Walk into any pharmacy, scroll through your social media feed, or simply ride the subway, and you’ll be bombarded with ads for supplements promising better sleep, sharper focus, and all-around improved health. But behind the glossy packaging and influencer endorsements, how do you know what really works—and what might be doing more harm than good?
Dr. Andrea Matsumura, known to her patients as Sleep Goddess MD, is a board-certified sleep medicine physician and menopause expert who’s seen the supplement craze firsthand. Speaking to The New York Post on October 24, 2025, she explained, “Melatonin is our primary circadian rhythm hormone. It works best as a timing signal for your body to increase the signals sent to your brain that it’s time to sleep.”
Melatonin, produced naturally in our bodies, helps regulate the sleep-wake cycle. It’s also one of the most popular supplements for sleep issues like insomnia and jet lag. But, as Dr. Matsumura cautions, more isn’t always better. “If you’re going to use it, take a low dose, especially at the beginning. I typically recommend around 0.5 milligrams to 3 milligrams sustained release about one to two hours before bedtime.” Higher doses, she warns, don’t increase effectiveness and can actually cause grogginess the next morning—a frustrating side effect for those seeking restorative rest.
Melatonin shines when it comes to sleep problems tied to your internal clock, such as adjusting to a new time zone or working night shifts. It can help you delay or advance your sleep schedule, which is a relief for frequent travelers or those with irregular routines. But it’s not a miracle cure. “Melatonin will not cure other sleep disorders,” Matsumura emphasized. “If your sleep troubles are caused by stress, pain or conditions like sleep apnea or restless legs syndrome, those need other approaches, and melatonin would only be a quick fix.”
So, what if your sleep woes persist? Matsumura’s advice is clear: If poor sleep lasts more than a few weeks, affects your daily functioning, or is accompanied by symptoms such as loud snoring, gasping, or daytime exhaustion, it’s time to see a sleep specialist. Sometimes what seems like a simple case of insomnia can mask more serious health issues.
While melatonin can be helpful, Dr. Matsumura recommends pairing it with other supplements and beverages for more restful slumber. “Magnesium glycinate can complement melatonin by helping the nervous system relax,” she said. Dubbed “nature’s Xanax,” magnesium relaxes muscles and may regulate neurotransmitters involved in sleep. Studies have found that magnesium supplementation, especially at doses of 200-400 mg daily, improves sleep quality in older adults and people with insomnia—particularly those with magnesium deficiencies.
Another supplement in her toolkit is L-theanine, an amino acid found in green tea. “L-theanine helps induce relaxation and calm, easing the body into sleep,” Matsumura explained. Experts recommend a 200-mg dose taken 30 to 60 minutes before bedtime. L-theanine increases alpha brain wave activity and reduces cortisol, the body’s stress hormone, making it easier to drift off.
Herbal teas, too, can play a supporting role. “Chamomile or valerian root can also help, as long as they don’t cause any digestive upset,” Matsumura added. Valerian root, for instance, enhances GABA activity in the brain, easing nervous system tension and anxiety. A cup of valerian tea or 300-600 mg of standardized extract one to two hours before bed is a common recommendation.
But before you fill your shopping cart with supplements, Matsumura urges an inside-out approach. “It’s important to keep in mind that supplements and sleep aids should be a second step,” she said. “You should always practice good sleep hygiene and give your body enough sleep opportunity first.” That means sticking to a regular bedtime, limiting screen time before bed, and ensuring your bedroom is cool, dark, and quiet.
Yet, navigating the supplement aisle isn’t easy. According to The Independent, the market is more crowded—and confusing—than ever. Misinformation runs rampant, especially on social media. Dr. Amos Ogunkoya, a GP and spokesperson for SafeSupp, told The Independent that “a worrying 39 per cent of people in the UK – rising to 60 per cent amongst those aged 25-34 – turn to influencers and online sources for supplement advice.” The problem? Many of these influencers promote products lacking clinical research, sometimes for financial gain without declaring sponsorships.
So, how do you separate the good from the bad? Experts agree: look for third-party testing and certifications like Good Manufacturing Practices (GMP). “Look for third party testing or a certificate because it’s really important to make sure it’s tested by an independent body. Make sure the brand is really transparent about the ingredients, and that the supplements don’t contain things such as ‘proprietary blends’,” Dr. Ogunkoya advised. Proprietary blends, he explains, often hide the actual amounts of active ingredients, making it hard to know what you’re really taking.
Fillers and additives are another minefield. Ingredients like brown rice flour, magnesium stearate, silicon dioxide, artificial colors (Red 40, Yellow 5), sweeteners (aspartame, sucralose), and titanium dioxide are common in supplements but raise red flags. Magnesium stearate, for instance, can reduce nutrient absorption and cause IBS symptoms. Silicon dioxide may contain microplastics, and brown rice flour sometimes carries traces of arsenic. Artificial colors and sweeteners have been linked to hyperactivity, cancer risks, and disruption of the gut microbiome. Titanium dioxide—a whitening agent—has been banned in the EU due to concerns about DNA damage but still appears in supplements sold elsewhere.
Hydrogenated oils, or trans fats, sometimes found in softgel capsules, can negatively affect cholesterol and increase the risk of heart attacks. Carrageenan, derived from red seaweed, is known to cause gut inflammation in some people. Even gelatin, used in capsules, can be problematic if sourced from low-quality farming practices and isn’t suitable for vegetarians or vegans.
Dosage matters, too. Supplements should never exceed your recommended daily intake, and labels should clearly state doses. Some nutrients—like vitamins A, D, E, and K, and minerals such as iron and zinc—can accumulate in the body and cause harm if taken unnecessarily. “If you’re not deficient in any nutrients, then your body can, and will, eliminate most of them, but there are some that can potentially accumulate in tissue,” Dr. Ogunkoya explained.
Cost isn’t always a marker of quality. While third-party testing and patented ingredients can increase the price, fancy branding doesn’t guarantee efficacy. “Some may claim high levels of active ingredients when, in reality, the product contains far less,” nutrition expert Ashley English told The Independent. The best supplements are transparent, well-researched, and free from unnecessary additives.
Ultimately, the safest bet is to consult a healthcare professional. Only 26 percent of people in the UK do this, leaving the majority at risk of taking ineffective or even harmful supplements. As Dr. Matsumura and other experts agree, supplements can be helpful tools—but only when chosen wisely, taken as directed, and used to complement—not replace—healthy habits and professional advice.
