Essentials: The Science of Love, Desire & Attachment

Welcome to Huberman Lab Essentials where we revisit past episodes for the most potent and actionable science based tools for mental health, physical health and performance. I'm Andrew Huberman and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. Today we are going to talk about the psychology and the biology of desire, love and attachment. One of the most robust findings in the field of psychology is this notion of attachment styles. And this was something that was discovered through a set of studies that were done by Mary ainsworth in the 1980s in which she developed a laboratory condition called the strange situation task. The strange situation task involves a parent, typically a mother in the studies that were done, but a parent or other caregiver bringing their child, their actual child, into a laboratory. And there's a room with a stranger and the mother enters the room with the child and there's some toys in the room. And typically the mother and the stranger will talk. Obviously the stranger is part of the experiment. It's not just some random person off the street. And the child is allowed to move about the room. They can play with toys or not. But then at some point the mother leaves and then at some point later, designated by the experimenter, the mother comes back. And what is measured in these studies is both how the child, the toddler, reacts to the mother leaving and how the child reacts to the mother returning at the end of the experiment. So there are a lot of variations of this, but the basic findings are that toddlers children fall into four different categories of attachment style. The first style is the so called secure attachment style. First, the secure attachment style is one in which the child will engage with the stranger with the experimenter while the parent is present in the room, but that when the parent or other caregiver leaves, the child does get visibly upset. However, when the caregiver meaning the mother or father or other caregiver returns, the child visibly expresses happiness that the caregiver has returned. And the interpretation of this is that the secure child feels confident that the caregiver is available and will be responsive to their needs and their communications. These children are also very good at exploring novel environments after the parent is gone and while the parent is there. The second category is the so called anxious, avoidant or insecurely attached. They do not exhibit distress on separation anxious and they generally tend to have some tendency to approach the caregiver when they return, but there doesn't seem to be a general expression of joy. The third category is the so called anxious Ambivalent, resistant, insecure category. The anxious, ambivalent, resistant, insecure Toddlers really show distress even before separation from their mother or other caregiver. And they tend to be very clingy and difficult to comfort when the caregiver returns. And the third category of attachment style is the so called disorganized or disoriented or D for the letter D babies. It seems like these children just don't really know how to react to a separation and they just start to manifest behaviors and emotional tones that aren't observed in other situations. Now, what's interesting about this from the perspective of desire, love and attachment is that the categorizations of children into one of these four different categories as toddlers is strongly predictive of their attachment style in romantic partnerships later in life, which is, to me, both amazing and surprising, and not surprising all at the same time. The good news is that these templates can shift over time. And one of the more powerful ways to shift those templates over time is, is purely by the knowledge that they exist and the understanding that those templates are malleable. So I mentioned that the neural circuits for child, parent or child caregiver attachment are repurposed for romantic attachment later in life. But what are these neural circuits? What do they do? I mean, it's so attractive, if you will, to think about a brain area that controls love, or a brain area that controls desire, or a brain area that controls attachment. But it simply doesn't work that way. Instead, there are multiple brain areas that through their coordinated action, create a sort of a song that we call desire, or a song that we call love, or a song that we call attachment. Not a literal song, but rather different brain areas being active in different sequences and with different intensities can make us feel as if we are in the mode that we call desire, in the mode of love or in the mode of attachment. But beneath all of that is this element of autonomic arousal. So the way to think about the autonomic nervous system is it's kind of a seesaw. We can be alert and calm, or we can be very, very alert. We can be in a state of panic. We can be fast asleep, so we can be extremely calm, or we can just be kind of sleepy, semi calm, but still also alert. So think about it like a seesaw. And that seesaw has a. A hinge. And that hinge defines how tight or loose that seesaw is, how readily it can tilt back and forth. Our autonomic tone is how tight that hinge Is. And there are biological mechanisms to explain this. But here I just want to stay with the analogy of the seesaw for now. The interactions between child and caregiver early in life take the child and the caregiver from one end of the seesaw to the other. From being very alert in a