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The need for vitamin D supplementation – who is at risk and how to diagnose
Choosing a suitable supplement – what are the risks of unlicensed vitamin D
The assurance of a licensed product
Stexerol-D₃ (colecalciferol) A licensed vitamin D treatment that meets the need of your patients

Click here for prescribing information (PDF).


The importance of vitamin D, needed for the body to absorb calcium and phosphorus from the food we eat, is a growing topic of interest. Vitamin D is essential for musculoskeletal health as it promotes calcium absorption from the bowel, enables mineralisation of newly formed osteoid tissue in bone and plays an important role in muscle function. Deficiency is common in the UK, particularly in older people.1


The need for vitamin D supplementation – who is at risk and how to diagnose

Sunlight does, indeed, ‘top up’ our vitamin D, but several factors influence the level of production.2 Most notably, much of the United Kingdom is too far north of the equator to provide sufficient vitamin D from sunlight from October to April3, so deficiency and insufficiency are prevalent – approximately 18% may be at risk of vitamin D deficiency4 and nearly 50% of the UK adult population may have insufficient levels of vitamin D.5

Those most at risk of deficiency and insufficiency include people over 65 years of age6, those who spend a lot of time indoors6, have darker skin6 or cover their skin with clothing or sunscreen6, people who are very overweight7 and those who follow a vegetarian3 or vegan7 diet. With public health advice increasingly recommending against prolonged sun exposure, the only way to restore adequate vitamin D concentrations is through supplementation.8,9

Many people fall short of recommended vitamin D levels1, with symptoms of insufficiency and deficiency varying from fatigue10 and difficulty thinking clearly11, to problems with bones and muscles resulting in weakness, deformities and pain.7

Measurement of serum 25(OH)D remains the best way of estimating vitamin D status. The National Osteoporosis Society (NOS) defines deficiency as 30 nmol/l or less of serum 25(OH)D: patients with this reading require treatment. Treatment may also be necessary for some individuals with insufficiency – readings between 30 and 50 nmol/l – and additional conditions which may be attributed to vitamin D deficiency. Recommended treatment for vitamin D deficiency is a fixed loading dose of 300,000 IU over a period of 6 to 10 weeks, followed by regular maintenance therapy doses of between 800 and 2,000 IU (occasionally up to 4,000 IU) daily.1

Recent guidance from NHS England recommends vitamin D should only be prescribed “in cases of medically diagnosed deficiency, including for those patients who may have a lifelong or chronic condition or have undergone surgery that results in malabsorption”. While maintenance therapy is recommended, it is not considered an exception to this guidance, as “supplements can be bought cheaply and easily”.12

Vitamin D treatment is not without risk. Toxicity from taking too much is a potentially serious adverse effect. Too high a dose can lead to hypercalcaemia – with symptoms ranging from thirst and polyuria, to vascular and organ calcification. Concentrations above 250 nmol/l are considered excessive, with concentrations above 375 nmol/l (150 mcg/l) associated with toxicity.8


Choosing a suitable supplement – what are the risks of unlicensed vitamin D?

The growing use of supplements has been described as associated with increasing reports of vitamin D toxicity. Reasons for toxicity include manufacturing errors, prescribing errors and the use of high dose products – and has particularly been seen in unlicensed preparations.8,13 A recent review of Medline articles on vitamin D toxicity found that many cases were a consequence of errors in formulation or fortification, inappropriate prescribing or dispensing, and errors in administration.8

For example, a study by Garg et al of 14 vitamin D₃ formulations available in New Zealand revealed while the two registered, prescription formulations were within acceptable range of the labelled amount, (90±4 and 97±2% respectively), the 12 non-registered, non-prescription dietary supplements had vitamin D levels ranging from 8±2% to 201±29% of the labelled amount.14

A US study by LeBlanc et al. of 15 vitamin D₃ preparations showed substantial variation compared with the stated dose in pills from the same bottle. The over-the-counter and compounded preparations ranged between 52% and 135% of expected dose. The one manufacturer that was US Pharmacopeial verified was highly accurate (101.7%), and all 5 pills tested were within 10% of expected dose.15

Finally, Koutkia et al reported hypercalcaemia and renal disease due to vitamin D toxicity in a patient in the USA who was taking an over-the counter vitamin D supplement with a stated dose of 2,000 IU per gram. When three batches of the product were analysed, they were found to contain 26 to 430 times the stated dose.16


The assurance of a licensed product

Licensed products are required to meet stringent requirements to demonstrate efficacy, safety and quality, and must be manufactured in accordance with robust standards of Good Manufacturing Practice for medicines. Licensed medicines are also required to provide comprehensive information to patients to support their appropriate use.

