The latest research from Rhonda Patrick on Melatonin and suggests that melatonin may prevent Alzheimer’s or at least add protection against it. And other ways it can help you. Different from Huberman!
Melatonin isn’t just the “sleep hormone”—it regulates over 500 genes and plays a key role in the body’s antioxidant defenses.
As we age, melatonin production declines significantly. By the time a person reaches 50 years old, melatonin levels are 50% of what they were at age 20. By age 80, melatonin production can be ten times lower than in teenagers. This reduction in melatonin is linked to changes in sleep patterns, circadian rhythm disruption, and overall health as we age.
Older adults who supplement with melatonin experience dramatic improvements in their sleep duration and sleep quality. But it’s not just older adults who benefit. Melatonin supplementation:
Because of its potent antioxidant effects, melatonin’s benefits extend to cardiovascular protection and cellular health. Its wide-reaching effects make it critical for much more than just a good night’s sleep. (I discuss several of these benefits in one of my recent Q&A episodes).
In fact, this hormone could protect against neurodegenerative conditions like Alzheimer’s disease and other forms of dementia.
Should we start to consider melatonin as a biomarker for healthy aging or potentially an anti-aging supplement? There’s a compelling reason to think so.
Melatonin and sleep
Melatonin is produced not only by the pineal gland but also in various tissues throughout the body like the gut.
Melatonin production follows a ~24 hour rhythm (a circadian rhythm) that’s synchronized to the light-dark cycle—melatonin levels rise in the afternoon, peak around midnight, and then fall to undetectable levels during the day.
When melatonin binds to receptors in the brain (MT1 and MT2), it synchronizes the body’s internal clock to promote feelings of sleepiness, reduces core body temperature (a signal for sleep onset), decreases the activity of wake-promoting neurons, and enhances the release of inhibitory neurotransmitters (i.e., GABA). Melatonin doesn’t necessarily force sleep, but rather, it promotes conditions conducive to it. That’s why supplementing with melatonin is incredibly effective at increasing sleep duration, reducing the time it takes to fall asleep, and enhancing sleep quality, particularly for older adults.
Does melatonin supplementation affect endogenous production?
Despite the well-known benefits and high safety profile of melatonin, some people are concerned that supplementing with it will impair our body’s natural production. This doesn’t appear to be the case, at least when using a low but effective dose at the right time of day. After all, we consume foods that contain tryptophan (and some that contain melatonin), an amino acid that gets metabolized and eventually converted into melatonin. Admittedly, the amount of melatonin we derive from these sources is incredibly small—we’d need to consume large amounts of them to achieve the melatonin content of a supplement. But even if you aren’t supplementing with melatonin, there’s a good chance you’re getting some through dietary sources.
Age-related declines in melatonin and neurodegeneration
While I don’t think that everyone should be taking melatonin, there’s a compelling argument that people with sleep problems, older adults who may be dealing with a disrupted sleep-wake cycle, and people with cognitive complaints may want to consider it. In fact, I’ve spoken before about how people aged 50 and older should take melatonin (around 0.3 mg per night) to offset the age-related reduction in melatonin; levels are about half as much at age 50 compared to age 20 and ten-fold lower at age 80 compared to teenage years. No wonder so many adults have sleep complaints!
Could these age-related declines in melatonin also be contributing to neurodegeneration? We know that sleep is one of the most important factors for maintaining cognitive health and resilience, and melatonin is intricately involved in our ability to sleep well.
If you’re someone who’s worried about cognitive decline or who suffers from sleep-related issues, melatonin should be on your radar. Even if you aren’t someone who’s worried about either of these, after reading this email, you still might be inspired to explore melatonin supplementation due to its other cellular benefits.
That’s because, as we’ll discuss, melatonin may have direct and indirect neuroprotective effects, and it may help reduce the burden of one of the most debilitating cognitive conditions of them all—Alzheimer’s disease.
