Serotonin, Melatonin, 5-HTP, and Diabetes







I wanted to do an article on serotonin and diabetes, and I also wanted to do one on melatonin and diabetes, but these two go together so we’ll cover both in this article.  These are not substances we often think about when looking at type 2 diabetes but both play a factor in the disease.

Serotonin is a neurotransmitter known as the feel good hormone, although it’s not a hormone.  Melatonin is a hormone though, and is responsible for your feeling tired when it gets dark, as levels of this hormone rise in the absence of light, at least typically anyway.

I mentioned 5-HTP in the title as well, as this is a precursor to serotonin, and many people take 5-HTP to keep their serotonin levels up, including myself.  I also take melatonin which is available in supplement form, and is well known as something that helps sleep quality and quantity.

Serotonin also converts to melatonin so the two are related in that way, although serotonin has several other important functions in the body as well.

So what do these two have to do with diabetes?  Well let’s start with serotonin.  Serotonin is found in the beta cells and is involved in proper insulin secretion, and it tends to be low in type 2 diabetics, so this has led some scientists to believe that this is involved in the pathology of type 2 diabetes by causing insufficient insulin secretion.

These folks don’t really understand the pathology of type 2 diabetes, and don’t seem to be aware that type 2 presents and is caused by excessive insulin secretion, not an insulin deficiency.  So low serotonin causing lower insulin secretion would actually be protective here, and is indeed one of the protective adaptations that type 2 diabetics have in order to slow down the progression of the disease.

However, there is a form of diabetes known as MODY that seems to be affected in a negative way by this, in a form of MODY anyway, where there is an actual insulin deficiency and serotonin deficiency seems to play a role.  If one has this, then raising serotonin would probably be a good thing to try.

There’s more to serotonin and type 2 diabetes than this though, although a lot of people do mistakenly believe that our disease is one of insulin deficiency even though that’s generally not the case at all.  It is true though that in the very late stages, after one’s beta cells have been bashed for a period of decades, the pancreas ends up losing its ability to produce normal insulin secretion, even though this may not be an organic deficiency but instead a long term adaptation to the toxicity of excess insulin for all this time.

So seratonin does tend to lower blood sugar and raising insulin is likely the mechanism behind it, but under the circumstances we must be careful in using this because we don’t want to raise insulin too much, and we may not want to raise it at all if it is too high.  However the effect here isn’t really that significant and as it turns out, serotonin benefits diabetics in other ways, most notably in balancing and controlling other hormones known as catacholamines, adrenaline for instance, which raises blood sugar.

So a simple way to put this is that if you are low in serotonin then this can cause a hormonal imbalance which not only makes you feel more tense but also causes higher blood sugar, and in a way we don’t really want to see, oversecretion of glucose by the liver.  So normalizing serotonin, by for instance taking 5-HTP, can help control your blood sugar, in spite of it perhaps raising insulin a little in situations where normally this would be something we would want to steer clear of.

Seroninin also plays a role in the gut, and there’s a lot we don’t know about the role the gut plays in diabetes but it seems to be a pretty significant one.

We do know though that the blood sugar lowering effects of serotonin is likely mostly from increasing insulin secretion, and they did an experiment on mice and found that it lowered the blood sugar of mice with a normal pancreas, but not in those who had their beta cells destroyed.  These weren’t diabetic mice though so this doesn’t mean that there isn’t other factors involved, but it’s likely mostly from the extra insulin.

Since we can monitor excessive insulin secretion pretty simply by just looking at our weight, this shouldn’t be a problem to manage, and if you are gaining weight by raising serotonin, this would indicate a problem, but the effect here is a pretty modest one and this wouldn’t be typical.

Low serotonion and low melatonin go together, and it’s not a coincidence, since once again, serotonin converts to melatonin, and if serotonin is low, melatonin will tend to be as well.  One can take melatonin separately, but I’ve personally found the two to be synergistic, and I’ve found a lot more benefit in taking them both together rather than just taking one or the other.

I’ve only recently tried this and this combination seems to help my blood sugar like nothing else.  Melatonin also helps manage blood sugar and we don’t have to look beyond what this does to enhance sleep quality to explain this, although it’s also involved in conversion of T4 to T3 and that’s a particular problem with me, and a lack of conversion and the resulting disturbance in thyroid hormone function at the cellular level, and the resulting increases in cortisol levels to compensate, which raises blood sugar, may be an even bigger deal here.

It’s also important to make sure that you get enough selenium as well for this conversion, and the relationship between thyroid hormone metabolism and diabetes isn’t one that comes up very much, but it’s a significant one.

So it starts with low melatonin, which ends up putting cortisol up, and cortisol is a huge culprit in hyperglycemia, as well as in thyroid disease.  So cortisol goes up, this puts blood sugar up, and high cortisol also interferes with T4 to T3 conversion as well, leading to a need for even more adrenal hormones and we end up with a vicious circle, where metabolism is downregulated and blood glucose is elevated, the sort of thing to prepare us for survival.

