diff --git a/studio/frontend/src/config/training.ts b/studio/frontend/src/config/training.ts
index 873e9aa203..10f7e93e5e 100644
--- a/studio/frontend/src/config/training.ts
+++ b/studio/frontend/src/config/training.ts
@@ -92,6 +92,19 @@ export const OPTIMIZER_OPTIONS: ReadonlyArray<{ value: string; label: string }>
   { value: "adamw_torch_fused", label: "AdamW (PyTorch Fused)" },
 ];
 
+// Optimizers the MLX trainer actually supports on Apple Silicon. Values must
+// match SUPPORTED_MLX_OPTIMIZERS in unsloth-zoo's mlx/trainer.py; on MLX the
+// bitsandbytes/torch names above have no meaning and are remapped to plain
+// AdamW, so Studio offers this list instead when running on a Mac.
+export const MLX_OPTIMIZER_OPTIONS: ReadonlyArray<{ value: string; label: string }> = [
+  { value: "adamw", label: "AdamW" },
+  { value: "adam", label: "Adam" },
+  { value: "lion", label: "Lion" },
+  { value: "muon", label: "Muon" },
+  { value: "sgd", label: "SGD" },
+  { value: "adafactor", label: "Adafactor" },
+];
+
 export const LR_SCHEDULER_OPTIONS: ReadonlyArray<{ value: string; label: string }> = [
   { value: "linear", label: "Linear" },
   { value: "cosine", label: "Cosine" },
diff --git a/studio/frontend/src/features/studio/sections/params-section.tsx b/studio/frontend/src/features/studio/sections/params-section.tsx
index 029fef4e19..3270eb4e3d 100644
--- a/studio/frontend/src/features/studio/sections/params-section.tsx
+++ b/studio/frontend/src/features/studio/sections/params-section.tsx
@@ -36,6 +36,7 @@ import {
   CONTEXT_LENGTHS,
   CPT_TARGET_MODULES,
   LR_SCHEDULER_OPTIONS,
+  MLX_OPTIMIZER_OPTIONS,
   OPTIMIZER_OPTIONS,
   TARGET_MODULES,
 } from "@/config/training";
@@ -204,6 +205,42 @@ export function ParamsSection(): ReactElement {
     setCtxInput(String(store.contextLength));
   }, [store.contextLength]);
 
