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Vitamin D in summer: stop or continue?

Lisbon in July is not Ireland in July. NHS winter advice, what skin can do in high summer, and why our pouch cannot drop the D on its own.

By Lina and Stanislava · Sep 2, 2026 · 5 min read

July: Lisbon is not Ireland. You cannot drop the D and keep the rest

One of us has an eleven-year-old whose vitamin D dips now and then. Not every time, and not only in January. We stopped guessing and started checking. The calendar is a blunt instrument for this nutrient. Latitude is not.

The short answer

Skin can make vitamin D in high summer. How much depends on where you are, how much skin is out, and for how long.
In Ireland the usual public advice is a daily supplement in autumn and winter. In Portugal and Spain, July is a different sky.
A blood test beats a season. 25-hydroxyvitamin D is the measurement a GP can order.
Our pouch is a fixed daily dose. You cannot take the D out for August and leave the rest. If you want a summer pause, that is a different product, or no product.

What the sky actually does

Vitamin D from the skin needs UVB. At Irish latitudes that UVB is weak for a large part of the year. From late March or April through September, the NHS says most people in the UK and Ireland can make what they need from ordinary time outdoors, uncovered arms and face, without burning. It also says to consider a daily 10 µg through the year if you are rarely outside, cover up, or have dark skin.

EFSA's adequate intake of 15 µg a day from age 1 was set assuming almost no sun. That is a winter number wearing a yearly coat. It is useful. It is not a photograph of a July afternoon in Cascais.

Portugal and Spain sit further south. In high summer, more UVB reaches the ground. People still work indoors, still use shade, still cover children at noon. "We live in the south, so we can stop" is only half a sentence. The other half is whether anyone actually got the sun on skin.

We live in Portugal. Winter vitamin D is a real question at 25 and at 45. Summer is less of one, if the week includes ordinary outdoor time. We will not pretend Lisbon in February is the same as Lisbon in August, and we will not pretend a desk week in August is a beach week.

What we may print

Vitamin D contributes to the maintenance of normal bones. It contributes to the normal function of the immune system. Those are the authorised sentences, because the nutrient is in the pouch above 15% NRV.

Sleep is not on that list. We already said so in the vitamin D and sleep piece. Summer does not change the register.

The blood-level target EFSA used to set the adequate intake is 50 nmol/L, which is 20 ng/ml. That is a population ruler, not a clinic range of 60 to 80 ng/ml. A summer decision that starts from a result is a medical conversation. A summer decision that starts from a podcast number is not.

What the pouch can and cannot do

Pocket Kids carries 25 µg a day. Teens and Adults carry 35 µg. Those amounts sit above 15 µg, in a powder that also carries K2 and the rest of the panel.

There is no summer version. There is no way to skip the D and keep the magnesium. If a household in Faro or Valencia wants to rely on skin in July and August, this product is the wrong tool for a two-month pause. Stop the pouch, or keep it. Do not invent a third setting.

If you keep it through summer, add any D drops you already use. The upper limit is still 50 µg a day to age 10, 100 µg from 11. Two sources in July can still add up. We wrote the ceilings properly in the vitamin D guide and in the upper-limits piece.

What we would actually do

Look at the week, not the month name. Time outdoors with some skin uncovered, or not.
In Ireland, follow the winter-supplement advice unless a GP has said otherwise. In Portugal and Spain, take high summer as a maybe, not an automatic stop.
If you have ever had a low result, or the eleven-year-old pattern of dips, ask for the blood test rather than guessing from the weather app.
If you pause a daily powder for summer, pause the whole thing. Do not keep a second D-only bottle "just in case" on top of it when you restart without adding the two up.

Sources

Written by Lina and Stanislava, founders of MyDailyPocket. This is here to be useful, not to replace your GP. No supplement is a substitute for a varied, balanced diet. Stay within the dose on the pack.