Decoding Your Skin Code: A Complete Guide

Most skincare routines fail not because the products are ineffective, but because they lack a guiding logic. You buy a serum here, a cream there, layering products without understanding why they go in a certain order or when each ingredient works best.

This is the gap between cosmetics and clinical skincare.

At Dr. Reju-All, every formula follows a prescription logic we call Skin Code (PD3)—a system built by doctors and pharmacists to ensure that every ingredient, every product, and every step in your routine delivers the right efficacy at the right time.

This guide will teach you how to read, layer, and maximize your routine using the same scientific principles we use to design our formulas.

What Is Skin Code (PD3)?

Skin Code is Dr. Reju-All's prescription framework. It stands for three sequential principles that transform random product use into targeted treatment:

Right Ingredients

Every active ingredient is selected based on pharmaceutical evidence, optimal concentration, and purity standards. No trend-chasing. No "ppm game." Just clinically-validated actives at concentrations that work.

Right Prescription

This is where most brands stop—and where we begin. We don't just tell you what ingredients are in a product. We prescribe when to use it (AM/PM/Sometimes), where it fits in your routine (step order), and how it interacts with other actives.

Right Efficacy

Efficacy isn't a marketing claim—it's an outcome. Right efficacy means stability (actives remain potent until application), safety (formulated to minimize irritation), and results you can feel over a 28-day skin renewal cycle.

Together, these three principles form your Skin Code—the prescription logic that turns products into a system.

The Universal Routine Structure

Before we dive into product-specific recommendations, understand the universal layering logic that applies to all skincare:

Rule 1: Thin to Thick
Apply products in order of texture—lightest (watery) to heaviest (cream). This ensures each layer can penetrate without being blocked by occlusive ingredients.

Rule 2: Active Before Barrier
Treatment ingredients (actives) go on before moisturizing or barrier-protecting layers. You want actives to reach the skin, not sit on top of a moisturizer.

Rule 3: Respect AM/PM Chemistry
Some ingredients are photosensitive (degrade in sunlight) or increase sun sensitivity. These belong in your PM routine. Others are protective and belong in AM.

Now let's apply this to the Dr. Reju-All system.

Your Complete Skin Code Routine

Morning (AM) Routine

Step 1: Toner
Prep your skin with a hydrating or pH-balancing toner. This optimizes absorption for the actives that follow.

Step 2: Serum
Apply any AM-appropriate serums. If you're using multiple serums, apply the thinnest consistency first.

Step 3: Advanced PDRN Rejuvenating Cream
Timing: Daily AM
Why now: PDRN supports skin regeneration throughout the day and layers well under sunscreen. Apply after serums but before your barrier cream.

• The Right PDRN: 1,200 ppm at 99% purity with particle size less than 1/3,000 of a pore
• What it does: Deep regeneration, improved elasticity, collagen synthesis
• Usage cycle: Consistent use over 28-day renewal cycles for cumulative results

Step 4: Advanced LC-Ceramide Barrier Cream
Timing: Daily AM
Why last: This seals in all previous layers while strengthening your skin barrier. Its long-chain ceramide structure is skin-identical and absorbs without heaviness.

• The Right Ceramide: Long-chain, patented (KR10-1816019), skin-identical composition
• What it does: Barrier strengthen · Deep hydration · Soothe & calm
• Why it's different: Most products use short-chain ceramides that feel heavy and don't match skin structure. Our long-chain version provides better skin fit and lasting barrier protection—lightweight even in humid climates

Step 5: Sunscreen (Essential)
Always finish your AM routine with broad-spectrum SPF 30 or higher.

Evening (PM) Routine

Step 1: Cleanser
Remove makeup, sunscreen, and daily buildup. Double cleanse if wearing heavy SPF or makeup.

Step 2: Toner
Reset your skin's pH and prep for active absorption.

Step 3: Advanced Retino-Mela Serum
Timing: PM (after toner, before other treatments)
Why PM: Retinoids work during skin's overnight repair cycle and can increase photosensitivity. PM application is both safer and more effective.

• The New Retinoid (HPR): 30× more stable than traditional retinol, ultra-gentle, beginner-friendly
• Four-way melanin control:
  1. HPR — Surface cell turnover
  2. Niacinamide 10% — Blocks melanin transfer
  3. Tranexamic Acid (TXA) 4% — Blocks melanin production
  4. α-Bisabolol — Blocks melanin production + soothing
• What it does: Brightening, anti-aging, texture refinement, pore minimization
• Tolerance note: Non-irritating in testing, but retinoids are potent. Start every other night if you're new to retinoids, then build to nightly use

Step 4: Advanced PDRN Rejuvenating Cream
Timing: Daily PM (after serum)
Why now: PDRN amplifies overnight regeneration. It works synergistically with retinoids—HPR creates turnover, PDRN supports repair.

Step 5: Advanced LC-Ceramide Barrier Cream
Timing: Daily PM (final step)
Why last: Lock in all actives and prevent transepidermal water loss while you sleep. Wake up with strengthened, hydrated skin.