Before prescribing an unlicensed medicine, prescribers should be satisfied that a licensed alternative wouldn’t better meet the patient’s needs. Therefore, when an unlicensed preparation is used in favour of a licensed preparation, greater responsibility is placed upon a healthcare professional to accurately prescribe, and particular attention should be paid to risk factors such as adverse reactions, product quality; or discrepant product information or labelling. The General Medical Council aligns with this thinking.17


Stexerol-D₃ – A licensed vitamin D treatment that meets the needs of your patients

From Kyowa Kirin, makers of the market-leading calcium vitamin D supplement Adcal-D₃, Stexerol-D₃ is a simple solution for the treatment and prevention of vitamin D deficiency in adult patients and adolescents.18 Stexerol-D₃ is licensed, giving assurance over pharmaceutical quality and consistency, and offers 1,000 and 25,000 IU tablet strengths to assist with the prescribing of vitamin-D₃ deficiency loading doses, and vitamin-D₃ maintenance therapy.18

Stexerol-D₃ is suitable for vegetarians18, is halal19 and kosher20 certified, and has a nut*, soya*, gluten* and gelatin-free* formulation18 offering choice to a wide range of patients, including those with specialist dietary or religious needs. To aid compliance, patients can opt in to a free text reminder service, StexerolConnect, which sends a daily, weekly or monthly reminder in line with dosing requirements.21 Stexerol-D₃ 1,000 IU is also stable for 28 days in a compliance aid.22

These patient-focused benefits make Stexerol-D₃ an excellent choice for the treatment of vitamin D deficiency and insufficiency.

* Vitamin D₃ is derived from lanolin contained in sheep wool, therefore may not be suitable for all vegans. Cannot guarantee the complete absence of traces of gluten, nuts or soya in Stexerol-D₃.


  • For more information about Stexerol-D₃, please click here to view a promotional video. The page is password protected – please use the following password to view: ScJTw89h
  • Click here to view Stexerol-D₃ on electronic Medicines Compendium (eMC).

Click here for prescribing information (PDF).



  1. National Osteoporosis Society. Vitamin D and Bone Health: A Practical Clinical Guideline for Patient Management. Bath: NOS, 2013.
  2. Holick, MF. Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease. Am J Clin Nutr 2004;80(suppl):1678S-88S.
  3. Pearce, S et al. Diagnosis and management of vitamin D deficiency. BMJ. 2010;340:142-147.
  4. Department of Health & Food Standards Agency. National Diet and Nutrition Survey. Headline results from Years 1, 2 and 3 (combined) of the Rolling Programme (2008/2009 – 2010/11).
  5. Hypponen E, Power C. Hypovitaminosis D in British adults aged 45 yr: nationwide cohort study of dietary and lifestyle predictors. Am J Clin Nutr. 2007;85(3):860-868.
  6. Vitamin D – advice on supplement for at risk groups. Letter from the Chief Medical Officers for the United Kingdom. Available at
  7. Bentley J (2013) Vitamin D deficiency: identifying gaps in the evidence base. Nursing Standard. 27, 46, 35-41.
  8. Taylor, P. Davies, JS. A review of the growing risk of vitamin D toxicity from inappropriate practice. Br J Clin Pharmacol (2018) 84 1121–1127 1121.
  9. Scientific Advisory Committee on Nutrition. Vitamin D and Health. London, 2016. Available at
  10. Roy S et al. Correction of Low Vitamin D Improves Fatigue: Effect of Correction of Low Vitamin D in Fatigue Study (EViDiF Study). N Am J Med Sci. 2014 Aug; 6(8): 396–402.
  11. Wilkins CH et al. Vitamin D Deficiency Is Associated With Low Mood and Worse Cognitive Performance in Older Adults. Am J Geriatr Psychiatry 2006; 14:1032–1040.
  12. NHS England. Conditions for which over the counter items should not routinely be prescribed in primary care: Guidance for CCGs. March 2018.10,16-17.
  13. Davies JS, Poole CD, Feldschreiber P. The medico-legal aspects of prescribing vitamin D. Br J Clin Pharmacol. 2014 Dec;78(6):1257-63.
  14. Garg S., Sabri, D., Kanji, J. et al. Evaluation of vitamin D medicines and dietary supplements and the physicochemical analysis of selected formulations. J Nutr Health Aging (2013) 17: 158.
  15. LeBlanc ES, Perrin N, Johnson JD, Ballatore A, Hillier T. Over-the-Counter and Compounded Vitamin D: Is Potency What We Expect? JAMA Intern Med. 2013;173(7):585–586.
  16. Koutkia P, et al. Vitamin D Intoxication Associated with an Over-the-Counter Supplement. N Engl J Med, Vol. 345, No.1. July 5, 2001. 66-67.
  17. General Medical Council. Good practice in prescribing and managing medicines and devices. Prescribing unlicensed medicines. Available at
  18. Stexerol-D₃ Summary of Product Characteristics.
  19. Halal Authority Board. Vitamin D Halal Certificate.
  20. Federation of synagogues. Vitamin D₃ Film Coated Tablets Kosher Certificate.
  21. Stexerol-D₃ Patient Information Leaflet. Available at
  22. Data on File, Kyowa Kirin Ltd - DOF-UK-030-Stexerol.


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