Oxytocin, often called the “love hormone,” plays a significant role in social bonding and empathy. The OXTR gene, which codes for its receptor, seems to affect how each individual processes and reacts to oxytocin. What does your DNA have to say, and which SNPs have the greatest impact? Learn more here.
What Are Your Genes for Oxytocin?
The oxytocin receptor gene OXTR determines sensitivity to oxytocin, commonly known as the “love hormone” for its role in social bonding [1, 2].
OXTR is recognized as an important gene for relationships and empathy, and it has attracted a great deal of attention in the research community for this reason. Many single nucleotide polymorphisms (SNPs, the fancy scientific term for simple variations within a gene) have been associated with differences in personality, social skills, attachment styles, and even brain development [2, 3].
The Most Significant Oxytocin SNP: rs53576
About 37% of the global population has the ‘GG’ genotype (two copies of the ‘G’ allele) at rs53576. This genotype is associated with increased optimism, empathy, and ease of handling stress .
The ‘GG’ genotype is associated with increased activity in the oxytocin system and enhanced effects of oxytocin supplementation .
The gene frequency varies by ethnicity: 61% of Africans have the ‘G’ allele, compared to 41% of Europeans (30% of Finns) and 10% of Asians .
The Benefits of ‘G’ at rs53576
In multiple studies, researchers have found that people with the ‘G’ allele were more likely to display positive social behaviors and to respond to the emotions of others. The following is a list of findings from some of the associative studies on rs53576:
- GG has a more positive ‘affect’ or disposition . AA and AG individuals were found to be less prosocial and displayed fewer nonverbal cues – head nods and smiles – compared to GG people. The authors reported that the association between and prosociality was stronger for men, but also significant for women.
- People with the GG genotype were more optimistic, empathetic, and able to handle stress.
- People with GG were better at accurately reading the emotions of others by observing their faces compared to AA or AG.
- People with GG were less likely to startle when blasted by a loud noise or to become stressed at the prospect of such a noise.
- People with GG were mellower and more attuned to other people than the AA or AG were.
- People with GG had higher non-verbal IQ .
- People with GG were reported to feel less lonely.
- People with GG were less likely to seek support from their peers.
- People with GG employed more sensitive parenting techniques.
- People with GG had lower rates of autism.
- People with GG had less difficulty hearing and understanding in noisy environments.
- In response to an interview, people with GG or AG had significantly lower cortisol responses to stress when they had social support. There were no differences in cortisol levels in subjects with the AA genotype receiving or not receiving social support. People with the AA genotype tended to have higher levels of cortisol throughout the session than G carriers (no differences between the genotypes were observed at baseline).
- People with GG had more gray matter volume in the hypothalamus and greater hypothalamus volume and more activation in the amygdala.
- People with GG were less predisposed to major depression .
The Negatives of ‘G’ rs53576
GG may affect how a person experiences social rejection. People with GG had significantly higher blood pressure and cortisol levels following rejection, effects not apparent among A carriers .
People with GG were less empathetic to pain experienced by racial ‘out-group’ vs racial ‘in-group’ members (Asians vs Europeans). However, AA experienced more pleasure from pain to racial out-groups. The authors suggested that these results could shed light on how and why people develop racial and social bias .
Other Oxytocin SNPs
People with the G allele at rs1042778 had higher oxytocin levels than T carriers (T=.37) .
GG or GT was associated more strongly with prosocial behaviors than the TT genotype. In a game that tested how generous people are (using the Israeli currency of shekels), people with TT gave on average 18.3 shekels to the ‘other’, while GG or GT gave on average 25 shekels to the other  About 14% of the global population has the TT genotype.
In romantic relationships, the TT genotype was associated with less empathic concern for their partner’s distress, lower social reciprocity in a support-giving interaction, and less persistence in attending to their partner’s communication and maintaining focus on providing support .
G is social allele at rs237887 , but as you’ll see the effects are mixed for this.
AG and AA (both 18.1) had the highest empathy in “perspective taking” (a tendency of placing yourself in the position of others) compared to GG (16.0) .
GG had the highest level of “personal distress” empathy (16.8) (subjective feelings when observing the anguish and pain endured by others) compared to AA (15.3) and AG (14.4) .
GG had the highest “Fantasy” empathy (18.5) (the extent to which people can immerse themselves in the conditions of the fictitious characters’ feelings and actions) compared to both AA and AG (15.1). Fantasy empathy probably is a factor in how much you like novels .
About 66% of the global population will have either GG or AG and about 34% of the global population has the AA version (less social).
At rs13316193, CC or CT has been associated with empathy, whereas TT (the risky version) has been linked to decreased expression of oxytocin receptors in the brain, depressive mood and greater risk for Autism .
~48% of the population has CT, ~36% has TT and 16% has CC (C=0.40)…
In romantic relationships, the TT genotype was associated with less empathic concern for a partner’s distress, lower social reciprocity in a support-giving interaction, and less persistence in attending to their partner’s communication and maintaining focus on providing support .
But based on a different study, total empathy wasn’t really different in most situations between groups. However, CT was associated with the most empathy in women .
At rs2268491, CT had the highest level of empathy (IRI=68.7), followed by TT (65.8) and then CC (60.7) .
The same was true for “cognitive empathy,” which is simply knowing how the other person feels and what they might be thinking. 59% of the population has CT, 32% have TT and 9% have CC .
According to one study, AG was the most empathetic genotype of rs2254298 (IRI=70.8), while GG and AA were equal in total empathy (~65.4). In cognitive empathy (putting yourself in someone else’s situation), AG (35.9) was the highest followed by GG (34.2) and AA (32.8) .
The A allele has been linked to lower risk for autism, depression and separation anxiety and with amygdala volume increase in both European and Asian populations .
In romantic relationships, the GG version was associated with less empathic concern to their partner’s distress, displayed lower social reciprocity in a support-giving interaction, and persisted less in attending to their partner’s communication and maintaining focus on providing support . This was based on observed behavior rather than self-reports. This study was looking at a group of genes in total, so it’s best not to read into it too much.
About 64% of the global population has GG, which is the less social version and 36% have either AA or AG (A=0.20).
Men with CC at rs4686302 were the most empathetic, especially with emotional empathy, and CT the least. Women with CT and TT were the most empathetic, by contrast. 49.5% of the population has CC, 27% has CT and 24% has TT .
At rs2268494, the TT genotype is associated with increased prosocial behavior. About 86% of the global population has TT. The A allele, which is not common (A=.07), was associated with risk for autism, which suggests lower oxytocin or less efficient oxytocin receptors .
In romantic relationships, people with the AA genotype experienced less empathic concern for their partner’s distress, displayed lower social reciprocity in a support-giving interaction, and persisted less in attending to their partner’s communication and maintaining focus on providing support .
The SNP rs237897 was significant only in men with regard to empathy/kindness (dictator game and social value orientation) .