Many Canadians are turning to sleep supplements. Do natural health products live up to their sleep-promoting claims?ISTOCKPHOTO
Sleep is considered a core pillar of health, right up there with healthy eating and regular physical activity.
Not getting enough sleep and/or having poor quality sleep on regular basis is tied to a greater risk of weight gain, Type 2 diabetes, high blood pressure, heart disease, stroke, anxiety and depression.
Yet many of us struggle to get the recommended seven to nine hours of quality sleep each night.
Busy schedules, stress, caffeine, alcohol, screens before bed and sleep disorders can all get in the way.
In the quest for a good night’s sleep, many Canadians are turning to sleep supplements.
A study published earlier this year in the journal Sleep Medicine reported that 29 per cent of Canadians used natural health products or over-the-counter sleep aids in the previous 12 months.
Do natural health products live up to their sleep-promoting claims? What to know about five popular sleep supplements.
Melatonin
Melatonin, a hormone produced by the brain, helps regulate the body’s circadian rhythms, including our sleep-wake cycle.
Melatonin increases when it’s dark and decreases when it’s light. Having high levels of melatonin can help you sleep better.
Being exposed to light at night suppresses melatonin production. Older age and chronic illness can also decrease the brain’s melatonin production.
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There’s good evidence that melatonin supplements help adults and children with delayed sleep phase syndrome, a sleep disorder that causes sleep and wake times to be delayed by two or more hours. Most clinical studies show that taking 0.3 to 5 mg of melatonin reduces the time needed to fall asleep.
The evidence is less clear, though, that melatonin benefits people with insomnia (i.e., have trouble falling asleep and/or staying asleep).
In healthy adults, research has shown that taking melatonin shortens the time it takes to fall asleep by only seven to 12 minutes and doesn’t improve sleep quality. Melatonin may increase sleep duration by eight minutes.
Melatonin doesn’t seem to help sleep problems unrelated to circadian rhythm issues.
Magnesium
Since magnesium influences the activity of certain brain chemicals that calm the central nervous system and relax muscles, it’s claimed to improve sleep. Yet there’s little evidence to support this.
An analysis of two small clinical studies in healthy older adults with or without insomnia suggests that taking 500 to 729 mg of magnesium oxide a day for up to eight weeks reduces the time to fall asleep by 17 minutes. Magnesium did not increase the time spent asleep.
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Another small study in people with poor sleep quality and low magnesium levels found that taking 320 mg of magnesium citrate daily for seven weeks had no effect on sleep quality.
A very small study involving 16 young adults without a sleep disorder showed that taking a supplement containing 300 mg magnesium along with L-tryptophan, glycine, tart cherry and L-theanine reduced time to fall asleep by 24 minutes and increased time asleep by 22 minutes. But it’s unclear if these effects were due to magnesium, another ingredient, or the combination.
Taking more than 350 mg of supplemental magnesium a day can cause diarrhea, abdominal cramping and nausea.
Valerian
Valerian, a plant native to Europe and Asia, has been widely studied for insomnia.
Most research shows that taking 300 to 600 mg of valerian whole root extract before bedtime improves sleep quality when compared to placebo. It can take up to four weeks to notice an effect.
The herbal supplement appears to have no effect on time to fall asleep or sleep duration.
When taken for up to six weeks, valerian is considered safe. People who are pregnant or breastfeeding should not use the supplement.
Valerian is generally well tolerated. Side effects may include headache, digestive upset and drowsiness.
Glycine
Glycine is an amino acid found primarily in meat, fish, dairy, soy and pulses.
In rats, glycine seems to lower core body temperature and increase serotonin levels in the brain, both of which may help promote sleep.
In people, however, there’s little evidence to back up the claim that glycine can promote restful sleep.
Data from two very small studies suggest that taking 3 g of glycine an hour before bed can improve sleep quality in people with insomnia.
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Another study conducted in 10 healthy males with short sleep found that taking 3 g of glycine 30 minutes before bed modestly reduced fatigue after the first night, but not the third night.
Not much to go on.
Glycine is considered safe when taken at doses up to 6 g for four weeks or 9 g for three days.
L-theanine
This amino acid is found naturally in green tea leaves. Sleep studies suggest it helps improve sleep quality by increasing brain chemicals that reduce anxiety and promote relaxation.
A 2019 randomized controlled trial conducted in 30 healthy adults found that taking 200 mg of L-theanine for four weeks reduced stress-related symptoms, including time to fall asleep and sleep disturbance, compared to placebo.
Consuming 200 mg of L-theanine appears safe for most people. Its safety has not been established during pregnancy and breastfeeding.
Bottom line
Sleep supplements aren’t a magic bullet to a sound sleep.
If you are experiencing poor sleep, consult your doctor before taking a supplement. Many underlying health problems can disrupt sleep.
To set yourself up for a better sleep, assess your sleep hygiene habits and make improvements where needed.
Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on Twitter @LeslieBeckRD