Vitamin C is an essential nutrient and a powerful antioxidant found mainly in fruits and vegetables. It is water-soluble and easily absorbed by the body's tissues when ingested. However, since the body does not store it, any excess is eliminated. It must therefore be taken every day, through food or supplements.
What is the role of vitamin C in human health?
The body needs vitamin C to produce blood vessels, cartilage, muscles, and bone collagen.
Here are some of the vital roles it plays in the body:
- It neutralizes free radicals before they can damage cells. Free radicals are unstable molecules produced naturally by the body or resulting from exposure to UV rays and pollution, smoking, and other factors. They can lead to oxidative stress, which in turn can cause cell damage, illness, and premature aging.
- It helps the body produce collagen, a protein necessary for the development and maintenance of healthy teeth, bones, gums, cartilage, intervertebral discs, skin, and blood vessels. Collagen also gives strength and elasticity to the skin.
- It improves the body's ability to absorb and store iron.
- It strengthens the immune system.
- It contributes to wound healing and curbs scar formation.
- It helps maintain healthy skin, allowing it to function as a barrier against toxins and external aggressors.
Vitamin C deficiency can lead to reduced immunity and increased susceptibility to infections. It can also cause swollen joints, bleeding gums and loose teeth, anemia, and fatigue.
How much vitamin C do I need and how do I get it?

The daily dose of vitamin C recommended by the World Health Organization (WHO) is 75 milligrams (mg) for women and 90 mg for men.
However, a recent study reviewed over 100 studies over 10 years and recommended a much higher dosage for optimal health. The study's researcher, Mark Moyad, MD, MPH, from the University of Michigan, stated: "The safe upper limit for vitamin C is 2,000 mg per day, and there is strong evidence that taking 500 mg per day is safe."
Since the body eliminates any excess vitamin C, overdose is not an issue. Nevertheless, it is not advisable to exceed the safe upper limit of 2,000 mg per day to avoid stomach upset or discomfort.
It is possible to consume enough vitamin C as part of a balanced diet, with food sources always being the best. Oranges (about 83 mg per fruit), grapefruits (92 mg per fruit), strawberries (58 mg per 100g), and raw bell peppers (80 mg per 100g) are good nutritional sources.
Orange juice is recognized as a valuable source of vitamin C, but most pre-packaged orange juices are pasteurized to extend their shelf life. Pasteurization is a heat process that destroys the vitamin C in the juice. Many manufacturers compensate for this by adding synthetic vitamin C after pasteurization. Freshly squeezed orange juice, drunk immediately, is best, as vitamin C also degrades with exposure to air.
Vitamin C supplements are another way to increase intake. The daily dose of Skin Diligent's Acne & Stress supplement provides 57 mg of natural vitamin C, from Acerola cherries. This cherry contains other phytonutrients that help the body absorb almost all of the vitamin C. In contrast, consuming vitamin C in the form of ascorbic acid (a synthetic form) has an absorption rate of about 20%.
What are the benefits of vitamin C in skin care?
Vitamin C is a valuable active ingredient for all skin types. Its brightening properties combat uneven skin tone and dark spots. By promoting collagen production, it smoothes skin texture and improves the appearance of fine lines and wrinkles. Some forms of vitamin C can offer protection against UV rays. As an antioxidant, vitamin C targets oxidative stress in the skin (it neutralizes free radicals that damage skin cells).
The most effective way to replenish vitamin C in the skin is direct application. In fact, it is claimed that applying vitamin C to the skin is 20 times more effective than ingesting it orally.
Serum is the ideal medium for vitamin C in skin care. Serums are concentrated forms of active ingredients and target specific problems.
The challenge of formulating vitamin C skincare products

Ascorbic acid is only stable in formulas with a pH below 3.5. This pH is significantly more acidic than facial skin, which ranges from 4.7 to 5.75, which explains why some vitamin C skincare products cause irritation.
Moreover, since it is water-soluble, ascorbic acid has difficulty penetrating the skin. To compensate for this, water-based serums contain high concentrations of vitamin C, knowing that a large part will be wasted and the risk of irritation will be higher.
All skincare products have a list of ingredients they contain. Here are the most common forms of vitamin C to look for on this list:
Water-soluble forms of vitamin C:
- ascorbic acid or L-ascorbic acid
- Magnesium Ascorbyl Phosphate
- Sodium Ascorbyl Phosphate
- Ascorbyl Glucoside
Oil-soluble forms of vitamin C:
- Ascorbyl Palmitate
- Tetrahexyldecyl Ascorbate, the one used in our Vitamin C Oil-Serum.
How is Skin Diligent's Vitamin C Oil-Serum different?
Our Vitamin C Oil-Serum is expertly formulated to eliminate absorption and irritation issues.
It contains a rare oil-soluble form of vitamin C. Oils have no pH and are easily recognized by the skin. As a result, they are better absorbed and more effective, without the risk of irritation or photosensitivity.
While vitamin C is key in the formula, this Oil-Serum is packed with other active ingredients that nourish and protect the skin. The 99.7% natural formula contains pomegranate extract, rich in punicic acid, which can help improve elasticity and even out skin tone, while promoting skin regeneration. It also contains hemp seed oil, rich in omega 3 and 6 fatty acids, and moringa oil, which helps rebalance sebum.

Results proven by clinical tests:
20 volunteers tested the Vitamin C Oil-Serum for 28 days under dermatological control.
100% of people reported their skin was softer
100% saw an improvement in their skin's appearance
100% had more hydrated skin
95% had a more even skin tone
90% saw a prevention of imperfections and pimples
90% saw a reduction in fine lines
Like all Skin Diligent products, the Vitamin C Oil-Serum respects the skin's microbiome and the integrity of the skin barrier. All our products are non-irritating and hypoallergenic and, as part of our efforts to reduce toxins in our lives, our skincare products are certified FREE of estrogenic endocrine disruptors.