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Scientists Create New Improved “Love Hormone” Without The Unwanted Side Effects


Stephen Luntz

Stephen has a science degree with a major in physics, an arts degree with majors in English Literature and History and Philosophy of Science and a Graduate Diploma in Science Communication.

Freelance Writer

This natural oxytocin molecule triggers four types of receptors in the human body but by changing three atoms, a molecule can be made that triggers some of these and not others. Molekuul_be/Shutterstock

Oxytocin, often known as the “love hormone” has earned itself a cult following in recent times. Thrilled by the positive feelings it induces in people, they get its structure as tattoos or necklaces. But great as it is, it also has side-effects, so a team at the University of Queensland decided to see if they could make a modified version that would provide all the good things without those drawbacks. Now they think they're on the road to success.

The body often repurposes the same molecule to fill multiple roles, and oxytocin is no exception. It bonds us to romantic partners, eases social interactions and assists in the process of giving birth, to name just three. Unfortunately, according to Dr Markus Muttenthaler of UQ, “Oxytocin... can [also] have serious side effects such as cardiovascular problems or uterine rupture when used for too long or at a too-high dose."


Muttenthaler and colleagues modified oxytocin to create what he calls “a small library” of similar but slightly different molecules and tested their effects. Replacing the disulfide bond with diselenide and a nitrogen atom with an oxygen created a new molecule that triggers receptors more selectively. “It didn’t activate heart muscle cells, and produced a more regular contraction pattern in uterine tissue, which indicates improved safety for mother and baby,” Muttenthaler said in a statement.

Muttenthaler explained to IFLScience the molecule works because the body has four different types of receptors that respond to oxytocin. A molecule that only triggers one of these induces certain responses without others. The practicality of this particular modification was demonstrated by reducing social fear in mice, while having no effect on heart cells.

Oxytocin is being studied for a variety of applications, including improving learning in children with autism and softening hard hearts. There could soon be strong demand for a substitute that can achieve the same positive effects, but be safe for long-term use.

The work has been published in Science Signaling, but Muttenthaler told IFLScience there is a long way to go before the modified molecule will be available for use. When that point comes, it may well not involve the exact molecule produced so far. “The main short-term outcome is a molecular tool for further study,” Muttenthaler said. So far experiments have only been done on mice, and far more work is required before it will even be ready for clinical trials.


“As an academic lab, we do the hard yards in terms of discovery,” Muttenthaler told IFLScience. “Then we will need partnerships to move forwards.”

Fortunately, chemical synthesis of this particular modification is relatively easy, and hopefully the same will be true of other similar but different molecules.


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  • Oxytocin,

  • receptors,

  • love hormone,

  • molecular modifications