Love and Peptides

By George Gillson MD PhD CCFP

Here at the EvolveWell clinic, Sexual Health has been designated as the official clinic theme for the month of February.

Things were looking a little grim when we sat down early in January to plan out the monthly clinic themes for 2023. With January being designated as Pelvic Health month and February as Sexual Health month I felt some trepidation.  What in the heck was I going to talk about in February without repeating what I already said in January? I was sitting there, kind of stumped, when suddenly the Angel of Peptide Chemistry appeared, kissed me on the cheek and the word oxytocin popped into my head!

Everybody knows that oxytocin (OT) is a peptide neurohormone or hormone produced by specialized neurons in the posterior pituitary, typically located in the brain. Among its many other jobs, OT stimulates contractions of the uterus and in Greek, oxytocin is roughly translated as “swift childbirth”. OT was the first polypeptide to be synthesized and won a Nobel Prize in 1955 for American biochemist Vincent du Vigneaud. Not that you care.

Oxytocin is commonly known as the hormone of love (and breastfeeding) but it has its metaphorical fingers in a lot of other pies including, in no particular order: empathy, chocolate, pair bonding, orgasm, generosity, wound healing, cardiac health, cuddling, childbirth, ejaculation, dogs, natural anti-depressant effect, flowers, and last but not least, Sleepless In Seattle. I swear that I made up no more than 6.7% of the items on that list.

I’m not going to get into the many fascinating biochemical ways that oxytocin plays a role in survival. I’ll let Christian Gruber, a researcher at the Center for Physiology and Pharmacology, Medical University of Vienna, have the stage:

“In humans and other mammalian species, oxytocin and vasopressin mediate a range of peripheral and central physiological functions that are important for osmoregulation, reproduction, complex social behaviors, memory and learning. The origin of the oxytocin/vasopressin signaling system is thought to date back more than 600 million years. All vertebrate oxytocin- and vasopressin-like peptides have presumably evolved from the ancestral nonapeptide vasotocin by gene duplication and today are present in vertebrates, including mammals, birds, reptiles, amphibians and fish. Oxytocin- and vasopressin-like peptides have been identified in several invertebrate species, including molluscs, annelids, nematodes, politicians and arthropods.”

In short, oxytocin and its close relatives are important for life on Earth. I just can’t get into the details.

I DO need to get into the “chocolate and oxytocin” problem, though. Many websites I visited in my research for this article stated that chocolate consumption boosts OT. Try as I might though, I couldn’t locate a single paper which measured OT before and after eating chocolate.

I also found a site hosted by the McGill University Office for Science and Society (Motto: If There’s A Parade, We’ll Rain On It) which debunked the notion that chocolate is also an aphrodisiac:

I did, however, find a small unpublished study sponsored by Bloom & Wild, a flower delivery business located somewhere in England. The researchers determined that simply receiving a gift of chocolate increased the level of OT in saliva.  Furthermore, a chocolate gift had a larger effect on OT compared to receiving a gift of flowers or-wait for it-a gift bottle of water.

Two points for Science!

There are pharmaceutical options to boost OT in the form of prescription injections and nasal spray but in the words of neuroscientist Bianca Jones Marlin: “Why would anyone buy it?…If you want more oxytocin, just go hug someone.”

She’s right.

I have nothing against Integrative/Functional Medicine, having spent the last 25+ years in the field.  Knowledge of biochemical pathways, peptides, enzymes, neurotransmitters, nutrients, cofactors, hormones, etc. is important to help us lead long, healthy and productive lives, chock full of oxytocin. But the longer I study the biochemistry, the more I keep coming back to the essential aspects of longevity/health maintenance that we’ve known about since we walked the Earth.  And they’re free.

Here’s the list of free oxytocin-boosting strategies:


-Welcome touch (especially skin-to-skin)

-Nipple stimulation (look it up if you don’t believe me)

-Sun exposure


-Petting your dog, cat, iguana, etc.



-Gift receiving


-Daydreaming about your lover

-Listening to pleasant music

-Watching romantic comedies

-Making love (hammock optional)

The thing is, the more you do the activities listed above, the more you want to do them. OT is addictive.

Image credit

The other nugget of wisdom was to always ask men about their erections, as erectile dysfunction (ED) is a gauge of the overall health of the cardiovascular tree.

These are still great pieces of advice but the problem with the erection nugget is that it is male-centric. I was talking to my wife, Jeanette, who incidentally also happens to be the owner of EvolveWell clinic, about what to write for this post. I commented that we recognize the connection that ED has to cardiac health in males but nobody says a word about cardiac health and the possible effects on perfusion of female genitalia.

Jeanette said, “Oh my gosh,” and began typing busily at the keyboard of her computer.  Seconds later, this appeared in my inbox:

Just don’t forget the chocolate and flowers, thanks to Bloom & Wild’s ground-breaking study. Remember. Valentine’s Day is right around the corner!

Interesting Links


George Gillson MD PhD

Author: George Gillson, MD, PHD, CCFP
EvolveWell Medical Director


de Boer A, van Buel EM, Ter Horst GJ. Love is more than just a kiss: a neurobiological perspective on love and affection. Neuroscience. 2012 Jan 10;201:114-24. doi: 10.1016/j.neuroscience.2011.11.017. Epub 2011 Nov 15. PMID: 22119059.

Fujii T, Schug J, Nishina K, Takahashi T, Okada H, Takagishi H. Relationship between Salivary Oxytocin Levels and Generosity in Preschoolers. Sci Rep. 2016 Dec 8;6:38662. doi: 10.1038/srep38662. PMID: 27929138; PMCID: PMC5144141.

Gruber CW. Physiology of invertebrate oxytocin and vasopressin neuropeptides. Exp Physiol. 2014 Jan;99(1):55-61. doi: 10.1113/expphysiol.2013.072561. Epub 2013 Aug 16. PMID: 23955310; PMCID: PMC3883647.

Wasserman AH, Huang AR, Lewis-Israeli YR et al. Oxytocin promotes epicardial cell activation and heart regeneration after cardiac injury. Front Cell Dev Biol. 2022 Sep 30;10:985298. doi: 10.3389/fcell.2022.985298. PMID: 36247002; PMCID: PMC9561106.