Melatonin and Metabolic Health – The Nighttime Hormone That Shapes Your Metabolism

What You’ll Discover Inside:

• A deep dive into the circadian hormone that influences insulin sensitivity and mitochondrial function
• How nighttime habits, light exposure, and stress blunt metabolic recovery
• The unexpected impact of this hormone on appetite regulation and fat storage
• Why common supplement protocols may backfire without genetic context
• Nutrient and lifestyle strategies that enhance endogenous production safely
• Testing options to assess hormonal circadian alignment and insulin response

Resources and Links:

• See the Full Transcript here
• Download our FREE Metabolic Health Guide here
• Join the Next-Level Health Practitioner Facebook group here for resources and community support
  
• Visit INEMethod.com for advanced practitioner training and clinical mentorship
• Explore other podcast episodes here
  

References

• Reiter RJ, et al. Melatonin in mitochondria: roles in oxidative stress and aging. J Pineal Res. 2010.
• Cipolla-Neto J, et al. Melatonin and energy metabolism. Mol Cell Endocrinol. 2014.
• Lane JM, et al. MTNR1B gene variant and glucose metabolism. Diabetes. 2016.
• Tuomi T, et al. MTNR1B variants impair beta-cell function. Cell Metab. 2016.
• Anderson G, et al. Melatonin’s role in insulin sensitivity. Sleep Med Rev. 2015.
• Gómez-Abellán P, et al. Circadian rhythms and metabolic regulation. Int J Obes. 2020.
• Arendt J. Human circadian rhythms and melatonin. J Endocrinol. 2005.
• Khan A, et al. Cinnamon improves glucose and lipid metabolism. Diabetes Care. 2003.
  

 

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Transcript

Dr Ritamarie  

You've probably been told that melatonin is just for sleep. After all, it is considered the sleep hormone. But what if I told you that one of the most powerful regulators of blood sugar, insulin, and fat burning isn't a medication, it's not a supplement, it's not a food, but it's a hormone that your body makes naturally while you sleep? Yep, you guessed it. It's melatonin. And most people think melatonin is just for sleep.

 

But the truth of the matter is that melatonin is one of the most underappreciated metabolic regulators in the entire endocrine system.

 

Today we're going to go beyond the bedroom, and we're going to go deep into the biochemistry of melatonin and how it impacts insulin signaling, blood sugar regulation, and mitochondrial health.

 

We're going to explore how melatonin affects insulin receptors and GLUT4 transporters. We're going to look at the impact on leptin and appetite regulation. We're also going to look at the melatonin serotonin connection and how genetics, specifically the MTNR1B SNP can influence your client's response to melatonin. So let's dive in. 

 

Dr Ritamarie (01:40)

Melatonin is produced primarily by the pineal gland, and it's stimulated by lack of light. But it's also synthesized in the gut and inside the mitochondria of every cell. Its primary job is to regulate the circadian rhythm, but it also enhances insulin receptor sensitivity. It reduces oxidative stress and mitochondrial dysfunction, and it improves the GLUT4 receptor translocation, helping glucose to get inside those cells.

 

Plus it modulates leptin secretion, which affects satiety and appetite and also fat storage. Melatonin production follows a circadian pattern. It increases after dark, it peaks in the middle of the night, and then by morning, it drops down to baseline levels. Disruption in the rhythm impairs glucose tolerance and reduces insulin sensitivity. 

 

This is one of the reasons why sleep is so, so important for good glucose control. It does this, because it upregulates the Glut4 transporters in the skeletal muscle and thus enhances glucose uptake in response to insulin.  So when melatonin is low, we have problems. 

 

It also improves the sensitivity of insulin receptors, helping insulin work more efficiently in the cells. So by reducing reactive oxygen species, melatonin supports healthy mitochondria, which play a role in insulin signaling and energy production is its thing, right? 

 

And melatonin interacts with leptin, the hormone that regulates hunger and fat storage. It's produced by those fat cells. It tells you when you're full. When melatonin levels are low due to light exposure at night or stress or aging, leptin resistance becomes more common. And that's a common sequela of insulin resistance, and they often go hand in hand. This means that the body no longer feels or hears the I’m full signal leading to increased hunger, increased fat storage, and worsening of insulin resistance. 

 

Melatonin is made from serotonin, which is derived from the amino acid tryptophan. This means that poor gut health, stress, or nutrient insufficiencies can impact melatonin production, and it impacts melatonin levels indirectly, and thus insulin control.

 

Dr Ritamarie (04:00)

Taking melatonin supplements may work for some people, but can cause problems for other people. So it's not just a blanket thing that we should be doing. That's why it's exciting to be able to support melatonin with food and lifestyle. 

