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Key takeaways (TL;DR)
The essentials about the "sunshine vitamin":
- The form: Always favour Vitamin D3 (cholecalciferol), 87% more effective and better absorbed than D2.
- Overall health: It acts as a crucial hormone for bones, immunity, muscles, and skin renewal.
- The correct dosage: ANSES recommends 15 µg (600 IU) per day. A daily dose is preferable to large ampoules.
- Optimal assimilation: Being fat-soluble, it should always be accompanied by lipids and ideally by Vitamin K2.
The sun is often blamed for the harmful effects of its UV rays. But it's also our main natural source of vitamin D , and a large portion of the population now has insufficient levels. Yet this molecule, and more specifically its D3 form (cholecalciferol) , plays a vital role in our overall health , as well as in the skin barrier and skin aging. In this article, Nooance-Paris reviews the benefits of vitamin D3 and the best ways to naturally increase your daily intake.
What is vitamin D3?
The term “vitamin D” actually refers to two different molecules:
- Vitamin D2 , or ergocalciferol. Of plant origin, it is mainly derived from certain fungi and yeasts exposed to UV light.
- Vitamin D3 , or cholecalciferol, is synthesized by the skin under the influence of UVB rays and is also present in certain foods of animal origin. It is the most active and best-absorbed form: 87% more effective according to scientific studies.
Once produced or ingested, it is transformed in the liver into 25-hydroxyvitamin D, or 25(OH)D , the circulating form measured in the blood to assess vitamin status. Although it is called a “vitamin,” it actually acts as a true hormone, involved in many mechanisms essential to the body's balance.
7 scientifically proven health benefits
- Bone health : it promotes the proper absorption of calcium and phosphorus, two minerals essential for skeletal mineralization. It thus helps prevent osteoporosis.
- Immune defenses : Vitamin D3 modulates innate and adaptive immune responses. It also regulates inflammation, thus contributing to better defense against viral and bacterial infections.
- Muscle function : it helps maintain muscle strength and contraction, which reduces the risk of cramps, falls and muscle weakness in older people.
- Dental health : by facilitating calcium absorption, it contributes to the proper mineralization of enamel and the maintenance of tooth strength.
- Mood and emotional balance : Vitamin D3 plays a role in nerve transmission and emotion regulation. A deficiency is often associated with an increase in mood disorders and seasonal depression.
- Cell division : it is an essential vitamin for the tissue regeneration process, thus playing a role in cell growth and development.
- Skin health : Keratinocytes, the main cells of the skin, synthesize D3: this regulates their proliferation and differentiation, which helps to maintain a strong and functional skin barrier.
To learn more about the role of micronutrients in skin radiance and quality, also check out our guide: Vitamin C: the benefits for the skin .
A deficiency that affects 80% of French people
Unless you live in a country with year-round sunshine, vitamin D3 deficiency is very common: in France, it affects 70 to 80% of the population, particularly in winter. Our current lifestyles, often spent indoors, limit sun exposure and increase this risk of deficiency.
Furthermore, the sunscreens we use protect the skin from UVA rays and skin aging , but they also block a large part of the UVB rays, which allow the synthesis of D3.
To reconcile sun exposure and sun protection, opt for an exposure of approximately 15 minutes , followed by the application of a sunscreen, in order to preserve the skin from photoaging while respecting its natural biological mechanisms.
What are the signs of a vitamin D deficiency?
Here are the main symptoms associated with a vitamin D3 deficiency:
- Persistent and unexplained fatigue
- Muscle weakness, cramps or decreased muscle tone
- Diffuse bone and joint pain
- Low morale, irritability
- Weakened immune system (repeated infections or chronic illnesses)
In more severe and prolonged cases, the consequences can be more marked: rickets (in children) or osteomalacia (in adults, weakening of the bones).
