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Hey everyone, Miki here. You're listening to Mini Micropedia on a Monday. And to continue on my metabolic mastery series, I wanna talk about the role of melatonin, particularly as it pertains to metabolic syndrome, which of course is all about our metabolic health. And we shall call this the overlooked hormone in metabolic health. To be fair, I don't think that it's overlooked by everyone by any stretch of the imagination. And it...

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absolutely comes up when we are discussing the role that sleep has in overall metabolic health, but its role goes much deeper than just sleep. Research shows melatonin plays a significant role in glucose regulation, fat metabolism, appetite control, and blood pressure. So melatonin is a neurohormone primarily produced by the pineal gland in response to darkness.

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It helps regulate sleep-wake cycles and synchronizes circadian rhythms. It is also produced in smaller amounts in the gut, retina, and bone marrow, where it plays roles in immunity, metabolism, and antioxidant defense. And indeed, melatonin is thought of as a major antioxidant in the body, in some health circles. So melatonin is synthesized from tryptophan, which is an amino acid, into serotonin.

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which is what is known as our feel-good hormone, into melatonin, with production peaking at night and being inhibited by light exposure, and also cortisol, but more on that later. The body produces around 0.1 to 0.3 mg of melatonin per night, and it peaks in the early morning hours. Melatonin levels decline with age, leading to poorer sleep and potential metabolic disruptions in older adults.

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And this absolutely contributes to reduced metabolic flexibility that we see clinically and in research in women over 40 and of course in men as well. But just to the notion that women are more metabolically flexible, that's not necessarily true and particularly as we age. Just so you know, over-the-counter melatonin supplements, which I'll talk about more later, typically range from 0.5 milligrams to 10 milligrams. So quite a lot more.

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than our natural levels. And some studies do suggest that high dose melatonin may desensitize our receptors over time, while others indicate benefits for sleep, metabolism, and oxidative stress. Sublingual and time-released formulations are designed to mimic natural melatonin rhythms, but their effectiveness does vary by individual. Which might explain why if you've ever tried melatonin,

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It might not necessarily be effective for you, depending on the formulation that you've tried. So, supplementation may be helpful in certain contexts, but lifestyle factors such as light exposure, sleep hygiene, and diet remain the best ways to optimize a natural melatonin production. It is worth noting when it comes to sleep that melatonin doesn't work in isolation. It interacts with adenosine, cortisol, and neurotransmitters to regulate when

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and how well you sleep. So it isn't just about sleep onset. Adenosine is our body's sleep pressure molecule. It builds up throughout the day and makes you feel sleepy at night. And melatonin and adenosine work together because adenosine accumulates as a byproduct of ATP, energy breakdown, reaching peak levels before bedtime. Melatonin amplifies adenosine's effects, signaling to the brain that it's time to slow down and sleep.

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Caffeine blocks adenosine receptors, delaying sleepiness even if melatonin levels are rising. So if your melatonin is in sync, but you struggle with sleep, obviously caffeine intake or disrupted adenosine buildup could be the issue. I mentioned cortisol just before. This opposes melatonin in the sleep-wake cycle. So cortisol, as you know, is our wake-up alertness hormone.

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rising in the morning to help us feel alert and peaking about 30 minutes after waking. That's that cortisol awakening response. They have an inverse relationship. Malatonin peaks at night, helping the body wind down. Cortisol drops at night but starts to rise just before waking to promote that alertness. Chronic stress or circadian misalignment can cause high night-time cortisol, suppressing melatonin and leading to poor sleep and metabolic

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dysfunction. So if you're waking up 2 or 3 a.m. in the morning wired, as I know many people do, high nighttime cortisol from stress, late workouts, alcohol intake or blood sugar drops could be suppressing melatonin's sleep stabilizing effects. So melatonin doesn't knock you out like a sedative, but it does help regulate our non rapid eye movement sleep or deep sleep.

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Some research suggests melatonin supports a slow wave sleep, especially in older adults who produce melatonin. It also does help in our dreaming phase or our rapid eye movement sleep, so it influences it indirectly with low levels linked to REM sleep disturbances. Melatonin may be particularly beneficial for people with sleep fragmentation, helping stabilize sleep cycles rather than just making them feel drowsy and that on-set sleep.

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If you fall asleep easily but wake up often, supporting melatonin rhythms through light exposure and meal timing could actually improve sleep continuity. And I know this is about metabolic health, but obviously sleep is a huge part of metabolic health. This is why I'm focusing on this now. So just as a reminder to help optimize melatonin sleep regulating effects, you want to get that morning sunlight. This suppresses melatonin early.

