Your liver is a vital organ and essential part of your body’s detoxification system.
Melatonin taken as an oral supplement (such as gummies or tablets) must pass through your digestive system- and therefore your liver- before it's absorbed. It’s worth wondering how melatonin affects your liver- but also how your liver affects your melatonin supplement.
Overview: your liver
One of the liver's main functions is to metabolize substances and chemicals that pass through your body's digestive system, breaking them down into parts that are easier for your body to absorb (or excrete) before it circulates your bloodstream.
For example, your liver converts alcohol, which is toxic to your body, into acetate, which other tissues can safely break down into carbon dioxide and water.
In the case of alcohol, your liver is able to break it down. But extended or heavy alcohol consumption can inflame your liver, resulting in liver damage. Over time, it could lead to alcoholic liver disease, where the scarring to your organ is irreversible and impairs your liver’s ability to function properly.
How does melatonin affect your liver?
Most studies show no significant negative impact to your liver from ingesting melatonin supplements, even long-term. This study found that melatonin showed no implication in exacerbating clinical liver injuries.
In fact, one clinical study found that melatonin actually had an improvement on some factors related to non-alcoholic fatty liver disease, including blood pressure and liver enzyme elevation.
A separate study found that melatonin had protective effects against liver injuries, albeit the potential clinical applications for liver disease were limited in research.
Similar studies lend to the suggestion that melatonin is not entirely harmful to the liver, and that oral supplements can be taken safely for most healthy adults. By comparison, melatonin is not as dangerous to your liver as alcohol is (although you should avoid mixing the two).
However, those with a liver condition should still consult with their physician before they take supplements that might affect their liver function.
Your liver affects how supplements work: bioavailability
While melatonin might not impact your liver, your liver does have an impact on how well your melatonin supplement works.
Melatonin bioavailability describes how well your body uses melatonin.
Poor bioavailability means that your body doesn’t absorb and use all of the melatonin you take. Melatonin with high bioavailability means your body absorbs most if not all of it, thus using it more efficiently.
Your liver affects melatonin's bioavailability.
One of the liver’s many functions is to remove substances you ingest from circulating in your bloodstream. These substances are degraded (metabolized) and then excreted. What remains is what your body absorbs and uses. This is known as first pass metabolism, or the first pass effect.
Because of this first-pass effect, only a fraction of the melatonin you ingest gets actually absorbed; over 80% is degraded, resulting in oral melatonin’s poor bioavailability.
Different types of melatonin vs. melatonin gummies
Melatonin is naturally produced in your brain's pineal gland. In the absence of light exposure, your brain’s pineal gland increases melatonin production which is then distributed through your bloodstream.
Naturally produced melatonin doesn't go through the first-pass effect in your liver. Oral melatonin, such as gummies and tablets, do.
There are other forms of melatonin that aren't metabolized by your liver. Nasally administered melatonin, such as Ascent Sleep, provide a more direct pathway to your brain and bypass the first pass effect.
A study comparing methods of absorption found the greatest potential in intranasal absorption, which was absorbed much more quickly compared to other methods including oral and transdermal melatonin.
Overall, harmless but less efficient
In an overview, taking melatonin orally does not appear to have a negative impact on your liver, albeit at the cost of efficiency.
Alternative forms of taking melatonin- such as nasal supplements which aren’t processed through your liver- will have better bioavailability than said oral supplements.