Vitamin D3 injection — where to find it and who should give it to you
It is searched for in pharmacies, by brand name and by dose. Which injectable forms exist, what the difference is between 100,000 and 300,000 IU, and why the right question is not "where can I find it?" but "do I need it?".
English translation of content medically reviewed in Romanian by Dr. Claudiu Ruscu, intensive care physician (anaesthesia & intensive care)· Romanian text reviewed 13 September 2026
"Where can I find vitamin D3 injection?" is a very common search in Romania — by pharmacy name, by dose, by brand name. We answer it, but also the question behind it, which is more important.
Which injectable forms exist
The active substance is cholecalciferol — vitamin D3. The most searched-for brand name is Dibase: the ANM product record reproduced on prospecte.ro, with data from the official list of June 2023, describes Dibase 100,000 IU/ml solution for injection, in boxes of 6 ampoules of 1 ml, dispensed on a prescription that is retained by the pharmacy.
What you will find today, however, is something else. In the Nomenclature of ANM (the National Agency for Medicines' register of medicines authorised in Romania) updated on 11 September 2026, Dibase no longer appears, and under vitamin D3 (ATC code A11CC05) only oral forms are listed — drops and tablets. If you have been prescribed an injectable form, the pharmacist confirms availability, and you check the strength and method of administration in the leaflet of the product you receive. The doses used in practice for intramuscular administration are 100,000 IU and 300,000 IU.
100,000 or 300,000 IU — what is the difference
The difference is not "better" versus "weaker". It is how large the deficiency is and over what period it is being corrected.
Vitamin D is fat-soluble and is stored in adipose tissue, from which it is released gradually. A higher dose means a larger store and a longer interval until the next administration — but also a greater risk of over-correction if the dose was not needed.
That is why the choice between the two is not made by preference. It is made on the basis of the measured level, body weight and the clinical situation.
The right question is not "where can I find it?"
It is "do I need it?".
Injectable vitamin D is not a supplement to take preventively, at random. Unlike water-soluble vitamins, where the surplus is eliminated, vitamin D accumulates. Overdose is not theoretical: it leads to hypercalcaemia, with real symptoms.
The contraindications in the leaflet include hypercalcaemia, hypervitaminosis D and severe kidney failure.
So the step before administration is the blood test: 25-OH vitamin D, which measures the level in your body. Without it, you are giving a high dose without knowing whether, and how much, you need.
Why injectable and not oral
The oral form works well for most people. The injectable route makes sense in specific situations:
- difficulty sticking to a daily or weekly oral schedule;
- malabsorption — digestive conditions that limit absorption;
- the need to correct quickly a significant deficiency, confirmed by tests.
If none of these applies, the oral form is simpler and cheaper. We say this even though we give the other option.
Farmacia Tei or another pharmacy: the rule is the same
Many searches combine "vitamin D3 injection" with the name of a pharmacy — for example, Farmacia Tei (a well-known Romanian pharmacy). The answer does not depend on the pharmacy: a prescription-only injectable medicine is dispensed only on prescription, wherever you look for it, and the pharmacist tells you what is in stock at any given time. Do not buy ampoules from sources without a prescription and without a leaflet in Romanian.
Who actually needs extra vitamin D
The Endocrine Society guideline published in 2024 analysed randomised trials of vitamin D given without prior testing, for prevention, in people without an established medical indication. Its conclusions are more cautious than the advertising suggests:
- it suggests supplementation for children and adolescents (aged 1–18), adults over 75, pregnant women and people with high-risk prediabetes;
- it does not suggest doses above the recommended daily intake for healthy adults under 75;
- for people over 50 who have an indication, it suggests daily administration, not high doses at long intervals.
The guideline does not apply to people who already have a medical indication for treatment or testing — for example, a condition that reduces absorption. There, the decision is the doctor's.
For context, the 2011 Institute of Medicine report set the requirement at 600 IU a day between the ages of 1 and 70 and 800 IU a day over 70. Injectable doses of 100,000 or 300,000 IU are in a completely different category — hence the need for a clear reason.
What the 25-OH vitamin D test measures
The test measures 25-hydroxyvitamin D, the main form in which vitamin D circulates in the blood. Its half-life is about 15 days, while vitamin D stored in adipose tissue turns over much more slowly, in around two months. That is why the test reflects the last few weeks, not yesterday.
The result may be given in ng/ml or in nmol/L; 20 ng/ml corresponds to 50 nmol/L. The thresholds are debated: the 2011 report considered that a level of at least 20 ng/ml covers the needs for bone health in almost the whole population, and noted that higher values were not consistently associated with greater benefits. The 2024 guideline says there is no clear evidence for an optimal target level for prevention and does not recommend routine testing in people without an established indication.
