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Why IGF-1 Levels Dont Matter As Much As You Think

2026-03-29 · 22:14 · 4 min read

A lot of people getting into peptides assume IGF-1 is the holy grail marker for growth hormone optimization. Test it, see if it's low, supplement, retest, done. I get why people think that way. We do it with testosterone all the time. But IGF-1 doesn't work like testosterone, and treating it that way will lead you down the wrong path.

Why IGF-1 Isn't Like Testosterone

With testosterone, things are pretty cut and dry. Total and free testosterone give you a clear picture. Levels are low, you supplement, you feel better.

IGF-1 is way messier than that.

The numbers can swing wildly from one blood draw to the next. I've personally had IGF-1 come back at 180 on one test and 370 on the next, doing the exact same protocol with the same dose of growth hormone. Same body, same peptide, very different number on paper.

That's the problem with relying on one marker.

Why HGH or Peptides Might Not Move IGF-1 The Way You'd Expect

People assume if they start ipamorelin or tesamorelin, IGF-1 jumps from 150 to 450 overnight. Doesn't always work like that. Here's why.

Receptor sensitivity. As we age, IGF-1 receptors get less sensitive. The liver may not crank out as much IGF-1 even when growth hormone is being released.

Age-related decline. The whole growth hormone to IGF-1 axis becomes less efficient as we get older. A 40-year-old and a 60-year-old can take the same dose of tesamorelin, get the same pituitary signal, and convert very different amounts into IGF-1.

Lifestyle factors. Poor nutrition, chronic stress, and inflammation all blunt IGF-1 production. Take a 45-year-old mom under chronic stress, sleeping four hours a night, with an underactive thyroid. She starts ipamorelin and feels nothing. That makes total sense. If cortisol is sky-high and there's no testosterone in the system, no peptide is going to fix that on its own.

Pulsatile release. Growth hormone gets released in pulses, mostly during deep sleep. A single IGF-1 reading can't capture what's actually happening in your body across 24 hours.

Why The Number You Get Back Is So Variable

IGF-1 can read differently at 7am versus 10am versus 5pm. Bad sleep the night before? Suppressed reading. Took a big dose of growth hormone peptide before bed and got tested at 7am? Inflated reading.

Add in protein intake, stress, inflammation, age, and genetics, and you've got a marker bouncing all over the place.

Compare that to testosterone, which fluctuates but stays in a much tighter range. IGF-1 is a roller coaster.

What To Look At Instead

If you're trying to figure out whether you'd benefit from growth hormone peptides, ask symptom-based questions. This is what I'd actually walk someone through.

Muscle and strength. Have you noticed a decline despite training consistently? Are workouts less effective?

Body fat. Are you gaining fat, especially around the abdomen, that won't budge with diet and exercise?

Energy. Do you feel persistently tired even when you're sleeping enough?

Recovery. Are injuries taking longer to heal? Are you sore for days after workouts that used to be easy?

Sleep. Trouble falling asleep, staying asleep, or waking up unrested? Growth hormone is one of the better frontline tools for sleep, in my experience.

Skin and hair. Thinning hair, drier skin, loss of elasticity?

Cognitive. Brain fog, memory issues, trouble focusing?

Mood. More irritable, anxious, less motivated than you used to be?

Joints and bones. Stiffness, pain, reduced bone density?

Immune system. Getting sick more often than you used to?

If you're saying yes to three or four of these, you're probably a candidate for growth hormone peptides.

The C-Word Concern

A lot of people avoid HGH because they're worried about cancer risk. My honest take is that healthy IGF-1 levels actually support immune function. We're not pushing IGF-1 to 1000. We're getting it back into a healthy range. I don't believe HGH causes cancer, but if that fear is real for you, I'm not going to talk you into using it.

Peptides Aren't A Magic Fix

The biggest mistake I see is people throwing growth hormone peptides at a problem when the foundation is broken.

