Which goes on first: Polyglutamic Acid (PGA) or Retinol?

Apply Polyglutamic Acid (PGA) (Viscosity Tier 2, pH 5.5–6.5) first. Allow 2 minutes before applying Retinol.

Are Polyglutamic Acid (PGA) and Retinol safe during pregnancy?

Polyglutamic Acid (PGA) is classified as PERMITTED. Retinol is classified as DEFER IN PREGNANCY. Always verify with your obstetrician.

Can I Use Polyglutamic Acid (PGA) and Retinol Together?

Active A · Osmolytes & HumectantsTier 2 Viscosity

Polyglutamic Acid (PGA)

Ideal Formulation pH: 5.5 – 6.5

Preferred Routine Slot: AM/PM

Pregnancy Safety: PERMITTED

Typical Clinical Dose: 1% – 5%

View Polyglutamic Acid (PGA) Monograph →

Active B · Cell Turnover / RetinoidsTier 2 Viscosity

Retinol

Ideal Formulation pH: 5.5 – 6.5

Preferred Routine Slot: PM

Pregnancy Safety: DEFER IN PREGNANCY

Typical Clinical Dose: 0.1% – 1.0%

View Retinol Monograph →

🧪Viscosity & pH Application Order

How to Layer These Actives in Your Routine

Step 01Viscosity Tier 2

Polyglutamic Acid (PGA)

Apply first to clean, dry skin. Operates at pH 5.5–6.5.

⏱️Wait 2 Minutes

Allows cutaneous acid mantle to equilibrate before the next step.

Step 02Viscosity Tier 2

Retinol

Layer over the initial active. Operates at pH 5.5–6.5.

Biochemical Mechanism & Pharmacology

Polyglutamic Acid (PGA) provides vital physiological lipids and humectants that reinforce the stratum corneum lipid matrix, preventing trans-epidermal water loss (TEWL) and buffering against irritation from Retinol without attenuating its therapeutic cellular benefits.

Cutaneous pH Stability Note:

Apply the lower viscosity product first, or buffer by applying Polyglutamic Acid (PGA) prior to Retinol for sensitive skin (the sandwich method).

Recommended 7-Day Routine Blueprint

Morning (AM) Routine	Evening (Night A)	Evening (Night B)
✓Gentle Cleanser ✓Polyglutamic Acid (PGA) ✓Broad-Spectrum SPF 50+	•Polyglutamic Acid (PGA) •Retinol •Barrier Seal	•Polyglutamic Acid (PGA) •Retinol •Barrier Seal

Obstetric & Pregnancy Safety Summary

View Full Pregnancy Directory →

Polyglutamic Acid (PGA) is classified as PERMITTED during pregnancy, while Retinol is classified as DEFER IN PREGNANCY under clinical guidelines. Always cross-reference with your physician if expecting.

Clinical Studies & Pharmacological Citations

[1]Cosmetic Dermatology: Principles and Mechanisms of Topical Actives (PubMed PMID: 24993850)

[2]Mechanisms of Retinoids in the Treatment of Skin Aging (PubMed PMID: 17515510)