the skin edit.
Vitamin C Serum can cause irritation. Here’s why ours doesn’t.

A great Vitamin C serum will brighten the complexion, firm and tone the skin, and reduce dark spots and hyperpigmentation. But why does it irritate the skin?
Whenever an amazing active ingredient bursts onto the skincare scene, the first question people ask is: will it irritate my skin? When it comes to Vitamin C, there’s one reason it’s known to cause skin irritation: Vitamin C is an acid.
Vitamin C quick facts
- Vitamin C is a water-soluble antioxidant.
- It’s essential for collagen production and your skin’s overall appearance, but our bodies can’t produce it naturally. This means it’s an important part of any skincare routine.
- Vitamin C is also a powerful anti-inflammatory agent that can reduce redness and swelling in the skin (like sunburn or acne flareups).
- Lastly, vitamin C acts as an effective lightener when applied topically to pigmented areas such as freckles or age spots.
In short, a great Vitamin C serum will brighten the complexion, firm and tone the skin, and reduce dark spots and hyperpigmentation. So what’s the problem?
Pure Vitamin C can irritate your skin.
Pure vitamin C is acidic, so it can irritate your skin. The pH level of L-ascorbic acid is 2 to 3.7. That’s about the same pH as orange juice, coffee or wine—and similar enough to cause some amount of irritation for most people.

Most Vitamin C degrades in sunlight.
Vitamin C is notoriously difficult to incorporate into a formulation in a such a way that it retains potency and remains at an effective and safe concentration for skin to use. It degrades on exposure to oxygen and light, and because it’s water-soluble. It doesn’t penetrate the skin easily and works best at a pH of 3, too acidic for human skin.
So to create a Vitamin C product that actually works, keeps working once opened and feels amazing on the skin was quite a challenge!
Our Vitamin C 2 Phase Serum contains 3 types of high performance Vitamin C (aka ascorbic acid) to boost the effectiveness of the formula. Ascorbic acid needs to be properly preserved so it doesn’t degrade over time—which is why we use non-GMO lecithin that’s extracted from sunflower seeds instead of soybeans (which can easily go rancid). The lecithin in our formula keeps the ascorbic acid stable so you get an effective dose of active ingredients every time you use it.
We added ferulic acid to stabilize our Vitamin C and make it gentler.
We’ve added ferulic acid to stabilize our vitamin C and make it gentler. Ferulic acid is an antioxidant, and it also helps with collagen production. It’s gentle enough for even the most sensitive skin, but also helps stabilize vitamin C so that it doesn’t break down as quickly after application, which means you get more of its benefits.
Our Vitamin C serum is not sticky.
Pestle & Mortar co-founder Sonia Deasy wanted to create a highly effective Vitamin C serum. With five children, busy mornings and dark skin that’s prone to pigmentation, Sonia’s goal was to develop a skin serum that would deliver optimal Vitamin C benefits with every use and feel like velvet on the skin.
Drawing inspiration from her heritage in Indian Natural Healing, Sonia combined skin-brightening tamarind extract with three types of superior quality vitamin C. Natural tamarind is known to clarify, soothe and brighten the skin. It’s a powerhouse natural ingredient that has been used for centuries throughout India to remedy a lacklustre complexion. Sonia’s Indian grandmother would often mix tamarind with milk to use as a skin-brightening facemask.
Next up packaging: Vitamin C 2 Phase serum is stored inside the bottle in 2 phases – an oil phase and a water phase. When the product is pumped, both phases are mixed together in one perfect, silky soft dose. The water phase includes 3 types of high quality vitamin C, tamarind extract and pumpkin fruit ferment. The oil phase combines the ultra-lightweight Evening Primrose Oil and squalane, both of which are highly penetrative. This means that the vitamin C is carried deep into the dermal layers where it can get straight to work repairing collagen synthesis and correcting hyperpigmentation from the inside out.

Our Vitamin C serum is potent enough to work.
Our Vitamin C 2 Phase Serum combines 3 types of active Vitamin C at 16% concentration, combined, dispensed, and packaged in such a way that skin gets maximum benefits without irritation:
Ethyl-L-Ascorbic Acid
Ethyl-L-Ascorbic Acid is a highly stable derivative of Vitamin C that is extremely absorbent. It works on the deep layers of the skin to repair skin cells, enhance skin structure and accelerate collagen synthesis, delivering a dramatically firmer and smoother complexion.
Encapsulated Vitamin C
A stable form of Vitamin C, encapsulated Vitamin C functions as an antioxidant and is particularly effective for dealing with dark spots and brightening the skin, ensuring that your skin gets optimal Vitamin C benefits all day long.
Sodium Ascorbate
Sodium ascorbate is the milder mineral salt of ascorbic acid. It is a powerful skin soothing agent that improves the appearance of ageing and evens out skin tone.
The 3 types of high performance Vitamin C in our serum means that your skin gets extraordinary Vitamin C benefits with every use. You’ll notice a dramatically brighter looking complexion and your skin will appear fresher, smoother and more toned with consistent use.
2 years in the making but worth it! ✨
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