Leptin The Primary Fat Loss Hormone
By now you’ve probably at least heard of the hormone leptin.
Leptin is a hormone secreted by your fat cells which are primarily responsible for helping your body regulate your body weight (1) and your metabolism.
It is the single most important hormone when it comes to managing your weight, hands down.
No other hormones come close.
Not thyroid hormone, not insulin, not cortisol.
Yes, all of these other hormones are important when it comes to your weight but they all play smaller roles when compared to leptin.
Why then, if leptin is so important, do we never really talk about it?
When was the last time your doctor, for instance, mentioned your leptin level or even tested it?
Probably never (unless you frequently read my blog).
This is a shame because understanding your leptin level is incredibly important if you are interested in weight loss.
With that in mind, we are going to talk about how to interpret and understand what your leptin level means, whether or not you want high or low leptin, and how that will influence your ability to lose weight.
Let’s jump in:
Leptin Levels: What Do you want?
There is a lot of confusion regarding leptin levels and what your leptin level should be.
Let me first start by explaining how leptin works so you get an idea of what I am talking about.
Leptin levels are secreted from your fat cells and they signal to your brain to INCREASE your metabolism and to INCREASE fat burn (2).
The bigger your fat cells are (remember fat cells grow they do not multiply) the more leptin is secreted.
And this makes sense, right?
The more fat you have on your body the more leptin you want to be secreted in order to help IMPROVE your metabolism to help your body BURN that fat.
It makes perfect sense!
Ah, but there is one big problem.
This works well in theory but what most people misunderstand is that high leptin levels lead to something called leptin resistance or decreased leptin sensitivity.
This is why there is so much confusion about leptin levels in general.
Increasing your leptin levels doesn’t always result in weight loss.
In fact, increasing your leptin levels can do the exact opposite thing in many cases.
So if you are someone who is confused about what your leptin level ought to be then this information is for you!
In order to understand where your leptin level should be you need to understand something called leptin sensitivity.
Understanding Leptin Sensitivity
Leptin sensitivity refers to how sensitive your cells are to the leptin that is floating around in your bloodstream.
It’s very possible for you to have incredibly high levels of leptin hormone in your bloodstream but your body is not able to recognize those levels or even utilize them.
When this occurs, and it does in many people, you are considered to have leptin resistance.
Leptin resistance means that your cells are quite literally resistant to the leptin that they see.
And this process occurs in the same pattern as insulin resistance and progesterone resistance.
Both of these resistance syndromes stem from high levels of the target hormone.
And they occur because of feedback loops that your body uses to prevent excessively high levels of certain hormones from causing issues in your body.
They are kind of like a fail-safe system that your body uses.
And this is why you don’t necessarily want high levels of leptin.
Instead, you want a high level of leptin SENSITIVITY.
Leptin sensitivity refers to how sensitive your cells are to the leptin levels that they encounter.
High levels of leptin sensitivity are REQUIRED for your leptin to work which means they are REQUIRED for weight loss.
And high levels of leptin from lots of fat cells lead to leptin resistance and DECREASED leptin sensitivity.
Low levels of leptin INCREASE leptin sensitivity and REDUCE leptin resistance.
Understanding this concept is so important! Make sure you read and re-read it if it isn’t sinking in on the first pass.
High Leptin Levels – Good or Bad?
When do you want high leptin levels?
You’ll commonly see bodybuilders talk about leptin levels and why you want HIGH leptin levels.
They promote high leptin levels because they will obviously help your body burn fat and lose weight.
But this only works IF, and this is a big if, your body is ALREADY sensitive to leptin!
And in order for your body to be sensitive to leptin, you really need to be around whatever is considered a “normal” weight for your body.
If you are someone who is 30+ pounds overweight and you are listening to bodybuilders on YouTube talk about how to increase your leptin level you are listening to the WRONG information.
Their information would be helpful but really only if you were 5-15 pounds overweight and IF your body is already somewhat sensitive to leptin.
