Best iS Clinical Serums for Anti-Ageing, Sorted by Mechanism

iS Clinical splits its anti-ageing serums into three mechanisms rather than one formula: AHA/BHA acid resurfacing (Active Serum), vitamin C antioxidant protection at three strengths (Super Serum Advance+, Pro-Heal Serum Advance+, GeneXC Serum), and peptide/growth-factor rebuilding (Youth Serum, Youth Complex). Which one suits you depends on what your skin needs first, not which sounds strongest. Below, all six sorted by how they work, not by price or popularity.

Why sort by mechanism, not a single ranking

An acid-resurfacing serum, a vitamin C antioxidant serum and a peptide growth-factor serum address different layers of ageing skin — surface texture and turnover, environmental defence, and the skin's deeper collagen-building processes. iS Clinical's own multi-step regimes combine an acid step with vitamin C or peptides rather than relying on one serum. This guide groups the six by mechanism instead of ranking them against each other.

Quick-reference: iS Clinical anti-ageing serums by mechanism

Prices reflect the UK Skintique listing and can change — check the current PDP before buying.

Route 1: AHA/BHA resurfacing — Active Serum

Active Serum (PDP) is iS Clinical's best-known product and the range's only acid-resurfacing serum, combining Glycolic Acid (Sugar Cane), Lactic Acid (Bilberry), Salicylic Acid (Willow Bark) and Kojic Acid (Mushroom Extract), plus Arbutin. iS Clinical's own description says the blend "provides controlled exfoliation whilst targeting fine lines, acne, and hyperpigmentation," and lists it for all skin types including ageing, acne-prone and sun-damaged skin. It's the only serum here with salicylic acid, so it also targets texture and pore congestion — the vitamin C and peptide routes below don't exfoliate.

Expect a brief cool, tingling sensation on application, which iS Clinical describes as normal; introduce it gradually if you're new to acids, and pair with daily SPF.

Best for: uneven texture, fine lines and hyperpigmentation together.
Skip if: you already use a separate exfoliating acid or retinoid — a straight vitamin C or peptide serum won't compete with what you're using.

Route 2: vitamin C antioxidant — three strengths

This section is scoped to iS Clinical's own vitamin C line. For a cross-brand shortlist, see our best vitamin C serums in the UK guide instead.

Super Serum Advance+ — the standard entry point

Super Serum Advance+ (PDP) pairs 15% time-release L-Ascorbic Acid with bioidentical Copper Tripeptide-1 growth factor, Centella Asiatica, Arbutin and Hyaluronic Acid. iS Clinical states its own research has shown improvement in hypertrophic (raised) scar tissue and fine stretch marks over roughly six months — the brand's own reported research, not an independently verified trial. Positioned for all skin types including sensitive and acne-prone.

Best for: a general vitamin C step that also targets scarring and stretch marks over time.
Skip if: you need calming for redness — try Pro-Heal Serum Advance+ instead.

Pro-Heal Serum Advance+ — for sensitive, reactive or post-procedure skin

Pro-Heal Serum Advance+ (PDP) uses the same 15% time-release L-Ascorbic Acid, formulated for compromised, reactive and inflamed skin, adding Olive Leaf Extract, Vitamin E and 1% Retinol. iS Clinical markets it toward rosacea, cystic acne, contact dermatitis and post-procedure recovery, with vitamin C delivered continuously over 72 hours. It's the one confirmed fragrance-free vitamin C serum of the three, per iS Clinical's own description.

Best for: rosacea-prone, reactive or fragrance-sensitive skin that still wants vitamin C.
Skip if: you already use a separate retinoid at night — the 1% Retinol here means layering retinol twice.

GeneXC Serum — the strongest concentration

GeneXC Serum (PDP) is the most concentrated of the three, built around 20% L-Ascorbic Acid alongside the brand's proprietary Extremozymes® technology — enzymes iS Clinical describes as sourced from land and sea for cellular protection and hydration. It's priced identically at £169 for the 15ml and 30ml sizes, unusual for the range, so check the live PDP before ordering. Its colour may naturally darken over time from the pure vitamin C content, which doesn't affect performance.

Best for: established vitamin C users wanting the brand's most concentrated option.
Skip if: you're new to vitamin C — start with Super Serum Advance+ at 15% first.

