diff --git a/pkg/metric/metric_test.go b/pkg/metric/metric_test.go
index 65eafc0db..57e24601e 100644
--- a/pkg/metric/metric_test.go
+++ b/pkg/metric/metric_test.go
@@ -1127,7 +1127,7 @@ func TestMetricProfiling(t *testing.T) {
 
 			// Check the header
 			lines := bufio.NewScanner(f)
-			expectedHeader := "Time (ns)\t" + strings.Join(test.metricNames, "\t")
+			expectedHeader := metricsPrefix + "Time (ns)\t" + strings.Join(test.metricNames, "\t")
 			lines.Scan()
 			header := lines.Text()
 			if header != expectedHeader {
@@ -1141,7 +1141,7 @@ func TestMetricProfiling(t *testing.T) {
 			prevValues := make([]uint64, numMetrics)
 			numDatapoints := 0
 			for lines.Scan() {
-				line := lines.Text()
+				line := strings.TrimPrefix(lines.Text(), metricsPrefix)
 				numDatapoints++
 				items := strings.Split(line, "\t")
 				if len(items) != (numMetrics + 1) {
diff --git a/pkg/metric/profiling_metric.go b/pkg/metric/profiling_metric.go
index ae5b0d5d0..1964b709c 100644
--- a/pkg/metric/profiling_metric.go
+++ b/pkg/metric/profiling_metric.go
@@ -30,6 +30,8 @@ import (
 const (
 	snapshotBufferSize     = 1000
 	snapshotRingbufferSize = 16
+	// metricsPrefix is prepended before every metrics line.
+	metricsPrefix = "GVISOR_METRICS\t"
 )
 
 var (
@@ -85,7 +87,8 @@ func StartProfilingMetrics(profilingMetrics string, profilingRate time.Duration)
 	}
 
 	var values []func(fieldValues ...*FieldValue) uint64
-	header := strings.Builder{}
+	var header strings.Builder
+	header.WriteString(metricsPrefix)
 	header.WriteString("Time (ns)")
 	numMetrics := 0
 
@@ -136,6 +139,7 @@ func StartProfilingMetrics(profilingMetrics string, profilingRate time.Duration)
 	writeCh := make(chan writeReq, snapshotRingbufferSize)
 	go collectProfilingMetrics(&s, values, profilingRate, writeCh)
 	go writeProfilingMetrics(&s, header.String(), writeCh)
+	log.Infof("Profiling metrics started.")
 
 	return nil
 }
@@ -213,6 +217,7 @@ func writeProfilingMetrics(s *snapshots, header string, writeReqs <-chan writeRe
 		s.curWriterIndex.Store(int32(req.ringbufferIdx))
 
 		for i := 0; i < req.numLines; i++ {
+			out.WriteString(metricsPrefix)
 			base := i * numEntries
 			// Write the time
 			prometheus.WriteInteger(out, int64(s.ringbuffer[req.ringbufferIdx][base]))
diff --git a/runsc/cli/BUILD b/runsc/cli/BUILD
index 000d3f033..df7226ca0 100644
--- a/runsc/cli/BUILD
+++ b/runsc/cli/BUILD
@@ -15,7 +15,6 @@ go_library(
     deps = [
         "//pkg/coverage",
         "//pkg/log",
-        "//pkg/metric",
         "//pkg/refs",
         "//pkg/sentry/platform",
         "//pkg/sentry/syscalls/linux",
diff --git a/runsc/cli/main.go b/runsc/cli/main.go
index c44ad0cb5..0e79ef39b 100644
--- a/runsc/cli/main.go
+++ b/runsc/cli/main.go
@@ -31,7 +31,6 @@ import (
 	"golang.org/x/sys/unix"
 	"gvisor.dev/gvisor/pkg/coverage"
 	"gvisor.dev/gvisor/pkg/log"
-	"gvisor.dev/gvisor/pkg/metric"
 	"gvisor.dev/gvisor/pkg/refs"
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/pkg/sentry/syscalls/linux"
@@ -55,11 +54,10 @@ var (
 	// system that are not covered by the runtime spec.
 
 	// Debugging flags.
-	logFD              = flag.Int("log-fd", -1, "file descriptor to log to.  If set, the 'log' flag is ignored.")
-	debugLogFD         = flag.Int("debug-log-fd", -1, "file descriptor to write debug logs to.  If set, the 'debug-log-dir' flag is ignored.")
-	panicLogFD         = flag.Int("panic-log-fd", -1, "file descriptor to write Go's runtime messages.")
-	coverageFD         = flag.Int("coverage-fd", -1, "file descriptor to write Go coverage output.")
-	profilingMetricsFD = flag.Int("profiling-metrics-fd", -1, "file descriptor to write sentry profiling metrics.")
+	logFD      = flag.Int("log-fd", -1, "file descriptor to log to.  If set, the 'log' flag is ignored.")
+	debugLogFD = flag.Int("debug-log-fd", -1, "file descriptor to write debug logs to.  If set, the 'debug-log-dir' flag is ignored.")
+	panicLogFD = flag.Int("panic-log-fd", -1, "file descriptor to write Go's runtime messages.")
+	coverageFD = flag.Int("coverage-fd", -1, "file descriptor to write Go coverage output.")
 )
 
