What you carry at this position in your DNA and what research says about it.
Stress and Heart Health: 6/10 evidence, 27 publications.
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Sample genotype (not yours): G/G
Typical Stress Response and Heart Risk
Carrying two copies of the common G allele is associated with a typical stress response and baseline cardiovascular risk. However, there may be a slightly higher likelihood of weight gain if taking certain antipsychotic medications.
What this genotype means: Standard cortisol release under stress; Baseline cardiovascular risk profile; Slightly higher sensitivity to antipsychotic-induced weight gain.
Sample genotype (not yours): C
Elevated Stress Response and Heart Risk
Carrying a single copy of the C allele on the X chromosome is linked to a heightened cortisol response to stress and an increased risk of cardiovascular events. Managing emotional stress is particularly important for heart health.
What this genotype means: Exaggerated cortisol spike during emotional stress; Increased risk of stress-related cardiovascular events; Higher vulnerability to mood fluctuations under chronic stress.
Sample genotype (not yours): C/C
Carrying two copies of the C allele is linked to heightened cortisol release under stress and an increased risk of cardiovascular events. Emotional stress may have a stronger physical impact on heart health.
Sample genotype (not yours): G
Carrying a single copy of the common G allele on the X chromosome is associated with standard stress hormone levels and typical cardiovascular risk. There is a standard baseline for emotional and physical stress reactivity.
Sample genotype (not yours): G/C
Carrying one G allele and one C allele generally results in a typical stress response and standard cardiovascular risk. This heterozygous state appears to function similarly to the common G/G genotype.
What this genotype means: Standard cortisol release under stress; Baseline cardiovascular risk profile; Typical response to most psychiatric medications.
Gene function and biological role
Gene Function: The HTR2C gene encodes the serotonin 2C receptor, a key protein in the central nervous system that regulates mood, appetite, and endocrine pathways [1]. This receptor is highly active in brain regions that control the hypothalamic-pituitary-adrenal axis, which coordinates the body's response to stress [2]. Serotonin signaling through this receptor directly influences the release of stress hormones like cortisol [2]. Variations in this gene have been widely studied for their impact on emotional regulation, psychiatric conditions, and metabolic responses to medications [3].
Variant Impact: The rs6318 variant is a missense mutation in the HTR2C gene that alters the receptor's structure [4]. This genetic change replaces the amino acid serine with cysteine at position 23 of the protein [4]. The variant receptor is constitutively more active, meaning it signals continuously even in the absence of serotonin [2]. This altered baseline activity affects how the brain processes emotional stress and regulates hormone release [5].
Key Insight: The variant receptor is continuously active even without serotonin, leading to a heightened baseline stress response. This single genetic change on the X chromosome links emotional stress directly to physical heart health.
Location: HTR2C. Chromosome X · Xq23 · 114.7 Mb
Estimated prevalence by population
Global 64.5%; European 69.9%; African 40.7%; East Asian 97.6%; South Asian 79.5%; Americas 80.2%; Ashkenazi 61.4%; Finnish 78.3%; Middle Eastern 55.4%; Amish 67.8%.
Estimated GG genotype frequency.
Global 30.3%; European 27.4%; African 46.2%; East Asian 2.4%; South Asian 19.3%; Americas 18.7%; Ashkenazi 33.9%; Finnish 20.4%; Middle Eastern 38.1%; Amish 29.1%.
Estimated GC genotype frequency.
Global 5.2%; European 2.7%; African 13.1%; East Asian < 0.1%; South Asian 1.2%; Americas 1.1%; Ashkenazi 4.7%; Finnish 1.3%; Middle Eastern 6.5%; Amish 3.1%.
Estimated CC genotype frequency.
Showing effects for G/G genotype
Cardiovascular & Metabolic
Heart Disease
Heart Health. Evidence: 3/10. Source: PMID 24386118. Typical Risk.
Lifestyle, Fitness & Aging
Stress Response & Resilience
Stress Reactivity. Evidence: 3/10. Source: PMID 21967853. Typical Response.
Neurology & Mental Health
Mood Disorders
Mood and Depression. Evidence: 3/10. Source: PMID 25514629. Typical Risk.
Pharmacogenomics
Antidepressant & Psychiatric Drug Response
Antipsychotic Weight Gain. Evidence: 6/10. Source: PMID 19193342. Elevated Risk.
Showing effects for C genotype
Heart Health. Evidence: 3/10. Source: PMID 24386118. ~1.2x Increased Risk.
Stress Reactivity. Evidence: 3/10. Source: PMID 21967853. Elevated Cortisol.
Mood and Depression. Evidence: 3/10. Source: PMID 25514629. Elevated Risk.
Antipsychotic Weight Gain. Evidence: 6/10. Source: PMID 19193342. Typical Risk.
