Two serums, near-identical prices, and a shelf position that puts them side by side in every “clinical skincare” conversation. Perricone MD Cold Plasma Plus+ and iS Clinical Super Serum Advance+ both sit at the same price tier, both have a devoted following, and both get recommended to the same person for the same complaint. They’re built on completely different chemistry, and the difference isn’t a nuance. It changes who should buy which.
Here’s the short version before the reasoning: if you want measurable brightening and texture change, the iS Clinical is the stronger formula. If your skin is dry, reactive, or tired of stinging, the Perricone is the one you’ll keep using. The best serum is the one that doesn’t end up at the back of a drawer in March.
What’s in each bottle
Super Serum Advance+ is built around 15% L-ascorbic acid — vitamin C in its free, unmodified, most-studied form — paired with Copper Tripeptide-1. That combination is the entire pitch. L-ascorbic acid at 15% is a real working concentration, well above the 8-10% where the research starts showing consistent results, and copper tripeptide has a decent body of evidence behind it for collagen support and wound repair. There’s hyaluronic acid, kojic acid, and mushroom extract rounding it out for brightening and hydration.
Cold Plasma Plus+ takes the opposite approach. It’s an emulsion rather than a fluid, and it’s carrying a longer list of smaller-dose actives: DMAE, alpha lipoic acid, a vitamin C ester, niacinamide, omega fatty acids, and phospholipids in a delivery system Perricone has been refining for two decades. Nothing in it is present at a headline concentration. The formula’s argument is that the combination does more together than any single active would alone.
The vitamin C difference matters more than the marketing suggests
Both products say vitamin C on the box. They don’t mean the same thing.
iS Clinical uses free L-ascorbic acid, which is the form nearly every clinical study on topical vitamin C was run with. It works. It also has a low pH, oxidises when it meets air and light, and stings on compromised skin. That’s the trade you make for the evidence base.
Perricone uses a vitamin C ester — an oil-soluble, pH-neutral derivative that’s far more stable, far gentler, and penetrates a lipid barrier more comfortably. The catch is that an ester has to convert to ascorbic acid in the skin to do the work, and how efficiently that conversion happens is much less settled than the marketing implies. Research suggests the ester forms are milder but less potent than an equivalent dose of L-ascorbic acid. You’re trading measurable performance for tolerability.
For dry or mature skin that hates acids, that’s a reasonable trade. For someone who wants their vitamin C to visibly shift pigmentation over three months, it isn’t.
One honest complication
Copper peptides and high-dose L-ascorbic acid have a contentious relationship in formulation chemistry. Copper can catalyse the oxidation of ascorbic acid, and plenty of formulators will tell you the two don’t belong in the same bottle. iS Clinical has clearly done work to keep the formula stable, and users don’t report the browning you’d expect from a badly built vitamin C serum. Still, it’s the sort of thing worth knowing before you assume both actives are delivering at full strength.
This is also the reason it’s worth storing that bottle away from a sunny windowsill and using it within a few months of opening rather than treating it as a year-long purchase.
Texture, and what it means for your routine
Super Serum Advance+ is a thin, slightly tacky fluid. It absorbs fast, layers under moisturizer, and doesn’t do much hydrating on its own. It’s a treatment step, and it needs a moisturizer after it.
Cold Plasma Plus+ is closer to a light lotion. On dry skin it can replace a moisturizer entirely in the morning, and that’s a real practical advantage — fewer steps, less product, less cost per routine than the price tag suggests. On oily or congested skin the same richness reads as heavy, and the omega fatty acids and phospholipids that make it comfortable for dry skin are the same ingredients that make it feel like too much on skin that’s already producing plenty of its own.