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reinforcing a strong circadian rhythm. We want to avoid blue light at night because this blocks melatonin production. We want to be mindful of caffeine intake to allow adenosine to build. And we want to reduce nighttime stresses. Also consider the meal timing because late night eating can interfere with melatonin's metabolic effects. And I'll talk about that in a minute. So let's talk about melatonin and blood sugar regulation.

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So melatonin naturally reduces insulin secretion at night, which is why late night eating can lead to high blood sugar levels. There are also genetic mutations, for example, in the gene MTNR1B, which affects melatonin receptors, and this can increase diabetes risk. Research is quite mixed about whether or not actually taking melatonin improves glucose metabolism.

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because some show that it can almost impair insulin sensitivity, depending on the timing. So melatonin appears to be a regulator of insulin resistance and blood sugar control, but should people who require insulin, so people with type 1 diabetes, be caught as about melatonin supplements? Well, melatonin reduces insulin secretion at night, which, as I've just said, is a normal physiological response to help body transition to a fasting state.

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So if someone takes melatonin too close to a meal or at the wrong time, it can impair insulin function and cause higher blood sugar levels overnight. So it makes sense that if someone requires insulin, they have to be mindful about the timing of their melatonin supplement if they're choosing to take melatonin and absolutely speak to their doctor about it. So what about melatonin's role in fat metabolism, which is obviously a key part of metabolic health?

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as we discussed last week with visceral fat. So melatonin helps regulate cholesterol and lipid metabolism. So it can reduce total cholesterol, LDL, and importantly, triglycerides while increasing HDL. As you know from a metabolic health standpoint, triglycerides do tend to be a bit of a smoking gun with regards to cardiovascular disease risk, dyslipidemia, and overall metabolic health.

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Malatonin supplementation has been shown to enhance metformin effects in women with metabolic syndrome, which is super interesting. And a perinealectomy, which is the removal of the melatonin-producing perineal gland, does worsen fat metabolism, which can lead to increased body fat and dyslipidemia. So if this is the case, then can melatonin be a potential tool for fat loss?

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And short answer for this is yes, it has potential benefits for fat metabolism and weight regulation, but it isn't a magic bullet fat loss. Obviously nothing is, but it does work indirectly by improving sleep, circadian alignment, and metabolic function. Melatonin can help regulate energy balance. It affects the balance between white fat and brown fat, which is super interesting. The way that it affects the balance between white fat and brown fat is by encouraging brown fat activation.

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What studies show is that melatonin can stimulate the browning of white adipose tissue. By browning, I mean that it enhances that mitochondrial content, which is responsible for color, and of course, responsible for the increased thermogenic and calorie burn. Melatonin also improves sleep quality, as we've just talked about, and poor sleep is linked with high cortisol, increased hunger hormones, and lower leptin, which is a satiety hormone.

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both of which are factors that can drive overeating and fat gain. And melatonin supports mitochondrial function. It acts as a mitochondrial antioxidant, enhances fat oxidation and energy production. So melatonin can support fat metabolism, but its effects are indirect. And the biggest benefits probably come from improving circadian rhythm, reducing stress, and enhancing metabolic efficiently, unsurprisingly.

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What about melatonin and blood pressure regulation? What we know is that low melatonin levels are linked to high blood pressure and increased hypertension risk. Melatonin relaxes blood vessels and lowers nighttime blood pressure. And what we know is that low melatonin levels are linked to high blood pressure and increased hypertension risk. And we see this in certain populations such as pregnant women. And we know that melatonin can relax blood vessels and lowers nighttime blood.

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Does this mean that melatonin could be a natural alternative to blood pressure medication? Well, this is possibly could be the case, but only in specific instances where low melatonin levels contribute to that high blood pressure. Melatonin, as I mentioned, has a vasodilatory effect, meaning that can help regulate blood pressure, particularly at night. And this is because it can also, in addition to being a vasodilator,

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regulate the autonomic nervous system, balancing sympathetic and parasympathetic responses. If you recall, sympathetic is our fight, flight or freeze, and parasympathetic is our rest and digest. So it's blood pressure improving effects could be super helpful, but it's likely only going to be as beneficial for individuals who have nocturnal hypertension and also people with disrupted circadian rhythms.

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You might want to look at that if they also have high blood pressure. It might be helpful for older adults who can present with both high blood pressure and low melatonin levels, and potentially people with high oxidative stress and endothelial dysfunction, which melatonin may help mitigate. There are tests that you can do to have a look at metabolic stress in the body, looking at organic acid production through urine.

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your hypertension, melatonin is likely to be effective. If you don't, then melatonin as a treatment for blood pressure is not going to move the needle. And in fact, blood pressure responds really well a lot of the time to dietary changes, which I talk about in the metabolic mastery series over the last few weeks. Now in terms of appetite, leptin and ghrelin are really influenced by melatonin.

