Supplements for Sleep: Evidence-Based Options

A third of UK adults report poor sleep — can supplements help?

According to the NHS, roughly one in three UK adults struggles with sleep. "Supplements for sleep" is now one of the fastest-growing search categories in the wellness space, and the options are overwhelming: magnesium, ashwagandha, melatonin, valerian, 5-HTP, GABA, and dozens more.

But which ingredients actually have clinical evidence behind them? And which claims are legally permitted in the UK?

This guide separates the evidence from the marketing.

What makes a sleep supplement claim legal in the UK?

This is where most supplement brands gloss over the detail — and where you should pay the most attention.

In the UK, any health claim made about a food supplement must be authorised under EU Regulation 432/2012, retained in UK law post-Brexit and enforced by the Food Standards Agency.

Very few ingredients have authorised claims that relate to sleep:

Melatonin — "contributes to the reduction of time taken to fall asleep" (at 1mg dose, taken shortly before bedtime). This is the only authorised direct sleep claim.
Magnesium — "contributes to normal functioning of the nervous system" and "contributes to normal psychological function." These are relevant to sleep regulation but are not direct sleep claims.
Vitamin B6 — "contributes to normal functioning of the nervous system" and "contributes to normal psychological function." Same category as magnesium — relevant but indirect.

If a supplement brand tells you their product "improves sleep" or "helps you fall asleep faster" using an ingredient other than melatonin at 1mg, they are likely making an unauthorised claim.

We are transparent about this because it matters. The ingredients below have clinical research supporting their role in sleep quality, but the authorised claims are more nuanced than most marketing suggests.

Magnesium — the strongest nutritional evidence for sleep support

Magnesium contributes to normal functioning of the nervous system and normal psychological function — both of which are directly involved in the transition from wakefulness to rest.

We have covered this topic in detail in our dedicated article on magnesium for sleep, but here is a brief summary of the key clinical evidence:

Abbasi et al. (2012) — a double-blind, placebo-controlled trial in 46 elderly participants found that 500mg magnesium supplementation over 8 weeks was associated with statistically significant improvements in subjective sleep quality, sleep time, and sleep onset latency compared to placebo.

Held et al. (2002) — demonstrated that magnesium supplementation was associated with changes in slow-wave sleep patterns in healthy participants.

These studies have limitations — small sample sizes and specific populations — but the overall direction of evidence is consistent: magnesium contributes to conditions that support sleep quality, particularly in those with suboptimal dietary intake.

The National Diet and Nutrition Survey consistently shows that a significant proportion of UK adults fall below recommended magnesium intake, which makes it one of the most practical nutritional interventions for sleep support.

The form of magnesium matters too. PARTICULAR uses magnesium citrate — one of the most bioavailable and well-studied forms. For a detailed comparison of forms, see our guide to magnesium glycinate vs citrate.

Ashwagandha (KSM-66®) — clinical evidence for sleep quality

Ashwagandha, and specifically the KSM-66® root extract, has been the subject of several randomised controlled trials examining its effects on sleep quality.

Langade et al. (2019) — a double-blind, randomised, placebo-controlled study in participants with insomnia and anxiety. The KSM-66® group showed significant improvements in sleep onset latency, sleep quality, and total sleep time compared to placebo over 10 weeks.

Langade et al. (2021) — a double-blind, randomised, parallel-group, placebo-controlled study in both healthy volunteers and insomnia patients. Both groups showed significant improvement in sleep parameters with ashwagandha root extract, with improvement being more pronounced in the insomnia group.

Deshpande et al. (2020) — a randomised, double-blind, placebo-controlled study specifically in healthy adults found that ashwagandha extract improved sleep quality and helped in managing insomnia.

It is important to be clear: ashwagandha does not have an EU-authorised health claim related to sleep. These are clinical trial findings, not regulatory approvals. The mechanism is thought to be related to ashwagandha's effects on cortisol and the stress response, rather than direct sedation.

PARTICULAR includes KSM-66® ashwagandha — the same standardised extract used in these clinical trials — when your questionnaire responses indicate elevated stress and poor sleep quality.

Vitamin B6 — contributes to normal psychological function and nervous system function

Vitamin B6 contributes to normal functioning of the nervous system and normal psychological function — both authorised EU health claims.

The relevance to sleep is mechanistic: vitamin B6 is a necessary cofactor in the synthesis of serotonin from tryptophan. Serotonin is in turn a precursor to melatonin — the hormone that regulates circadian rhythm. Without adequate B6, this synthesis pathway is impaired.

Vitamin B6 also contributes to normal homocysteine metabolism and the reduction of tiredness and fatigue, both of which have downstream relevance to sleep quality.

This does not mean that supplementing B6 will directly affect sleep in someone who already has adequate levels. It means that B6 deficiency can impair the biochemical processes that support normal sleep regulation — and correcting that deficiency through supplementation is a reasonable approach.