Are you hormonally optimized? How's your thyroid? How's your stress? Your diet? Your training? Your sleep? Your relationships?

Get those right first. Then peptides actually do what they're supposed to do.

I always say hormone optimization should come first. Testosterone, thyroid, then peptides. Most people do it backwards because they'd rather take a pill than start with the basics.

My Take

Yes, I still test my IGF-1 every time I pull blood. I want to know where I'm at. But I don't stress when it comes back at 180 one time and 370 the next on the same protocol. The number tells me something, but it doesn't tell me everything.

The real question is how you feel. Do you wake up with energy? Are you lean? Are you recovering well? Are you sleeping? Do you feel ready to attack the day?

That's what growth hormone peptides should be evaluated against. Symptom resolution and how you actually live your life. Not a single number on a lab report that's going to be different next Tuesday.

Almost any aging adult, meaning anyone in their 30s and beyond, can benefit from optimizing growth hormone. Ipamorelin is one of the best gateway peptides because side effects are rare and most people notice better sleep within a couple weeks. Just don't expect a number on a blood test to confirm what your body is already telling you.

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Full transcript click any paragraph to jump video

Hey everybody. This is Hunter Williams. I hope you were doing amazing wherever you are at in the world. Today's video is going to be about why testing your IGF one levels doesn't really matter. It does, but what I want to do is kind of paint the picture of One, what IGF-1 level testing really even gives us, but then also two, why it's not always a catch-all for necessarily optimizing growth hormone. And what I mean by that is, I think the best way to kind of look at this is through the lens that we kind evaluate testosterone therapy.

So it's pretty easy, right? You go get your testosterone tested. Um, if the levels are low, it took an idea to supplement with testosterone therapy or your free testosterone levels were low. It's a good idea. The supplement was testosterone. Therapy. I don't want to say like completely black and white, but it was more cut and dry than a lot of other things that we optimize. And as more and more people come into the peptide ecosystem, I think obviously one of the biggest, uh, areas that people look to optimize their growth hormone through growth on peptides and It has come to my realization Just through all of the coaching and communities that we have that a lot of people

looked to treat growth Hormone deficiency By looking at IGF one levels and while that is not necessarily wrong. It's not the best thing to do because IG F1 when looking it is oftentimes a Um, extremely variable in the reports that we get back on blood work. So what I want to do today is explain why testing IGF-1 levels isn't really a marker that should use for supplementing with human growth hormone,

a human-growth hormone peptide, and what we should do instead. And unfortunately, while it would always be easier to have an objective metric that can say, hey, that level is low. I need to introduce a peptides or a hormone therapy in order to address it. Supplementing with growth hormone or growth-hormone peptides is going to be much more of a subjective, I guess, qualification that we look at in order to do so. Now, the flip side to all that is that IGF-1 levels more or less fall off a cliff after the age of 30 for people.

So I think it's like every decade, they go down by 15% on average among people, so it is one of those things, really, once we get past our 30s, that can benefit massively from, even if it was just through peptide, looking at some exogenous supplementation to really help with IGF-1 production. Because again, the benefits are far and wide. We have fat loss, we have muscle building, and we skin, hair, anti-aging. I could keep going. So what we're going to look at today is why your IG-F1 levels don't really matter and what can we do to assess whether or not supplementing with growth

hormone peptide is something we need to do. I think the answer is obviously yes. But what I did is I'm going to have an explanation and then we're just going have kind of like a set of questions that I would walk through anyone that is thinking about supplementing with a growth hormone peptide and how they should go about assessing their own need to do so. So, uh, before I share my screen, I just say, thank you. I want to say thank It's been supporting the channel lately. It has been growing a lot. Thank you guys so much. As always, if you have questions about peptides, specifically growth hormone peptide, you can check out the Peptide Cheat Sheet.

