How to use a vitamin C serum like a pro!
The lightening and anti-aging virtues of vitamin C have been amply demonstrated by scientific studies. And I believe that those who have tested pure vitamin C serums have seen convincing results when they were able to withstand its irritating effects. However, some members of the community asked me why the application of a vitamin C serum made them tan, or more precisely, changed the color of their skin as if they'd applied a bad self-tanner. And after some investigation, I figured out what the mechanism was. And I investigated! This phenomenon is linked to the oxidation of your serum! And I'm going to tell you how to avoid this inconvenience? To use vitamin C like a pro!
As a reminder, this molecule is undoubtedly one of the most effective at reducing brown spots and the signs of ageing associated with photoaging. It boosts collagen and elastin production. It reduces and prevents skin slackening while combating oxidative stress. On the other hand, some members of the community have noticed, after its application, a slightly browned skin as if they had used a badly spread self-tanner.
So why can your pure vitamin C serum stain your skin?
As some of you already know, the pure vitamin Coxidizes very easily. This phenomenon is activated by exposure to light or oxygen. To stabilize ascorbic acid, manufacturers use antioxidants, opaque, hermetically sealed bottles and acidic pH formulas, and sometimes denatured alcohol to facilitate skin absorption, at the cost of increased skin irritation.
However, once ascorbic acid is on your skin, it is once again exposed to light and ambient air. As a result, it can quickly become denatured, and the vicious circle begins on your face. In fact, once oxidized, vitamin C generates a cascade of chemical reactions that can lead to the formation of spots on the surface of our epidermis. Without getting too chemical, this table is taken from an article published in 2011 entitled Vitamin C Degradation Products, which explains how vitamin C is degraded.
Don't worry, I'll try to be brief. Oxidized ascorbic acid is degraded to dehydroascorbic acid and then to 2,3 diketogulonic acid, which in turn is transformed into erythrulose.
Erythrulose sound familiar? It's an ingredient found in self-tanning products, often combined with DHA, as in this serum from Typology. On contact with the skin, erythrulose reacts with amino acids present in the stratum corneum to form pigments called melanoidins. These substances impregnate and accumulate in the dead cells of our epidermis, coloring it. They remain there until their natural desquamation. Hence the appearance of orange or brown areas on our face.
So should we say goodbye to vitamin C serum? Absolutely not! This molecule is an essential part of your anti-aging and anti-dark spot routine. All you need to do is follow a few easy-to-follow recommendations, and be able to visually recognize the color of oxidized ascorbic acid so you don't have to apply it.
And here are my 6 tips for using vitamin C like a pro!
1: Always apply sunscreen
Tip number 1: when using a pure vitamin C serum, always finish your skincare routine with a sun cream in the morning or a moisturizer in the evening. This will prevent the vitamin C from coming into contact with the air, and your sunscreen will protect your skin and your vitamin C from UV rays. I also think you should wait until your vitamin C is fully absorbed before applying another skin care product on top of it. The aim is to avoid contact with oxygen in the air and light, so as to prevent oxidation reactions. However, once absorbed by your skin, vitamin C is a formidable anti-oxidant.
2: Apply vitamin C at the beginning of your skincare routine
Tip number 2, I recommend you apply vitamin C at the very beginning of your skincare routine, just after cleansing to improve its absorption. You can then use a lotion, serum or cream. In fact, you should always start with the lightest, most watery textures. Oily serums and creams come last.
Another fundamental parameter for good penetration of pure ascorbic acid is its pH. This study, carried out by Dr. Pinnel, demonstrated that PH should be below 3.5 for optimal vitamin C penetration, but also for better stabilization. After that, many other factors come into play, such as the presence of alcohol, which enhances vitamin C penetration into the skin, or the presence of other anti-oxidants to stabilize vitamin C, which brings me to tip number 3.
3: Choose a vitamin C serum containing vitamin E + ferulic acid.
I recommend choosing vitamin C products containing other antioxidants. One of the best possible combinations is: vitamin C + vitamin E + ferulic acid.
Ascorbic acid alone provides photoprotection of tissues, but its antioxidant activity is multiplied when it works in synergy with vitamin E, which is also a powerful antioxidant. Together, they limit the daily damage caused by exposure to the sun, preserving the very interior of your cells, but you need to combine them with a sunscreen to be truly effective.
