iS Clinical Super Serum Advance+ vs GeneXC Serum

iS Clinical Super Serum Advance+ and GeneXC Serum are both built around a time-released vitamin C, both sit at the top of the brand's serum range, and their names get shortlisted together constantly. The real difference isn't strength — both are vitamin C treatment serums aimed at the same job — it's the technology each one pairs with that vitamin C, and how each one needs to be stored.

Super Serum Advance+ vs GeneXC at a glance

What they have in common

Both are treatment-step serums built around a time-released vitamin C, designed to be applied after cleansing and before moisturiser, with a broad-spectrum SPF layered on top in the morning. Both are lightweight, fast-absorbing formulas rather than thick or oily-feeling serums, and both are tagged by the brand as suitable across a wide range of skin types, including sensitive skin. Both are also vegan, paraben-free and phthalate-free, and neither is on Skintique's MAP-restricted price list, so the shop page shows the current price directly rather than a band. Framed correctly, both serums help protect the appearance of skin from environmental stress — neither is presented here as offering any deeper, DNA-level protection claim, whatever the wider marketing around vitamin C sometimes implies.

Where they actually differ

The technology paired with the vitamin C

This is the real distinction. Super Serum Advance+ combines its 15% time-release L-Ascorbic Acid with bioidentical Copper Tripeptide-1 Growth Factor — a peptide ingredient not present in GeneXC. GeneXC instead pairs its time-released vitamin C with iS Clinical's proprietary Extremozyme® blend, built around Terminalia Ferdinandiana (Kakadu plum) fruit extract, plankton extract and arginine ferulate, alongside a longer list of plant and fruit extracts including sugarcane, rocket leaf and citrus extracts. If you specifically want a copper peptide in your vitamin C step, that's Super Serum Advance+. If you'd rather have the broader botanical-extract blend instead, that's GeneXC.

Storage — the practical dealbreaker for some people

Super Serum Advance+ recommends refrigeration to maintain vitamin C stability and efficacy. GeneXC's guidance is simply to store it somewhere cool and out of direct sunlight or heat — no fridge requirement. If you don't want to keep a skincare product in the fridge, or you're travelling and won't have one, that alone can settle the choice.

Suggested frequency

Super Serum Advance+ can be used once or twice daily. GeneXC's PDP guidance is specifically morning and evening. In practice both are formulated for regular daily use — check either product's own instructions before starting, particularly if you're introducing vitamin C to your routine for the first time.

What to expect from the texture and colour

Both are lightweight and fast-absorbing rather than heavy or greasy. GeneXC's own product information notes that its colour may vary or darken over time — this is normal for pure vitamin C formulations and doesn't affect how the product performs, but it's worth knowing in advance so it isn't mistaken for the serum having gone off.

Which one should you choose

• Choose Super Serum Advance+ if: you specifically want a copper peptide alongside your vitamin C, and you're happy to keep it in the fridge for stability.
• Choose GeneXC if: you'd rather avoid a fridge-stored product, or you're drawn to the broader Extremozyme® botanical-extract blend over a peptide pairing.
• If neither strongly applies to you: both are well-specified vitamin C serums tagged for sensitive skin, so the deciding factor is genuinely storage convenience and ingredient preference rather than one being the stronger product.

Either serum can also be introduced gradually if you're new to vitamin C — a mild tingling on first few applications is a known reaction some people notice with time-released L-Ascorbic Acid formulas, and it typically settles as skin adjusts.

What neither of these covers

Neither serum is a resurfacing or retinoid-based treatment — for that, see our review of Active Serum. For the fuller anti-ageing serum shortlist across the range, including where Pro-Heal Serum Advance+ fits in, see our Best iS Clinical Serums for Anti-Ageing guide. For the wider range context, start at our iS Clinical reviews hub.

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

Our verdict

These are two well-built vitamin C serums solving the same core job — helping protect the appearance of skin from everyday environmental stress — through different formulation routes. Super Serum Advance+ pairs 15% time-release L-Ascorbic Acid with bioidentical Copper Tripeptide-1, and is best for people who don't mind a fridge routine and want a peptide alongside their vitamin C. GeneXC pairs time-released vitamin C with iS Clinical's Extremozyme® botanical blend, and suits people who want a lower-maintenance, cool-and-dark storage serum with a broader plant-extract ingredient list. Neither is the objectively stronger product — they're different routes to the same antioxidant goal, and the deciding factor is usually storage practicality and which extra ingredients you'd rather have alongside your vitamin C.

FAQs

iS Clinical Super Serum Advance+ vs GeneXC Serum — what's the actual difference?

Both are time-released vitamin C serums. Super Serum Advance+ pairs 15% L-Ascorbic Acid with bioidentical Copper Tripeptide-1 and is best stored in the fridge. GeneXC pairs its vitamin C with the Extremozyme® botanical-enzyme blend and only needs a cool, dark storage spot — no fridge required.

Does Super Serum Advance+ really need to go in the fridge?

The brand's own guidance is that refrigeration is recommended to maintain the product's stability and vitamin C efficacy. GeneXC's storage guidance is cool and out of direct sunlight or heat, without a fridge requirement.

Can I use Super Serum Advance+ and GeneXC together?

Both are vitamin C serums aimed at the same treatment step, so layering both isn't necessary and may be more product than your skin needs in one routine — speak to our skincare team if you'd like personalised guidance on combining or switching between iS Clinical actives.

Why has my GeneXC Serum changed colour?

According to the product information, colour variation or darkening over time is normal for pure vitamin C formulations like GeneXC and doesn't affect how the product performs.

Which is better for sensitive skin?

Both are tagged by iS Clinical as suitable for sensitive skin. If you're new to vitamin C or have reactive skin, introduce either gradually and patch test first.

Are Super Serum Advance+ and GeneXC Serum safe to use during pregnancy?

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