That's in the link in description of the video. And obviously the best community on the planet is Fully Optimized Health. $99 a month. You can cancel anytime, but we definitely have I know at this point the most crowdsourced data around peptides, how to use them and how do, you know, tinker and experiment with all these different things that I talk about in my channel. So without further ado, let's look at the slides and get into it for today's lesson on IGF levels. All right. My name is Hunter Williams and today we're going to be looking at testing IGF-1 levels and whether or not it really matters.

So let's jump into it. Let's just first kind of look at why IG-F1 is not always a reliable marker for HGH therapy itself. And again, whether that's with exogenous HTH or peptide. There's tons of biohackers that are getting into the space, hormone optimization. We're obviously looking for tangible metrics to guide our interventions, right? HRV, testosterone levels, all these different things we look at. So when it comes to testosterone therapy, metrics like total free testosterone provide very clear indications of whether or not introducing testosterone

for men or women is going to be beneficial. However, with HGH and peptides, relying on IGF-1 is a soul marker. A lot of times can be misleading and ineffective and I think lead people down the wrong path. What I want to explain first is why even in the presence of HGH or HCH peptides, the IGF-1 levels might not actually change. And let me explain what that means. So one of the key misconceptions about HTH therapy is the expectation that IG-F1 level will always rise significantly.

We kind of think of, or I think in like prevailing you know, mass consciousness that, okay, boom, if I introduce HGH or impamerelin or testamerelin, then IGF is going to go from 150 to 450. Boom, problem solved, right? And doesn't always really work that way. So let's look at why. First, it has to do with receptor sensitivity. Depending on someone's age, IG-F1 receptors can be more or less sensitive. The liver may not produce as much IG F1, even with adequate HG stimulation.

Meaning that if we are relying on a peptide to produce or send a signal to the pituitary gland that then raises IG or growth hormone, which subsequently will raise IGF one. Um, as we age, that process becomes less and less effective due to age oxidative stress, all the different things that may have going on in my body, amount of inflammation, you know, the list goes on. So, um, we have age related factors. Aging reduces the efficiency of the gross growth, hormone IG F1 access, Which leads to a blunted IG f1 response, regardless of how much of a peptide that

I'm taking. Obviously, like I said, nutritional lifestyle factors play a key, so poor nutrition, chronic stress, or systemic inflammation can inhibit the body's ability to convert HCH into IGF-1 effectively. So some people may take ipamerelin or tessamerelin. Take, you know, let's just say like a 45-year-old mom. She's under stress. Uh, she has an impaired thyroid. He has three kids. she sleeps four hours a night and she starts taking it up and rolling. And she's like, I don't feel anything. Well, that would make sense because if your cortisol is ramped through the roof, if you have no testosterone in your body,

no amount of ipamerelin is going to really do anything because even if the pituitary gets the signal to produce more growth hormone, the growth hormones is gonna have a much harder time converting into IGF, which is lead to the fat loss, muscle building, enhanced sleep, and all these other things. And then there's also going to be just variable responses and peptide action. So some peptides simulate H2H release more subtly or target different pathways, which may not always result in measurable IGF-1 increases, but still provide symptomatic benefits like better recovery, fat loss, or improved sleep.

So again, it's not as cut and dry as unfortunately it would be nice to have. So there's also this idea of individual variability. IGF1 levels can vary wildly among people based on their age and sex, diet, and overall health. And this variability makes it difficult to establish a one-size-fits-all threshold for initiating HGH peptides. It's impossible to look at a man or woman, especially like it and say, OK, boom, your IGF is 210. No, you don't need testosterone.

Or yes, do you need to testosterone? That's really, really hard to assess, again, just based on the variability of people everywhere. We also have to look at the pulsatile nature of human growth neurons. So HGH is secreted in pulses throughout the day, primarily during deep sleep. These fluctuations mean that a single IGFI reading that we get on our blood work may not actually represent the body's HGH activity. So in contrast, testosterone remains relatively stable, more or less, at least in comparison to IGF-1.

