I Took Vitamin D for 30 Days: Here’s What My Tests Revealed

My name is Mathieu, I’m 35 years old, and I’m what you’d call a “redhead”: fair skin, freckles, and flaming hair. With this phenotype, I always thought my body naturally synthesized record doses of vitamin D, even with minimal sun exposure. That is, until a blood test revealed a severe deficiency, likely explaining my persistent fatigue and low mood. As soon as the diagnosis was made, I started a 30-day supplement regimen, with results that were as rapid as they were spectacular. Let me tell you about it.

Pale, tired, irritable: The signs that pushed me to check my vitamin D levels

For several months, I had been feeling flat, lacking energy, unable to concentrate at work. I attributed it to the endless winter days, the lack of light in my basement office, my somewhat hectic lifestyle… But despite rebalancing my lifestyle, nothing worked: I remained as dim as a burnt-out lightbulb, irritable at the slightest setback.

A blood test finally pinpointed the source of the problem: my vitamin D level was rock bottom, at 21 nmol/L, well below the recommendations (minimum 50 nmol/L). With such a deficit, no wonder I was dragging myself around like a zombie! My doctor then prescribed a high-dose vitamin D3 cure to quickly replenish my stores: 10,000 IU per day for 1 month, enough to jumpstart the machine.

10,000 IU per day: The breakthrough from the 2nd week!

Honestly, I didn’t feel anything transcendent for the first 10 days. I religiously took my vitamin D3 drops at breakfast, with no noticeable effect on my energy or mood. I admit I doubted the value of this “shock treatment,” having thought until then that vitamin D only concerned the elderly or those with osteoporosis…

And then after 2 weeks, it was as if a veil had been lifted: I felt more alert, more energetic, with prolonged endurance throughout the day. Gone were the afternoon “slumps,” the jaw-dropping yawns at the office. In the evening, I even had enough energy to enjoy time with my children or go for a run, without collapsing on the couch.

Week after week, the benefits were confirmed: better concentration at work, improved mood, joint pains gone (a bonus effect I hadn’t anticipated!). It was as if my entire body was restarting after a long hibernation… The magic of vitamin D, this natural “antidepressant” that quietly works on all our tissues.

1 month later, my vitamin D level doubled!

At the end of my 30 days of intensive supplementation, I went back for a blood test, eager to know if the “D refill” had worked. The verdict was clear: my level had skyrocketed, going from 21 to 45 nmol/L in just 1 month! Thanks to this simple oral cure at home, I had more than doubled my vitamin D level, almost reaching the optimal zone.

Encouraged by this result, I decided to continue with a long-term maintenance supplementation of 2000 IU per day. To never fall back into the red zone and continue to enjoy this newfound vitality. I also invested in a light therapy lamp for my office, and I try to take a short walk outside every noon between tasks.

Most importantly, this experience taught me that even with red hair and a “healthy complexion,” you can suffer from vitamin D deficiency without knowing it. We wrongly associate this vitamin with darker or black skin, which are more vulnerable, but in reality, deficiency lurks for everyone in our latitudes, especially with our confined lifestyles. So don’t hesitate to have your “D level” checked, at least once a year. This simple blood test can reveal quite a few surprises!

Your questions about my vitamin D supplementation experience

Do you need a prescription to buy vitamin D at the pharmacy?

Not necessarily, “standard” doses (up to 2000 IU/day) are available over the counter. But beyond that, and for an “attack” cure, it’s safer to get medical advice and a blood test to adjust the dosage to your deficit. Vitamin D is not toxic at usual doses but can become so at very high doses.

Why did you choose vitamin D3 and not D2?

D3 (cholecalciferol) is the natural form, synthesized by the skin under the effect of sunlight. D2 (ergocalciferol) is the plant form, less well assimilated by the body. Unless contraindicated, D3 is therefore recommended as it corrects deficiencies more effectively, although vitamin D2 remains an option for strict vegans.

How often should you check your vitamin D level?

In the absence of proven deficiency, a check every 2-3 years is sufficient for healthy adults. But in case of deficiency, chronic illness, for those over 65 or infants, annual monitoring is recommended. Also consider having your vitamin D tested before and after winter to adjust your intake if needed.

Which foods contain the most vitamin D?

Few foods contain it naturally: wild fatty fish (salmon, mackerel, herring), egg yolk, shiitake mushrooms… The rest comes from fortified or “supplemented” foods like milk, orange juice, cereals… Knowing that 80 to 90% of our intake depends on sun exposure, eating a varied diet is often not enough. Hence the interest in a small winter cure!