+  // On Apple Silicon the MLX trainer supports a different optimizer set than
+  // the CUDA/bitsandbytes list, so offer the MLX names there.
+  const isMac = platformDeviceType === "mac";
+  const optimizerOptions = isMac ? MLX_OPTIMIZER_OPTIONS : OPTIMIZER_OPTIONS;
+
+  // On Mac, the MLX backend normalizes every CUDA/bitsandbytes optimizer in
+  // OPTIMIZER_OPTIONS (including the shared default) to plain AdamW, so show
+  // AdamW for those to keep the control truthful and non-blank. Any other
+  // value -- an MLX optimizer the user picked, or an unrecognized/non-canonical
+  // imported one -- is shown as-is rather than mislabeled as AdamW, since the
+  // backend would run or reject it on its own terms. Non-Mac display unchanged.
+  const isCudaAliasOptimizer = OPTIMIZER_OPTIONS.some(
+    (o) => o.value === store.optimizerType,
+  );
+  const selectedOptimizer =
+    isMac && isCudaAliasOptimizer ? "adamw" : store.optimizerType;
+
+  // LoftQ is not supported on MLX (the backend rejects it), so clear a stale
+  // selection to lora on Apple Silicon -- whether persisted, applied from a
+  // model default, or imported -- so the backend never receives it.
+  const setLoraVariant = store.setLoraVariant;
+  useEffect(() => {
+    if (isMac && store.loraVariant === "loftq") {
+      setLoraVariant("lora");
+    }
+  }, [isMac, store.loraVariant, setLoraVariant]);
+
+  // Packing is not supported on MLX (the backend forces it off), so clear it on
+  // Apple Silicon -- the checkbox is disabled and the flag is never sent.
+  const setPacking = store.setPacking;
+  useEffect(() => {
+    if (isMac && store.packing) {
+      setPacking(false);
+    }
+  }, [isMac, store.packing, setPacking]);
+
   const trySetContextLength = (input: string): number | null => {
     const n = Number(input);
     if (Number.isInteger(n) && n > 0) {
@@ -706,8 +743,9 @@ export function ParamsSection(): ReactElement {
                       <button
                         key={opt.value}
                         type="button"
+                        disabled={isMac && opt.value === "loftq"}
                         onClick={() => store.setLoraVariant(opt.value)}
-                        className={`flex-1 corner-squircle rounded-xl border px-3 py-2 text-left transition-colors cursor-pointer ${
+                        className={`flex-1 corner-squircle rounded-xl border px-3 py-2 text-left transition-colors cursor-pointer disabled:cursor-not-allowed disabled:opacity-60 ${
                           store.loraVariant === opt.value
                             ? "border-ring-strong bg-primary/5"
                             : "border-border hover:border-foreground/20"
@@ -715,7 +753,9 @@ export function ParamsSection(): ReactElement {
                       >
                         <p className="text-xs font-medium">{opt.label}</p>
                         <p className="text-ui-10 text-muted-foreground">
-                          {opt.desc}
+                          {isMac && opt.value === "loftq"
+                            ? "Not supported on Apple Silicon"
+                            : opt.desc}
                         </p>
                       </button>
                     ))}
@@ -765,7 +805,11 @@ export function ParamsSection(): ReactElement {
                     label={t("studio.params.optimizer")}
                     tooltip={
                       <>
-                        {t("studio.params.optimizerTooltip")}{" "}
+                        {t(
+                          isMac
+                            ? "studio.params.optimizerTooltipMlx"
+                            : "studio.params.optimizerTooltip",
+                        )}{" "}
                         <a
                           href="https://unsloth.ai/docs/get-started/fine-tuning-llms-guide/lora-hyperparameters-guide"
                           target="_blank"
@@ -778,14 +822,14 @@ export function ParamsSection(): ReactElement {
                     }
                   >
                     <Select
-                      value={store.optimizerType}
+                      value={selectedOptimizer}
                       onValueChange={(v) => store.setOptimizerType(v)}
                     >
                       <SelectTrigger className="w-48">
                         <SelectValue />
                       </SelectTrigger>
                       <SelectContent>
-                        {OPTIMIZER_OPTIONS.map((opt) => (
+                        {optimizerOptions.map((opt) => (
                           <SelectItem key={opt.value} value={opt.value}>
                             {formatOptimizerLabel(opt.value, opt.label, t)}
                           </SelectItem>
@@ -1105,14 +1149,37 @@ export function ParamsSection(): ReactElement {
                       <Checkbox
                         id="packing"
                         checked={store.packing}
+                        disabled={isMac}
                         onCheckedChange={(v) => store.setPacking(!!v)}
                       />
                       <label
                         htmlFor="packing"
-                        className="text-xs cursor-pointer text-muted-foreground"
+                        className={`text-xs text-muted-foreground ${
+                          isMac
+                            ? "cursor-not-allowed opacity-60"
+                            : "cursor-pointer"
+                        }`}
                       >
                         {t("studio.params.enablePacking")}
                       </label>
+                      {isMac && (
+                        <Tooltip>
+                          <TooltipTrigger asChild={true}>
+                            <button
+                              type="button"
+                              className="text-foreground/70 hover:text-foreground"
+                            >
+                              <HugeiconsIcon
+                                icon={InformationCircleIcon}
+                                className="size-3"
+                              />
+                            </button>
+                          </TooltipTrigger>
+                          <TooltipContent>
+                            Packing is not supported on Apple Silicon (MLX).
+                          </TooltipContent>
+                        </Tooltip>
+                      )}
                     </div>
                   )}
                   {!store.isEmbeddingModel && !isCpt && !isRawText && (
diff --git a/studio/frontend/src/features/studio/sections/progress-section.tsx b/studio/frontend/src/features/studio/sections/progress-section.tsx
index 105657e2ef..ad813e888e 100644
--- a/studio/frontend/src/features/studio/sections/progress-section.tsx
+++ b/studio/frontend/src/features/studio/sections/progress-section.tsx
@@ -19,7 +19,8 @@ import {
   PopoverTrigger,
 } from "@/components/ui/popover";
 import { Progress } from "@/components/ui/progress";
-import { OPTIMIZER_OPTIONS } from "@/config/training";
+import { usePlatformStore } from "@/config/env";
+import { MLX_OPTIMIZER_OPTIONS, OPTIMIZER_OPTIONS } from "@/config/training";
 import { setTrainingCompareHandoff } from "@/features/chat";
 import {
   useTrainingActions,
@@ -92,6 +93,7 @@ export function ProgressSection({
 }: ProgressSectionProps): ReactElement {
   const t = useT();
   const navigate = useNavigate();
+  const platformDeviceType = usePlatformStore((s) => s.deviceType);
   const trainingMethodLabel = getTrainingMethodLabel(data.trainingMethod);
 
