Vitamin D is one of the most important micronutrients for our body. It plays a key role in bone health, the immune system, muscle function, and even our mood. However, many people are unsure: When should they take vitamin D? Morning, midday, or evening? And how does the time of intake affect the absorption and effectiveness of vitamin D? In this article, you'll learn everything you need to know about taking vitamin D, how to maximize bioavailability, avoid mistakes, and whether combining it with vitamin K2 makes sense.
Why vitamin D is so important
Vitamin D is a fat-soluble vitamin that acts like a hormone in the body. It promotes calcium absorption in the intestines and is therefore essential for strong bones and teeth. But its effects extend far beyond this: Vitamin D strengthens the body's immune system, regulates inflammatory processes, influences muscle function, and is involved in numerous metabolic processes. Studies suggest that good vitamin D levels can reduce the risk of autoimmune diseases, cardiovascular disease, and even depression.
A vitamin D deficiency often goes undetected for a long time. Fatigue, frequent infections, muscle weakness, or low mood are typical but non-specific symptoms. Especially in the winter months, when sunlight is low, targeted vitamin D supplementation is therefore beneficial for many people to avoid a deficiency.
When to take vitamin D – the best time of day
There's no set time, but many experts recommend taking vitamin D in the morning or mid-morning. There are several reasons for this:
For one thing, the body's hormone production follows a natural circadian rhythm. Vitamin D can influence this rhythm – similar to cortisol, which naturally rises in the morning. Taking vitamin D in the morning therefore supports the natural wakefulness and activity cycle and is better tolerated by many people than taking it in the evening.
Some observations suggest that taking vitamin D in the evening can disrupt sleep in sensitive individuals due to its indirect effect on melatonin production. While this varies from person to person, those prone to sleep problems should avoid taking vitamin D in the evening and instead opt for a dose by early afternoon at the latest.
With a meal together
Vitamin D is a fat-soluble vitamin, meaning it requires dietary fat to be properly absorbed by the body. Without fat, its bioavailability decreases significantly. Therefore, vitamin D should always be taken with a meal containing healthy fats. Particularly suitable foods include:
- Avocado
- Nuts and seeds
- high-quality oils (e.g. olive oil, linseed oil)
- fatty fish
- Eggs
Combining it with a classic breakfast (e.g., yogurt with nuts, an omelet with olive oil, or avocado toast) is ideal. Taking it with omega-3 fatty acids can also have a synergistic effect—many people combine their vitamin D intake with omega-3 capsules to better integrate both active ingredients into their daily routine.
Take vitamin D in the evening?
It's generally not a problem to take vitamin D in the evening, as the effect isn't immediate but rather has a long-term impact on blood levels. However, some people report difficulty falling asleep when taking high doses of vitamin D late in the day. This is likely related to the effect on the circadian rhythm, especially in sensitive individuals.
If you don't have the opportunity to take it during the day, taking vitamin D in the evening is better than not taking it at all – although you should not take it directly before going to bed, but rather with dinner, for example.
Combination of vitamin D3 and K2 – why is it useful?
An important aspect of vitamin D intake is its combination with vitamin K2. Vitamin D promotes calcium absorption, but vitamin K2 ensures that the calcium gets to where it belongs: the bones and teeth, not the arteries. Without K2, unwanted calcium deposits can occur in blood vessels. Our MTM D3/K2 drops combine high-quality D3 and K2 in one product.
Especially with regular or high-dose vitamin D intake (e.g., 2000 IU and more), vitamin K2 supplementation (ideally as MK-7 all-trans) is recommended. The synergy of both vitamins is scientifically well-documented—especially in the prevention of osteoporosis and arteriosclerosis.
Dosage recommendation
Recommendations for vitamin D dosage vary widely. The German Nutrition Society (DGE) recommends a flat rate of 800 IU per day, but many experts consider 1000–2000 IU per day safe and sensible, especially with minimal sun exposure.
Anyone who wants to know their actual needs should have their blood vitamin D (25-OH-D) levels checked regularly. According to many professional associations, ideal values are between 40 and 60 ng/ml. High-risk groups such as the elderly, people with dark skin, chronically ill individuals, or those who rarely go outdoors often require higher doses – with medical supervision, 4000 IU or more daily are possible.
Which foods contain natural vitamin D?
Getting a complete supply of vitamin D from food alone is difficult, as few foods contain significant amounts. Vitamin D-rich foods include:
- fatty fish such as salmon, herring, mackerel, sardines#
- Liver (especially beef liver or cod liver oil)
- egg yolk
- fortified products such as margarine or plant milk
- certain mushrooms (e.g. UV-irradiated mushrooms)
Nevertheless, these sources often only provide a fraction of the daily requirement. Especially during the winter months, targeted vitamin D supplementation remains essential for many.
How much vitamin D should you take?
The recommended daily amount for adults is between 800 and 2000 IU (International Units). However, individual needs can vary greatly, so a blood test with a doctor is recommended to determine your individual needs. High-risk groups such as the elderly, pregnant women, or those with little sun exposure may require higher amounts. Here is one of our articles on vitamin D dosage .
Risks of overdose
Even though undersupply is more common than overdose, moderation is important. A sustained intake of more than 4000 IU daily without medical supervision can lead to hypercalcemia (excess calcium in the blood). Symptoms include nausea, muscle weakness, headaches, or kidney problems. Those taking high doses (e.g., weekly boost doses) should have their calcium and vitamin D levels regularly checked by a doctor.
Conclusion
The optimal vitamin D intake depends on your lifestyle and daily routine. For most people, taking it in the morning or mid-morning with a fatty meal is ideal. Combining it with vitamin K2 increases safety and effectiveness and helps the body optimally utilize calcium. Make sure you have regular blood tests, especially with higher doses, and combine supplementation with a healthy diet and as much sunlight as possible.
This way, you can safely close supply gaps, support your health in the long term – and benefit optimally from the effects of this essential vitamin.
Sources:
-
Holick, MF (2007).
Vitamin D deficiency.
New England Journal of Medicine, 357 (3), 266-281. https://doi.org/10.1056/NEJMra070553 -
Wacker, M., & Holick, M.F. (2013).
Sunlight and Vitamin D: A global perspective for health.
Dermato-Endocrinology, 5 (1), 51–108. https://doi.org/10.4161/derm.24494 -
EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). (2016).
Scientific opinion on the tolerable upper intake level of vitamin D.
EFSA Journal, 14 (10), 4547. https://doi.org/10.2903/j.efsa.2016.4547 -
Knapen, MHJ, Braam, LAJL, Drummen, NEA, Bekers, O., Hoeks, APG, & Vermeer, C. (2013).
Menaquinone-7 supplementation improves arterial stiffness in healthy postmenopausal women.
Thrombosis and Haemostasis, 109 (6), 1245–1250. https://doi.org/10.1160/TH12-11-0855