Vitamin D — emerging evidence linking low status with poor sleep quality

Vitamin D contributes to the normal function of the immune system and has a role in cell division — those are its authorised claims. It does not currently have an authorised claim related to sleep.

However, observational evidence is accumulating. Gao et al. (2018) — a systematic review and meta-analysis of nine studies involving 9,397 participants — found that vitamin D deficiency was associated with a significantly increased risk of sleep disorders (OR: 1.50, 95% CI: 1.31–1.72), poor sleep quality, and short sleep duration.

This is observational data, which means it shows association rather than causation. It is plausible that low vitamin D status and poor sleep share common causes (such as low outdoor activity), rather than one directly causing the other.

That said, vitamin D insufficiency is widespread in the UK — Public Health England recommends that all adults consider supplementing vitamin D during autumn and winter at minimum. If your vitamin D status is low, correcting it through supplementation is sensible for general health, and the emerging sleep data adds to that case.

PARTICULAR uses vitamin D3 (cholecalciferol) from a vegan lichen source. See our full article on vitamin D supplements for more detail on forms.

What about melatonin?

Melatonin is the only ingredient with an authorised UK health claim directly related to sleep: "contributes to the reduction of time taken to fall asleep" at a dose of 1mg, taken shortly before bedtime.

So why does PARTICULAR not include melatonin?

Melatonin is a hormone, not a nutrient. In the UK, melatonin at doses above 2mg is classified as a prescription-only medicine. At lower doses (1mg or below), it can be included in food supplements, but its regulatory status is distinct from vitamins and minerals.

PARTICULAR focuses on nutrients and botanical extracts that support the underlying systems involved in sleep — nervous system function, psychological function, and stress adaptation — rather than providing an exogenous hormone. This is a deliberate formulation choice, not an oversight.

If you are considering melatonin, it is worth discussing with your GP, particularly if you have a circadian rhythm disorder or jet lag.

What about valerian, lavender, 5-HTP, and GABA?

These are among the most commonly marketed sleep supplements, so it is worth addressing them honestly:

Valerian — has a long history of traditional use, but systematic reviews of clinical evidence are inconclusive. The European Medicines Agency lists it as a traditional herbal remedy for sleep, meaning it can be marketed based on historical use rather than clinical proof of efficacy.
Lavender — some trials show improvements in self-reported sleep quality, but study quality is variable and lavender is not a nutrient — it is an aromatic compound.
5-HTP — a serotonin precursor with limited clinical evidence specifically for sleep. It has potential interactions with antidepressants and other serotonergic medications.
GABA — an inhibitory neurotransmitter, but oral GABA supplements have limited evidence of crossing the blood-brain barrier in meaningful quantities.

None of these are included in the PARTICULAR formula. That is not because they are worthless — some may have real effects for some people — but because the clinical evidence does not meet the threshold we require for inclusion, and they fall outside the scope of personalised nutritional supplementation.

Why sleep supplementation should be personalised

Sleep problems are not all the same, and neither are their nutritional solutions.

Someone with low magnesium intake and muscle tension at night has different needs from someone whose sleep is disrupted by chronic stress. A person with low vitamin D status in January has different needs from someone who spends significant time outdoors.

This is why a one-size-fits-all sleep supplement often misses the mark. The PARTICULAR questionnaire captures:

Sleep quality — how long it takes you to fall asleep, how often you wake, how rested you feel
Stress levels — whether stress and anxiety are contributing to poor sleep
Dietary patterns — whether you are likely getting adequate magnesium, B6, and vitamin D from food
Lifestyle factors — exercise, alcohol, caffeine, and shift work

Based on your responses, your personalised formula adjusts the inclusion and dosage of magnesium, ashwagandha KSM-66®, vitamin B6, vitamin D3, zinc, and other ingredients to match what your body actually needs.

Your formula arrives as loose microgranules in a pouch — one daily scoop, with each granule individually coated so that ingredients are released and absorbed independently in the gut, avoiding the competitive absorption issues that affect standard multivitamin tablets.

Key takeaways

Melatonin is the only ingredient with an authorised UK sleep claim — at 1mg, it "contributes to the reduction of time taken to fall asleep." PARTICULAR does not include melatonin as it is a hormone, not a nutrient.
Magnesium has the strongest nutritional evidence for sleep support. It contributes to normal nervous system function and normal psychological function. Multiple RCTs support its role in sleep quality, particularly for those with low dietary intake.
Ashwagandha KSM-66® has RCT evidence for improving sleep quality, likely through stress reduction — but it does not have an authorised EU health claim for sleep.
Vitamin B6 is a cofactor in serotonin and melatonin synthesis. Deficiency can impair sleep regulation.
Vitamin D deficiency is associated with poor sleep quality in observational studies. Supplementation is already recommended in the UK for general health.
Popular alternatives (valerian, lavender, 5-HTP, GABA) have mixed evidence and are not included in the PARTICULAR formula.
Sleep supplementation works best when personalised to your specific nutritional gaps and lifestyle factors. Take the questionnaire to find out which ingredients are relevant for you.

Sources cited in this article: