diff --git a/src/app/api/auth/me/modules/route.ts b/src/app/api/auth/me/modules/route.ts
index 5c10e8d93..abeceb8de 100644
--- a/src/app/api/auth/me/modules/route.ts
+++ b/src/app/api/auth/me/modules/route.ts
@@ -44,6 +44,7 @@ import {
 } from "@/lib/optimistic-lock";
 import { resolveModuleMap, normalisePrefs } from "@/lib/modules/gate";
 import { modulePrefsPatchSchema } from "@/lib/validations/modules";
+import { recomputeSupplementsIfNutrientsTurnedOn } from "@/lib/medications/ingredients/recompute-job";
 
 export const dynamic = "force-dynamic";
 
@@ -140,6 +141,12 @@ export const PATCH = apiHandler(async (req: Request) => {
   });
   if ("conflict" in guarded) return guarded.conflict;
 
+  await recomputeSupplementsIfNutrientsTurnedOn(
+    user.id,
+    existing?.modulePreferencesJson,
+    merged,
+  );
+
   // A module toggle can add or remove a Health Score pillar, so the
   // cached composite was computed from a composition that no longer
   // holds. Without this the score stays stale for up to an hour after a
diff --git a/src/app/api/auth/me/timezone/__tests__/route.test.ts b/src/app/api/auth/me/timezone/__tests__/route.test.ts
index 8fa2a9216..5cd3cfff8 100644
--- a/src/app/api/auth/me/timezone/__tests__/route.test.ts
+++ b/src/app/api/auth/me/timezone/__tests__/route.test.ts
@@ -31,6 +31,12 @@ vi.mock("@/lib/rollups/medication-compliance-rollups", () => ({
   enqueueUserMedicationComplianceBackfill: refoldMock,
 }));
 
+// The supplement nutrient rows are keyed by the same local day.
+const nutrientMock = vi.hoisted(() => vi.fn(async () => ({ queued: true })));
+vi.mock("@/lib/medications/ingredients/recompute-job", () => ({
+  enqueueSupplementNutrientRecompute: nutrientMock,
+}));
+
 vi.mock("next/headers", () => ({
   headers: vi.fn(async () => ({ get: () => null })),
   cookies: vi.fn(async () => ({
@@ -118,6 +124,7 @@ describe("PUT /api/auth/me/timezone", () => {
     const res = await PUT(mkReq({ timezone: "America/New_York" }));
     expect(res.status).toBe(200);
     expect(refoldMock).toHaveBeenCalledWith("user-1");
+    expect(nutrientMock).toHaveBeenCalledWith("user-1");
   });
 
   it("does not re-fold when the zone is unchanged", async () => {
@@ -130,6 +137,7 @@ describe("PUT /api/auth/me/timezone", () => {
     const res = await PUT(mkReq({ timezone: "Europe/Berlin" }));
     expect(res.status).toBe(200);
     expect(refoldMock).not.toHaveBeenCalled();
+    expect(nutrientMock).not.toHaveBeenCalled();
   });
 
   it("trims whitespace before validating", async () => {
diff --git a/src/app/api/auth/me/timezone/route.ts b/src/app/api/auth/me/timezone/route.ts
index 0bc0c0503..ad4ff0485 100644
--- a/src/app/api/auth/me/timezone/route.ts
+++ b/src/app/api/auth/me/timezone/route.ts
@@ -29,6 +29,7 @@ import {
 import { annotate } from "@/lib/logging/context";
 import { auditLog } from "@/lib/auth/audit";
 import { invalidateUserTimezone, isValidTimezone } from "@/lib/tz/resolver";
+import { enqueueSupplementNutrientRecompute } from "@/lib/medications/ingredients/recompute-job";
 import { enqueueUserMedicationComplianceBackfill } from "@/lib/rollups/medication-compliance-rollups";
 
 export const PUT = apiHandler(async (request: NextRequest) => {
@@ -69,6 +70,8 @@ export const PUT = apiHandler(async (request: NextRequest) => {
   // job; best-effort, the singleton key collapses rapid re-picks.
   if ((before?.timezone ?? null) !== tz) {
     const refold = await enqueueUserMedicationComplianceBackfill(user.id);
+    // The supplement nutrient rows are keyed by the same local day.
+    await enqueueSupplementNutrientRecompute(user.id);
     annotate({
       meta: {
         timezone_compliance_refold_enqueued: refold.enqueued,
diff --git a/src/app/api/record-settings/[family]/route.ts b/src/app/api/record-settings/[family]/route.ts
index c899bd3ba..86b6b465c 100644
--- a/src/app/api/record-settings/[family]/route.ts
+++ b/src/app/api/record-settings/[family]/route.ts
@@ -1,5 +1,6 @@
 import type { NextRequest } from "next/server";
 
