How does melatonin work?

Last updated: January 2026

TL;DR: Melatonin is a hormone produced by your brain's pineal gland that signals your body when it's time to sleep. Production is triggered by darkness and suppressed by light, even at low levels. Melatonin supplements take 30-60 minutes to kick in but have low bioavailability (as little as 15%). While supplements can help with jet lag and short-term sleep issues, managing your light environment is a more effective long-term strategy for healthy melatonin production.

You've probably heard melatonin called the "sleep hormone." Maybe you've even tried the supplements. But if you're still struggling to fall asleep or stay asleep, you're not alone.

The issue often isn't your melatonin levels. It's what's suppressing them. Understanding how melatonin actually works in your body reveals why popping a pill isn't always the answer, and what you can do instead.

What Is Melatonin and Where Is It Produced?

Melatonin is a naturally occurring hormone produced primarily by the pineal gland, a small structure deep in your brain. From there, it's secreted into your bloodstream, where it travels throughout your body signaling that it's time to wind down and prepare for sleep.

Your body also produces small amounts of melatonin in other tissues, including your gut and eyes. But the pineal gland is the main source, and its production follows a predictable daily rhythm tied to light exposure.

Man-made melatonin supplements have become increasingly popular, available as tablets, gummies, liquids, and patches. According to a ConsumerLab report, 29.5% of daily supplement users take melatonin, making it one of the most commonly used supplements in America.

How Melatonin Works in Your Body

Two factors control your melatonin levels: your internal circadian rhythm and environmental light.

Your body's melatonin production typically begins rising in the evening, peaks around 2 am, and drops to barely detectable levels during daylight hours. This cycle repeats daily, helping regulate when you feel alert versus sleepy.

Here's where light becomes critical. Your eyes contain specialized receptors that detect light and send signals to your brain's suprachiasmatic nucleus, your body's master clock. When these receptors detect light, they tell your pineal gland to stop producing melatonin. In darkness, production resumes.

This system evolved long before artificial lighting existed. Today, exposure to bright indoor lights, phone screens, and LED indicators can suppress melatonin production even when it's biologically nighttime. Research from the American Chemical Society confirms that even moderate indoor lighting can significantly inhibit melatonin release.

How Long Does It Take for Melatonin to Kick In?

Melatonin supplements typically take 30-60 minutes to start working. However, several factors affect this timeline.

Form matters - Liquid melatonin and dissolvable tablets absorb faster than standard pills or gummies. Fast-release formulations work quicker but wear off sooner, while slow-release versions provide steadier levels throughout the night.

Dosage plays a role - Higher doses don't necessarily work faster or better. In fact, research published in PubMed found that oral melatonin has bioavailability as low as 15%, meaning 85% passes through your system without reaching your bloodstream.

Individual factors vary - Your metabolism, age, body composition, and whether you've eaten recently all influence absorption speed. Some people feel effects within 20 minutes; others need a full hour.

The timing recommendation: Take melatonin 30-60 minutes before your intended bedtime for best results.

Pros and Cons of Melatonin Supplements

Before reaching for supplements, it's worth understanding what the research actually shows about their effectiveness.

Potential Benefits

Jet lag relief. This is melatonin's strongest evidence base. Studies show it can reduce jet lag symptoms for travelers crossing five or more time zones, particularly when traveling east.

Short-term sleep support. Some research suggests melatonin can help healthy adults fall asleep faster and improve sleep quality in the short term. It may be particularly helpful when your sleep schedule is disrupted.

Shift work adjustment. While evidence is limited, some shift workers report melatonin helps them sleep during daylight hours. However, Sleep Foundation research notes that studies have had small sample sizes and mixed results.

Potential Drawbacks

Low bioavailability. As mentioned, only about 15% of oral melatonin actually reaches your bloodstream. You're essentially paying for a supplement your body largely doesn't absorb.

Not effective for chronic insomnia. Research published in PubMed found no conclusive evidence that melatonin helps with long-term, chronic insomnia. Doctors generally recommend against using it as an ongoing treatment.