Sun, food, dietary supplements: where to find it naturally?
| Source | Recommendation & Contribution |
|---|---|
| Sun (UVB) | Exposure of 15 to 20 minutes per day (arms and face) between March and October. Covers 80 to 90% of needs during the summer season. |
| Food | Oily fish (salmon, mackerel), cod liver oil, egg yolks, fortified dairy products. |
| Dietary supplements | Prioritize vitamin D3 (better absorbed). Maintenance dosage: 15 µg per day (600 IU) . |
Note : During autumn-winter or in case of limited sun exposure, supplementation is often essential.
What is the role of D3 on our skin?
The skin is capable of producing vitamin D3: keratinocytes , the main cells of the epidermis, trigger this synthesis under the effect of UVB exposure. Once formed, this fat-soluble molecule can be stored in various tissues of the body, including the liver, muscles, and adipose tissue , thus constituting a mobilizable reserve.
Beyond its production, vitamin D3 plays a role in cell renewal : it regulates cell multiplication and maturation, thus helping to maintain a healthy skin barrier. In parallel, other non-invasive approaches such as photobiomodulation can support cellular activity without any UV exposure.
Dosage and recommendations according to ANSES
According to ANSES (French Agency for Food, Environmental and Occupational Health & Safety):
- Reference intake (RNP) is set at 15 µg per day (600 IU) for adults.
- Safety limit: It is not recommended to exceed 100 µg per day (4000 IU) without medical advice.
- Frequency: Supplementation during the winter period is strongly recommended in France.
Expert opinion: the 3 golden rules for perfect assimilation
For Vitamin D3 supplementation to be truly effective and safe for the body, three biological conditions must be met:
- Absolute synergy with Vitamin K2: this is the most important rule. Vitamin D3 helps the blood absorb calcium. However, it is Vitamin K2 that is responsible for guiding this calcium to the bones and teeth. Without K2, calcium risks being deposited in the arteries or soft tissues.
- The lipid environment: Vitamin D3 is fat-soluble. It must be consumed with a source of lipids to cross the intestinal barrier.
- Physiological dosage (Daily > Ampoule): The body is designed to receive a small dose of sunlight each day, not a massive dose every three months. A daily intake of approximately 15 µg helps maintain stable blood levels without overloading the liver.
The holistic approach to nutricosmetics
To fully meet these biological requirements, intelligent supplementation is key. Incorporating a complete beauty supplement allows you to tick all these boxes. The 360° Beauty Concentrate has been formulated with an optimal dosage, certified by ANSES (French Agency for Food, Environmental and Occupational Health & Safety), of 15 µg of Vitamin D3, precisely combined with 37.5 µg of highly bioavailable Vitamin K2 to ensure proper calcium absorption. Furthermore, the presence of Ceramosides™ (plant lipids) in the formula provides the perfect lipid environment for maximum daily D3 absorption, while supporting the structure of your skin and bones.
###360 Beauty Collagen Food Supplement###
FAQ: Your frequently asked questions about vitamin D
What is the difference between vitamin D2 and D3?
Vitamin D3, from sun exposure or of animal origin, is the form most assimilated by the human body: it is approximately 87% more effective than vitamin D2 (products of plant origin) in maintaining normal blood levels.
When to take vitamin D: morning or evening?
The time of day makes no difference: the key is to combine it with a source of lipids (a handful of almonds, eggs, avocado, oily fish…) to promote its absorption, since it is a fat-soluble vitamin.
Dietary supplement or ampoule: which form to choose?
It is more appropriate to prioritize regular, daily supplementation with a dose of approximately 15 μg (600 IU). This allows for stable maintenance of blood levels, rather than relying on widely spaced ampoules that cause abrupt fluctuations in blood levels.
Does sunscreen block its synthesis?
Yes, it partially reduces the penetration of UVB rays necessary for skin production. Moderate exposure of 15 to 20 minutes before applying sunscreen helps to naturally stimulate this synthesis, while limiting the risk of photoaging.
