Vitamin C has long been crowned a skincare hero — praised for brightening, boosting collagen, and fighting free radical damage. But a persistent myth continues to circulate online: that taking vitamin C supplements works better for your skin than applying it topically.
According to cosmetic chemist and science communicator Dr. Michelle Wong, PhD, that claim simply doesn’t hold up.
“I just wanted to talk about this idea that vitamin C supplements work better than vitamin C in skincare,” Wong explained in a recent TikTok. She pointed to the book Clean by Dr. James Hamblin, where the claim is referenced. “It’s a really common myth — even with scientists and doctors,” she said.
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Why Topical Vitamin C Delivers More to the Skin
The confusion largely comes down to how vitamin C moves through the body.
When you ingest vitamin C, it enters the bloodstream and is distributed throughout the body — including the skin. But because vitamin C is water-soluble, your body tightly regulates how much stays in circulation.
“If you eat too much in supplements, your kidneys will catch it and you end up peeing it out,” Wong explains. This process is called excretion. It’s also why overdosing on vitamin C supplements is relatively difficult — the body eliminates the excess.
The downside? There’s a cap on how much vitamin C can circulate in your blood and ultimately reach your skin.
Topical application works differently. “You can get a much higher concentration in the skin by going through the top — so putting a skincare product on and having it soak through — than through the bottom,” Wong says, referring to delivery via the bloodstream.
Unlike internal regulation, the skin does not have the same systemic excretion controls at the surface level. That allows well-formulated vitamin C serums to deliver higher localized concentrations directly where they’re needed.
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The Research Supports Topical Use
Wong also addressed the claim made in Clean, noting that in a section referencing dermatologist Dr. Leslie Baumann, the suggestion appears that supplements may be more effective.
However, Wong says that may be a misunderstanding. In the most recent edition of Baumann’s dermatology textbook, the guidance is clear: “Along with retinol and sunscreen, vitamin C is one of the most important cosmeceutical ingredients for skin rejuvenation. It is used in anti-aging skincare regimens to increase collagen production.”
The textbook also states: “Unfortunately, there are no studies that demonstrate that ingestion of oral vitamin C increases the levels of vitamin C in the skin. Consequently, topical vitamin C preparations have become popular.”
In other words, while oral vitamin C is essential for overall health, there’s currently no strong evidence showing that supplements meaningfully boost skin vitamin C levels. Topical formulations, on the other hand, have research supporting their ability to improve collagen production and protect against environmental damage — when used at effective concentrations.
Should You Ditch Supplements?
Not necessarily. Vitamin C is vital for immune function, wound healing, and overall health. But when your goal is brighter skin, collagen support, and protection against photoaging, dermatologic evidence favors topical application.
The bottom line: If you’re investing in vitamin C specifically for skin benefits, a well-formulated serum is likely to deliver more targeted results than a supplement alone. As Wong’s breakdown highlights, sometimes the most effective route isn’t from the inside out — it’s directly onto your skin.