I understand testosterone fluctuates up and down throughout the day, and it can be different day to day based on life circumstances, you know, for instance, if you don't sleep well one night. But atleast testosterone is a little bit more straightforward. like lots of other blood markers, but IGF can be kind of crazy all over the map. So it might be different if you get your blood work done at 7am versus 10am. It might different to get bloodwork done 10 am versus 5pm in the evening. Um, it's gonna have like much more of a roller coaster in terms of the range that we're looking at. Um, and then also to take, for instance, say, um, you know, your kids are up at night and you don't sleep very well the night before your blood tests.

Well, You may have suppressed IGF one the next day or say. Um. You know? Like, I don' know you took a huge bolus of a growth hormone peptide a night. Before bed. And then you go in and get your. Blood work done at 7 a.m. Your IG F is high. Like okay, it's working. Um, but then the next day it kind of like tapers off and it's like, well, is the peptide working or is it not, um, ultimately we're going to talk about like how to determine that. Um. The point being that it was really hard to like track how this is playing out, just through one single blood marker.

Like I said, IGF-1 levels are sensitive to external influences such as diet, stress, inflammation, chronic disease. For instance, poor protein intake, Chronic stress or systemic inflammation can reduce IG-F1 level independently of how much HEH is being secreted in the body. So again, let's take poor-protein intake for instance. Let's say you have a woman, she's 130 pounds. She really should be getting 125 to 130 grams of protein per day. in most cases, and she's only eating 75 or 80 grams of protein per day.

Well, I don't care how much improvement she is taking. She's not going to build muscle or burn fat the way she would if she was getting enough protein in the body. So again, you know, would you look at a woman and say like, okay, well her IGF is 130, like it's guaranteed that she needs to increase the IGP. Yeah, probably. But what other things could she be doing that could actually give her a better chance of having normalized IGDF levels without supplementing with peptides? Um, so that when she does decide to supplement with peptides work way better. So, um, there's also this idea that I hinted at this a little bit that, uh, we have age related decline and there was a reason that.

Heptides, especially growth hormone peptides do not work as well for people that are in their 60s and 70s as they do for in our 30s or 40s. As we age, both HGH secretion from the pituitary and IGF-1 levels decline. However, the sensitivity of IG F1 receptors and downstream signaling also changes, making IG-F1 one levels a poor standalone indicator of HTH status. Meaning that let's take a 40 year old man and a 60 year man. Let's say their pitutary gland secretes actually the same amount of HGH because they're on the same peptide. So let's say they'll take in one milligram testosterone.

Boom, the pituitary is signaled to produce the exact same amount of growth hormone. The guy that's 40 in most cases is going to convert more of that growth from on into IGF, which is then going the peptide versus the guy at the 60 is less likely to convert as much of that growth hormone in IGF, which then will confer benefits. So there's that too that we have to look at when it comes to our age and how this works.

As always, as should be the case with testosterone therapy, independent of your levels, we want to look at the role of symptoms in HGH therapy. So rather than just hanging on and clinging to this IGF-1 marker, it's good, bad, high, low, the decision to use HCH peptides or HTH should focus on symptom resolution rather than laboratory numbers. So what are some symptoms? Well, if this sounds like you, you could be a candidate to decrease muscle mass and strength. Is that happening? Increased body fat, a special, especially visceral body, fat reduced exercise capacity, poor recovery from injuries, decreased bone density and reduced

cognitive function and mood. Now I understand that sounds exactly like someone who's aging decade over decade. This is probably something that you struggle with the older that Why is that? Because as we age, IGF is falling off cliffs. So it kind of coincides with all these symptoms. Again, just to sum up, blood tests are not the reliable marker. Yes. Do I get my IGIF-1 tested when I give my blood marker drawn? Absolutely. I want to know what it is.