 

So tryptophan-rich foods like seeds, leafy greens, and oats provide the needed precursor amino acid. But that's not enough. We have to have good stomach acid. We have to have a good microbiome in the gut in order to support digestion and tryptophan absorption. Magnesium and B6 are co-factors in the conversion of serotonin into melatonin. So foods that are rich in these nutrients are helpful, including my favorite chocolate and my other favorite green leafy vegetables and also nuts and seeds.

 

Some people carry a variant of the gene SNP MTNR1B. That's the melatonin receptor. And this SNP is linked to reduced insulin secretion in response to melatonin, particularly if melatonin is supplemented. So high levels that we get in high dose supplementation may be detrimental for people with this variant. And taking melatonin at night can reduce or worsen glucose control by the next morning. So people with the Dawn effect, you know, that might be a problem. So we should be looking at that. 

 

Those with the MTNR1B gene variant benefit from natural methods to support melatonin production, not by supplementation. 

 

So we always want to assess the picture, right? We want to look at genetic testing and monitoring of fasting glucose, monitoring of fasting insulin, and looking at people, especially if they're using melatonin, and they're not really seeing improvement, or they're getting worsening of their insulin resistance symptoms. 

 

So when you want to assess melatonin functioning, you can run the DUTCH test, which looks at the 6-OH melatonin sulfate as a part of the organic acid panel of the DUTCH test. You can also look at sleep patterns, right? How well are they sleeping? How are they falling asleep, staying asleep? We also can look at fasting insulin, morning glucose, and ask about evening and morning light exposure.

 

Dr Ritamarie (06:16)

We need less light exposure in the evening and more light exposure during the day, right? So this is all really important. And also, what's their nighttime eating patterns? A lot of people eat right up till bedtime, and this is going to mess with this. 

 

So there's few ways to boost melatonin naturally. Certainly supplementation of nutrients, but there's also certain foods and there's certain circadian biology support functions that we can do. 

 

So morning light exposure. This anchors the biological clock. So get out in the sun before noon, preferably within an hour of waking up and be out for 10 – 15 minutes at least. So what about going outside and meditating, laying in the lounge chair and meditating in the morning outside? That would get you both things, lower stress levels, lower cortisol levels, and get the stimulation for melatonin production. 

 

We want to avoid screens and bright lights after sunset, so blue light blocker glasses. There's some applications where you can reduce that on your screens, on your computer, on your phone. And also just shutting down the electronics early on. 

 

Avoid eating within three to four hours before bed. This is a hard one for lots of people, including me. Late meals disrupt your circadian insulin sensitivity, and it's going to cause that extra weight around the middle, even if you're not eating too many calories.

 

And sleeping in a fully dark room can be very helpful. Even small light sources can suppress the melatonin production. 

 

Some of the things you can supplement with are vitamin B6 and magnesium and tryptophan before bed. There are some foods like tart cherries and flaxseeds that are natural melatonin sources, but we're telling you not to eat close to bedtime. So what I find helpful is a tart cherry juice extract. You can get it as a powdered extract, or you can get it as a tincture type extract.

 

And that can be taken before bed without disrupting and turning on the digestion and the whole insulin process. So it's easy to find and very helpful and very effective without disrupting all the insulin patterns.

 

Dr Ritamarie (08:24)

So even though microdosing melatonin, 0.3 to 1 milligram, that's a really small dose, may be helpful in a lot of cases, like jet lag or shift workers or even Hashimoto's, long-term use at higher doses can down-regulate melatonin receptors and suppress your internal endogenous production of melatonin. 

 

So I believe that we should always assess first. And when you feel like supplementation is warranted, consider microdosing. Start with 0.3 milligrams one to two hours before bed and avoid long-term high doses and watch to see how people respond. Sometimes people do not respond well. They either don't respond, or they have a negative response. They'll have nightmares, or it has an opposite effect. You always want to pair the supplementation with lifestyle strategies to assess metabolic labs if things don't improve. 

 

Melatonin is more than just a sleep hormone. It's a metabolic messenger. And when you support its natural ebb and flow, you support insulin, blood sugar, mitochondrial health, and so much more. 

 

So those of us who are committed to putting the care back into healthcare and looking beyond surface symptoms to restoring rhythm, resilience, and function at the root are the future of healthcare.

 

We're looking at interactions between hormones, interactions between nutrients, and not supplying a one-size-fits-all approach that doesn't work for everybody and doesn't necessarily get to the root causes. So we are the future of health care.

 

So if you're ready to take your practice to the next level, visit inemethod.com. And if you want to dive deeper into blood sugar regulation and functional hormones, check out the show notes for links to my latest tools, courses, and metabolic guides. We have a list of references down there, so if you want to go deeper, you can. Together, let's continue the movement to reinvent health care. And until next time, shine on.