D - panthenol; provitamin B5 (humectant, emollient)

**D-Panthenol**, also known as **provitamin B5**, is a **water-soluble humectant and emollient** widely used in skincare and haircare for its **hydrating, soothing, and barrier-repairing** properties.

### 🌿 **Key Benefits**:
– **Moisturizing**: Attracts and retains water in the skin, improving **hydration and softness**
– **Emollient Action**: Smooths and softens the skin by filling in **micro-cracks** in the stratum corneum
– **Barrier Support**: Enhances **lipid synthesis** and supports **skin regeneration**, reducing **transepidermal water loss (TEWL)**
– **Soothing & Anti-Inflammatory**: Calms **irritation, redness, and itching**, making it ideal for **sensitive or compromised skin**
– **Wound Healing**: Promotes **fibroblast proliferation** and **collagen production**, aiding in **skin repair**

### 🧴 **Formulation Notes**:
– Typically used at **1–5%** in creams, serums, and lotions
– Water-soluble; added to the **aqueous phase**
– Compatible with **low to neutral pH** systems
– Often paired with **niacinamide, allantoin, or hyaluronic acid** for synergistic soothing effects

D-Panthenol is the **biologically active enantiomer** of panthenol and is more effective than the racemic DL-form. It’s especially valued in **after-sun care, baby products, barrier creams, and scalp treatments**.