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We know that higher melatonin can result in lower hunger and improved leptin sensitivity, so better fullness signals. And melatonin also helps improve insulin sensitivity, so reduces blood sugar spikes and energy crashes that can drive cravings. Of course, its role in sleep quality allows us to have a better regulated appetite and fewer late night cravings.

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So if you do struggle with cravings and sleep, optimizing melatonin may help enhance and rebalance those hunger signals. And what about melatonin in general for fat loss and metabolic health? Well, I've mentioned a few of these, but just in summary, we know it encourages fat burning, lipolysis, and it helps activate brown adipose tissue. And this is more thermogenically and metabolically active.

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We know that melatonin improves mitochondrial function. I just mentioned that it reduces late night snacking and cravings, so it can help align eating patterns with circadian rhythms. And these factors can help shift the body to be more metabolically flexible and allow for better fat burning, better appetite control, thus allow someone to more naturally reduce calories to create that deficit and improve that energy expenditure.

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So overall, this is really favorable for fat loss and metabolic health under the right conditions. But of course, it isn't about taking a supplement. To my mind, it's about optimizing melatonin through getting that morning sunlight. I mentioned this already, limiting blue light exposure at night, eating meals earlier in the evening, maintaining a consistent sleep schedule, and avoiding caffeine and alcohol late in the day. I think one thing I do wanna

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briefly about is of course supplements for melatonin because people will take a melatonin supplement and rely on it for all sorts of reasons. I mean obviously for sleep but if you're thinking about it for your metabolic health there are just some things that you do need to consider. I mentioned about the dosage and when it comes to supplements less is often more because of how much our body naturally produces which is between 0.1 and 0.3 milligrams.

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and the fact that supplements contain 1 to 10 milligrams. So lower doses, 0.3 to 1 milligrams, may be more effective for sleep in circadian support, while higher doses of 5 to 10 milligrams may be useful for jet lag and or short-term use. And I've got a, I think a 5 milligram supplement that I use for jet lag. Too much melatonin may desensitize receptors over time, means it's going to lose its effectiveness.

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But we have to be really mindful of the type of supplement, because studies have shown that melatonin content in supplements can vary by up to 478% from what's on the label. And some products contain contaminants, synthetic fillers, or serotonin analogues, which could be harmful. The reason why the analogues may be harmful is because they may disrupt serotonin signaling, leading to unintended neurological or cardiovascular effects.

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So you do want to be really mindful of the purity of your supplements. What you want to look for is third party tested brands such as USP or United States Pharma Copia, which is an independent organization that sets quality, purity and potency standards for medications, supplements and food ingredients, or NSF, which is National Sanitation Foundation, which is a third party organization that tests and certifies supplements for safety.

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label accuracy and absence of contaminants. An NSF certified for sport is a common certification for athlete approved supplements. And you've also got GMP certified, so good manufacturing practices to ensure consistency. If you are considering supplementation, do be mindful of bioavailability and formulation. So you've got the immediate release, which is best for falling asleep faster.

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This is absorbed quickly, peaking within 30 to 60 minutes. You've got sustained release, which is good for staying asleep longer, which is released more gradually over six to eight hours. You've got sublingual, so under the tongue for rapid absorption, and this avoids the need to digest and break it down. And then you've got liposomal for enhanced absorption, and there is some suggestion this may improve bioavailability.

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So look for sustained release if you're waking up often or immediate release if you struggle to fall asleep. And there are synthetic versus natural sources and you might think that natural sources is better but actually synthetic lab tested melatonin is safer and more consistent with regards to the amount in getting what you think you're getting. So how to take melatonin.

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Take it 30 to 60 minutes before bed for sleep onset issues. For jet lag, this is how I take it. Take it at the destination's bedtime for two to three nights, and avoid taking it in the middle of the night as it may cause grogginess the next day. So there are some things to think about with regards to the type of supplement if you take it. Malotony is so important for metabolic health.

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both through its sleep promoting and circadian benefits. But as I mentioned, it's just got a lot of interaction with other pathways that impact on metabolic health, like its antioxidant roles, its roles in fat metabolism, in blood pressure, in blood sugar regulation, that optimizing your natural melatonin production should be a key part in you addressing your metabolic health, both through behaviors. And of course, Alex Bartle is on the podcast.

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think he'll be on this week actually. So he's a great one to listen to with regards to optimizing sleep patterns. And if you need to take a supplement, having some of these tips that I've mentioned to be able to choose a good supplement is super important. All right, team, hope you enjoyed that. Please let me know, hit me up in the DMs. I'm @mikkiwilliden on Instagram,

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@mikkiwilliden over on Facebook or head to my website mikkiwilliden.com and book a one-on-one call with me. Have the best week. See you later.