The short answer
Vitamin D helps your body take in calcium and supports healthy bones and muscles. Your body makes most of it from sunlight on your skin, and in a New Zealand winter there's a lot less of that, so a daily vitamin D3 supplement is a simple way to support your levels if you spend little time outside, live in the South Island or have other risk factors. Keep your total under the adult upper limit of 80 micrograms (3,200 IU) a day. Not sure it suits you? Try our Supplement Finder.
In this article
Maybe you work indoors all week, you train before sunrise and after dark, or you're just feeling the short days. Whether you're new to supplements or already have a routine, this guide covers who's most likely to run low, what sun and food can do, how much to take and which vitamin D to choose.
Should I take vitamin D in winter?
Yes, if you're more likely to run low. Health New Zealand lists five main risk factors. If none of them apply and you get outside most days, sun and food may cover you. [1]
Check yourself in seconds
Are you likely to run low?
- Little time outdoors: because of work, illness or age
- South Island: and spending little time outside
- Darker skin or covering up: naturally very dark skin, or covering most of your skin outdoors
- Avoiding the sun: because of a health condition, like a history of skin cancer, or a medication
- Absorption: a condition that affects absorption, such as coeliac disease or Crohn's disease
Health New Zealand risk factors [1]. None apply and you're outside most days? Sun and food may cover you.
What does vitamin D actually do?
It helps your body take in calcium from food, and it supports healthy bones and muscles. [1] Your body can't store much of it, so it needs regular topping up.
Can I get enough from the sun and food?
Sun is the main source, and the best time to get it changes with the season. Food helps, but it's very hard to get enough from food alone. [1]
What to do this month
Your vitamin D year
May to August
A walk or other outdoor activity around the middle of the day, with your face, arms and hands uncovered [1].
September to April
Early morning or late afternoon, with sun protection when the UV is 3 or higher [1].
Sun through a window doesn't count, because glass blocks the rays your skin needs [1].
Adds a little [1]
- Oily fish like salmon and sardines
- Egg yolks
- UV-exposed mushrooms
- Some fortified margarines and milks
Do I need a blood test first?
Usually not. Testing isn't recommended for most people, and a doctor can usually suggest vitamin D based on your risk factors alone. A test is mainly used when they suspect a problem caused by very low vitamin D, like soft or painful bones. [3]
How much do I take?
Take it as directed, or follow your doctor's advice if they've given you a dose.
Know the units. Vitamin D is measured in micrograms (mcg or µg), international units (IU) or both. 1 microgram equals 40 IU, so 25 micrograms is 1,000 IU. [5]
More isn't better. The upper limit for adults is 80 micrograms (3,200 IU) a day from all sources. [4] Too much over time can push the calcium in your blood too high, which can cause nausea, weakness, confusion and kidney problems. [5]
Add up everything you take. A multivitamin, a bone health product and a vitamin D on its own can all contain it.
Check first
Who should check with a doctor first?
If you're pregnant or breastfeeding, have kidney disease, take medication that affects calcium or vitamin D, or have ongoing bone pain, muscle weakness or a fracture, talk to your GP before choosing a product.
For babies, Health NZ recommends a vitamin D supplement until age one if they're fully or partly breastfed. Use a product made for infants, as advised by your midwife or doctor, never an adult product. [2]
Which vitamin D should I buy?
Vitamin D3 (cholecalciferol). It tends to raise vitamin D levels more than D2. [5] If you're vegan, go for a D3 made from lichen, as most D3 comes from sheep's wool.
Tablets and capsules are the simplest to dose. If you prefer drops, measure carefully and stick to the directions, since amounts can be given per drop or per millilitre.
Our pick
For a simple daily D3: Sanderson Vitamin D3 1000iu. One small softgel gives you 1,000 IU (25 micrograms) of vitamin D3 as cholecalciferol, to support an adequate daily intake when winter sun is limited. Take one capsule daily with food and don't exceed the stated dose. Check with your doctor first if you have high blood calcium, heart disease or take heart or blood-pressure medication.
Save 52%For a simple daily D3
Sanderson Vitamin D3 1000 IU 100 Softgels
- Rating
- New
- Per serve
- $0.19
Want a plan built around you?
Inception Nutrition builds your winter nutrition, supplements and lifestyle into one plan around your goals, your routine and the foods you like, with weekly check-ins wherever you are in NZ. Not sure where to start? Take their free metabolic audit. Not sure which product suits you? Try our Supplement Finder or email us at info@supplementsolutions.co.nz. No question is too basic.
References
5 sources
- 1.Health New Zealand: Getting your daily vitamin D Risk factors, seasonal sun advice and food sources for New Zealand.
- 2.Health New Zealand: Dietary supplements Vitamin D for breastfed babies.
- 3.bpacnz: Vitamin D supplementation: an update (2025) When vitamin D testing is useful in New Zealand.
- 4.Australia and New Zealand Nutrient Reference Values: Vitamin D Daily intakes and the upper limit.
- 5.NIH Office of Dietary Supplements: Vitamin D fact sheet for health professionals Units, D3 and D2, and the effects of too much vitamin D.
Sources shown: the research is linked in the references. Product details and doses come from the brand. Product suggestions show what’s available now. Last updated 22 October 2026.
This guide is general information, not a diagnosis or medical advice. Take products as directed, and check with a qualified health professional first if you're pregnant, breastfeeding, taking medication or managing a health condition.
