iS Clinical C Eye Serum Advance+ Review

What is iS Clinical C Eye Serum Advance+?

iS Clinical C Eye Serum Advance+ is a lightweight, water-based serum for the under-eye area, built around 7.5% time-released vitamin C and Copper Tripeptide-1. It's formulated for the delicate periorbital skin specifically, rather than a general-purpose face serum used near the eyes, and it's ophthalmologically tested for that reason.

Key ingredients

• 7.5% time-released vitamin C (L-Ascorbic Acid) — a lower, slow-release concentration designed for the thinner skin around the eyes rather than the higher strengths used on the rest of the face.
• Copper Tripeptide-1 — a peptide included to support the look of the eye contour over time.
• Sodium Hyaluronate — a hyaluronic acid derivative for surface hydration and plumping.
• Zinc Sulfate — included as part of the antioxidant complex.

What it's formulated to do

This serum is positioned as a targeted eye treatment rather than a broad anti-ageing product. The combination of time-released vitamin C and Copper Tripeptide-1 is formulated to help improve the appearance of fine lines, under-eye puffiness and a tired-looking eye area, while the hyaluronic acid component adds immediate surface hydration. As with any cosmetic serum, results depend on consistent use and individual skin — none of this is a substitute for a dermatologist's assessment of skin concerns around the eyes.

Texture and how it feels

The formula is a thin, watery serum rather than a rich cream, which is a deliberate choice for the eye area — it absorbs quickly, sits comfortably under makeup or an eye cream, and doesn't leave the heavy or tacky residue that thicker eye balms can. It's designed to layer into both morning and evening routines without disrupting the rest of a skincare regime.

Who it's suited to

It's aimed at people who want a dedicated, gentle eye treatment — including those with sensitive skin around the eyes — who are seeing early fine lines, puffiness or an uneven tone in that area. Because it's a vitamin C serum rather than a retinoid, it sits at the gentler end of the eye-care spectrum; anyone wanting a more active, retinoid-based approach to the eye area may prefer to compare it against iS Clinical Youth Eye Complex, which takes a different route to similar concerns.

How to use it

Apply a small amount to clean, dry skin around the eyes, morning and/or evening, before heavier creams or makeup. A little goes a long way given the concentrated, water-thin texture. As with any vitamin C product, daytime use should be paired with sun protection.

Pregnancy and breastfeeding

If you're pregnant or breastfeeding, please contact our team for advice before use.

What to expect over time

With any vitamin C and peptide serum, the immediate effect is hydration and a brighter, less tired-looking under-eye area — the plumping from Sodium Hyaluronate is noticeable within the first few applications. Changes to fine lines and skin texture are more gradual and tend to build with consistent daily use over several weeks, which is typical of peptide-based formulas generally rather than something specific to this product. We haven't been able to source brand-published before-and-after data or trial figures for this particular serum, so we're not repeating any specific improvement percentages here — just describing what the ingredient profile is formulated to do.

Things to know before buying

• It's an eye-area serum, not a full-face treatment — apply it as a targeted step, not as a replacement for your regular face serum.
• The texture is thin and watery rather than creamy, so if you prefer a richer eye cream feel, layer this underneath one rather than expecting it to replace it.
• Vitamin C serums can be sensitive to light and air; keep the cap on tightly and store away from direct sunlight to help the formula stay stable.
• Patch-test before full use if you have known sensitivities, as with any new active skincare product.

How it compares within the range

Within iS Clinical's line-up, C Eye Serum Advance+ is the eye-specific counterpart to the brand's face serums. For a broader, whole-face vitamin C and peptide treatment, see our review of iS Clinical Super Serum Advance+. For the full range of iS Clinical products we've reviewed, visit the iS Clinical brand hub. Anyone comparing vitamin C serums more broadly across brands can also see our independent roundup of the best vitamin C serums in the UK — this page focuses specifically on the iS Clinical formulation. To understand the ingredients in more depth, our glossary covers vitamin C in skincare and copper peptides.

Our approach

The ingredients, texture and usage details above are drawn from this product's live Shopify listing. We haven't repeated the brand's own "clinically-proven" language, as no accessible study data was provided to support it — see the data gap below. We don't run star ratings on this page; it's an independent breakdown to help you decide if this serum is the right eye treatment for you, not a review-platform score.