diff --git a/backend/innercontext/api/routines.py b/backend/innercontext/api/routines.py
index 4322132..ad52e8c 100644
--- a/backend/innercontext/api/routines.py
+++ b/backend/innercontext/api/routines.py
@@ -1,4 +1,5 @@
 import json
+import math
 from datetime import date, timedelta
 from typing import Optional
 from uuid import UUID, uuid4
@@ -306,10 +307,9 @@ def _build_recent_history(session: Session) -> str:
 
 def _build_products_context(
     session: Session,
-    time_filter: Optional[str] = None,
+    products: list[Product],
     reference_date: Optional[date] = None,
 ) -> str:
-    products = _get_available_products(session, time_filter=time_filter)
     product_ids = [p.id for p in products]
     inventory_rows = (
         session.exec(
@@ -400,6 +400,7 @@ def _build_products_context(
 def _get_available_products(
     session: Session,
     time_filter: Optional[str] = None,
+    include_minoxidil: bool = True,
 ) -> list[Product]:
     stmt = select(Product).where(col(Product.is_tool).is_(False))
     products = session.exec(stmt).all()
@@ -407,12 +408,32 @@ def _get_available_products(
     for p in products:
         if p.is_medication and not _is_minoxidil_product(p):
             continue
+        if not include_minoxidil and _is_minoxidil_product(p):
+            continue
         if time_filter and _ev(p.recommended_time) not in (time_filter, "both"):
             continue
         result.append(p)
     return result
 
 
+def _filter_products_by_interval(
+    products: list[Product],
+    routine_date: date,
+    last_used_on_by_product: dict[str, date],
+) -> list[Product]:
+    """Remove products that haven't yet reached their min_interval_hours since last use."""
+    result = []
+    for p in products:
+        if p.min_interval_hours:
+            last_used = last_used_on_by_product.get(str(p.id))
+            if last_used is not None:
+                days_needed = math.ceil(p.min_interval_hours / 24)
+                if routine_date < last_used + timedelta(days=days_needed):
+                    continue
+        result.append(p)
+    return result
+
+
 def _extract_active_names(product: Product) -> list[str]:
     names: list[str] = []
     for a in product.actives or []:
@@ -596,17 +617,23 @@ def suggest_routine(
     grooming_ctx = _build_grooming_context(session, weekdays=[weekday])
     history_ctx = _build_recent_history(session)
     day_ctx = _build_day_context(data.leaving_home)
-    products_ctx = _build_products_context(
-        session, time_filter=data.part_of_day.value, reference_date=data.routine_date
-    )
     available_products = _get_available_products(
         session,
         time_filter=data.part_of_day.value,
+        include_minoxidil=data.include_minoxidil_beard,
     )
     last_used_on_by_product = build_last_used_on_by_product(
         session,
         product_ids=[p.id for p in available_products],
     )
+    available_products = _filter_products_by_interval(
+        available_products,
+        data.routine_date,
+        last_used_on_by_product,
+    )
+    products_ctx = _build_products_context(
+        session, available_products, reference_date=data.routine_date
+    )
     objectives_ctx = _build_objectives_context(data.include_minoxidil_beard)
 
     mode_line = "MODE: standard"
@@ -762,7 +789,13 @@ def suggest_batch(
     skin_ctx = _build_skin_context(session)
     grooming_ctx = _build_grooming_context(session, weekdays=weekdays)
     history_ctx = _build_recent_history(session)
-    products_ctx = _build_products_context(session, reference_date=data.from_date)
+    batch_products = _get_available_products(
+        session,
+        include_minoxidil=data.include_minoxidil_beard,
+    )
+    products_ctx = _build_products_context(
+        session, batch_products, reference_date=data.from_date
+    )
     objectives_ctx = _build_objectives_context(data.include_minoxidil_beard)
 
     date_range_lines = []
diff --git a/backend/tests/test_routines_helpers.py b/backend/tests/test_routines_helpers.py
index d37326a..40cce52 100644
--- a/backend/tests/test_routines_helpers.py
+++ b/backend/tests/test_routines_helpers.py
@@ -15,6 +15,7 @@ from innercontext.api.routines import (
     _ev,
     _extract_active_names,
     _extract_requested_product_ids,
+    _filter_products_by_interval,
     _get_available_products,
     _is_minoxidil_product,
 )
@@ -204,9 +205,8 @@ def test_build_products_context(session: Session):
     session.add(s)
     session.commit()
 
