IGF1 rs35767: Understanding This Common Promoter Variant
The rs35767 variant is a common single nucleotide polymorphism located in the promoter region of the IGF1 gene. It is frequently studied for its potential influence on circulating insulin-like growth factor 1 (IGF-1) levels, muscle development, and various metabolic health outcomes.
What each genotype means
Baseline IGF-1 expression
This genotype is often used as the reference point in studies examining IGF-1 promoter activity. Research suggests that individuals with this genotype may exhibit lower circulating levels of IGF-1 compared to those carrying the T allele. Please note that these associations are based on population-level statistical trends and do not predict individual health outcomes.
This is a common genotype found in many global populations, though frequencies vary significantly by ancestry.
Intermediate IGF-1 association
Carrying one copy of the T allele is associated with intermediate effects on IGF-1 expression compared to the CC and TT genotypes. Some research indicates that the T allele may influence athletic performance and metabolic markers, though findings remain mixed across different studies. These observations reflect statistical associations in research cohorts rather than individual clinical predictions.
This heterozygous genotype is frequently observed in European and East Asian populations, consistent with the reported minor allele frequency of 0.15-0.20.
Elevated IGF-1 association
Individuals with this genotype have been observed in some studies to have higher circulating levels of IGF-1 compared to those with the CC genotype. While some research links this variant to potential advantages in power and endurance sports, other studies have associated it with different rates of renal function decline or metabolic risk factors. Because these findings are complex and sometimes conflicting, they should be viewed as broad statistical trends rather than personal health indicators.
This genotype is less common than the CC or CT genotypes, occurring at a frequency consistent with the minor allele distribution in specific ancestral groups.
What is the rs35767 Variant?
The rs35767 variant is a specific genetic change, often described as a T to C substitution, located within the promoter region of the IGF1 gene. A promoter region is a segment of DNA that acts as a control switch, determining how much of a specific protein is produced by the cell. Because rs35767 sits in this regulatory area, researchers hypothesize that it may influence the expression levels of the IGF-1 protein. By altering the efficiency of the gene's 'on' switch, this variant could theoretically lead to higher or lower concentrations of IGF-1 circulating in the bloodstream. It is classified as a common variant, meaning it appears frequently across many human populations, rather than being a rare mutation that causes a specific, severe genetic disorder.
The Role of the IGF1 Gene
The IGF1 gene provides instructions for making insulin-like growth factor 1, a protein that plays a critical role in growth and development throughout the human lifespan. IGF-1 is a growth-promoting ligand that travels through the blood and binds to specific receptors on the surface of cells, triggering pathways that encourage cell growth, division, and survival. It is particularly important for bone and muscle development during childhood and continues to influence metabolic processes and tissue maintenance in adulthood. Because of its central role in these fundamental biological processes, variations in the IGF1 gene are of significant interest to scientists studying everything from physical performance and muscle mass to longevity and metabolic conditions like type 2 diabetes.
Research Associations and Evidence Strength
Scientific research has explored the link between rs35767 and various health phenotypes, though the evidence remains limited and sometimes mixed. Some studies suggest that individuals carrying the T allele may exhibit different circulating levels of IGF-1 compared to those with the C allele. Other research has investigated potential associations with muscle mass, renal function, and metabolic risks, such as type 2 diabetes or uric acid regulation. However, it is important to note that these findings are often based on statistical associations in specific study populations. Because many of these traits are 'polygenic'—meaning they are influenced by hundreds of different genes and environmental factors—the individual impact of rs35767 is generally considered small. Current evidence does not support using this variant to predict individual health outcomes or diagnose medical conditions.
Population Frequency
The rs35767 variant is widely distributed across global populations. In many European and East Asian ancestry groups, the minor allele frequency is typically observed in the range of approximately 0.15 to 0.20. This means that a significant portion of the population carries at least one copy of the minor allele, making it a common feature of human genetic diversity rather than an outlier.
Interpreting Your Genetic Information
If you have received information about your rs35767 genotype, it is essential to view it within the context of your overall health and lifestyle. Genetic variants like rs35767 are not deterministic; they do not 'cause' a specific health outcome on their own. Instead, they represent small variations that may contribute to a person's biological baseline. You cannot use this information to diagnose yourself with a condition or to predict your future physical performance. If you are concerned about your metabolic health, muscle mass, or growth-related markers, the most effective approach is to consult with a healthcare professional. They can order clinically validated blood tests to measure your actual IGF-1 levels and provide guidance based on your complete medical history, rather than relying on a single genetic marker.
How common is this variant?
The minor allele frequency for rs35767 is approximately 0.15-0.20 in European and East Asian ancestry groups, making it a common variant.
Frequently asked questions
Does the rs35767 variant cause disease?
No, rs35767 is a common genetic variant and is not considered a disease-causing mutation. While it has been statistically associated with certain physiological traits in research studies, it does not determine your health status.
Can I use rs35767 to predict my muscle mass?
No. Muscle mass is a complex trait influenced by diet, exercise, and many different genes. A single variant like rs35767 has a very small effect and cannot be used to predict your physical potential.
Should I get my IGF-1 levels tested because of this variant?
You should only get your IGF-1 levels tested if a doctor recommends it based on your clinical symptoms or medical history. Genetic results alone are not a reason to seek diagnostic blood work.
Is this variant the same as a mutation?
In genetics, 'variant' is a neutral term for a difference in DNA sequence. While 'mutation' is sometimes used, it often implies a rare change that causes a disorder, whereas rs35767 is a common variation found in healthy people.
Sources & further reading
Educational information only, last refreshed 9/21/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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