If you are someone who has leptin resistance (again, go back to that 30+ pounds as an example) then increasing your leptin levels will only make things WORSE.
Higher leptin levels, in the setting of leptin resistance, will only yield worsening leptin resistance and therefore difficulty in weight loss.
This point is often lost on people who don’t understand the concept of leptin sensitivity and leads to a LOT of confusion.
Are the bodybuilders wrong when they say you want high leptin levels to help burn fat?
Not at all, but they are supposing that you are already leptin-sensitive.
If you aren’t, then their advice really doesn’t apply to you.
Low Leptin Levels
But do you really want to have low leptin levels?
The answer here is obviously no as well.
In fact, having no leptin levels is just as bad as having EXTREME leptin resistance.
Both low leptin and extreme leptin resistance lead to the same symptoms:
- Weight gain
- The inability to lose weight (weight loss resistance)
- Extreme food cravings
- Inability to lose weight despite exercising
- And so on…
The treatment for both is obviously different but the manifestation of the symptoms is the same.
When researchers first discovered leptin they were super excited because they thought that they found the “cure” for obesity.
If you could simply give someone a leptin shot or leptin in medication form then surely you could help anyone lose weight, right?!
In theory, yes, but they quickly found out that giving people leptin actually increases weight through the process of leptin resistance (discovered above).
Now we know that prescription medications targeted at treating obesity do much better for weight loss when they target leptin SENSITIVITY and not your leptin level.
Does that mean leptin medications do not have a place in the treatment of obesity?
Not at all.
There is still a place for medications that contain leptin but only for those people who have genetic mutations which leave them with virtually no leptin levels.
In this case, some leptin is required for fat burning.
But you can’t really consider those with zero leptin in the same boat as those with low leptin or leptin resistance in terms of treatment requirements.
So, if you are someone with leptin resistance meaning you have high leptin levels and the inability to lose weight, do you really want to lower your leptin levels?
Yes, but only slightly and only for a short period of time.
For instance, if you are someone who is 50+ pounds overweight and your fasting serum leptin level is 45 then it’s a good idea to reduce that leptin level by 10-15 points in order for weight loss to occur.
This drop in leptin still maintains a relatively high leptin level (which is required for fat burning) but one that is lower than your “old” leptin level.
Lowering the leptin level here helps to IMPROVE leptin sensitivity while simultaneously keeping the leptin level somewhat high to help stimulate both metabolism and fat burn.
Treating Leptin Resistance
How do you treat leptin resistance if you have it?
As I mentioned previously, most doctors are completely clueless when it comes to this topic.
To make matters worse, pharmaceutical medications are not really targeted at leptin (yet).
This leaves you with few pharmaceutical options and of those which are available they must be used off-label.
They still can and do work, but getting them from your doctor can be difficult.
Prescription medications that help target leptin resistance include:
- GLP-1 agonists
- SGLT-2 inhibitors
- Salmon calcitonin
- Metformin
- And Naltrexone
I’ve written about these medications in detail in this article which I would encourage you to read if you are overweight and trying to lose weight.
Is it possible to improve leptin sensitivity through the use of over-the-counter supplements?
The answer to that question is yes and I’ve had great success with certain supplements.
Supplements are great because they do NOT require a physician’s prescription and they can be used right away.
Supplements that I find to be effective in treating leptin resistance include:
- GAGs (glycosaminoglycans)
- High doses of fish oil
- L-glutamine
- Supplements that improve thyroid function
- Supplements that improve insulin resistance
These therapies are all designed to help MANAGE or regulate leptin levels by improving leptin sensitivity.
That’s how they help with weight loss, by regulating your hormones.
If you have leptin resistance you will want to layer therapies on top of each other.
So make sure that you ALSO exercise and that you ALSO eat healthy when taking leptin supplements or when using leptin medications.
Final Thoughts
Balancing your leptin level is probably one of the most important things you can and should do if you are interested in weight loss.