Showing effects for C/C genotype
Heart Health. Evidence: 3/10. Source: PMID 24386118. ~1.6x Increased Risk.
Showing effects for G genotype
Showing effects for G/C genotype
What this genotype means for the people who carry it
Sample genotype: GG (Homozygous)
Having two copies of the common G allele means the serotonin 2C receptors function at a standard baseline level [1]. During times of emotional or physical stress, the body releases typical amounts of the stress hormone cortisol [2]. This standard hormonal response is associated with a baseline risk for cardiovascular events, with studies showing no elevated risk of heart attacks or related complications [3]. In psychiatric contexts, this genotype is linked to a standard response to antidepressants [4]. However, some research suggests a higher susceptibility to weight gain when prescribed certain antipsychotic medications like olanzapine [5]. Maintaining healthy stress-management habits and a balanced lifestyle supports overall cardiovascular and emotional well-being.
Standard cortisol release under stress; Baseline cardiovascular risk profile; Slightly higher sensitivity to antipsychotic-induced weight gain.
Sample genotype: C (Single copy)
Having a single copy of the C allele on the sole X chromosome results in a more active form of the serotonin 2C receptor [1]. This heightened receptor activity is associated with a two-fold larger increase in cortisol levels during emotional stress [2]. The exaggerated release of stress hormones can place additional strain on the blood vessels and heart over time [3]. Long-term clinical tracking has linked this genotype to a 1.2-fold increased risk of major cardiac events [3]. There is also an associated vulnerability to mood fluctuations and depressive symptoms under chronic stress [4]. Conversely, some studies suggest a lower susceptibility to weight gain when taking certain antipsychotic medications [5]. Prioritizing stress-management techniques and regular cardiovascular checkups can help mitigate these genetic tendencies.
Exaggerated cortisol spike during emotional stress; Increased risk of stress-related cardiovascular events; Higher vulnerability to mood fluctuations under chronic stress.
Sample genotype: CC (Homozygous)
Having two copies of the C allele leads to the production of a highly active serotonin 2C receptor [1]. This increased receptor activity triggers a significantly larger release of the stress hormone cortisol during emotional challenges [2]. Over time, elevated cortisol levels and heightened stress reactivity can strain the cardiovascular system [3]. Clinical studies have observed a 1.6-fold increased risk of serious cardiac events, such as heart attacks, in individuals with this genotype [3]. Additionally, this genetic profile is associated with a higher vulnerability to depressive symptoms when experiencing major life stressors [4]. On the positive side, some research indicates a lower risk of antipsychotic-induced weight gain and potentially better responses to certain medications [5]. Implementing proactive stress-reduction techniques like mindfulness or cognitive behavioral strategies can be highly beneficial.
Sample genotype: G (Single copy)
Having a single copy of the common G allele on the sole X chromosome means the serotonin 2C receptors operate at standard baseline levels [1]. During stressful situations, the body produces a typical cortisol response rather than an exaggerated hormonal spike [2]. This standard physiological reaction supports a baseline risk profile for cardiovascular health, with no elevated risk of heart attacks [3]. In mental health contexts, this genotype is associated with a typical baseline for mood stability and standard antidepressant responses [4]. However, some pharmacogenomic research indicates a higher likelihood of experiencing weight gain if prescribed certain antipsychotic medications [5]. Standard healthy lifestyle choices, including regular exercise and balanced nutrition, are effective for maintaining long-term wellness.
Sample genotype: GC (Heterozygous)
Having one copy of each allele on the X chromosomes typically results in a standard physiological profile [1]. Research indicates that females with this heterozygous genotype generally exhibit a standard cortisol response to emotional stressors [2]. This typical hormonal pattern helps maintain a baseline risk level for cardiovascular events, showing no significant elevation in heart attack risk [3]. The presence of the G allele appears to buffer against the heightened stress sensitivity associated with the C allele [3]. In pharmacogenomic studies, this genotype is associated with a standard response to various psychiatric medications [4]. Some studies suggest a moderate risk of weight gain when using specific antipsychotics, though less pronounced than in other genotypes [5]. Overall, this genetic profile is considered neutral and supports standard emotional and physical health.
Standard cortisol release under stress; Baseline cardiovascular risk profile; Typical response to most psychiatric medications.
Variants with shared genetic architecture
rs3813929 · HTR2C Gene · Chr X · Antipsychotic Weight Gain
rs1414334 · HTR2C Gene · Chr X · Antipsychotic Metabolic Risk
rs518147 · HTR2C Gene · Chr X · Antipsychotic Side Effects
Focus on HTR2C: A possible suggestion for genetic studies of complex disorders.
Further evidence supporting the association between 5HTR2C gene and bipolar disorder.
Content updated August 2026.
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