Chemical Attraction: The Science of Love
Love is in the brain of the beholder, literally! It’s measurable in brain chemical levels and even visible on imaging technology. Knowing where love begins and ends is leading to new and potential treatments for sexual dysfunction, anxiety,1 depression1 and substance abuse.2 Discoveries are also helping support greater sexual satisfaction and helping strengthen romantic relationships.
What’s Known About Love
- It’s in your brain but not your “head,” meaning it’s real and universal. Similar definitions of love and its experience exist in every human culture.3
- It serves multiple purposes beyond sexual reproduction.
- Although “love addiction” is not a formal medical diagnosis, new love’s euphoria involves dopamine and brain chemicals that drive motivation and reward neural pathways. Some people can’t get enough of it and chase the high!
- Monogamy may ultimately be a choice, but it's highly promoted by brain chemicals.
Stages of Love
Depending on which study you read, love has 2-4 stages. Regardless, consensus is romantic love mainly involves the brain’s happy hormones - dopamine, oxytocin, serotonin and other neurohormones kisspeptin and vasopressin.
For the purposes of this blog, we’ll focus on two of the stages of love: lust and attachment.
Stage 1: Lust: Two people meet and if they are drawn together romantically, dopamine is at work. It creates pleasure and your brain wants more of it. Sex guarantees it. That’s why dopamine is essential for reproduction.
Stage 2: High levels of dopamine and related serotonin and other endorphins return to normal. You “return to earth” and the "cuddle hormone" oxytocin takes over. It builds trust and creates a bond. This is when you decide to stay together for the long haul. Kisspeptin and vasopressin also appear to promote partner preference and monogamy.4,5
Two studies using imaging technology showed kisspeptin administration in males increased brain activity related to monogamy, reward, motivation, mood, sexual response, and visual6 and olfactory cues that drive attraction to females 7
Nasal Oxytocin’s Impact On Couple’s Sexual Satisfaction
The sexual response cycle has four stages: desire, arousal, excitement and resolution. Oxytocin levels build during the first two stages then plateaus in stage 3, the orgasm. In stage 4 resolution, the brain releases oxytocin. Each person feels sexually satisfied and filled with bliss. Bonding develops and strengthens.
In a study of 29 healthy heterosexual couples intranasal administration of oxytocin before sex increased itensity of orgasm and contentment after sexual intercourse in both partners, especially men.8 Additionally, women also reported feeling more relaxed and able to communicate their desires.8
In two separate case studies, intranasal oxytocin successfully treated males with sexual dysfunction. In each case, the doctor’s attributed the outcome to oxytocin’s role in enhancing intimacy.9,10
Oxytocin’s Effect on Couple Communication and Conflict Resolution
Another study of oxytocin recorded higher oxytocin levels in new couples than single individuals. Additionally in couples, reciprocated behavior such as affectionate touch and attention increased oxytocin levels.12
Oxytocin may also serve as a crisis hormone aimed at rescuing struggling relationships.13 Researchers measured changes in oxytocin levels in 223 couples when they thought about their partner. Each partner registered increased levels but oxytocin rose more in partners with greater emotional stake. They reported that the study supported their hypothesis of “identify and invest," meaning when one partner suspects that the other is less interested, oxytocin motivates that partner to work harder to bring the other along.
4 Ways to Use Your Neuropeptides to Strengthen Your Romantic Connection
- Give each other massages: Physical touch increases dopamine, serotonin and oxytocin and reduces the "stress" hormone cortisol.14,15
- Address sexual dysfunction in your relationship and seek resolutions. Male and female sexual dysfunction have a wide range of causes including physical illness, psychological issues, stress, anxiety and many more. Several studies show, when one partner with sexual dysfunction is successfully treated, sexual satisfaction may increase in the other. It may also create a synergistic effect that enhances the success of the medication.
In one study, men treated with tadalafil (Cialis) reported their partner’s increased sexual satisfaction boosted their confidence, mood and mental health.16 Another study involved women with sexual dysfunction whose partners had ED. The study reported that successful treatment of ED with Viagra (sildenafil) and tadalafil improved the women’s sexual satisfaction and experience.17
- Activate melanocortin receptors in the brain with PT-141 to treat sexual dysfunction. PT-141 (bremelanotide) is a lab-made peptide that stimulates melanocortin receptors in the brain. It is FDA-approved as an injection under the brand name Vyleesi to treat female Hypoactive Sexual Desire Disorder (HSDD). HSDD is defined as consistent lack of sexual fantasies and thoughts, desire for sex or arousal from sexual activity that causes that caused distress or interpersonal difficulties.
Additionally, studies show PT-141 nasal spray and PT-141 injection may successfully treat ED in men.18 Studies involving and injection report similar outcomes. PT-141 offers promise to treat sexual dysfunction in men and women who have not had success with the PDE5 inhibitors Viagra (sildenafil) and Cialis (tadalafil), or can't take them.
- Protect hypothalamic health. The hypothalamus produces dopamine, vasopressin, oxytocin and gonadotropin-releasing hormone (GnRH). GnRH stimulates the pituitary gland to produce and secrete luteinizing hormone (LH) and follicle stimulating hormone (FSH). LH and FSH modulate fertility, estrogen and testosterone production. Regular exercise, maintaining healthy weight and getting enough quality sleep help maintain hypothalamic health. Women with low estrogen and/or testosterone may have low libido. Maintaining healthy testosterone levels is key to male sexual function.
- Exercise together. Working out increases oxytocin. Double the benefits by doing it together!
