Vitamin D in autumn: why London is low, and what an injection changes
Between October and March the sun in London is too low in the sky for skin to make vitamin D at all. Most of us run on reserves. Many run out.
Skin makes vitamin D from sunlight, but only when the sun is high enough. In London that is roughly April to September. For the other half of the year the body lives on what it stored, and by January most people are well below the level their bones, muscles and immune system would prefer.
What low vitamin D feels like
- Tiredness that is more like heaviness than sleepiness.
- Aching muscles and joints without an obvious reason.
- Low mood through the dark months.
- Catching everything that goes round.
None of these is specific, which is why it gets missed. A blood test through your GP settles it.
Tablet or injection
Daily tablets work if they are taken daily, which is where most people fall down. A single injection into the muscle stores a larger dose that the body draws on over the following months. For someone who wants it dealt with in October and not thought about until spring, that is the point of it.
The appointment
A short conversation about what you take and any conditions that matter, the medical form if it is your first visit, and an injection into the muscle of the upper arm or hip. It takes a minute. A dull ache for a day is the most anyone notices. The dose is a stored one, drawn on over the following months, which is the whole point of having it as an injection rather than a daily tablet you may or may not remember.
Who should have a blood test first
- Anyone already taking a vitamin D supplement, because the injection adds to it.
- Anyone with a kidney condition, sarcoidosis or a history of high calcium.
- Anyone who has felt the symptoms above for more than a season; the test may show something else.
- Anyone curious. The test is simple, and a number is a better reason for a course than a feeling.
Through the winter
One injection at the start of the dark months and another after the new year carries most people through to the spring, when the sun climbs high enough for the skin to make its own again. Vitamin D and B12 are often had together at the first visit, since the tiredness that brings people in is frequently a mixture of the two. Neither replaces daylight, and a walk at midday in winter still does more for the mood than either.
Questions people ask
Can I have too much: yes, which is why the clinic asks about supplements and suggests a test for anyone unsure. Will it help my mood: for people who are low, often, though daylight and a walk at midday still do more. Is it the same as the tablets: the same vitamin, given as a stored dose rather than a daily one, so it suits people who would not remember the tablet. Can I have it with B12: yes, in the same visit, and many people do at the start of autumn.
- One injection in October or November, and one after the new year.
- A blood test through your GP if you have never been measured.
- Sun on the skin from April onwards, which the injection is standing in for until then.
The whole appointment is ten minutes, and it books online without a consultation.
Many people have vitamin D and B12 together at the start of autumn. They do different jobs; the appointment for both is the same short visit.
Common questions
How long does one injection last?
Typically two to three months, sometimes longer. One in October and one in January covers the winter for most people.
Does it hurt?
A small injection into the upper arm or hip. A dull ache for a day at most.
Can children have it?
Not at the clinic. Vitamin D for children is a matter for a GP or pharmacist.
Ask us about this
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