keg.new(d) } : []
     keg = kegs.find(&:linked?) || kegs.find(&:optlinked?) || kegs.max_by(&:scheme_and_version)
 
@@ -1187,6 +1199,7 @@ def self.from_rack(rack, spec = nil, alias_path: nil, force_bottle: false, flags
       alias_path:,
       force_bottle:,
       flags:,
+      prefer_stub:,
     }.compact
 
     if keg
@@ -1199,7 +1212,7 @@ def self.from_rack(rack, spec = nil, alias_path: nil, force_bottle: false, flags
   # Return whether given rack is keg-only.
   sig { params(rack: Pathname).returns(T::Boolean) }
   def self.keg_only?(rack)
-    Formulary.from_rack(rack).keg_only?
+    Formulary.from_installed(rack.basename.to_s).keg_only?
   rescue FormulaUnavailableError, TapFormulaAmbiguityError
     false
   end
@@ -1213,6 +1226,7 @@ def self.keg_only?(rack)
       alias_path:   T.any(NilClass, Pathname, String),
       force_bottle: T::Boolean,
       flags:        T::Array[String],
+      prefer_stub:  T::Boolean,
     ).returns(Formula)
   }
   def self.from_keg(
@@ -1220,7 +1234,8 @@ def self.from_keg(
     spec = nil,
     alias_path: nil,
     force_bottle: false,
-    flags: []
+    flags: [],
+    prefer_stub: false
   )
     tab = keg.tab
     tap = tab.tap
@@ -1234,6 +1249,7 @@ def self.from_keg(
       warn:         false,
       force_bottle:,
       flags:,
+      prefer_stub:,
     }.compact
 
     f = if tap.nil?
@@ -1252,6 +1268,30 @@ def self.from_keg(
     f
   end
 
+  sig {
+    params(
+      name:          String,
+      spec:          Symbol,
+      alias_path:    T.nilable(Pathname),
+      force_bottle:  T::Boolean,
+      flags:         T::Array[String],
+      ignore_errors: T::Boolean,
+    ).returns(Formula)
+  }
+  def self.from_installed(
+    name,
+    spec = :stable,
+    alias_path: nil,
+    force_bottle: false,
+    flags: [],
+    ignore_errors: false
+  )
+    loader = FromKegLoader.try_new(name, warn: false)
+    raise FormulaUnavailableError, name unless loader
+
+    loader.get_formula(spec, alias_path:, force_bottle:, flags:, ignore_errors:)
+  end
+
   # Return a {Formula} instance directly from contents.
   sig {
     params(
diff --git a/Library/Homebrew/installed_dependents.rb b/Library/Homebrew/installed_dependents.rb
index 14eaf239a0eb2..56cb4f80dbadf 100644
--- a/Library/Homebrew/installed_dependents.rb
+++ b/Library/Homebrew/installed_dependents.rb
@@ -26,7 +26,7 @@ def find_some_installed_dependents(kegs, casks: [])
     kegs_by_source = kegs.group_by do |keg|
       # First, attempt to resolve the keg to a formula
       # to get up-to-date name and tap information.
-      f = keg.to_formula
+      f = keg.to_installed_formula
       keg_formulae << f
       [f.name, f.tap]
     rescue
@@ -47,7 +47,7 @@ def find_some_installed_dependents(kegs, casks: [])
         dependent.missing_dependencies(hide: keg_names)
       when Cask::Cask
         # When checking for cask dependents, we don't care about missing or non-runtime dependencies
-        CaskDependent.new(dependent).runtime_dependencies.map(&:to_formula)
+        CaskDependent.new(dependent).runtime_dependencies
       end
 
       required_kegs = required.filter_map do |f|
diff --git a/Library/Homebrew/keg.rb b/Library/Homebrew/keg.rb
index 92e9b1796a946..ee30de93afccf 100644
--- a/Library/Homebrew/keg.rb
+++ b/Library/Homebrew/keg.rb
@@ -411,7 +411,7 @@ def scheme_and_version
   end
 
   def to_formula
-    Formulary.from_keg(self)
+    Formulary.from_installed(name)
   end
 
   def oldname_opt_records
diff --git a/Library/Homebrew/uninstall.rb b/Library/Homebrew/uninstall.rb
index 62c421cd7f800..09c726fb4de16 100644
--- a/Library/Homebrew/uninstall.rb
+++ b/Library/Homebrew/uninstall.rb
@@ -32,7 +32,7 @@ def self.uninstall_kegs(kegs_by_rack, casks: [], force: false, ignore_dependenci
         else
           kegs.each do |keg|
             begin
-              f = Formulary.from_rack(rack)
+              f = Formulary.from_installed(keg.name)
               if f.pinned?
                 onoe "#{f.full_name} is pinned. You must unpin it to uninstall."
                 break # exit keg loop and move on to next rack
@@ -157,7 +157,7 @@ def are_required_by_deps
     end
 
     def self.rm_pin(rack)
-      Formulary.from_rack(rack).unpin
+      Formulary.from_installed(rack.basename.to_s).unpin
     rescue
       nil
     end
diff --git a/Library/Homebrew/utils/autoremove.rb b/Library/Homebrew/utils/autoremove.rb
index 3e0c136c09a1c..bb88754c3b8e2 100644
--- a/Library/Homebrew/utils/autoremove.rb
+++ b/Library/Homebrew/utils/autoremove.rb
@@ -23,10 +23,16 @@ def removable_formulae(formulae, casks)
       # @private
       sig { params(casks: T::Array[Cask::Cask]).returns(T::Array[Formula]) }
       def formulae_with_cask_dependents(casks)
-        casks.flat_map { |cask| cask.depends_on[:formula] }
-             .compact
-             .map { |f| Formula[f] }
-             .flat_map { |f| [f, *f.runtime_formula_dependencies].compact }
+        casks.flat_map { |cask| cask.depends_on[:formula] }.compact.flat_map do |name|
+          f = begin
+            Formulary.from_installed(name)
+          rescue FormulaUnavailableError
+            nil
+          end
+          next [] unless f
+
+          [f, *f.installed_runtime_formula_dependencies].compact
+        end
       end
 
       # An array of all installed bottled {Formula} without runtime {Formula}
@@ -37,7 +43,7 @@ def formulae_with_cask_dependents(casks)
       def bottled_formulae_with_no_formula_dependents(formulae)
         formulae_to_keep = T.let([], T::Array[Formula])
         formulae.each do |formula|
-          formulae_to_keep += formula.runtime_formula_dependencies
+          formulae_to_keep += formula.installed_runtime_formula_dependencies
 
           if (tab = formula.any_installed_keg&.tab)
             # Ignore build dependencies when the formula is a bottle