By Dr. Bev Walpole – Clinical Psychologist based in Guelph & Founder of Haven Wellness by Design

For years, melatonin has been the go-to “natural” fix for restless nights — a quick, seemingly harmless shortcut to better sleep. In fact, I often discuss the benefits of melatonin with my patients, both adults and parents who are interested in exploring melatonin use with their kids. And I too use melatonin a few times a week when I’m feeling a little more rangy-tangy than usual and need a little sleep drive boost.

But new research suggests that too much of a good thing might not be so harmless after all.

Last week, researchers presented data at the American Heart Association Scientific Sessions 2025 that raised important questions about the long-term safety of melatonin. In one of the largest analyses to date, investigators reviewed the electronic health records of over 130,000 adults with insomnia across multiple countries.

The results were sobering: people who had taken melatonin regularly for more than a year were 90 percent more likely to develop heart failure and had double the overall risk of death compared to non-users.

That’s not the kind of bedtime story anyone wants to hear.

As a female psychologist in Guelph, I often see women juggling careers, families, and the invisible emotional labour that comes with “doing it all.” Chronic stress, anxiety, and hormonal shifts — especially in perimenopause — can disrupt the delicate interplay between cortisol, estrogen, and melatonin.

When we turn to supplements for relief, we sometimes bypass the body’s natural rhythm-regulating systems. Melatonin isn’t just a sleep hormone — it influences the cardiovascular system, immune function, and even blood pressure regulation. Over-supplementation may dull the body’s own melatonin production and alter heart-rate variability, a key marker of nervous-system balance and resilience.

For anyone seeking mental health support for women in Guelph, understanding these physiological underpinnings can help prevent unintentional harm and empower more aligned, holistic self-care.

Here’s the nuance: melatonin is not inherently dangerous. Short-term use in small doses can be effective — especially when prescribed for jet lag or circadian rhythm disorders. But “natural” does not equal “risk-free.”

The supplement industry is largely unregulated in North America, and actual melatonin content can vary by 400 percent or more between brands. What looks like a mild 3 mg dose might actually contain much higher levels.

This is where collaboration with trusted practitioners like Dr. Katie Thomson Aitken, Naturopathic Doctor in Guelph, becomes essential. Dr. Katie has long advocated for a root-cause approach — balancing hormones, gut health, and nervous-system regulation — before turning to supplements as a Band-Aid. However, Dr. Katie points out that the study’s limitations are worth paying attention to, and she’s right.

While the headlines sound alarming, the research does come with important caveats:

• It’s not peer-reviewed — the study was presented as a conference abstract, meaning the findings are preliminary.
• It’s observational, showing correlation rather than causation. The data cannot prove that melatonin causes heart failure.
• The dataset mixes countries where melatonin is prescription-only with those where it’s sold over the counter, introducing bias.
• Because many U.S. consumers buy melatonin off the shelf, their use may not be recorded in medical charts — some “non-users” may actually have been users.
• Other confounding factors like insomnia severity, cardiovascular health, and medication interactions were not fully controlled.

In short, the study opens an important door — but it doesn’t close the case.

Before reaching for the pill bottle, it’s worth exploring how your environment and habits support natural sleep regulation.

Research in neuroaesthetics and environmental psychology shows that your surroundings directly influence melatonin production, cortisol levels, and nervous-system balance.