-    ctx = _build_products_context(
-        session, time_filter="am", reference_date=date.today()
-    )
+    products_am = _get_available_products(session, time_filter="am")
+    ctx = _build_products_context(session, products_am, reference_date=date.today())
     # p1 is medication but not minoxidil (wait, Regaine name doesn't contain minoxidil!) -> skipped
     assert "Regaine" not in ctx
 
@@ -215,9 +215,8 @@ def test_build_products_context(session: Session):
     session.add(p1)
     session.commit()
 
-    ctx = _build_products_context(
-        session, time_filter="am", reference_date=date.today()
-    )
+    products_am = _get_available_products(session, time_filter="am")
+    ctx = _build_products_context(session, products_am, reference_date=date.today())
     assert "Regaine Minoxidil" in ctx
     assert "Sunscreen" in ctx
     assert "inventory_status={active:2,opened:1,sealed:1}" in ctx
@@ -375,6 +374,106 @@ def test_extract_active_names_uses_compact_distinct_names(session: Session):
     assert names == ["Niacinamide", "Zinc PCA"]
 
 
+def test_get_available_products_excludes_minoxidil_when_flag_false(session: Session):
+    minoxidil = Product(
+        id=uuid.uuid4(),
+        name="Minoxidil 5%",
+        category="hair_treatment",
+        is_medication=True,
+        brand="Test",
+        recommended_time="both",
+        leave_on=True,
+        product_effect_profile={},
+    )
+    regular = Product(
+        id=uuid.uuid4(),
+        name="Cleanser",
+        category="cleanser",
+        brand="Test",
+        recommended_time="both",
+        leave_on=False,
+        product_effect_profile={},
+    )
+    session.add_all([minoxidil, regular])
+    session.commit()
+
+    # With flag True (default) - minoxidil included
+    products = _get_available_products(session, include_minoxidil=True)
+    names = {p.name for p in products}
+    assert "Minoxidil 5%" in names
+    assert "Cleanser" in names
+
+    # With flag False - minoxidil excluded
+    products = _get_available_products(session, include_minoxidil=False)
+    names = {p.name for p in products}
+    assert "Minoxidil 5%" not in names
+    assert "Cleanser" in names
+
+
+def test_filter_products_by_interval():
+    today = date.today()
+
+    p_no_interval = Product(
+        id=uuid.uuid4(),
+        name="No Interval",
+        category="serum",
+        brand="Test",
+        recommended_time="both",
+        leave_on=True,
+        product_effect_profile={},
+    )
+    p_interval_72 = Product(
+        id=uuid.uuid4(),
+        name="Retinol",
+        category="serum",
+        brand="Test",
+        recommended_time="pm",
+        leave_on=True,
+        min_interval_hours=72,
+        product_effect_profile={},
+    )
+    p_interval_48 = Product(
+        id=uuid.uuid4(),
+        name="AHA",
+        category="exfoliant",
+        brand="Test",
+        recommended_time="pm",
+        leave_on=True,
+        min_interval_hours=48,
+        product_effect_profile={},
+    )
+
+    last_used = {
+        str(p_interval_72.id): today - timedelta(days=1),  # used yesterday -> need 3 days
+        str(p_interval_48.id): today - timedelta(days=3),  # used 3 days ago -> 48h ok
+    }
+
+    products = [p_no_interval, p_interval_72, p_interval_48]
+    result = _filter_products_by_interval(products, today, last_used)
+    result_names = {p.name for p in result}
+
+    assert "No Interval" in result_names  # always included
+    assert "Retinol" not in result_names  # used 1 day ago, needs 3 -> blocked
+    assert "AHA" in result_names  # used 3 days ago, needs 2 -> ok
+
+
+def test_filter_products_by_interval_never_used_passes():
+    today = date.today()
+    p = Product(
+        id=uuid.uuid4(),
+        name="Retinol",
+        category="serum",
+        brand="Test",
+        recommended_time="pm",
+        leave_on=True,
+        min_interval_hours=72,
+        product_effect_profile={},
+    )
+    # no last_used entry -> should pass
+    result = _filter_products_by_interval([p], today, {})
+    assert len(result) == 1
+
+
 def test_product_details_tool_handler_returns_product_payloads(session: Session):
     p = Product(
         id=uuid.uuid4(),