Um, I will say from personal experience, My IGF sometimes has been 180 taking two, I use a growth hormone a and other times it's been like three 70 taking the same amount to I us of growth from home for day. So what's the difference? I don't know. Maybe it was the night, like the nights sleep I had before, maybe it my body fat levels during that time. But I know that my life is better with those two I use of growth hormone from a symptom resolution standpoint and a performance enhancement standpoint

than it was without it. So, like we said, you know, it's not always the most accurate thing. You know we kind of went over all of These items, what I wanted to talk about was a diagnostic tool. So again, let's just say we have to throw IGF. Let's pretend that you couldn't get blood work done with IGIF or you can get done HGH, which is measured less. I still think it's good to look at. But again let just that we can do it. What will we do? Well, I would ask the following questions.

First I want to categorize physical health and fitness. When I look in my muscle mass, have I noticed a decline in muscle or strength despite regular exercise and resistance training? And then are my workouts less effective and there's recovery slower than it used to be. Next question is gonna be around body fat. So are you experiencing an increase in bodyfat, particularly visceral fat around the abdomen, this resistant to diet and exercise. Energy levels, do I feel a persistent lack of energy or fatigue even after adequate sleep and rest or an attempt to get adequate sleeping rest?

Because a lot of times people try to sleep, and they're not. And the my exercise capacity, have I experienced a decrease in stamina, endurance, or physical performance during exercise or even my strength in terms of how much weight I can lift. Let's look at my recovery. So injury recovery, am I taking longer to heal from injuries, sprains or strains than I did in the past? I think everyone in this aging could say that. Sleep quality, do I have trouble falling asleep or staying asleep? And do you wake up feeling rested? You know, with sleep, I hear from so many people that have sleep problems.

And in my opinion, there's a whole list of things that you can do to optimize sleep. But I think growth hormone therapy is one of like the frontline defenses in that. So if you're having problems falling asleep, and I thinking more cases, it's beneficial if your having problem staying asleep as I'm waking up throughout the night. It can be beneficial. Then have I noticed a thinning of my hair, dryer skin or a loss of skin elasticity over time? Well, obviously I that's kind of a no brainer. We all experienced that, When I look at my cognitive and emotional wellbeing, have I experienced issues with focus, memory or mental clarity often referred

to as brain fog? And then am I feeling more irritable, anxious or less motivated than I used to? Again, I'm going to ask myself these questions much more so than i'm gonna ask what my IGF-1 levels are if I, you know, to begin experimenting with a growth hormone or growth from on peptide. Bone and joint health. Do I experience joint discomfort, stiffness or pain that impacts your mobility or quality of life? And then bone density. Have you been diagnosed with respect or suspect a reduction in bone? Uh, I E osteopenia or osteoporosis.

Um, and then when I look at aging and longevity, Um, do I feel that the physical signs of aging such as reduced vitality, slower recovery, reduced strength, everything we talked about or impacting my quality of life and not allowing me or not enabling me to, uh, live the life that I want to live. And this is a very less talked-about aspect of HGH and. IGF-1 levels is immune system. And a lot of people talk about the C word and HGH and like, oh, I would never use that because I'm going to increase my risk of the c word.

The answer to that, in my opinion, is, well, that IG-F1-levels correlate with immune-system function. Meaning that if I optimize my IG F1 Levels, meaning that I don't take them up to a thousand, but I have healthy levels of IG f1 circulating through my body, my immune systems going function better. Does HGH cause the C word? In my opinion, no, but I can't go someone that's afraid that that is what they're going to get or the presence of that scares them.

I cannot tell them not to or I could not tell to take it. Um, are you experiencing more frequent illnesses or a weakened immune system compared to your younger years? I think everybody does that. And then when we just look at long-term goals, so do you have biohacking goals around performance, longevity, or body composition? Do you want to lose body fat? a healthy, um, on the lower end body fat because that reduces inflammation that produces any sort of chronic disease that I may, be susceptible to based on aging and then my lifestyle factor.