So we feel tired, wired, and don’t sleep well, and if we’re diabetic, we have higher blood sugar as well.  This is a lot of people.  So to try to break this cycle, if we add things like serotonin and especially melatonin, as well as selenium, we can improve our thyroid hormone function, and end up helping our blood sugar and diabetes at the same time.

Serotonin itself is known to reduce excess cortisol directly and that’s the main reason why we want to make sure our serotonin levels are kept up if we have type 2 diabetes.  If we are on a low carb diet to manage our blood sugar, this lowers serotonin and raises cortisol, and also inhibits thyroid function, so it’s important to look to compensate for this by taking something like 5-HTP.

When our melatonin levels decline in the morning, this is when we see what’s known as the dawn phenomenon, higher blood sugar upon waking.  Melatonin and cortisol are inversely related and a deficiency of melatonin will tend to raise cortisol, and higher levels of cortisol will tend to lower melatonin.

So these two substances are well worth checking out and looking to balance if you suffer from either diabetes or stress, or both, and they do go together.

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11 Comments on “Serotonin, Melatonin, 5-HTP, and Diabetes

  1. have you had your genome sequenced, like through 23andme? lots of interesting stuff (and scary stuff) you can learn. have you investigated the role of light in inhibiting melatonin production, or in other ways to increase serotonin such as making sure vitamin d levels are sufficient?

    1. I haven’t done the genome sequencing, although I agree this can be interesting, although issues do present themselves by way of symptoms and that’s still the most basic method of diagnosis. There’s more to this than just light, if someone’s melatonin production is low, light often doesn’t inhibit this, nor does lack of light promote it enough. So people can produce plenty but at the wrong times. Vitamin D and omega 3 has been shown to help with serotonin production so thanks for mentioning that.

      1. can you tell me when ( one hour before bed?) and how much (100 mg 5 htp together with 5 mg melatonin?) you take of melatonin and serotonin together? how long have you been taken them together (6 months? 2 years?)

          1. Sorry I missed that one. 200 mg of 5-HTP a little before bedtime, like 20 minutes to a half hour, but with me it’s not so much getting to sleep as it is staying asleep. Someone who had trouble falling asleep may want to take it an hour before bed. As far as melatonin goes, I’ve taken them together with no issues, although just off an on, when I feel that I need it. Mostly off though as this dose of 5-HTP does the trick for me, and what I’m after isn’t so much better sleep as the other benefits of it. I simply feel better and it helps manage my diabetes as well. I’ve been doing a fair bit of reading on leptin and it turns out that 5-HTP has been shown to help, especially if you are a normal weight diabetic as I am. It’s just a great supplement and maybe the most important one overall. Now with melatonin I’ve always been low, since I was a kid I was a night owl, and when I’m not sleeping like I want to I’ll add 5 mg of that and that gets me on track. It’s all what works for you personally. If you are here I’m betting you’re having some issues with this and therefore you might want to see what plan and dosage suits you the best, I would say that 5 mg of melatonin is the high end of this, it’s a fairly high dosage actually, and some people take less if they feel too groggy in the morning, that’s a sign you’ve overdone it a little. I think it’s generally better to start with 5-HTP and add melatonin if you need to, as 5-HTP will bring up your melatonin levels naturally, somewhat anyway. Whether it does so enough is something you’ll have to decide. Some people end up taking less 5-HTP than they need, we’ll say 100 mg, and say that didn’t work enough so let’s add some melatonin. An alternative would be to bump up the 5-HTP, not necessarily taking more at bedtime but mixing in a few 50 mg caps during the day. I think that 100 mg at bedtime is on the lower side of what may be effective. The brand I take suggests 100-200 mg 3 times per day. I can’t tell people what to take but by going with that, well the 300 TDD that some websites talk about may be on the lower side. I’ve taken 200 twice a day and it’s worked fine for me although the once a day works well too. So there’s some playing around involved here, these dosages are just general really, although I personally wouldn’t exceed the dosage on my bottle, the 100-200 up to 3x a day.

