Double cleansing and vitamin C serums: what the evidence says

What did @mysistersskin actually say?

The creator, a self-described licensed aesthetician, walked through four skincare habits she credits with improving her skin over the past year: double cleansing, daily vitamin C serum, exfoliation two to three times a week, and a retinol. The boldest line was about vitamin C, which she said "slows down aging and protects your skin cells, no matter what." She also claimed her pores are "so much smaller" after a year of consistency, and pushed back on viewers who expect single-product miracles. At 50 years old, she's speaking from personal experience with some professional backing. That context matters.

The core message is patience over quick fixes. That part is genuinely good advice. But some of the scientific framing is a bit looser than it needs to be, and one phrase in particular deserves a closer look before 5.6 million people take it as gospel.

Does the science back this up?

Mostly yes, with one caveat. Vitamin C, retinol, and exfoliation all have real evidence behind them. The "no matter what" qualifier on vitamin C is where things get slippery.

Vitamin C (ascorbic acid) is one of the better-studied topical antioxidants. A 2017 review by Pullar, Carr, and Vissers in Nutrients confirmed its role in collagen synthesis and photoprotection, but effects vary significantly by formulation stability and concentration. It does not work uniformly across all products or all skin types.

Retinol is even better supported. Multiple randomized controlled trials, including a 1995 study by Griffiths et al. in the Archives of Dermatology, showed measurable improvements in fine lines and skin texture with consistent topical retinoid use over 24 weeks. A year of use, as she recommends, is well within the evidence-based window.

Double cleansing has less rigorous clinical data, but the logic is sound: oil-based cleansers dissolve sunscreen and sebum that water-based cleansers may miss. It is reasonable to recommend, especially for people who wear makeup or SPF.

Exfoliation two to three times a week is within standard dermatological guidance, though frequency should adjust for skin sensitivity and product strength.

What did they get wrong (or right)?

The "no matter what" claim about vitamin C is the one flag here. It is not technically accurate, and in a video with 5.6 million views it matters.

Topical vitamin C is notoriously unstable. L-ascorbic acid oxidizes quickly when exposed to light and air, meaning a poorly formulated or old product can be largely inert by the time it hits your face. A 2012 analysis by Telang in the Indian Dermatology Online Journal noted that efficacy is highly dependent on pH (ideally below 3.5) and packaging. So no, it does not work "no matter what." Formulation quality is not a minor footnote; it is most of the story.

The pore size claim is also worth flagging. Pore size is largely determined by genetics and sebum production. What skincare can do is make pores appear smaller by keeping them clear and improving surrounding skin texture. Retinol and exfoliation genuinely help with that. But the pores themselves do not physically shrink. A 2016 review in the Journal of Clinical and Aesthetic Dermatology by Roh et al. confirmed this distinction.

On the other hand, the core advice is solid. Consistency over one year is exactly what the clinical literature supports. The four-step framework she describes maps closely to what evidence-based dermatologists recommend. And she does not oversell any single product. That restraint earns credit.

What should you actually know?

If you are building a routine from scratch, these four steps are a reasonable foundation. But the details matter more than the categories.

For vitamin C, look for L-ascorbic acid at 10 to 20 percent concentration, pH below 3.5, in opaque or airtight packaging. Applying it to dry skin, as she mentions, is correct: water dilutes the formulation and raises pH, reducing absorption. A 2013 study by Pinnell in Dermatologic Surgery found skin penetration drops significantly when pH rises above 3.5.

For retinol, start low (0.025 to 0.05 percent) and increase slowly. Most people who quit retinol do so in the first six weeks because of irritation that would have resolved with slower titration. The long-term payoff is real, but the early phase requires patience.

Exfoliation is context-dependent. If you are using a retinol, you may not need aggressive exfoliation on the same nights. Over-exfoliation is a real and common mistake that wrecks the skin barrier, the opposite of what anyone wants.

And double cleansing is most useful if you wear SPF or makeup. If you have dry or sensitive skin and skip both, a gentle single cleanse at night may be enough.