LEVEL 4 – pH OPTIMUM RETINOL RESTORING - 8000 IUs - Dr Koo Private Practice
LEVEL 4 – pH OPTIMUM RETINOL RESTORING - 8000 IUs - Dr. Koo Private Practice
LEVEL 4 – pH OPTIMUM RETINOL RESTORING - 8000 IUs - Dr. Koo Private Practice
LEVEL 4 – pH OPTIMUM RETINOL RESTORING - 8000 IUs - Dr. Koo Private Practice
LEVEL 4 – pH OPTIMUM RETINOL RESTORING - 8000 IUs - Dr. Koo Private Practice
LEVEL 4 – pH OPTIMUM RETINOL RESTORING - 8000 IUs - Dr. Koo Private Practice
Advanced concentration of medical grade retinol for cell renewal

Dr Koo Level 4 Retinol | Intensive Renewal Serum

$215.00
WHAT IT DOES Repairs Collagen and Elastin, Improves Firmness, Smoothes Visible Lines, Boosts Skin Vibrancy
WHO ITS FOR Deeper Wrinkles, Rough Texture, Significant Pores
KEY INGREDIENTS Retinol, Niacinamide, Squalane, Vitamins D and F, phytosterols, low molecular weight Hyaluronate
Quantity:
Pickup available at Dr Koo Private Practice Skincare Usually ready in 2-4 days

Dr Koo Level 4 Retinol | Intensive Renewal Serum

Dr Koo Private Practice Skincare

Pickup available, usually ready in 2-4 days

10435 Clayton Road
Suite 120
Frontenac MO 63131
United States

+13149848331
Complimentary Shipping on Every Order

Level 4 is the category-defining maximum — 8000 IUs of retinol, buffered to perfection for change without irritation. For skin showing significant aging, from lost firmness to deep wrinkles, the retinol is encapsulated into a formula with niacinamide and Vitamin D and Vitamin F that repairs collagen and elastin and accelerates cell renewal at every layer. Low-molecular-weight hyaluronic acid sustains hydration through nightly use; over time, texture softens and firms and tone grows more even.

Independent clinical evidence — this formulation system
Measured on Level 3 (5000 IUs). Essex Testing Clinic · 33 women, ages 46–69 · nightly use for 8 weeks · evaluated at baseline, 4 and 8 weeks · each participant compared with her own baseline.

  • Fine lines & wrinkles (Visia CR 2.2 imaging): 8.9% improvement at 4 weeks, 13.4% at 8 weeks — 100% of participants improved
  • Elasticity (Cutometer): +8.4% at 4 weeks, +16.1% at 8 weeks — 94% improved
  • Firmness (Cutometer): 28.6% improvement at 4 weeks — 91% improved
  • Radiance (imaging): improved at 4 and 8 weeks — 70% improved at 8 weeks
  • Irritation: none observed in any participant at any visit; 97% reported no significant sensitivity compared with other retinols

All improvements above were statistically significant (p<0.001, except radiance at 4 weeks p=0.032). Signed final report on file.

Level 4 is the same formulation system at a different retinol concentration (8000 IUs), matched to your skin's tolerance and need. The measurements above were taken on Level 3 (5000 IUs); they are not a result for Level 4.