So am I currently maintaining a health lifestyle? So before you ever do any of this, it should always be, Hey, am my dieting, my training, living insulin controlled? Am I reducing my stress? My enjoying my life and I'm emotionally healthy. Do I have good relationships? That should be something that you have to ask yourself, you know So how do we use this if you answered yes to I would say at least like three or four of these questions Most likely you would be a candidate to Look at leased HGH peptides and potentially even HTH. I'm not gonna get into like which one you do on this video It's important to remember it is a not a magic fix Again, and this is like so many times when

I hear people say oh, it's not working Well, are you hormonally optimized to begin with? What does your thyroid health look like? Was your stress look? Like was your diet training look, like was her family life and relationships look. So obviously you want to have discussion with someone that, you know, as a healthcare provider or someone who has expertise around these topics. That is it for the slides. And that is why your IGF-1 levels don't matter. Now, obviously I say that they do matter to an extent and I still look at them every time I get blood work done to see where I'm at.

But just to close out with an example, like I said earlier, I've had IGF levels come back at like 180 and 370 on the same protocol doing the thing. And I really don't stress about it too much. And I think ultimately at the end of the day, growth hormone or growth, hormone peptides should be used in the context of what they do for me from a symptom resolution standpoint. So, so many times people get into like tracking all these things. And, uh, if I could sit down with them, I would say, how do you feel though?

Like, are you happy when you get up in morning? Are you lean? feel good. Do you have energy? Are you like ready to attack the day? And unfortunately, most people walking the planet right now don't experience those things. So, um, my kind of like goalpost or framework is like, okay, what can I optimize? What's out there? Or what tools I have access to? what do I need to look at in my life that I could do, you know, do it. And I think like relative to everything that's out there growth hormone peptide at least the peptides are something like everyone can benefit from like

there are almost hardly any very few cases to which like an aging person meaning that like your 30s 40s and beyond aging right quote unquote that would not benefit From optimizing growth hormonal levels in the body And again, when we look at like optimization, what is it about? It's about feeling good and being healthy. And yeah, looking good is nice. You know, if we have six pack abs, you know and the tone physique, that's nice, but like I want to feel good.

Um, I think everyone can benefit from these. I also think there are probably two, some of the better gateway peptides to get into. Um. Meaning that like, for instance, you always say like Ipermarylin is one of best peptide for newbies because someone can take it in almost zero cases. Does anyone have side effects? Not all cases, but like. It's one of like the fewest side effects, meaning just you only get like rashes, nausea or anything like that. And people at least notice they sleep a little bit better. A lot of times after a few weeks, their body composition starts to improve. So I think they're a good gateway for people to like kind of kickstart and get going in the right direction and obviously like go down the path of hormone optimization.

I always say hormone optimization first, meaning testosterone and thyroid first. But I realize that's not going to be the path of most people. They'd rather take a pill than a peptide and then look into hormones when it should be other way around. Hopefully this was helpful to you guys as more and more people start to become aware on this planet of Peptides and the amazing benefits of them. This is gonna be a question. I know it comes up a lot So it's why I did this video day So I'd love to hear your feedback on this one whether this is helpful or not or if you disagree

with me I Know that it is one of those things like yeah, there's probably some people that disagree With that out there and that's totally cool. It's just you know, one those thing I wanted to make people at least aware to kind of change how they think around this topic because so many people are like, you Know, obviously you're smart if your listening to a video like this as we get in you like okay Well, what do I what metrics do? I got a track to look at it and you know, some of these concepts, you have to kind of think differently about it. So, uh, love you guys. Thank you so much. Uh, I have so many gratitude for everyone out there that's listening to this. And I mean that in the most sincere way possible.

thank you. so, much, hopefully that comes across in my demeanor and the content I create and, um, thank for all the feedback that I get. Absolutely. makes the content better. And I was able to make this video because of just the feedback that I'd been getting from all the people we have in communities and you know, whatever it is that you're out there. So appreciate you guys much love and I will see you the next one. Peace.