I am of the opinion that EVERYONE who is overweight has SOME issues with leptin.
I think in the coming years (probably a decade) we will start to understand just how important this fat-regulating hormone is.
In the meantime, however, it will be up to you to do your own research and find your own therapies/treatments.
Until then, if you follow the standard weight loss advice of eating less and exercising more you will continue to have about a 1% success rate in losing weight and keeping it off (these aren’t my statistics but the actual numbers from people trying to lose weight).
The key to long-lasting weight loss is targeting the hormones that regulate your body weight such as leptin (the primary one) but also others such as thyroid hormone.
Now I want to hear from you:
Do you have leptin resistance?
Have you had your serum fasting leptin levels checked?
If so, what were your numbers? How high is your leptin?
How sensitive do you think your body is to leptin?
Leave your questions or comments below and share your experience/thoughts!
Scientific References
#1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3281561/
#2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4069066/
I am curious on what the genetic mutations that you mention. Could you say what those might be?
Hi Jill,
The mutations referenced here are not common and you would know if you have them. They typically present at birth.
My Leptin Was 8. I am about 20-25 Pds heavier then I would like to be and have tried everything to lose weight. Without any good results
Hi Jami,
You should also look at other hormones such as thyroid hormones and insulin.
My Leptin is 54.7 and I have started taking metformin and Victoza – presently titrated up to 0.9 ml and have lost 4 lbs since Jan 1 (the date I checked my labs). How long should I wait until I recheck my Leptin?
Hi Lynda,
You don’t really need to recheck leptin all, to be honest. The metric you are looking for is whether or not you are losing weight.
Hi Dr. Childs,
Thank you for responding to all the posts over the years.
I am 48 female, 5’8” 143 lbs. Leptin is 3.7. I’m never hungry. Eat one meal a day but eat more if I work out more. All thyroid is fine. Glucose and A1C are in range and fine.
I obviously don’t need to lose weight. And if I pig out for a week, I notice the scale moves up so I’m sure I’d gain weight if I ate more meals a day.
I’m confused if I am at risk for leptin resistance? My leptin has been 3.7 since early 2020 when first checked. I have always been a toothpick and fast metabolism but I have also had periods in my life where my weight went up to 175 lbs. max. But I take it off with really hard exercise and good choices.
Should I just accept that I have low leptin and that there’s nothing to worry about?
Thank you!
Rebekah
Hi. I just looked back and had my leptin levels checked in March of 2019. My leptin level serum is 32.4. Is that high? I am 46 year old female, 40 lbs overweight and no matter what I do, I can’t seem to lose weight. I eat well and exercise. So frustrating!!!! I also take naturthroid (it helps with “puffiness” but not necessarily weight loss at all).
Hi April,
If that was a fasting leptin then yes.
Just had mine checked. My leptin is 2.6 and my body fat/ level of leanness is roughly 18% which doesn’t correlate to how extremely low my leptin level is. I also checked my fasting glucose was 75 & fasting insulin was low too at 2.7. Thyroid is considered in normal range. Do you think I’d be a candidate for leptin replacement therapy? I never feel full and can eat a ton but I just resist because I’m a physique athlete so naturally I have to be mentally strong and not give in to food cravings because otherwise I’d never be able to complete in my sport. In my opinion, I feel like having extremely low leptin is just as bad as being leptin resistant. Not sure what to do because “carbing up” does nothing for me. :(. Thanks
I had my Leptin level checked in May 2017 and my level was 43.0. My Endocrinologist never told me this was bad or good; didn’t say much about it at all.
My highest weight was 552 pounds in May 2010. I was dealing with life stuff at that time and lost my appetite for 4 months, losing 80 pounds in those 4 months (I wasn’t eating at all; could hardly drink a glass of water). After 4 months, my appetite came back and I started eating very little; started exercising; continued to lose weight.
Fast forward two years and by July 2012 I was down 225 pounds and was preparing to have a Vertical Gastro-Sleeveectomy procedure which would remove two thirds of my stomach.