   const config = useTrainingConfigStore(
@@ -187,9 +189,18 @@ export function ProgressSection({
   const cfgLoraDropout = cfg?.loraDropout;
   const cfgLoraVariant = cfg?.loraVariant;
 
+  // Mirror the training form: on Mac the CUDA/bitsandbytes optimizer names run
+  // as plain AdamW (the MLX backend normalizes them), so label them AdamW here
+  // too rather than by the requested, unnormalized name.
+  const effectiveOptimizer =
+    platformDeviceType === "mac" &&
+    OPTIMIZER_OPTIONS.some((o) => o.value === cfgOptimizerType)
+      ? "adamw"
+      : cfgOptimizerType;
   const optimizerLabel =
-    OPTIMIZER_OPTIONS.find((o) => o.value === cfgOptimizerType)?.label ??
-    cfgOptimizerType;
+    [...OPTIMIZER_OPTIONS, ...MLX_OPTIMIZER_OPTIONS].find(
+      (o) => o.value === effectiveOptimizer,
+    )?.label ?? effectiveOptimizer;
 
   const configItems: ConfigGroup[] = [
     {
diff --git a/studio/frontend/src/i18n/locales/en.ts b/studio/frontend/src/i18n/locales/en.ts
index 57f06ceb7e..a0f9bfc1cd 100644
--- a/studio/frontend/src/i18n/locales/en.ts
+++ b/studio/frontend/src/i18n/locales/en.ts
@@ -1051,6 +1051,8 @@ export const en = {
       optimizer: "Optimizer",
       optimizerTooltip:
         "Optimization algorithm. 8-bit variants reduce memory usage. Fused is recommended for vision models.",
+      optimizerTooltipMlx:
+        "Optimization algorithm. AdamW is the default. Lion uses less memory but usually needs a lower learning rate.",
       lrScheduler: "LR scheduler",
       lrSchedulerTooltip:
         "How the learning rate changes over training. Linear decays steadily; cosine decays in a curve.",
diff --git a/tests/studio/playwright_ui_font_scale.py b/tests/studio/playwright_ui_font_scale.py
index 7dbe36127c..89c7894929 100644
--- a/tests/studio/playwright_ui_font_scale.py
+++ b/tests/studio/playwright_ui_font_scale.py
@@ -38,7 +38,11 @@ def fail(m):
     raise AssertionError(f"[font-scale] FAIL: {m}")
 