Which one for which problem
| What you want fixed | The better buy | Why |
|---|---|---|
| Dark spots, dullness, uneven tone | iS Clinical | 15% L-ascorbic plus kojic acid is a real brightening formula; the ester in the Perricone is gentler and slower |
| Fine lines on dry, tired skin | Perricone | The emulsion base plumps and comforts immediately, and DMAE gives a short-term tightening effect people genuinely like |
| Post-acne marks and texture | iS Clinical | Copper tripeptide and vitamin C both have evidence for remodelling; this is the formula’s home ground |
| Sensitive or reactive skin | Perricone | pH-neutral, no free acid, nothing that stings on a compromised barrier |
| Fewest possible steps | Perricone | It moisturizes. The iS Clinical doesn’t, so it costs you an extra product |
| Oily or congested skin | iS Clinical | The lightweight fluid layers cleanly; the Perricone’s lipids sit heavy |
What neither of them replaces
Both of these are adjuncts. Neither is a sunscreen and neither is a retinoid, and those two do more for skin than any serum at any price. If you’re choosing between one of these and getting a daily SPF habit established, the SPF wins and it isn’t close.
Timelines are worth setting properly too. A 30ml bottle of either lasts roughly two to three months at a few drops daily. Brightening from vitamin C shows up around the eight to twelve week mark if it’s going to, and texture change takes longer. Judging either of these at three weeks is judging them before they’ve done anything.
Store both away from heat and light, and don’t stockpile. Vitamin C in either form degrades on the shelf, and a spare bottle bought in a sale is a bottle quietly losing potency in a cupboard. Buy one, finish it, then decide whether it earned a repurchase.
What to reach for
iS Clinical Super Serum Advance+
The stronger formula of the two. Free L-ascorbic acid at a working concentration plus copper tripeptide, aimed squarely at tone and texture. Needs a moisturizer over it.
Perricone MD Cold Plasma Plus+ Face
Gentler, richer, and a treatment and moisturizer in one step. The better choice for dry or reactive skin and for anyone who’s abandoned a vitamin C serum because it stung.
Timeless 20% Vitamin C + E Ferulic Serum
If what you want is the L-ascorbic acid and not the rest, this delivers it for a fraction of either price. Less elegant, shorter shelf life, same core active.
La Roche-Posay Toleriane Double Repair Moisturizer
The moisturizer to put over the iS Clinical. Ceramides and niacinamide, no fragrance, and it costs a fraction of what you just spent on the serum.
Prices move constantly, so we link to live listings instead of printing a number that is wrong by the time you read it. Links go to Amazon, which is where a referral gets credited.
How we picked
We compared these on formulation rather than on claims: the form and concentration of the vitamin C, whether the supporting actives have independent evidence behind them, and how the base texture changes what else you need to buy. Where the two overlap on paper, we weighted the version using the better-studied active at the higher dose. We also weighted the practical stuff people abandon products over — sting, absorption, and whether a serum forces an extra step.
FAQ
Can you use both?
You can, but not in the same routine step, and there’s little reason to. Both are doing overlapping work at a combined cost that’s hard to defend. If you’re determined, use the iS Clinical in the morning under sunscreen and the Perricone at night.
Does the iS Clinical really help stretch marks and scars?
The formula includes actives with evidence for collagen remodelling, and the brand leans on that hard in its marketing. Expect softening of color and texture on newer marks over months, not removal. Mature white stretch marks don’t respond much to anything topical. For a raised or spreading scar, talk to a dermatologist rather than a serum.
Why does the Perricone feel tighter right after I apply it?
That’s the DMAE. It produces a short-term firming effect that’s cosmetic and temporary, and it wears off. It’s a pleasant thing, not a structural one, and it’s a large part of why the product has such loyal repeat buyers.
Is either worth the price?
The iS Clinical is defensible on its active concentrations alone — you’re paying prestige margin, but you’re also getting a real dose. The Perricone is harder to justify on ingredients and easier to justify on experience. If price is the deciding factor, the Timeless serum above gets you the core active for a small fraction of either.
Bottom line
Buy the iS Clinical if you want a serum that changes tone and texture and you’re willing to add a moisturizer behind it. Buy the Perricone if your skin is dry or easily provoked and you’d rather have one comfortable product you’ll finish than a stronger one you’ll flinch at.
And if the price is the part you’re stuck on, that’s a fair place to be stuck — it’s worth reading our take on where the money in a premium jar actually goes before you commit. More verdicts on specific products live in the Buy, Dupe, or Splurge archive, and the rest of our serum coverage sits in Skin.