Fun fact: The gene KISS1, which is responsible for encoding kisspeptin, got its name from Hershey Kisses.19
According to the Meriam-Webster dictionary, the history of the word kiss is not related. Kiss comes from Old English cyssan; similar to Old High German kussen to kiss, which means to press lips together.
So there you have it. As if you didn't know, love is quite complicated. The good news is your brain is all in favor of it. So pop a Hershey's Kiss and repeat stage 1.
1 Behnia B, et al. Differential effects of intranasal oxytocin on sexual experiences and partner interactions in couples. Horm Behav. 2014 Mar;65(3):308-18. doi: 10.1016/j.yhbeh.2014.01.009. Epub 2014 Feb 3. PMID: 24503174.De Cagna F, Fusar-Poli L, Damiani S, et al. The Role of Intranasal Oxytocin in Anxiety and Depressive Disorders: A Systematic Review of Randomized Controlled Trials. Clin Psychopharmacol Neurosci. 2019;17(1):1-11. doi:10.9758/cpn.2019.17.1.1
2 Lee MR, Weerts EM. Oxytocin for the treatment of drug and alcohol use disorders. Behav Pharmacol. 2016;27(8):640-648. doi:10.1097/FBP.0000000000000258
3 Karandashev, V. (2015). A Cultural Perspective on Romantic Love. Online Readings in Psychology and Culture, 5(4). https://doi.org/10.9707/2307-0919.1135
4 Yang, L., Comninos, A.N. & Dhillo, W.S. Intrinsic links among sex, emotion, and reproduction. Cell. Mol. Life Sci. 75, 2197–2210 (2018). https://doi.org/10.1007/s00018-018-2802-3
5 Carter CS. The Oxytocin-Vasopressin Pathway in the Context of Love and Fear. Front Endocrinol (Lausanne). 2017;8:356. Published 2017 Dec 22. doi:10.3389/fendo.2017.00356
6 Comninos AN, Wall MB, Demetriou L, et al. Kisspeptin modulates sexual and emotional brain processing in humans. J Clin Invest. 2017;127(2):709-719. doi:10.1172/JCI89519
7 Yang L, Demetriou L, Wall MB, et al. Kisspeptin enhances brain responses to olfactory and visual cues of attraction in men. JCI Insight. 2020;5(3):e133633. Published 2020 Feb 13. doi:10.1172/jci.insight.133633
8 Behnia B, et al. Differential effects of intranasal oxytocin on sexual experiences and partner interactions in couples. Horm Behav. 2014 Mar;65(3):308-18. doi: 10.1016/j.yhbeh.2014.01.009. Epub 2014 Feb 3. PMID: 24503174.
9. IsHak WW, Berman DS, Peters A. Male anorgasmia treated with oxytocin. J Sex Med. 2008 Apr;5(4):1022-1024. doi: 10.1111/j.1743-6109.2007.00691.x. Epub 2007 Dec 14. PMID: 18086171.
10. Dr. Ananya Mandal M. Oxytocin may offer hope for male sexual dysfunction. News-Medical.net. https://www.news-medical.net/news/20120410/Oxytocin-may-offer-hope-for-male-sexual-dysfunction.aspx. Published 2021.
11. Ditzen B, et al. Intranasal oxytocin increases positive communication and reduces cortisol levels during couple conflict. Biol Psychiatry. 2009 May 1;65(9):728-31. doi: 10.1016/j.biopsych.2008.10.011. Epub 2008 Nov 22. PMID: 1902710
12. Schneiderman I, Zagoory-Sharon O, Leckman JF, Feldman R. Oxytocin during the initial stages of romantic attachment: relations to couples' interactive reciprocity. Psychoneuroendocrinology. 2012 Aug;37(8):1277-85. doi: 10.1016/j.psyneuen.2011.12.021. Epub 2012 Jan 26. PMID: 22281209; PMCID: PMC3936960.
13. Norwegian University of Science and Technology. (2017, May 18). Love hormone is released during crises: When you notice your partner is less interested than you are, your brain may send out a hormone that can help you fix the relationship. ScienceDaily. Retrieved from www.sciencedaily.com/releases/2017/05/170518104023.htm
14. Morhenn V, Beavin LE, Zak PJ. Massage increases oxytocin and reduces adrenocorticotropin hormone in humans. Altern Ther Health Med. 2012 Nov-Dec;18(6):11-8. PMID: 23251939.
15. British Psychological Society. "Rub each other up the right way: Couples massage relieves stress." Retrieved from www.sciencedaily.com/releases/2017/05/170503213543.htm.
16. Seftel, A., Buvat, J., Althof, S. et al. Improvements in confidence, sexual relationship and satisfaction measures: results of a randomized trial of tadalafil 5 mg taken once daily. Int J Impot Res 21, 240–248 (2009). https://doi.org/10.1038/ijir.2009.22
17. Conaglen, H., O'Connor, E., McCabe, M. et al. An investigation of sexual dysfunction in female partners of men with erectile dysfunction: how interviews expand on questionnaire responses. Int J Impot Res 22, 355–362 (2010). https://doi.org/10.1038/ijir.2010.25
18. Diamond, L., Earle, D., Rosen, R. et al. Double-blind, placebo-controlled evaluation of the safety, pharmacokinetic properties and pharmacodynamic effects of intranasal PT-141, a melanocortin receptor agonist, in healthy males and patients with mild-to-moderate erectile dysfunction. Int J Impot Res 16, 51–59 (2004). https://doi.org/10.1038/sj.ijir.3901139
19. Gottsch ML, Clifton DK, Steiner RA. From KISS1 to kisspeptin: An historical perspective and suggested nomenclature. Peptides. 2009;30(1):4-9. doi:10.1016/j.peptides.2008.06.016