 
-def near(a, b, tol = 0.35):
+def near(
+    a,
+    b,
+    tol = 0.35,
+):
     return a is not None and b is not None and abs(a - b) <= tol
 
 
@@ -86,9 +90,7 @@ def open_appearance(page):
         page.wait_for_timeout(700)
     if page.get_by_role("dialog").count() == 0:
         fail("settings dialog did not open")
-    page.get_by_role("dialog").get_by_role("button").filter(
-        has_text = "Appearance"
-    ).first.click()
+    page.get_by_role("dialog").get_by_role("button").filter(has_text = "Appearance").first.click()
     page.wait_for_timeout(600)
 
 
@@ -153,9 +155,7 @@ def main():
         page.wait_for_timeout(400)
 
         step("overflowing select scrolls its Radix viewport")
-        page.get_by_role("dialog").get_by_role("button").filter(
-            has_text = "Voice"
-        ).first.click()
+        page.get_by_role("dialog").get_by_role("button").filter(has_text = "Voice").first.click()
         page.wait_for_timeout(600)
         page.set_viewport_size({"width": 1440, "height": 480})
         page.locator("[aria-label='Dictation language']").click()
@@ -194,9 +194,7 @@ def main():
         page.wait_for_timeout(400)
 
         step("default restores exactly")
-        page.get_by_role("dialog").get_by_role("button").filter(
-            has_text = "Appearance"
-        ).first.click()
+        page.get_by_role("dialog").get_by_role("button").filter(has_text = "Appearance").first.click()
         page.wait_for_timeout(500)
         set_input(page, "UI font size", DEFAULT)
         final = measure(page)
diff --git a/tests/studio/test_ui_font_scale_contract.py b/tests/studio/test_ui_font_scale_contract.py
index 62bf80e82b..393c60dd6b 100644
--- a/tests/studio/test_ui_font_scale_contract.py
+++ b/tests/studio/test_ui_font_scale_contract.py
@@ -15,9 +15,7 @@ from pathlib import Path
 REPO = Path(__file__).resolve().parents[2]
 SRC = REPO / "studio/frontend/src"
 INDEX_CSS = (SRC / "index.css").read_text(encoding = "utf-8")
-STORE = (SRC / "features/settings/stores/appearance-custom-store.ts").read_text(
-    encoding = "utf-8"
-)
+STORE = (SRC / "features/settings/stores/appearance-custom-store.ts").read_text(encoding = "utf-8")
 SELECT = (SRC / "components/ui/select.tsx").read_text(encoding = "utf-8")
 
 # Raw numeric fontSize props are only allowed where a scaled stylesheet rule
@@ -70,9 +68,7 @@ def test_ui_token_families_exist():
 
 
 def test_explicit_code_font_size_is_never_multiplied():
-    match = re.search(
-        r"html\[data-code-font-size\][^{]*\{([^}]*)\}", INDEX_CSS
-    )
+    match = re.search(r"html\[data-code-font-size\][^{]*\{([^}]*)\}", INDEX_CSS)
     assert match is not None
     body = match.group(1)
     assert "var(--custom-code-font-size)" in body
@@ -83,7 +79,9 @@ def test_radix_select_viewport_owns_the_scroll_state():
     viewport = SELECT[SELECT.index("SelectPrimitive.Viewport") :]
     assert "overflow-y-auto" in viewport.split("</SelectPrimitive.Viewport>")[0]
     # The rounded surface itself must not scroll (WebKit squares its corners).
-    content_cls = re.search(r"SelectPrimitive\.Content[\s\S]*?className=\{cn\(\s*\"([^\"]+)\"", SELECT)
+    content_cls = re.search(
+        r"SelectPrimitive\.Content[\s\S]*?className=\{cn\(\s*\"([^\"]+)\"", SELECT
+    )
     assert content_cls is not None
     assert "overflow-hidden" in content_cls.group(1)
     assert "overflow-y-auto" not in content_cls.group(1)