Is it better to get vitamins from food or supplements?

Food sources are generally preferred, as they provide nutrients alongside other beneficial compounds. Supplements can be useful where deficiencies exist or dietary intake is insufficient, particularly during winter months in the UK.

Can vitamin deficiencies cause insomnia?

Vitamin deficiencies do not always cause insomnia directly, but they can contribute to poor sleep quality, frequent waking, or conditions such as restless legs syndrome, which can interfere with sleep.

How long does it take for vitamins to affect sleep?

Some people notice changes within a few days, particularly with magnesium, but consistent improvements usually take several weeks as nutrient levels stabilise.

Are sleep vitamins safe to take every day?

Vitamins are generally safe when taken within NHS-recommended limits. Long-term or high-dose supplementation should be discussed with a GP, especially for iron and vitamin D.

Should vitamins be taken at a specific time of day for sleep?

Magnesium is often taken in the evening to promote relaxation. Vitamin D is usually taken earlier in the day, while other vitamins are commonly taken with meals unless advised otherwise.

Can vitamins replace sleep medication?

Vitamins may support better sleep but are not a replacement for prescribed sleep medication. Ongoing sleep problems should be assessed by a healthcare professional.

Who should be cautious about taking supplements?

Anyone who is pregnant, breastfeeding, managing a long-term health condition, or taking medication should seek medical advice before starting supplements to avoid interactions or excessive intake.

The Best Vitamins for Sleep (UK 2026)

Annie Wouters
Jan 10
5 min read

Whilst sleep is often touted as a miracle cure-all, the truth is that it's just one piece of the puzzle when it comes to your health. Good sleep often goes hand-in-hand with exercise, an active social life and nutrition. In fact, making sure your body gets the right vitamins and minerals is one of the most impactful ways to improve your sleep quality. In this guide, we cover the best and most important vitamins for a good night's sleep.

Three ripe bananas with a light brown stem rest on a textured gray surface, showcasing their vibrant yellow color. — Bananas are an excellent source of Vitamin B6

Understanding Sleep and the Role of Nutrition

Good sleep is not only about duration; quality is just as important. Many people spend eight hours in bed yet wake feeling unrefreshed due to poor sleep efficiency, frequent awakenings, or insufficient time spent in restorative sleep stages. When sleep is fragmented or unbalanced, the body and brain miss out on essential recovery, even if total sleep time looks adequate on paper.

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Sleep progresses through light sleep, deep sleep, and REM sleep, each serving a distinct role in physical repair, cognitive function, and emotional regulation. Vitamins and minerals help regulate this cycle by supporting neurotransmitters such as serotonin and GABA, aiding melatonin production, and reducing stress that interferes with falling or staying asleep. In some cases, nutrient deficiencies may also contribute to issues like insomnia or restless leg syndrome, which is why targeted nutritional support can play a meaningful role in improving sleep quality.

Good sleep isn't just about duration; quality matters significantly. While some people might sleep for eight hours, they may still wake up feeling fatigued due to poor sleep efficiency.

1. Vitamin D

Eggs on toast with greens on a black plate, surrounded by whole eggs, seeds, and flowers, on a dark background. Bright and appetizing. — Eggs are an excellent source of Vitamin D

Vitamin D deficiency is common in the UK, particularly during the winter months when sunlight exposure is limited. The NHS reports that approximately 1 in 5 adults in the UK have low vitamin D levels. Research suggests that vitamin D deficiency is linked to poor sleep quality, shorter sleep duration, and increased risk of sleep disorders such as insomnia and sleep apnea.

According to David Klapper, MD, a sleep medicine expert at Hartford HealthCare:

“When vitamin D is low, the overall research shows that many people have poor sleep. For example, vitamin D seems to affect how much melatonin is made in the body. Of course, that affects sleep.”

Vitamin D supports sleep by acting on receptors in the brain that help regulate circadian rhythms. Low vitamin D levels have been linked to poorer sleep quality, disrupted sleep patterns, and a higher risk of insomnia.

The main source is sunlight exposure between April and September, with supplementation recommended during autumn and winter at 10 mcg per day in line with NHS guidance. Dietary sources include oily fish such as salmon and mackerel, eggs, and fortified cereals.

2. Magnesium: The Sleep Mineral

Fresh green spinach leaves spill from a bowl onto a textured gray surface, creating a vibrant and healthy display.