Route 3: peptide / growth-factor — Youth Serum and Youth Complex

The Youth line works on a different axis: instead of exfoliating or providing antioxidant defence, both lean on Copper Tripeptide-1, a bioidentical growth-factor peptide iS Clinical uses to support the skin's own collagen-building processes.

Youth Serum — immediate tightening plus long-term collagen support

Youth Serum (PDP) combines Copper Tripeptide-1 with the brand's Extremozyme® technology and an encapsulated Vitamin A, C and E blend, plus Centella Asiatica. iS Clinical describes it as working on two levels: immediate surface-smoothing from the lightweight gel, and longer-term collagen support from the peptide and vitamin complex. Positioned for all skin types including sensitive and mature skin.

Best for: an immediate-feel serum that also targets longer-term firmness, in a lightweight gel.
Skip if: you want a richer hyaluronic-acid-and-fruit-acid formula — Youth Complex leans further that way.

Youth Complex — hydration-forward with fruit acid exfoliation

Youth Complex (PDP) pairs 15% botanically-derived Hyaluronic Acid and 10% Mixed Fruit Acid Extracts with the same Copper Tripeptide-1 growth factor and Panthenol (Vitamin B5). iS Clinical's own testing, run at BioScreen Testing Inc, reports 96% of users saw a textural improvement within one hour of application, and a significant improvement in overall skin tone after four weeks — the brand's own reported result, not an independently verified trial, and individual results vary. With a 10% fruit acid component alongside the peptide, it sits closer to Active Serum on exfoliation than Youth Serum does.

Best for: dry, sun-damaged or dehydrated skin wanting hydration, gentle exfoliation and collagen support in one step.
Skip if: you already use Active Serum for acid exfoliation — Youth Serum is the gentler peptide option instead.

Can you combine routes?

Yes — iS Clinical's own multi-step regimes bundle an acid step alongside other actives rather than relying on one serum. A common approach: Active Serum for resurfacing, a vitamin C serum under SPF in the morning, a Youth serum at night for peptides. High-strength acid and vitamin C together can be more than sensitive skin wants at once, so introduce one route at a time if you're new to actives.

Which iS Clinical serum should you start with?

• New to actives, or want resurfacing plus hyperpigmentation help: Active Serum.
• Standard vitamin C antioxidant step: Super Serum Advance+.
• Sensitive, reactive, rosacea-prone or post-procedure skin: Pro-Heal Serum Advance+.
• Already comfortable with vitamin C, want the strongest concentration: GeneXC Serum.
• Lightweight, immediate-feel peptide serum: Youth Serum.
• Hydration, gentle fruit-acid exfoliation and peptides together: Youth Complex.

For the full brand context, see the iS Clinical Reviews: The Skintique Academy Guide.

Pregnancy and breastfeeding

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

FAQs

Which iS Clinical serum is best for anti-ageing overall?

There isn't a single "best" — it depends on mechanism. Active Serum resurfaces via acids, the three vitamin C serums provide antioxidant protection at increasing strengths, and Youth Serum and Youth Complex work through Copper Tripeptide-1 growth factor. Most established iS Clinical routines combine more than one.

What's the difference between Super Serum Advance+, Pro-Heal Serum Advance+ and GeneXC Serum?

All three are vitamin C serums at different strengths. Super Serum Advance+ and Pro-Heal Serum Advance+ both use 15% L-Ascorbic Acid, but Pro-Heal is formulated for sensitive, reactive and post-procedure skin and adds 1% Retinol. GeneXC Serum steps up to 20%.

What's the difference between Youth Serum and Youth Complex?

Both use Copper Tripeptide-1 growth factor. Youth Serum is a lightweight gel focused on immediate tightening plus a Vitamin A, C and E complex, while Youth Complex is richer, built around 15% Hyaluronic Acid and 10% Mixed Fruit Acids for hydration and gentle exfoliation.

Can I use Active Serum and a vitamin C serum together?

Yes, but that's two actives layered together, so if you're new to actives, introduce them one at a time.

Does iS Clinical Youth Complex really work in one hour?

iS Clinical's own testing at BioScreen Testing Inc reports 96% of users saw a textural improvement within one hour — the brand's own study, not an independently verified trial.

Is iS Clinical safe to use if I'm pregnant or breastfeeding?

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