diff --git a/cmd/prometheus/main.go b/cmd/prometheus/main.go
index c43e39f927..5b05f225cc 100644
--- a/cmd/prometheus/main.go
+++ b/cmd/prometheus/main.go
@@ -853,6 +853,12 @@ func main() {
 
 	cfg.web.Flags = map[string]string{}
 
+	cfg.tsdb.PreInitFunc = func(db *tsdb.DB) {
+		if err = mapCommonLabelSymbols(db, logger); err != nil {
+			logger.Warn("Failed to map common strings in labels", slog.Any("err", err))
+		}
+	}
+
 	// Exclude kingpin default flags to expose only Prometheus ones.
 	boilerplateFlags := kingpin.New("", "").Version("")
 	for _, f := range a.Model().Flags {
@@ -1242,10 +1248,6 @@ func main() {
 					return fmt.Errorf("opening storage failed: %w", err)
 				}
 
-				if err = mapCommonLabelSymbols(db, logger); err != nil {
-					logger.Warn("Failed to map common strings in labels", slog.Any("err", err))
-				}
-
 				switch fsType := prom_runtime.Statfs(localStoragePath); fsType {
 				case "NFS_SUPER_MAGIC":
 					logger.Warn("This filesystem is not supported and may lead to data corruption and data loss. Please carefully read https://prometheus.io/docs/prometheus/latest/storage/ to learn more about supported filesystems.", "fs_type", fsType)
@@ -1801,6 +1803,7 @@ type tsdbOptions struct {
 	CompactionDelayMaxPercent      int
 	EnableOverlappingCompaction    bool
 	EnableOOONativeHistograms      bool
+	PreInitFunc                    tsdb.PreInitFunc
 }
 
 func (opts tsdbOptions) ToTSDBOptions() tsdb.Options {
@@ -1825,6 +1828,7 @@ func (opts tsdbOptions) ToTSDBOptions() tsdb.Options {
 		EnableDelayedCompaction:        opts.EnableDelayedCompaction,
 		CompactionDelayMaxPercent:      opts.CompactionDelayMaxPercent,
 		EnableOverlappingCompaction:    opts.EnableOverlappingCompaction,
+		PreInitFunc:                    opts.PreInitFunc,
 	}
 }
 
diff --git a/tsdb/db.go b/tsdb/db.go
index 9ab150c5b4..bd02ea4103 100644
--- a/tsdb/db.go
+++ b/tsdb/db.go
@@ -224,6 +224,9 @@ type Options struct {
 	// PostingsDecoderFactory allows users to customize postings decoders based on BlockMeta.
 	// By default, DefaultPostingsDecoderFactory will be used to create raw posting decoder.
 	PostingsDecoderFactory PostingsDecoderFactory
+
+	// PreInitFunc is a function that will be called before the HEAD is initialized.
+	PreInitFunc PreInitFunc
 }
 
 type NewCompactorFunc func(ctx context.Context, r prometheus.Registerer, l *slog.Logger, ranges []int64, pool chunkenc.Pool, opts *Options) (Compactor, error)
@@ -234,6 +237,8 @@ type BlockQuerierFunc func(b BlockReader, mint, maxt int64) (storage.Querier, er
 
 type BlockChunkQuerierFunc func(b BlockReader, mint, maxt int64) (storage.ChunkQuerier, error)
 
+type PreInitFunc func(*DB)
+
 // DB handles reads and writes of time series falling into
 // a hashed partition of a seriedb.
 type DB struct {
@@ -1011,6 +1016,10 @@ func open(dir string, l *slog.Logger, r prometheus.Registerer, opts *Options, rn
 		minValidTime = inOrderMaxTime
 	}
 
+	if db.opts.PreInitFunc != nil {
+		db.opts.PreInitFunc(db)
+	}
+
 	if initErr := db.head.Init(minValidTime); initErr != nil {
 		db.head.metrics.walCorruptionsTotal.Inc()
 		var e *errLoadWbl