state of play, for instance, to being nursed and being very soothed until we go to sleep. And of course, we each have a seesaw. The parent and the child has a seesaw and they're interacting. What do I mean by that? Well, there are beautiful studies and beautiful not in the sense that they focused on a pleasant topic, but beautiful because they were done so beautifully. Well, that looked at, for instance, the response of mothers and their physiologies and the response of children and their physiologies to during the bombing of cities during World War II. So an unpleasant situation. But what was revealed during the course of these studies was that if the mothers were very stressed during an onslaught of bombing of the city, the children's physiologies tended to be stressed also and persisted in being stressed long after that stressful episode was done. They actually followed that these children well out for many decades afterwards. Conversely, if the parent, and in this case again, it was mothers that were explored in these studies had turned this whole business of going into the bomb shelters into somewhat of a game, all right, taking it seriously, but essentially telling the children, okay, it's time to go, but not expressing much stress or distress. The children also didn't develop much stress or distress or trauma. Now, there were exceptions to this, of course, but in general that was the rule that the autonomic nervous systems of children tend to mimic the autonomic nervous systems of the primary caregiver. I'd like to take a quick break and acknowledge our sponsor, eight Sleep. Eight Sleep makes smart mattress covers with cooling heating and sleep tracking capacity. One of the best ways to ensure you get a great night's sleep is to make sure that the temperature of your sleeping environment is correct. And that's because in order to fall asleep and stay deeply asleep, your body temperature actually has to drop by about 1 to 3 degrees. And and in order to wake up feeling refreshed and energized, your body temperature actually has to increase by about 1 to 3 degrees. 8 Sleep automatically regulates the temperature of your bed throughout the night according to your unique needs. I've been sleeping on an eight sleep mattress cover for nearly five years now, and it has completely transformed and improved the quality of my sleep. The latest eight sleep model is the Pod 5. This is what I'm now sleeping on and I absolutely love it. It has so many incredible features. For instance, the Pod 5 has a feature called autopilot, which is an AI engine that learns your sleep pat and then adjusts the temperature of your sleeping environment across different sleep stages. It'll even elevate your head if you're snoring and it makes other shifts to optimize your sleep. If you'd like to try Eight Sleep, go to Eight Sleep.comhuberman to get up to $350 off the new Pod 5. Eight Sleep ships to many countries worldwide, including Mexico and the UAE. Again, that's Eight Sleep.comhuberman to save up to $350. So if I were to offer a set of tools around these topics of desire, love, and attachment, I would say first of all, you might want to think about whether or fall into the secure, insecure or other attachment styles. Second, I think it is vitally important for all of us, but certainly for people that are in relationships or seeking relationships, to be able to at least have some recognition of where our autonomic nervous system tends to reside, both in terms of when we are with somebody and when they leave. When we are apart for long periods of time, can we calm ourselves? Can we self soothe? Or are we very much dependent on the presence of another in order to feel soothed? Now, I absolutely want to emphasize that there is nothing wrong. In fact, there's everything right with feeling great in the presence of somebody else. That is actually a hallmark of strong and quality attachments. A key element of healthy interdependence is that yes, our autonomic nervous system is adjusted by the presence of another, but that also that we can adjust our own autonomic nervous system even in the absence of that person. So if the autonomic nervous system is one key component of desire, love, and attachment, what are the other two? Not surprisingly, the dopamine system in the brain is associated with desire, love and attachment, and mainly with desire, although to some extent love. Dopamine is a neurochemical sometimes associated with reward, but as some of you have heard me say before, it is mainly a molecule of motivation, craving and pursuit. And that motivation, craving and pursuit that relates to dopamine is not unique to attachment or love or sex or mating, et cetera. It is a universal generic currency in the brain for pursuing something. I want to just discuss the two neural circuits that use dopamine, that use serotonin and oxytocin and that collaborate with the autonomic nervous system to drive what we call desire, love and attachment. And the three circuits are. Autonomic nervous system. We talked about that one. Then there's the nervous system components, or the neural circuits for empathy, for being able to see and respond to and indeed match the emotional tone or the autonomic tone of another. And then there's the third category. And this might surprise some of you, it certainly surprised me. But the data point to the fact that the third neural circuit that's very important for establishing bonds is, is one associated with positive delusions. So given that the neural circuits for empathy are absolutely