Advanced Layering Logic: When to Adjust

The routine above is your foundation. But Skin Code is flexible—it adapts to your skin's needs, concerns, and tolerance.

Scenario 1: You're New to Retinoids

Adjustment: Use Advanced Retino-Mela Serum every other night for the first two weeks. On "off" nights, skip straight to PDRN after toner. This builds tolerance while maintaining regeneration.

Why it works: HPR is 30× more stable and gentle than retinol, but any retinoid requires an adjustment period. Alternating nights prevents irritation while your skin adapts.

Scenario 2: You Have Sensitive or Compromised Barrier

Adjustment: Use only LC-Ceramide Barrier Cream for 1–2 weeks (AM/PM). Once your barrier is restored (skin feels less reactive, no tightness or flaking), gradually introduce PDRN, then Retino-Mela.

Why it works: Long-chain ceramides rebuild barrier structure. A strong barrier is prerequisite for tolerating actives.

Scenario 3: Post-Laser or Aesthetic Treatment

Adjustment: Pause retinoids for 3–5 days. Use PDRN and Ceramide Barrier Cream exclusively. PDRN accelerates healing; ceramides protect compromised skin.

Clinical note: PDRN is used in clinical settings post-procedure for this exact purpose. Resume retinoids once skin has fully healed (no redness, no sensitivity).

Scenario 4: Targeting Specific Concerns (Hyperpigmentation)

Adjustment: Double down on Retino-Mela Serum—use PM consistently, and if tolerated well, add AM application (with mandatory SPF 50+). The four-way melanin control (HPR + Niacinamide 10% + TXA 4% + α-Bisabolol) works cumulatively.

Why it works: Each ingredient blocks melanin at a different stage—production, transfer, and surface accumulation. Consistent use over 28-day cycles shows progressive brightening.

The 28-Day Skin Code Cycle

Your skin renews itself approximately every 28 days. This is the timeframe for surface cells to be generated, migrate to the top, and shed. It's also the minimum timeframe to evaluate skincare efficacy.

Week 1: Tolerance and absorption—your skin adapts to new actives.
Week 2: Cellular activity—regeneration, turnover, and repair processes accelerate.
Week 3: Visible changes—texture refinement, subtle brightening, improved hydration.
Week 4: Cumulative results—barrier strength, elasticity, reduction in pigmentation or fine lines.

This is why consistency matters. Skipping days disrupts the cycle. Using products sporadically prevents cumulative benefits.

Prescription logic: Use your complete Skin Code routine for at least one full 28-day cycle before adjusting or adding new products.

Common Skin Code Questions

Can I use all three products together?

Yes. The routine is designed for layering. Each product serves a distinct function—turnover (Retino-Mela), regeneration (PDRN), barrier protection (LC-Ceramide)—and they work synergistically without redundancy.

Do I need to patch test?

We recommend patch testing, especially if you have sensitive skin or a history of reactions. Apply a small amount to your inner forearm and wait 24 hours. Full patch test guidance here.

Can I use these products if I'm pregnant?

PDRN and LC-Ceramide: These are cosmetic-grade ingredients. Patch test is advised, but generally safe. Consult your physician if you have concerns.
Retino-Mela (HPR): Retinoids are not recommended during pregnancy. Discontinue use if you are pregnant or planning to become pregnant.

What age should I start using these products?

Cosmetic-grade actives like PDRN and ceramides are generally suitable for ages 3+ (with patch testing). Retinoids like HPR are recommended for ages 18+ due to potency.

I live in a hot, humid climate. Will these feel heavy?

No. The LC-Ceramide Barrier Cream is specifically designed with a lightweight texture suitable for warm, humid regions. Long-chain ceramides absorb without greasiness—unlike short-chain versions that sit on the skin.

Your Prescription: Next Steps

Understanding Skin Code is the first step. Applying it consistently is how you achieve results.

Step 1: Identify Your Starting Point
Are you starting from scratch? Building on an existing routine? Post-procedure recovery? Your starting point determines your first product.

• If you have no routine: Start with LC-Ceramide Barrier Cream (build your foundation)
• If your barrier is strong: Add PDRN (introduce regeneration)
• If you're ready for actives: Layer in Retino-Mela Serum (add turnover and brightening)

Step 2: Follow the 28-Day Cycle
Commit to consistent use. Track changes weekly. Adjust only after completing a full cycle.

Step 3: Refine Your Prescription
Once you've established tolerance and seen initial results, you can adjust timing, frequency, or layering based on your skin's response.

This is Advanced Skincare. Backed by Science. Not guesswork. Not trends. A system built by doctors and pharmacists to deliver right ingredients, right prescription, right efficacy.

Explore the Science Behind Your Skin Code

Want to understand why these formulas work at the molecular level?

• Read Why PDRN Concentration Matters More Than You Think to understand optimal dosing vs. the "ppm game"
• Read HPR vs. Traditional Retinol: The Stability Test to see why stability determines efficacy
• Explore The Science Behind Dr. Reju-All for ingredient deep-dives and clinical research