How Magnesium Supports Sleep

Magnesium plays a central role in sleep regulation by supporting melatonin production, relaxing muscles, and calming the nervous system. Low magnesium levels are linked to increased stress and anxiety, which can make falling asleep more difficult, while adequate intake helps maintain healthy levels of GABA, a neurotransmitter that promotes relaxation and deeper sleep.

Good dietary sources include whole grains, leafy greens such as spinach and kale, nuts, and seeds. Magnesium supplements are commonly used in the UK, with typical adult intakes ranging from 200 to 400 mg per day. For sleep support, magnesium is best taken in the evening, around 30 to 60 minutes before bed, to help the body wind down and prepare for rest.

3. Vitamin B6

A white bowl of cereal with a spoon, two pears, a pitcher, and a honey dipper on a gray surface. Cereal spills from a jar, creating a cozy mood. — Fortified cereals are one of the primary sources of B6

Vitamin B6 supports sleep by enhancing the production of serotonin and melatonin, two compounds essential for regulating the sleep-wake cycle. Adequate levels of vitamin B6 are associated with improved sleep quality and fewer night-time disturbances.

Dietary sources include bananas, potatoes, chickpeas, and fortified cereals. When taken as a supplement, intakes of up to 10 mg per day are commonly used to support sleep without exceeding typical safety guidelines.

4. Calcium

Jar of yogurt with blueberries and zest on a pink plate beside pink flowers on a wooden table. Rustic and fresh setting.

Calcium supports sleep by contributing to melatonin production and helping to stabilise sleep cycles. Low calcium levels have been associated with more fragmented sleep and an increased likelihood of night-time awakenings.

Key sources include dairy products such as milk, cheese, and yoghurt, as well as fortified plant-based alternatives like almond or oat milk. The NHS recommends an intake of around 700 mg per day for adults, which can be met through diet or supplementation where necessary.

5. Iron

Grilled steak with herbs on a black plate, garnished with asparagus, carrots, and a bread roll. Dark background, elegant dining setting. — Red meat is a great option for increasing iron

Iron deficiency is common in the UK, especially among women, and has been linked to restless leg syndrome and sleep disturbances.

According to Dr Suzanne Wylie, GP and medical adviser for IQ Doctor

“Iron is essential for the production of dopamine, a neurotransmitter that helps to regulate movement and mood. Low dopamine levels can contribute to conditions such as restless leg syndrome (RLS), which causes uncomfortable sensations in the legs, which are often worse at night.”

Iron plays an important role in sleep by supporting dopamine production, a neurotransmitter involved in regulating sleep and wakefulness. Low iron levels are also closely linked to restless legs syndrome, a condition that can significantly disrupt sleep.

Dietary sources include leafy greens, beans, lentils, and fortified cereals, as well as lean meats for those who eat them. Iron supplements should only be taken under GP guidance, as excess iron can be harmful and underlying causes of deficiency should be properly investigated.

Best Practices for Supplementation

Before starting any vitamin or mineral supplement, it is important to seek advice from a healthcare professional, particularly during pregnancy, while breastfeeding, or when taking prescription medication. Supplements can interact with existing treatments and may not be appropriate in all circumstances.

It is also advisable to choose reputable UK brands that comply with NHS guidance and UK Food Standards Agency regulations, and to stick within recommended daily intakes to reduce the risk of overdosing or unwanted side effects.

Conclusion

Ensuring adequate intake of Vitamin D, Magnesium, Vitamin B6, Calcium, and Iron can substantially improve your sleep. Combine these vitamins with healthy sleep habits to experience maximum benefits. Remember, individual needs vary; consulting a GP for personalised advice is always recommended.

Start improving your sleep today by integrating these essential vitamins into your routine.

Frequently Asked Questions About the Best Vitamins for Sleep

Can vitamins alone cure insomnia?

Vitamins significantly improve sleep quality but may not fully resolve chronic insomnia without additional lifestyle adjustments or medical intervention.

Are sleep supplements safe?

Generally, vitamins are safe when taken within NHS-recommended doses. Always consult a healthcare professional if unsure.

How long before vitamins improve sleep?

Some notice improvements within days, but consistent results typically take several weeks.

Can vitamins really improve sleep quality?

Vitamins and minerals can support healthier sleep by regulating melatonin production, calming the nervous system, and reducing deficiencies linked to sleep disruption. They are most effective when combined with good sleep habits rather than used in isolation.

Which vitamin is most important for sleep?

There is no single most important vitamin. Vitamin D, magnesium, vitamin B6, calcium, and iron all influence sleep in different ways, from circadian rhythm regulation to muscle relaxation and neurotransmitter balance.