crucial for falling in love and maintaining stable attachments, I'd like to talk about those neural circuits and what they are. Now. Often when we hear empathy, we think, oh, empathy is really about listening to and really understanding what somebody else is feeling, maybe even feeling what they're feeling. And indeed that's the case. But what do we mean by that? Right. What is it to feel what another feels? Well, what it means is that their seesaw is driving your seesaw or your seesaw is somehow driving their seesaw. That's a form of empathic matching. And there are indeed neural circuits for that. The neural circuits for empathy. Again, there are many, but mainly two structures that you should know about. The prefrontal cortex, which is how we perceive things outside of us and make decisions on the basis of those perceptions, how we organize those decisions, and an area of the brain called the insula. I N S U L A the insula is a really interesting brain area that allows us to interocept, to pay attention to what's going on inside our body and to split some of our attention to exterocept. And the insula is essentially splitting one's attention between how we feel ourselves, how our body feels, what we're thinking with the thinking and the bodily sensations of the other. Okay, so we have the autonomic nervous system, and then we have this thing that we're calling empathy, which is really about autonomic matching. And again, the insula and the prefrontal cortex are neural circuits that are crucial for autonomic matching because they allow us to say what's out there and do I want to match to it or not? Okay, and then the third category is the neural circuit associated with self delusion. What do we mean by positive delusion? Positive delusion is belief that only this person can make me feel this way. Now, positive dilution is critical if you look at the stability of relationships over time. What you find is that there are some key features of interactions between individuals that predict that a relationship will last. And. And those are many, but mainly fall under this category of positive delusions. I'll return to those and what those exactly look like. But there are also just a handful of things that predict that a relationship will fail over time. This is largely the work of the Gottmans. It's actually a husband and wife team up at the University of Washington in Seattle, and they've identified what are called the four horsemen of relationships. Those four behaviors, what they call the four horsemen of the apocalypse for relationships, are one, criticism, two, defensiveness, three, stonewalling, and four, contempt, with contempt being the most powerful predictor of breaking up. Criticism, of course, does not mean that there's no place for criticism in stable relationships. Of course there is. It has to do with how frequent and how intensely that criticism is voiced. Defensiveness, of course, is defensiveness we know as the sort of lack of ability to hear another or to adopt their stance. So lack of empathy, I think, is one way to interpret defensiveness. Stonewalling, which is actually another form of lack of empathy. It's a turning off of this neural circuit that's so critical for desire, love, and attachment. The stonewalling essentially means the emotional response or the request of another is completely cut off and then contempt. And contempt has actually been referred to as the sulfuric acid of relationship. I didn't say that, but Gottman and colleagues have that. It is such a powerful predictor of divorce and breakups in the future. Contempt, of course, by definition, is the feeling that a person or thing is beneath consideration. Worthlessness or deserving scorn runs counter to all of the neural circuits, all three of the neural circuits that we talked about before. It certainly is. It is the antithesis of empathy. It is anything but a positive delusion. It's really looking at the other individual, either accurately or inaccurately, as somebody that you kind of despise. And then it is an absolute inversion of the autonomic seesaw matching that I was talking about before. It's a dissociating of your seesaw from their seesaw. They're very excited about something, you're unexcited by it, and therefore it's not surprising that is so strongly predictive of breakups. And in the case of married couples, of divorce. I'd like to take a quick break and acknowledge one of our sponsors, Function. Last year, I became a function member after searching for the most comprehensive approach to lab testing. Function provides over 100 advanced lab tests that give you a key snapshot of your entire bodily health. This snapshot offers you with insights on your heart health, hormone health, immune functioning, nutrient levels, and much more. Function not only provides testing of over 100 biomarkers key to your physical and mental health, but it also analyzes these results and provides insights from top doctors who are expert in the relevant areas. For example, in one of my first tests with function, I learned that I had elevated levels of mercury in my blood. Function not only helped me detect that, but offered insights into how best to reduce my mercury levels, which included limiting my tuna consumption. I'd been eating a lot of tuna while also making an effort to eat more leafy greens and supplementing with NAC and acetylcysteine, both of which can support glutathione production and detoxification. And I should say by taking a second function test, that approach worked. Comprehensive