1. Vitamin C Brightening Cleanser

1. Purpose: Prepares the canvas. Gently purifies while delivering an initial dose of Vitamin C to wash away impurities and dullness.
2. Key Description: "A refreshing, low-pH gel or foam that removes makeup and pollutants without stripping the skin. Infused with Vitamin C derivatives, it begins the brightening process from the very first step, leaving skin clean, soft, and prepped for treatment."

2. Vitamin C Brightening Toner

1. Purpose: Balances, hydrates, and enhances absorption.
2. Key Description: "An alcohol-free, hydrating toner that replenishes moisture and optimizes skin's pH. Formulated with Vitamin C and skin-soothing ingredients like Hyaluronic Acid or Centella Asiatica, it refines pores and ensures subsequent treatments penetrate deeper for maximum efficacy."

3. Potent Vitamin C Serum (The Star of the Set)

1. Purpose: The high-potency treatment for targeted correction.
2. Key Description: "A high-concentration, stabilized Vitamin C serum (often 10%-20%) combined with synergistic actives like Ferulic Acid, Vitamin E, or Niacinamide. This lightweight, fast-absorbing formula works at the cellular level to block melanin synthesis, visibly fade discoloration, and provide a powerful antioxidant shield."

4. Vitamin C Brightening Moisturizer

1. Purpose: Locks in actives, hydrates, and strengthens the skin barrier.
2. Key Description: "A nourishing yet non-greasy cream or emulsion that seals in the serum's benefits. Enriched with Vitamin C derivatives and brightening botanical extracts (like Licorice Root or Mulberry), it provides 24-hour hydration, reinforces the skin barrier, and ensures continuous brightening throughout the day or night."

5. Broad Spectrum SPF Sunscreen (AM Set Crucial Addition)

1. Purpose: Essential final step for daytime use to protect and prevent reversal of results.
2. Key Description: "A lightweight, non-comedogenic sunscreen (SPF 30/50+). Sun protection is non-negotiable in any whitening routine, as UV exposure is the primary cause of dark spots. This step safeguards your progress, prevents new damage, and ensures your brightening efforts are not undone."

Who Is It For? (Target Audience)

1. Individuals with dull, tired-looking skin lacking radiance.
2. Those struggling with uneven skin tone, sun spots, post-acne marks (PIH), or melasma.
3. All skin types, including sensitive (formulations are often gentle and stabilized). Oily and combination skin particularly benefit from Vitamin C's antioxidant and sebum-regulating properties.
4. Anyone seeking preventative anti-aging alongside brightening.

How to Use (Routine)

1. AM: Cleanser → Toner → Vitamin C Serum → Moisturizer → Sunscreen (MUST).
2. PM: Cleanser (or double cleanse) → Toner → Vitamin C Serum → Moisturizer.

Important Notes to Include:

1. "Whitening" vs. "Brightening": Clarify that the set aims to "brighten" (reduce hyperpigmentation, enhance glow) and even skin tone, not alter your natural skin color.
2. Patch Test: Always recommend a patch test for sensitivity.
3. Consistency is Key: Results are seen with consistent daily use, typically within 4-8 weeks.
4. Sun Protection Mandate: Emphasize that SPF is the most crucial step; without it, dark spots will persist or worsen.
5. Storage: Advise storing the serum (and sometimes the set) in a cool, dark place to maintain the potency of Vitamin C.

Final Marketing Boilerplate:

"Transform your skincare routine into a powerful brightening ritual. Our scientifically-balanced Vitamin C Whitening Set delivers multi-layer correction and defense for luminous, healthy-looking skin. See the difference with consistent use—a complexion that's not just brighter, but truly transformed."

This description covers the scientific appeal, emotional benefit (radiance, confidence), and practical usage, making it effective for both consumers and search engines.