Endorphin

What is endorphin?

Endorphin (Dutch: endorfine) is a natural opioid the body releases under pain and stress, and that adjusts pain perception, mood and reward. Endorphins arise from the precursor protein POMC, which is made mostly in the anterior lobe of the pituitary. Beta-endorphin is the best-known form. In BDSM explanations endorphin gets the credit for the high during a scene; that link has never been shown.

What endorphin has to do with a BDSM scene

In the explanation you run into everywhere: everything. In the measurements: far less.

The familiar story goes like this. During an intense scene the body floods with endorphin and adrenaline, that gives the floating high people call subspace, and when those substances drain away afterward the crash follows. You find that explanation on hundreds of pages, including the nineteen blog articles on this site where the word appears.

Sprott and Randall looked into it in Journal of Positive Sexuality and conclude that no research exists that has ever tested that physiological explanation of the dip right after a scene. The story gets copied from one to the next. That does not make it untrue, but it does make it unproven, and that is something else.

How endorphin works

Endorphin is a peptide that acts on the same receptors as morphine, and that your body makes itself. The StatPearls description puts it briefly: endorphins arise from POMC, a prohormone made mostly in the anterior lobe of the pituitary, and they adjust pain perception, mood and reward pathways. Beta-endorphin is the longest and physiologically most important form of them.

Now the problem the familiar story runs aground on. What you measure in blood does not have to reach your head. Siebers, Biedermann and Fuss argue in The Neuroscientist that endorphin in the bloodstream has no large effect on the brain, because its water-loving build keeps it from crossing the blood-brain barrier. Endocannabinoids are fat-loving, do get through, and are therefore the better candidate.

The same research group tested that in people. In a double-blind, randomized study with 63 participants they blocked the opioid receptors with naltrexone and had the participants run for 45 minutes. The euphoria came anyway, the anxiety dropped anyway, and the share of participants who reported a runner’s high was comparable in the naltrexone group and the placebo group. Their conclusion: in humans that high does not depend on opioid signaling.

What has actually been measured in BDSM, and what it gives you

One research group has asked exactly this question. Wuyts and colleagues tested 35 BDSM couples during a real interaction, alongside 27 people without BDSM interest in an ordinary social conversation, and tracked cortisol, beta-endorphin and the endocannabinoids 2-AG and anandamide.

So beta-endorphin was in there. In the reported outcomes it does not come back: those show that the submissive participants displayed a rise in cortisol and in endocannabinoids, and that the dominant participants displayed only more endocannabinoids when power play was involved. The review article the same group wrote two years later, across ten studies together, arrives at the same list: cortisol points to the stress system, endocannabinoids to the pleasure and reward system.

What does it give you?

• For the one receiving, the explanation shifts from “my endorphin is draining away” to something that was measured: stress that builds and then has to come back down.
• For the one in charge, it is useful to know that the measurable yield on that side hung on power play and not on pain.
• For a couple, it saves you false certainty. Explaining a dip with chemistry sounds reassuring and probably is not right.

None of this proves that endorphin plays no role. Blood values say little about what happens in the brain, the BDSM study was a pilot with Flemish participants, and the authors themselves note that the scale is limited.

Misconceptions about endorphin

“The high during a scene is an endorphin rush.” Never shown. In the only study that included beta-endorphin during BDSM, only cortisol and endocannabinoids come back in the outcomes.

“Endorphin explains the dip afterward.” Sprott and Randall point out that the described hormone changes play out in minutes and not in days. Their explanation for the late crash is at drop.

“What holds for runners holds here too.” True, but differently than people think: in runners the high actually stayed intact while the opioids were blocked.

“Endorphin and adrenaline are two sides of the same reaction.” They are different substances with their own route. What has been measured about that other one is at adrenaline.

What I see of it myself

I am Victor, a gigolo, twenty-five years in BDSM and trained as a psychotherapist. I used the word endorphin myself for years to explain what was happening. I do not do that anymore.

It makes people calmer, not more restless. “Your stress hormone has risen and has to come back down, and time and company help with that” lands better than a story about substances no one can check.

The practice matches the measurements just fine, by the way. Receiving costs more than it looks, and the bill comes not during but after. On a bdsm date I therefore plan that time afterward just as deliberately as the scene itself.

What you can do yourself

• Do not use the word endorphin as an explanation for what you feel; it explains something no one has measured.
• Look at the build-up instead of the substance. Starting slow works, and that is a reason to warm up even when the chemistry behind it is unclear.
• Treat a dip as stress that has to come down, with food, warmth and company, and not as a shortage you have to top up.
• Be suspicious of any page that knows exactly which substance does what, because the only BDSM study that measured it reports something else.
• Ask afterward how it is going and do it again two days later, because that is the measure that does rest on something.

Read more about endorphin

On this site you will find what has been measured about that other substance at adrenaline, the crash itself at drop, and the care around it at aftercare.

Off this site, the review article by Wuyts and Morrens is the best starting point: it brings together all ten studies that have ever measured a biomarker in BDSM, and is honest about how thin that stack still is.

Sources

• Between Pleasure and Pain: A Pilot Study on the Biological Mechanisms Associated With BDSM Interactions in Dominants and Submissives. Wuyts, De Neef, Coppens, Fransen, Schellens, Van Der Pol & Morrens, The Journal of Sexual Medicine 17, 784–792, 2020. 35 BDSM couples plus 27 control participants; cortisol, beta-endorphin and the endocannabinoids 2-AG and anandamide were tracked, and the outcomes show only the rise in cortisol and endocannabinoids in submissives and in endocannabinoids in dominants during power play.
• The Biology of BDSM: A Systematic Review. Wuyts & Morrens, The Journal of Sexual Medicine 19, 144–157, 2022. Ten studies brought together; cortisol changes in submissives point to the stress system, endocannabinoid changes to the pleasure and reward system.
• Exercise-induced euphoria and anxiolysis do not depend on endogenous opioids in humans. Siebers, Biedermann, Bindila, Lutz & Fuss, Psychoneuroendocrinology 126, 105173, 2021. 63 participants, double-blind and placebo-controlled; blocking the opioid receptors with naltrexone did not prevent the euphoria and the drop in anxiety after 45 minutes of running.
• Do Endocannabinoids Cause the Runner’s High? Evidence and Open Questions. Siebers, Biedermann & Fuss, The Neuroscientist 29(3), 352–369, 2023. Provides that endorphin in the bloodstream does not cross the blood-brain barrier because of its water-loving build and therefore has little effect on the brain, while endocannabinoids do.
• Biochemistry, Endorphin. Chaudhry & Rahimi, StatPearls, updated 2025. Provides that endorphins arise from the prohormone POMC in the anterior lobe of the pituitary, that they adjust pain perception, mood and reward pathways, and that beta-endorphin is the longest and physiologically most important form.
• Black and Blues: Sub Drop, Top Drop, Event Drop and Scene Drop. Sprott & Randall, Journal of Positive Sexuality 2, 2016. Provides that no research exists that has ever tested the physiological explanation of the immediate crash, and that the described hormone changes play out in minutes and not in days.

Related terms

• Adrenaline. The other substance from the same story, with what has been measured about it.
• Drop. The crash often attributed to endorphin.
• Aftercare. What does help once the scene is over.
• Domspace. The state on the giving side, measured as flow and not as chemistry.
• Warm-up. The phase endorphin is most often attributed to, and what happens instead.
• Pain threshold. The threshold that does measurably rise during a scene.
• Subspace is the closest neighbor.