Recommended products include Paula's Choice C15 Super Booster, which contains 15% of pure vitamin C and the famous combination of ferulic acid and vitamin E. Its PH is 30, and it costs 59 euros for 20 ml. We also have C Firma by Drunk Elephant, which also contains 15% pure vitamin C, 1 % vitamin E and 0.5 % ferulic acid. With this serum, we combine the vitamin C powder and the serum ourselves, and costs 75 euros for 26 ml. The most affordable is of course Geek and Gorgeous at 12.50 for 30 ml, which is as good as it gets in terms of price. It contains the classic 15% of pure vitamin C with ferric acid and vitamin E, and its PH ranges from 3.2 to 3.4. CE Ferulic is also very well formulated, but costs 165 euros. Vichy's is not bad, but contains a lot of alcohol, which may improve vitamin C penetration, but will above all irritate the most sensitive skins.
Another solution that solves the problem of stability is to buy vitamin C powder. The Ordinary sells a cheap one, but you can also use Garancia's which contains 10% of pure vitamin C, plant extracts and fragmented type1 collagen derived from bio-technology. I think this combination makes sense, because vitamin C is essential to our body's ability to produce collagen, and what could be more natural than combining it with a collagen component?
The question is, what do you mix your powders with? Garancia has a dedicated serum that's not bad, but it doesn't have an acid PH, so vitamin C penetration won't be optimal. If you use their serum, you'll get the action on spots and facial radiance, but not the real anti-aging action. If you want a deep action of vitamin C at dermal level and an anti-oxidant action, you'll need to mix these powders with an acid product. Ideally, you should use your own exfoliants, such as BHA from Paula's choice, glycolic acid solution from The Ordinary or an exfoliator from geek and gorgeous.
As for pure vitamin C serums with silicone, like the ones from L'Oréal and Laroche-Posay, I'm not really convinced. Firstly, their PH isn't acidic enough, but they try to compensate with alcohol, and you have to apply them at the beginning of your routine for them to be at least effective. What bothers me is that the silicone present in these serums has a slight occlusive side from 20 to 30%. I don't really mind silicone in a cream because it's applied at the end of the routine, but at the beginning I think it can interfere with the absorption of subsequent skincare products.
Tip number 4, buy your pure ascorbic acid skincare in an opaque, airtight container.
Ideally, you should also keep your serum in a cool place. Now, if you're wondering how to tell if your vitamin C serum has oxidized? It's simple: if your product takes on a yellow-orange color, it's a sign that you can unfortunately throw it away.
Tip number 5: some active ingredients do not mix well with pure vitamin C.
You need to be careful with retinol, as it's also an irritant, and you shouldn't start with both at the same time. I recommend starting with retinol and then, once it's well tolerated, slowly introducing vitamin C.
You should also avoid using copper peptides at the same time as vitamin C.
If it's already too late and your face has already fallen victim to its famous spots, don't panic! Stop using your oxidized vitamin C product and wait 28 days. That's how long the cell renewal cycle lasts. The natural desquamation of stained corneocytes will give way to healthy tissue. You can also apply an exfoliant, to accelerate desquamation and evacuate your cells punctuated with brown compounds more quickly.
Now's the time to tell you that pure vitamin C isn't for everyone. If you have sensitive skin or redness, I recommend using a vitamin derivative. They may not be as effective as pure vitamin C, but they do have a number of advantages. They're very stable, so there's no risk of oxidation.
Derivatives can be water- or fat-soluble, so it's easier to find your ideal product for your skin type.
These molecules mix with all the other active ingredients, especially retinol.
Here are a few treatments I recommend.
Ascorbyl tetraisopalmitate are lipophilic: in other words, they have an affinity with oil. You'll find them in rather rich, oily textures designed for normal to dry skin, like The Ordinary's ascorbyl tetraisopalmitate 20 % in vitamin F solution. A product that contains this derivative but has a texture I like is Théramid's vitamin C. It's not pure vitamin C, but a combination of several vitamin C derivatives, and it's not an oily serum, so all skin types can use it.
For normal, combination and oily skin, water-loving hydrophilic derivatives are preferred. Typology Sérum éclat vitamine C 11 % diffuses sodium ascorbyle palmitate in an aqueous, gel-like formula to reduce hyperpigmentation and prevent photo-aging. It also contains extracts of abre a soie bark with anti-oxidant properties and evodia Rutaecarpa Fruit Extrac with anti-inflammatory properties. The texture is very pleasant to use. The Ordinary also offers ascorbyl glucoside solution 12 %.
Things to remember :
1) Never use a product containing oxidized vitamin C, as this will result in a poor-quality self-tanning effect.
2Always apply a sunscreen or moisturizer at the end of a routine using pure vitamin C.
- Choose opaque, airtight packaging and acidic pH formulas, and apply your vitamin in the first stages of your routine.
- I think it's best to buy vitamin C on the internet by delivery to avoid these serums being stored in warehouses for too long.