Low IGF-1 Symptoms: What They May Mean and When to Talk to a Provider

Maybe you’ve been more tired than usual lately. You haven’t changed anything in your workout routine, but you’ve also noticed your workouts aren’t producing the results they used to. And maybe your body composition also seems to be changing, despite not changing your diet or training regimen.

It’s easy to chalk all of this up to a busy stretch or getting older. But sometimes, it can point to deeper hormonal issues, such as those involving IGF-1. In this article, we take a closer look at what this means, including what IGF-1 is, what low IGF-1 symptoms tend to look like in adults, how testing works, and when it makes sense to discuss these symptoms with your provider.

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What Is IGF-1? And Why Does It Matter?

IGF-1 stands for insulin-like growth factor 1. This hormone is produced mainly by your liver in response to growth hormone (GH) signals from the pituitary gland.

From there, IGF-1 goes on to carry out a large portion of GH’s effects in your tissues, including maintaining muscle and bone and supporting how your body handles repair and metabolism. 

And this is why providers often assess IGF-1 when they want to determine if you have adequate GH activity. While GH is released in short bursts and swings widely through the day, IGF-1 is more stable in the bloodstream, which makes it a more practical marker to measure.

IGF-1 naturally peaks during puberty, then gradually declines with age. Any significant or premature declines, however, may be associated with certain symptoms.

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What Causes Low IGF-1 Levels?

Low IGF-1 levels may happen due to various reasons, such as:

• Growth hormone deficiency (GHD): When the pituitary doesn’t release enough GH, IGF-1 production also decreases. GHD may be present from birth, acquired later (through pituitary damage, head injury, radiation, or a tumor), or idiopathic, meaning no clear cause is found. Adult growth hormone deficiency is relatively uncommon, estimated to impact about one per 10,000 adults.
• Age-related decline: IGF-1 levels naturally decrease as you age. This isn’t a disease, but it may contribute to symptoms often associated with increasing age, such as declining energy, changing body composition, and changes in recovery. 
• Nutritional factors: IGF-1 production may be suppressed by malnutrition, very low calorie intake, or insufficient protein.
• Liver dysfunction: Since IGF-1 is made in the liver, conditions that impair liver function may lower how much it produces.
• Chronic illness: Certain ongoing conditions, including poorly controlled diabetes and inflammatory disease, may be associated with lower IGF-1.
• Hypothyroidism: Low thyroid hormone may suppress GH secretion and, in turn, IGF-1 production.

Since low IGF-1 levels can have multiple causes, experiencing certain symptoms alone is not sufficient to identify or diagnose the cause. It’s always important to undergo a proper evaluation with a licensed healthcare provider, since they can account for your health history and other factors.

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Common Symptoms of Low IGF-1 in Adults

Many of these signs are non-specific and overlap heavily with other conditions. In other words, just because you have the symptoms below, it doesn’t mean you necessarily have low IGF-1 or GH levels.

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Persistent Fatigue and Low Energy

Fatigue is one of the commonly reported growth hormone deficiency symptoms in adults. This is largely because IGF-1 plays a role in how your cells produce and use energy. 

With fatigue and IGF-1, feeling tired often feels disproportionate to how active you’ve been, and it doesn’t fully resolve with rest. With that said, fatigue has a long list of causes, and low IGF-1 is only one of them.

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Changes in Body Composition

Adults with low IGF-1 or GH deficiency may experience an increase in body fat, particularly around the abdomen. This may coincide with a decrease in lean muscle mass, even without changes in your diet or exercise habits.

This happens because IGF-1 supports protein synthesis and muscle maintenance. In turn, lower levels of it may make muscle harder to build and hold onto. Simultaneously, GH and IGF-1 play a role in fat metabolism, meaning lower levels may be associated with increased fat accumulation.

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Reduced Exercise Capacity and Slower Recovery

Some adults with low IGF-1 report that workouts feel harder than they used to, that they tire faster, and that bouncing back takes longer. 

IGF-1 supports muscle repair after physical stress. This means that when levels are low, the recovery process may be less efficient, leading to prolonged soreness, reduced performance, and difficulty progressing in training.

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Sleep Disturbances

Trouble falling asleep, staying asleep, or waking up unrefreshed has been associated with growth hormone deficiency in adults. GH is released largely during deep sleep, and the relationship runs both ways: low GH and IGF-1 may disrupt sleep, and poor sleep may further blunt GH release.

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Bone Density Concerns

IGF-1 contributes to bone metabolism and helps maintain bone mineral density. Adults with chronically low IGF-1 levels may face a greater risk of reduced bone density over time, which may increase fracture risk. This is typically assessed with a bone density (DEXA) scan, and it's one reason a provider might order IGF-1 testing as part of a broader metabolic or bone health evaluation.

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Mood Changes and Cognitive Symptoms

Some adults with low growth hormone activity may report low mood, social withdrawal, trouble concentrating, or fuzzy short-term memory. 

Interestingly, IGF-1 receptors are present in the brain. In turn, this hormone may play some role in neurological function, though the mechanisms aren’t fully understood.

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Skin Changes

IGF-1 is involved in collagen production and skin cell turnover. This means that some adults with low levels may notice drier, thinner skin or more visible fine lines. However, like many other symptoms on this list, skin changes may be due to various conditions or causes.

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How Is IGF-1 Tested?

IGF-1 is measured with a standard blood test; a healthcare provider draws a sample. A lab then checks the concentration of IGF-1 in your blood serum.

As previously mentioned, unlike GH itself—which fluctuates significantly throughout the day based on activity, diet, and sleep—IGF-1 levels are relatively stable, making it a more reliable indirect marker of GH activity. 

However, reference ranges vary by age and sex. Because of this, a healthcare provider typically interprets IGF-1 results alongside your full clinical picture symptoms, including your medical history, other hormone levels, and sometimes additional tests. IGF-1 testing alone is not enough to diagnose a GH deficiency.

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When Should You Talk to a Provider?

A good rule of thumb is to talk to a healthcare provider when several of these symptoms show up together, persist, don’t have any obvious explanation, and start getting in the way of your daily life. This may include:

• Persistent fatigue that doesn’t improve with adequate sleep and rest
• Noticeable body composition changes (such as more abdominal fat and less muscle, without significant lifestyle changes)
• Recovery from exercise that’s slower than your training intensity would explain
• Mood changes, brain fog, or concentration trouble without a clear reason
• A recent lab result showing low IGF-1 that you’d like help understanding

However, a proper healthcare evaluation is the only way to tell whether low IGF-1 or growth hormone deficiency is actually involved. If several of the above symptoms are present in your life, Eden can help connect you with a licensed provider who can review your symptoms and health history. Our process starts with a brief online intake.

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What Support Options May Be Available?

For adults whose symptoms and lab work may suggest suboptimal GH activity, a provider may discuss ways to support the body’s own GH production.

Depending on your evaluation and test results, one option a provider might suggest is sermorelin. Sermorelin is a peptide that works by stimulating the pituitary gland to release GH. Eden offers Sermorelin through a fully online, provider-guided model that includes a consultation, provider-directed dosing, and ongoing support. Ultimately, a provider can help determine whether it’s appropriate for you and recommend the next best step in your health journey.

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