          2. Thanks, Ken! Could you tell me (you did before, but I forgot) what brand of 5 htp and melatonin you use? And what is your age and eye color? That last question probably is irrelevant. it’s just that right now i’m investigating whether i have an age-related (and maybe eye color-light green- eye lid (thin)-related) probably filtering out blue light. since i seem to be very sensitive to blue light, i think this is affecting my melatonin production. right now- only 3 short days- i have been getting good results with using the latest research from dr. panda on circadian timing. my first intake of a non-water substance (in my case coffee) is at 5 am. my mouth is empty of anything except for water at 5 pm (12 hour span). i have no screens except for a tv screen which is at a pretty good distance away from me from 5pm to 9pm (if i am watching tv). then i get very sleepy at 9pm and go to sleep in a completely dark room. i’ve had two night where i’ve woken up briefly at 1:30 am or 2:20 am, but i got back to sleep very quickly – this is all without supplements. i wake up at 5 am or 6 am with no alarm clock. right now i am on summer vacation as a teacher, so i have no stress and lots of natural light, but once school rolls around, the stress and hot flashes will begin again!!! anyway, this experiment with food and light timing (even avoiding bright lights from light bulbs in the evening) is working so far.

          3. I’m 56 with green eyes 🙂 I’ve no idea on the thickness of my eyelids 🙂 I don’t think that eye color matters that much but there is a genetic component to this. I would say that I’ve always been low on this and used to stay up until 3 AM even as a young kid, like 6 years old. I remember being in the hospital to get my tonsils out at that age and I had brought a radio with earphones and the nurses would bug the crap out of me to go to sleep, but that wasn’t happening, bug off 🙂 So on my mother’s side of the family people sure behaved like they didn’t get much melatonin. My natural rhythm is to sleep during the day actually. A lot of this is determined by cortisol rhythms as well. I think the major cause though is a deficiency of serotonin, and serotonin itself doesn’t cross the blood brain barrier, although 5-HTP does, which is one of the reasons it’s so effective. Serotonin converts to melatonin, that’s where we get it, so if someone is low on melatonin then they are almost certainly low on serotonin. If this other stuff is helping you, well whatever works. The hot flashes may respond to natural progesterone by the way, many women are helped by this, got to be the natural stuff though, the synthetic version is poison, as is the case with all synthetic drugs 🙂

  2. No, “we can monitor excessive insulin secretion pretty simply by just looking at our weight” isn’t true. Reactive hypoglycemia knows no weight description; there are fat and thin people who have this problem. And yes, it exists.

    1. I was speaking generally, and there are some people who have high insulin levels and aren’t overweight, and this has to do with a deficiency of leptin, rather than the excess leptin and leptin resistance that overweight people get. This is true as a general rule though simply because this is what insulin does, it stores fat, so unless there’s something weird going on to prevent fat storage, this will happen. Now with reactive hypoglycemia this is not people who tend to have hyperinsulinemia in general, where you get insulin resistant, in a way this is the condition of a lack of insulin resistance, a deficiency of it even. So you secrete a normal amount but it works better. Also, in a lot of cases, people who think they have hypoglycemia with this don’t really go low enough to be clinically hypoglycemic, it just feels that way, and this has to do with the symptoms they feel. A lot of the symptoms, the shakiness, etc, have to do with high levels of adrenalin, and the body is overreacting to blood sugar changes. In the end though, as far as insulin and weight goes, it’s not a perfect correlation, but it’s a very strong one, and what I was talking about with this remark is monitoring changes in insulin secretion by observing your weight, where more means more weight and vice versa. So you can see that you gained weight and can reasonably conclude that your insulin levels have risen, or gone down if you lost weight. If someone feels they have reactive hypoglycemia though they should buy a meter and test themselves when they think they are hypoglycemic. My wife was convinced this happened to her until I tested her a few times and her blood sugar was normal. One can do a 4 hour glucose challenge though and measure insulin levels if one is curious enough and can get this prescribed. This is one condition where they get it right, fast carbs is the culprit, but what they don’t realize is that this has to do with insulin clearing, it’s not that you secrete that much it’s that it sticks around like it does with type 2’s, but type 2’s have the higher blood sugar to balance this, with normal blood sugar this is going to put it down a little lower anyway. People who think they have this should definitely have this checked out though as true hypoglycemia isn’t a condition you want. Thanks for the comment!

  3. hi Ken,

    Are you still taking the Laura Vandervoot 5 htp? i am also having worsening problems with short term memory, and i just saw a scary article today saying that people with Mild Cognitive Impairment and Alzheimer’s all have lower levels of serotonin. On your side of the family that were night owls, any dementia?

    1. Yeah Laura Vanderhaeghe. I don’t think the brand matters that much although this is a quality brand. Low serotonon leads to a bunch of stuff, depression, anxiety, digestive disorders, carb craving, poor brain function, etc. Diabetics have lower levels and then when you cut the carbs this gets worse. I can do keto diets and not crave carbs when I take 5-HTP and without it I’m wanting them. No dementia in my family, Dad lived by himself at 93 before he passed and had no trouble other than the tendency to want to argue with me which was a lifelong disorder 🙂 One time he tried to tell me I was in the wrong lane at an intersection and I wasn’t, but the argument escalated to the point where we had to drive back there and stop the car in the middle of the road in traffic, we get out, and I say, see that arrow, that was the right lane!

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