The practical translation: the test is not screening for everyone. It is the mandatory step when a high injectable dose is being discussed. We will not interpret your result here — that is done at the assessment, with the rest of the context.
Injectable or oral: what direct comparisons show
There are studies that compared the same high dose, given once, by the two routes. In one, in 66 older people living in care institutions, 600,000 IU raised vitamin D levels by both routes; at 12 weeks the increase was greater after the injection, and 6 participants had raised calcium in their urine. In another study, in 100 adults with deficiency, a single dose of 200,000 or 600,000 IU, oral or intramuscular, corrected the deficiency in more than 70% of participants after two months, in all groups.
And a study that makes us cautious about "high dose, rarely": in 2,256 women over 70, an annual oral dose of 500,000 IU was associated with more falls and more fractures than placebo, with a higher risk in the first three months after administration. It is a study of the oral route and of a dose higher than the usual injectable ones, but the idea stands: a higher dose is not automatically safer or more effective.
What vitamin D excess looks like
Vitamin D toxicity is rare, but it can be serious. It shows as hypercalcaemia — raised calcium in the blood — and the symptoms described most often are:
- confusion and apathy;
- repeated vomiting and abdominal pain;
- frequent urination, intense thirst and dehydration.
The usual cause is the mistaken administration of extremely high doses. There are, however, also situations in which calcium rises at doses considered safe — through disorders of vitamin D metabolism or in some diseases, such as granulomatous conditions or certain lymphomas. These are things that come to light at the assessment, not after the injection.
How often it is repeated
There is no interval that applies to everyone. It depends on the measured level, the dose and the reason for administration. In the studies above, the level was measured again after 6–12 weeks or at 2, 4 and 6 months, and the dose was repeated only if it remained low. After the annual dose of 500,000 IU, the level remained above that of the placebo group even at 12 months.
The practical conclusion: it is not repeated "preventively", by the calendar, without a new assessment. The timing of the follow-up and of any new dose is set by the doctor.
How we work
We give vitamin D 100,000 IU — 200 RON — and 300,000 IU — 250 RON, intramuscularly, at the clinic or at home, only after a medical assessment. The injection takes a few minutes; the assessment beforehand is the part that matters.
If you have recent test results, bring them. If not, we will tell you exactly what to do beforehand. Details: vitamin D injection.
We do not sell ampoules and we do not recommend self-administration.
Sources
Informational article. The dose is set by a doctor, on the basis of the measured level — not from an article and not on request.
Frequently asked questions
- Where can I find vitamin D3 injection?
- An injectable vitamin D3 medicine is dispensed only on prescription, and the pharmacist confirms availability. Note: in the ANM Nomenclature (Romania's register of authorised medicines) updated on 11 September 2026, Dibase no longer appears and only oral forms are listed under vitamin D3; you check the exact form and strength in the leaflet of the product you receive. The more useful question remains whether you need it: vitamin D accumulates in the body, and the dose is set on the basis of the level measured by the 25-OH vitamin D test.
- What is the difference between 100,000 and 300,000 IU?
- The size of the store created and the interval until the next administration. Vitamin D is fat-soluble and is stored, then released gradually. A higher dose means longer cover, but also a greater risk of over-correction if it was not needed. The choice is made on the basis of the measured level, body weight and the clinical situation.
- Can I give myself the vitamin D injection?
- We do not recommend it. It is an intramuscular injection of a high dose of a vitamin that accumulates, and the contraindications — hypercalcaemia, hypervitaminosis D, severe kidney failure — are checked before, not after.
- Which test should be done beforehand?
- 25-OH vitamin D, which measures the level in your body. Without it, you are giving a high dose without knowing whether, and how much, you need. If you have recent results, bring them to the assessment.
- How much does injectable vitamin D cost at the clinic?
- 200 RON for 100,000 IU and 250 RON for 300,000 IU, with the medical assessment included. Available at the clinic or at home, in Bucharest and Ilfov.
- Should everyone have a vitamin D test?
- Not necessarily. The 2024 Endocrine Society guideline does not recommend routine testing in people without an established medical indication. The test does, however, become the mandatory step when a high injectable dose is being discussed, because vitamin D accumulates.
- What are the signs of a vitamin D overdose?
- Toxicity is rare and shows as raised calcium in the blood. The symptoms described most often are confusion and apathy, repeated vomiting, abdominal pain, frequent urination, intense thirst and dehydration. If they appear after a high dose, seek medical assessment without delay.
- How often can the vitamin D injection be repeated?
- There is no fixed interval. It depends on the measured level, the dose and the reason for administration. After a high dose, the level can stay raised for months, so the injection is not repeated by the calendar but after a new assessment, at the time set by the doctor.
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