Regulation concerns. As a dietary supplement, melatonin isn't strictly regulated by the FDA. What's on the label may not match what's in the bottle. Look for USP-verified products for more reliability.

Side effects. While generally considered safe for short-term use, some people experience daytime drowsiness, headaches, or dizziness. These effects are usually mild but worth noting.

Is Melatonin Safe?

Short-term melatonin use is considered safe for most adults, with few reported side effects. However, you should consult your doctor before taking melatonin if you:

• Take other medications (melatonin can interact with blood thinners, immunosuppressants, and diabetes medications)
• Are pregnant or breastfeeding
• Have a history of depression or other mental health conditions
• Have an autoimmune disorder
• Are over 65 (older adults may be more sensitive to effects)

Melatonin can also affect blood pressure in some individuals, so those with hypertension should discuss use with their healthcare provider.

Natural Ways to Support Melatonin Production

Rather than supplementing, you can work with your body's natural melatonin production by managing your light environment.

Dim lights in the evening - Start reducing light exposure 1-2 hours before bed. This signals your pineal gland that nighttime is approaching.

Eliminate light leaks in your bedroom - Even small amounts of light, whether from streetlights, device LEDs, or early morning sun, can suppress melatonin production while you sleep. Research on melatonin suppression shows that daytime-level light exposure at night dramatically reduces melatonin levels.

This is where your sleep environment matters more than supplements. Traditional blackout curtains block 85-99% of light, but gaps around edges still let light through. The Ultimate Blackout Shade uses sealed track technology to achieve true 100% light blocking, eliminating the gaps that suppress melatonin production. Over 600 customers report dramatically improved sleep quality after switching from traditional curtains.

For nighttime navigation without disrupting melatonin, the Motion Sensor Night Light uses red light at 620-625nm, a wavelength that doesn't suppress melatonin like blue or white light does.

Maintain consistent sleep times - Your circadian rhythm thrives on consistency. Going to bed and waking at the same times, even on weekends, strengthens your natural melatonin cycle.

Key Takeaways

• Melatonin is produced by your pineal gland and regulated by light exposure, not just your internal clock
• Supplements take 30-60 minutes to work but have only 15% bioavailability
• Evidence supports melatonin for jet lag and short-term use, but not chronic insomnia
• Managing your light environment is more effective than supplements for long-term sleep quality
• Complete darkness during sleep supports natural melatonin production throughout the night

Frequently Asked Questions

How long does melatonin take to work? Melatonin supplements typically take 30-60 minutes to start working. Liquid forms absorb faster than tablets or gummies. For best results, take melatonin 30-60 minutes before your intended bedtime. Individual factors like metabolism, age, and recent food intake can affect absorption speed.

What are the pros and cons of taking melatonin? Pros include relief from jet lag, support for short-term sleep issues, and general safety for short-term use. Cons include low bioavailability (only 15% absorption), lack of effectiveness for chronic insomnia, inconsistent product quality due to limited FDA regulation, and potential side effects like daytime drowsiness.

Is melatonin safe to take every night? Short-term nightly use is generally considered safe for most adults. However, there's no conclusive evidence supporting long-term daily use, and doctors typically recommend against it for chronic sleep issues. Consult your healthcare provider if you're considering regular melatonin use, especially if you take other medications.

Does light actually affect melatonin production? Yes, significantly. Light exposure is the primary external factor controlling melatonin production. Even moderate indoor lighting can suppress melatonin release, and exposure to light during sleep can reduce levels throughout the night. This is why a completely dark sleep environment often improves sleep more than supplements.

Where is melatonin produced in the body? Melatonin is primarily produced by the pineal gland, a small structure located deep in your brain. Smaller amounts are also produced in other tissues including the gut and eyes. The pineal gland releases melatonin into your bloodstream in response to darkness, following your natural circadian rhythm.

Can I improve my sleep without taking melatonin supplements? Yes. Managing your light environment is often more effective than supplements. Dim lights 1-2 hours before bed, eliminate all light sources from your bedroom (including LED indicators and light leaks around windows), and maintain consistent sleep and wake times. These strategies support your body's natural melatonin production rather than overriding it with external supplements.