On Nov. 7, 2012, I underwent the Gastro Sleeve procedure. My day of surgery weight was 327 pounds. I underwent the gastro procedure to help assist me in reaching my goal weight of 200 pounds.
Over the course of 8 months (July 2013) I only lost 30 pounds from the gastro procedure. I could not understand why I was struggling so hard to lose weight following my procedure when people who have this same type of surgery lose at least 100+ pounds within the first year.
By March of 2014 I had regained (from 298 pounds) 114 pounds and was weighing in at 412 pounds. I should state due to life events I stopped exercising/going to the gym in August 2013.
I had blood work done this last week and I am retesting my Leptin level.
I really could use some assistance or a referral to someone who can help me. I am currently at 454 pounds. I have been overweight since I was 3-1/2 years old. I can’t even begin to tell you what living with morbid obesity my entire life has done to me on an emotional level/living life level.
Thank you.
Hi Al, I struggle with my weight too and was wondering if you found any solutions. Not sure if you’ll see this.
Nobody said if they took that thyroid meds and lost weight on it.. how much weight should you lose on 1 mo supply
Hi Elizabeth,
Most people do not lose weight on thyroid medications. In fact, a great many gain weight when using the wrong type: https://www.restartmed.com/levothyroxine-weight-gain/
Hello – I have tried it all including bariatric bypass, I initially lost over 130 lbs then just as I was about to reach size 14 it stopped and I gained back and cant do anything. I work out, each fresh, no wheat, no corn, no dairy,etc stuck at the 260’s. My Leptin is at 34.7 which I found out was high. I started seeing a bariatric nutritionist otherwise I may never know of this test. He put me on Phentermine 37.5 and topiramate 25mg 1x a day, for my appetite which I dont think is the problem. Does this sound correct to you?
My fasting leptin was low at 4.4, fasting insulin a little higher than I would like to see it (4.8) and it looks like I have sub optimal thyroid without antibodies. (T4 free 1.0, TSH 2.73, T3 free 3.0, T4 Total 7.4). I’m planning on starting your thyroid glandular. Will treating my thyroid improve my leptin? I have about 10-15 pounds to lose, but no matter how hard I try the scale does not move.
My Leptin level was 201 (fasting) and I am about 50 lbs overweight and have RA so I am limited on exercises I can do. Any suggestions?
Hi Michelle,
Yep, lots! Check out these posts for more info:
https://www.restartmed.com/leptin-resistance-medications/
https://www.restartmed.com/leptin-supplements/
Hi! My fasting Leptin is 3.1 NG/ML. Is this considered too low? What can I take to raise this? Thank you!
Thanks for the information. I saw the podcast with Dr Hyman.
I am a 61yo female, BMI 30, Serum Leptin 31.7 ng/ml, A1C 5.4, Problems with weight loss, sleep and hair loss. I take NP thyroid 120mg, and progesterone 200mg. Which has not helped the hair loss
I started trying to lower my leptin last summer. I have been on T3 only since then, lifting and walking for exercise and have taken some of the supplements recommended on here. My leptin rose from Jan to this month and my weight is starting to go up again. I wish leptin was easier to target. My A1C (from supplements) fell to below normal from normal. That’s all that’s changed. I’m going to go back to taking the GAGs 2x a day & stop the berberine. My body fat % although I’ve been lifting for years & tracking food and macros has slowly risen to 33%.
I am a little confused – it sounds like the Leptin Supplement (probably paired with the Thyroid) would help even if your leptin levels are obscenely low, like mine. They have been between 1.7-2.7 for several months. In the article where you describe this, that is exactly what my body is doing – it is 30% body fat but thinks it is starving. I am having a very hard time getting clear information and research on this predicament.
Hi Jessica,
Both low leptin and leptin resistance tend to cause the same thing but it is true that those people with low leptin have more difficulty in losing weight compared to those with leptin resistance. The goal is still the same, though, in terms of treatment and that is to improve leptin sensitivity to whatever level you can so the treatments/supplements/etc. are very similar.
