The Truth Behind the Melatonin–Heart Failure Headlines

A recently released study has raised eyebrows in the medical community: long-term use of melatonin (3 - 10 mg in this study) was associated with a significantly increased risk of heart failure, hospitalizations, and even all-cause mortality in adults with chronic insomnia.

While the study was observational (meaning it found an association, not causation), it’s still an important reminder of something I’ve seen repeatedly in my practice: melatonin is a hormone, not a vitamin, and the dose matters.

And the doses used by most people are far above anything the human body is designed to handle.

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Melatonin Production Declines Sharply After 50

From testing I routinely perform in my office, I’ve repeatedly confirmed what the research shows:

• After age 50, natural melatonin output drops dramatically.

• In many patients, nighttime production is less than 25% of what it was earlier in life.

Why does this happen?

• Pineal gland calcification (very common with aging)

• Reduced retinal light signaling

• Weaker circadian rhythm amplitude

• Increased oxidative stress

• Decreased activity of key melatonin-producing enzymes

The result is exactly what many of you notice:

• more difficulty falling asleep

• waking up too early

• more fragmented sleep

• less restorative rest

• increased fatigue the next day

So yes — melatonin supplementation can help.

But only if we respect human physiology.

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Why High-Dose Melatonin (3–10 mg) Is Not Physiologic

Your pineal gland naturally produces about 0.01–0.08 mg of melatonin per night.

That means:

• A 3 mg tablet is 30–300× higher than normal.

• A 10 mg tablet is 100–1,000× higher than normal.

When you take those doses, the melatonin levels in your bloodstream become thousands of times higher than anything your brain has ever seen.

This may:

• desensitize melatonin receptors

• disrupt cortisol rhythms

• suppress the sympathetic nervous system too strongly

• shift the circadian clock

• create next-morning grogginess

• and, as the new study suggests, **may have cardiovascular consequences** when used long-term

This is why the findings of the heart failure study did not surprise me.

Physiology rarely rewards extremes.

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What I Recommend Instead: 0.5 mg

For years, I have recommended a 0.5 mg dose in the office.

We sell this exact dose here because it is hard to find and is:

• closer to the body’s natural nighttime levels

• effective for easing sleep onset

• unlikely to cause morning grogginess

• safe for long-term, physiologic circadian support

• far below the doses associated with adverse effects in the study

As melatonin production falls after age 50, a 0.5 mg supplement taken 3 hours before bed can gently restore the natural nighttime signal the brain expects.

And if you struggle with insomnia or difficulty falling asleep, this low dose is often enough to make a noticeable difference, without overwhelming your natural rhythms.

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The Bottom Line

Melatonin can be incredibly helpful when used properly.

But like all hormones, the dose matters.

The new study linking high-dose melatonin to heart failure risk is a reminder that “more” is not better. Supporting the body with physiologic doses is key to long-term health and longevity.

If you’ve been taking melatonin nightly, especially doses over 0.5 mg, let’s talk.

This is your sleep we’re optimizing, and also your longevity and cardiovascular health.

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To Your Good Health,

The Longevity Doctor®