 // Main is the main entrypoint.
@@ -202,12 +200,6 @@ func Main() {
 		f := os.NewFile(uintptr(*coverageFD), "coverage file")
 		coverage.EnableReport(f)
 	}
-	if *profilingMetricsFD >= 0 {
-		metric.ProfilingMetricWriter = os.NewFile(uintptr(*profilingMetricsFD), "metrics file")
-		if metric.ProfilingMetricWriter == nil {
-			log.Warningf("Failed to use -profiling-metrics-fd")
-		}
-	}
 	if conf.TestOnlyAllowRunAsCurrentUserWithoutChroot {
 		// SIGTERM is sent to all processes if a test exceeds its
 		// timeout and this case is handled by syscall_test_runner.
diff --git a/runsc/cmd/boot.go b/runsc/cmd/boot.go
index 1f72e8165..665fec975 100644
--- a/runsc/cmd/boot.go
+++ b/runsc/cmd/boot.go
@@ -153,6 +153,9 @@ type Boot struct {
 	// FDs for profile data.
 	profileFDs profile.FDArgs
 
+	// profilingMetricsFD is a file descriptor to write Sentry metrics data to.
+	profilingMetricsFD int
+
 	// procMountSyncFD is a file descriptor that has to be closed when the
 	// procfs mount isn't needed anymore.
 	procMountSyncFD int
@@ -215,6 +218,7 @@ func (b *Boot) SetFlags(f *flag.FlagSet) {
 
 	// Profiling flags.
 	b.profileFDs.SetFromFlags(f)
+	f.IntVar(&b.profilingMetricsFD, "profiling-metrics-fd", -1, "file descriptor to write sentry profiling metrics.")
 }
 
 // Execute implements subcommands.Command.Execute.  It starts a sandbox in a
@@ -478,7 +482,8 @@ func (b *Boot) Execute(_ context.Context, f *flag.FlagSet, args ...any) subcomma
 	// but before the start-sync file is notified, as the parent process needs to query for
 	// registered metrics prior to sending the start signal.
 	metric.Initialize()
-	if metric.ProfilingMetricWriter != nil {
+	if b.profilingMetricsFD != -1 {
+		metric.ProfilingMetricWriter = os.NewFile(uintptr(b.profilingMetricsFD), "metrics file")
 		if err := metric.StartProfilingMetrics(conf.ProfilingMetrics, time.Duration(conf.ProfilingMetricsRate)*time.Microsecond); err != nil {
 			l.Destroy()
 			util.Fatalf("unable to start profiling metrics: %v", err)
diff --git a/runsc/config/flags.go b/runsc/config/flags.go
index a3e44a9e5..96d6bd1f3 100644
--- a/runsc/config/flags.go
+++ b/runsc/config/flags.go
@@ -63,7 +63,7 @@ func RegisterFlags(flagSet *flag.FlagSet) {
 	// Metrics flags.
 	flagSet.String("metric-server", "", "if set, export metrics on this address. This may either be 1) 'addr:port' to export metrics on a specific network interface address, 2) ':port' for exporting metrics on all interfaces, or 3) an absolute path to a Unix Domain Socket. The substring '%ID%' will be replaced by the container ID, and '%RUNTIME_ROOT%' by the root. This flag must be specified in both `runsc metric-server` and `runsc create`, and their values must match.")
 	flagSet.String("profiling-metrics", "", "comma separated list of metric names which are going to be written to the profiling-metrics-log file from within the sentry in CSV format. profiling-metrics will be snapshotted at a rate specified by profiling-metrics-rate-us. Requires profiling-metrics-log to be set. (DO NOT USE IN PRODUCTION).")
-	flagSet.String("profiling-metrics-log", "", "file name to use for profiling-metrics output. (DO NOT USE IN PRODUCTION)")
+	flagSet.String("profiling-metrics-log", "", "file name to use for profiling-metrics output; use the special value '-' to write to the user-visible logs. (DO NOT USE IN PRODUCTION)")
 	flagSet.Int("profiling-metrics-rate-us", 1000, "the target rate (in microseconds) at which profiling metrics will be snapshotted.")
 
 	// Debugging flags: strace related
diff --git a/runsc/sandbox/sandbox.go b/runsc/sandbox/sandbox.go
index dbc068a46..b5feb4228 100644
--- a/runsc/sandbox/sandbox.go
+++ b/runsc/sandbox/sandbox.go
@@ -772,9 +772,6 @@ func (s *Sandbox) createSandboxProcess(conf *config.Config, args *Args, startSyn
 			return err
 		}
 	}
-	if err := donations.DonateDebugLogFile("profiling-metrics-fd", conf.ProfilingMetricsLog, "metrics", test); err != nil {
-		return err
-	}
 
 	// Relay all the config flags to the sandbox process.
 	cmd := exec.Command(specutils.ExePath, conf.ToFlags()...)
@@ -1075,6 +1072,13 @@ func (s *Sandbox) createSandboxProcess(conf *config.Config, args *Args, startSyn
 	// Note: this must be done right after "cmd.SysProcAttr.Ctty" is set above
 	// because it relies on stdin being the next FD donated.
 	donations.Donate("stdio-fds", stdios[:]...)
+	if conf.ProfilingMetricsLog == "-" {
+		donations.Donate("profiling-metrics-fd", stdios[1])
+	} else {
+		if err := donations.DonateDebugLogFile("profiling-metrics-fd", conf.ProfilingMetricsLog, "metrics", test); err != nil {
+			return err
+		}
+	}
 
 	totalSysMem, err := totalSystemMemory()
 	if err != nil {