How does one improve leptin sensitivity when leptin is too low (below 3.5) in order to facilitate fat loss?
Hi Jen,
For the most part, the treatments for leptin resistance apply to those with low leptin levels as well.
Hi, Dr Childs. I appreciate all the info you share and have done a lot of research on you site and others. I finally got my dr to Rx Ozempic for my leptin resistance and weight, along with t3 5mcg bid. I started Ozempic 8 days ago and will start t3 this week. Is it accurate that for leptin reinsurance, GLP1 tx is usually 3-9 mo, depending on severity of leptin resistance? My level in May was 24, and 44 in august.
I’ve already normalized most levels… vit D, zinc, selenium, fe, iodine……
Thanks,
Suzi
my leptin is 0.7, i’m at a healthy weight but feel like i’m VERY HUNGRY 24/7 and have to resist against VERY strong urges to eat. I’ve had this problem ever since my brain surgery where they removed a hippocampus. are there any medications that alleviate this?
Hi Jack,
I believe there may be some treatments but I’m not 100% sure. I remember reading about pediatric treatments for those who can’t produce leptin but I can’t recall them off of the top of my head.
THe exogenous leptin treatment apparently is only approved for people with congenitial deficiency with absolutely 0 leptin so thats not on the menu of options. My hunger problem improved as of going off lamictal(caused insulin resistance), no change in leptin though. Also to give my other data. Fasting glucose is 68(excellent) and TSH is 2.01 and CRP is 0.3. Cortisol is a bit high however coming in at 22. I think my odds of getting GLP’s are very poor given i’m not overweight and they are expensive. I also suspect i have a sleep disorder and was wondering, Can this effect leptin?
No matter what i do i can to lose weight. I’m a 39 year old female (soon to be 40) and I’ve been working with a nutritionist and trainer and they’re stumped too. I’m dairy and gluten free for medical reasons and earlier this year had my gallbladder removed due to sludge and stones. I had a bunch of blood work done recently due to a 10lb weight gain in 6 weeks and the following were the results. All testing was done after fasting for 12 hours.
Leptin 3.3ng/mL.
Cortisol 13.0 ug/dL.
TSH 2.46 uIU/mL.
Cholesterol 206 mg/dL
Triglyceride 305 mg/dL
High Density Lipoprotein(HDL) 42 mg/dL
Very Low Density Lipoprotein 61 mg/dL
Low Density Lipoprotein 103 mg/dL
Estimated Average Glucose 97 mg/dL
My doctor hasn’t done anything and it’s been two weeks. After Googling the result (I know # 1 thing NOT to do) I’m concerned I’m insulin resistant as my HDL is low and Triglycerides are high and my glucose is very close to the 100 mg/dL benchmark for pre diabetes. Can you provide any help as to what i need to do next? or ask for?
Hi Jennifer,
I would recommend looking at this program for more ideas as to what works: https://www.restartmed.com/hormone-mastery/
Do the Leptin lowering effects of Statins play a role in prevention of weight loss by preventing the body from burning the required energy to lose weight? Do statins alter the weight loss mechanism?
Hi Rich,
Perhaps theoretically but I don’t think it is clinically relevant, at least not in most people.
hello, I had my Leptin checked and it states I have 17.0 but i am reacting as if I have high leptin levels. I have been lifting weights and macro counting for nearly two years and cannot lose a single pound of fat. Is it possible that is too high for ME personally? and I should try to lower that?
Hi Mel,
If your leptin is elevated and you aren’t losing weight then leptin resistance is present. If your leptin is high it should be helping you lose weight and if you are unable to do so that speaks to an issue of resistance. There may also be other hormone issues at play as well that would be worth evaluating.
Hello!
