Blog Banner

Skincare Clinical Testing

Learn more about what patch testing is

Patch testing is a controlled way to check whether a product can cause acute skin irritation when it sits on the skin under occlusion (covered) for a defined time. A measured amount of product is applied in a small chamber (often on the forearm or back), left for a set duration, then the site is assessed by trained staff/dermatologist for visible reactions like erythema (redness) and oedema (swelling).

Why this matters for complex skincare formulas

Complex formulas—especially those with multiple actives and higher active loads—raise a legitimate scientific concern: does combining many bioactive ingredients increase irritation risk?

PATCH TESTING IS ONE OF THE CLEANEST FIRST ANSWERS BECAUSE IT:

✓ Standardizes dose
✓ Assessment
✓ Contact time
✓ Dermatological Control

Understanding M.C.I.I Measurement

In standardized patch testing, skin reactions are graded using predefined numerical scales that assess erythema (E), which refers to redness, and oedema (O), which refers to swelling.

Each visible reaction is scored according to intensity.
These scores are then combined and averaged to calculate the M.C.I.I.

  • Redness

  • Swelling

  • Dryness or Discomfort

What the M.C.I.I. Scale Tells You

The M.C.I.I. provides a quantitative measure of irritation potential under the specific study conditions.
Interpretation Scale (Maximum possible value: 6)

Why this number matters

PATCH TESTING IS ONE OF THE CLEANEST FIRST ANSWERS BECAUSE IT:

High-actives =
higher irritation risk
Barrier damage
is widespread
Sensitive skin is
increasing globally
Irritation builds
over time

Even well-marketed “active” products can trigger subclinical
irritation that weakens the skin barrier over time.
M.C.I.I. protects against that risk.

Sensitive + Normal Skin AVLˇs Testing benchmark

AVL's Testing benchmark

Skin responses vary across populations. For that reason, our internal standard is to evaluate each finished product:

This dual-cohort design ensures that compatibility is assessed across different reactivity profiles, rather than relying on a single skin type. The result is a more robust assessment of primary irritation potential prior to broader consumer use.

*All testing is conducted under dermatological supervision:
Performed at an independent external clinical investigation center.