+import { enqueueSupplementNutrientRecompute } from "@/lib/medications/ingredients/recompute-job";
 import {
   apiHandler,
   requireGuardianAuth,
@@ -239,6 +240,8 @@ export const PATCH = apiHandler(
           }
           if (patch.timezone !== undefined) {
             invalidateUserMedications(access.recordId, { evict: true });
+            // The supplement nutrient rows are keyed by the local day.
+            await enqueueSupplementNutrientRecompute(access.recordId);
           }
           settings = {
             ...record,
diff --git a/src/lib/medications/ingredients/__tests__/recompute-on-switch.test.ts b/src/lib/medications/ingredients/__tests__/recompute-on-switch.test.ts
new file mode 100644
index 000000000..85a96b078
--- /dev/null
+++ b/src/lib/medications/ingredients/__tests__/recompute-on-switch.test.ts
@@ -0,0 +1,41 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+const send = vi.hoisted(() => vi.fn(async () => "job-1"));
+vi.mock("@/lib/jobs/boss-instance", () => ({
+  getGlobalBoss: () => ({ send }),
+}));
+vi.mock("@/lib/db", () => ({ prisma: {} }));
+vi.mock("@/lib/logging/context", () => ({ annotate: vi.fn() }));
+vi.mock("../recompute", () => ({
+  recomputeSupplementNutrientsForUser: vi.fn(),
+}));
+
+import { recomputeSupplementsIfNutrientsTurnedOn } from "../recompute-job";
+
+beforeEach(() => send.mockClear());
+
+describe("the supplement recompute after a module switch", () => {
+  it("queues the full recompute when nutrients comes back on", async () => {
+    await recomputeSupplementsIfNutrientsTurnedOn(
+      "user-1",
+      { nutrients: false },
+      { nutrients: true },
+    );
+    expect(send).toHaveBeenCalledTimes(1);
+    expect(send.mock.calls[0]?.[1]).toMatchObject({ userId: "user-1" });
+  });
+
+  it("queues nothing when the switch did not move to on", async () => {
+    await recomputeSupplementsIfNutrientsTurnedOn(
+      "user-1",
+      { nutrients: true },
+      { nutrients: true, mood: false },
+    );
+    await recomputeSupplementsIfNutrientsTurnedOn(
+      "user-1",
+      { nutrients: true },
+      { nutrients: false },
+    );
+    expect(send).not.toHaveBeenCalled();
+  });
+});
diff --git a/src/lib/medications/ingredients/recompute-job.ts b/src/lib/medications/ingredients/recompute-job.ts
index 2f0e00759..e42624420 100644
--- a/src/lib/medications/ingredients/recompute-job.ts
+++ b/src/lib/medications/ingredients/recompute-job.ts
@@ -17,6 +17,8 @@
 import { prisma } from "@/lib/db";
 import { getGlobalBoss } from "@/lib/jobs/boss-instance";
 import { annotate } from "@/lib/logging/context";
+import { normalisePrefs } from "@/lib/modules/gate";
+import { isOptInModule } from "@/lib/modules/registry";
 
 import { recomputeSupplementNutrientsForUser } from "./recompute";
 
@@ -67,6 +69,28 @@ export async function enqueueSupplementNutrientRecompute(
   return { queued: false };
 }
 
+/** The account's own `nutrients` switch in a stored preference blob. */
+function nutrientsSwitchOn(prefs: unknown): boolean {
+  const value = normalisePrefs(prefs).nutrients;
+  return isOptInModule("nutrients") ? value === true : value !== false;
+}
+
+/**
+ * Queue the full recompute when a preference write turned the account's
+ * `nutrients` switch back on. While the module is off nothing is written
+ * (`recompute.ts`), so a dose removed, a composition changed or a zone moved
+ * in the meantime left the stored rows as they were; the first pass after
+ * the switch puts them right instead of the next unrelated change.
+ */
+export async function recomputeSupplementsIfNutrientsTurnedOn(
+  userId: string,
+  before: unknown,
+  after: unknown,
+): Promise<void> {
+  if (nutrientsSwitchOn(before) || !nutrientsSwitchOn(after)) return;
+  await enqueueSupplementNutrientRecompute(userId);
+}
+
 /** The pg-boss handler body for one job. */
 export async function runSupplementNutrientRecompute(
   payload: SupplementNutrientRecomputePayload,
diff --git a/src/lib/record-settings/modules.ts b/src/lib/record-settings/modules.ts
index 13428f2ad..0c2df12e9 100644
--- a/src/lib/record-settings/modules.ts
+++ b/src/lib/record-settings/modules.ts
@@ -35,6 +35,7 @@
 import { invalidateUserHealthScore } from "@/lib/cache/invalidate";
 import { getOrCreateCycleProfile } from "@/lib/cycle/profile";
 import { prisma, toJson } from "@/lib/db";
+import { recomputeSupplementsIfNutrientsTurnedOn } from "@/lib/medications/ingredients/recompute-job";
 
 export interface RecordModuleWrite {
   /** The record whose modules these are — never the actor, under a switch. */
@@ -59,10 +60,19 @@ export async function writeRecordModulePreferences(
   input: RecordModuleWrite,
 ): Promise<{ cycleTrackingEnabled: boolean | null }> {
   if (input.modulePreferences !== undefined) {
+    const before = await prisma.user.findUnique({
+      where: { id: input.recordId },
+      select: { modulePreferencesJson: true },
+    });
     await prisma.user.update({
       where: { id: input.recordId },
       data: { modulePreferencesJson: toJson(input.modulePreferences) },
     });
+    await recomputeSupplementsIfNutrientsTurnedOn(
+      input.recordId,
+      before?.modulePreferencesJson,
+      input.modulePreferences,
+    );
   }
   if (input.cycleTrackingEnabled !== undefined) {
     await getOrCreateCycleProfile(input.recordId);