First, I want to thank you for clarifying resistance vs. just high or low lepton levels. I am a toxic mold recovering patient, about 4 years into treatment following the Shoemaker protocol. My leptin hormone levels have been all over the board. What I have observed is that I continue to gain weight inspire of eating well. Diet attempts have failed miserably. I am now 150+ pounds overweight. All occurring within the past 5 years.
To answer your posted questions:
1. Do you have leptin resistance?
I have not been clinically told I do or do not, but it would appear that I do.
2. Have you had your serum fasting leptin levels checked? If so, what were your numbers? How high is your leptin?
YES!
About every 6 months.
Currently as of 10/11/22: 82
Previously on 4/12/22: 165.2
3. How sensitive do you think your body is to leptin?
I would say it has no sensitivity since I continue to gain weight at a crazy speed and despite all attempts.
What is your insight and advice?
Hi Katrina,
I would agree that you have very little sensitivity to leptin. Please see this article for more information on how to treat it: https://www.restartmed.com/leptin-resistance-thyroid-resistance/
Hello,
I recently had my leptin levels (fasted) tested and it was 0.5 ng/ml. I’m 49, have a BMI of 22 and have a very active lifestyle. I’m struggle with sugar cravings especially in the evening. Are my levels too low?
Dr Childs, your posts are incredible!! Makes so much sense!! I was fine with levothyroxine for a long time. Didnt know any better. Then I wasdiagnosed with lyme….as the lowered my thyroid medication.I went slowly up to my pregnancy weight of 230 from 175. The docs said it was from lyme. I have inflammation galore and no hormones since menopause 5 years ago. Just got my bloodwork. My tyroid is almostnormal, but my leptin is at 70!!! I SO WISH YOU WERE PRACTICING OR AT LEASTCONSULTED BLOODWORK. At 55, I have never felt worse.. .so heavy makes this active person unable to do what my mind wants to. I asked my doc for t3, she saiditwas in the dessicated thyroid….so frustrating. Is there a t3 you prefer? I live in Gilbert,Az, Iwould be at your officein a heartbeat!! With 6 kids and 5 grandkids….I need this weight off. It never flucuates! My daughted had a goiterat 13tr…she is on 9 grains of tirosent that I requested…but she still has weight issues at 28. Any tips for us?And again, thank you for your posts!!
Hi Cheryl,
I would recommend checking out these case studies which I think can provide further information and give you a better idea of what may be necessary as far as treatment is concerned:
https://www.restartmed.com/weight-loss-naturethroid/
https://www.restartmed.com/weight-loss-hypothyroidism-success/
https://www.restartmed.com/diabetes-reversed/
https://www.restartmed.com/thyroid-weight-loss/
https://www.restartmed.com/victoza-weight-loss/
https://www.restartmed.com/adding-t3-ndt/
I am a 33 year old female. 5’2″ 130 pounds (BMI: 23.8).
My leptin level is 32.3 ng/mL.
This sounds very concerning. What are your thoughts?!
Hi Spencer,
It depends on your weight. A high fasting leptin could be a good thing if you are trying to lose weight and it’s working. If not then you probably have an issue.
Hi Dr. Childs, I am a 60 year old woman with a fasting leptin level of 9.2. I am 5’7″, 203 pounds, recently lost 17 pounds. Insulin level is 8.3. I have seen so many numbers on what is normal and not and its confusing. I intermittent fast 8pm to 10am everyday easily. I don’t overeat and I’m active but loosing weight has been a struggle. Still in perimenapause. Would you consider that level leptin resistant?
Hi Helen,
If you are actively able to lose weight then you can’t say for sure that you are leptin resistant. In order to diagnose leptin resistance two things must be true:
#1. You need an elevated leptin.
And #2. You need to be unable to lose weight.
Hi Dr Child,
I had blood work done twice through Dr Mark Hyman’s Function Health program and both times my fasting leptin results were 2.5 L. I am 57, very active, fit 125 pounds, 5 6″ and I understand that I do not have insulin resistance but my low number is concerning. Can you offer any advice?
Thank you Jackie