blood testing is vitally important. There's so many things related to your mental and physical health that can only be detected in a blood test. The problem is, blood testing has always been very expensive and complicated. In contrast, I've been super impressed by function, simplicity, and at the level of cost, it is very affordable. As a consequence, I decided to join their scientific advisory board, and I'm thrilled that they're sponsoring the podcast. If you if you'd like to try Function, you can go to functionhealth.com Huberman Function currently has a wait list of over 250,000 people, but they're offering early access to Huberman podcast listeners. Again, that's functionhealth.com huberman to get early access to function, I want to now talk about an article that came out a little over 10 years ago that talked about the universality of love and the ability to fall in love. An article was published in the New York Times in 2015 that related to some psychological studies that were done, as well as some clinical work, as well as some what I would call pop psychology or things that fall outside the domains of academic science. And the whole basis of this article was 36 Questions that Lead to love. And it involved a listing out, indeed of 36 questions, a set divided into set one, set two, and set three, that progress from somewhat ordinary questions about life experience and self report to more, let's call them, deep questions about people's values and things that are emotionally close to them. And I'll just give an example of a few of these. Some of the questions in set number one were, for instance, what would constitute a perfect day for you for what in your life do you feel most grateful? Kind of standard questionnaire stuff in set two, what is your most treasured memory? What is your most terrible memory? So these are, as you can tell, are drilling a little bit deeper into one's personal experience and emotional system. And then set three, questions 25 through 36 are things, you know, what is a very embarrassing moment in your life? When did you last cry in front of another person and by yourself? What is something that's too serious to be joked about? So it's going deeper into one's emotional system now, the reason this article got so much traction and the reason I'm bringing it up today is that there was a statement that was made in and around this article that if two people went on a date or simply sat down and asked each other these questions, that by the end of that exchange, where one person asks 36 questions and the other person answers all 36, and then the other person asks all 36 and the other person answers all 36S that they would fall in love, right? Which seems like kind of a ridiculous thing. And yet it is the case that people who go through this exercise report feeling as if they know the other person quite well and feeling certain levels of attachment or even love and desire for the other person that they would not have predicted had they not gone through that process. So what's going on in this exchange of questions and answers of a progressively more emotional and deep level? We know, based on recent studies, and I've covered this before on this podcast, but I'll mention again that when individuals listen to the same narrative, their heart rates tend to synchronize or at least follow a very similar pattern, even if they're not in the same room listening to a given narrative. So I'm not all that surprised that people find that they fall in love with, in quotes after answering these questions to one another. Because essentially the way these questions are laid out is they establish a narrative. They establish a very personal narrative, and the other person is listening very closely. So I don't want to seem overly reductionist. I'll never propose that all of our sensation, perception, action and experience in life boils down to us just being bags of chemicals and the action of those chemicals or any aspect of our nervous system. And yet, in looking across the psychological literature of development of attachment, in the psychological literature of adult and romantic attachment and what makes and breaks those attachments, it's very clear to me, and I think courses through the literature at multiple levels, that autonomic coordination Is a hallmark feature of desire, A hallmark feature of what we call love, and a hallmark feature of what we call attachment. You hear a lot out there that you know, in order to form a really strong relationship, you have to have a good relationship with yourself or you have to love yourself. Or you often hear, for instance, that you know it's exactly when you're not looking for a relationship that you're going to find one. You hear this stuff, right? But none of that is really grounded in any studies. There's a particular study that I found. This was published in Frontiers in Psychology, but it's a experimental study that involves neuroimaging. The title of this study is Manipulation of Self Expansion alters responses to Attractive Alternative Partners. And I love the design of this study. What they did in this study is they took couples and they evaluated members of that relationship for what's called self expansion. Now, self expansion is a metric that involves one's perception of self as seen through the relationship to the other. In other words, that one of the reasons why many people enter relationships is that it makes us feel good about ourselves and more capable. And I would see that as a healthy interdependence, not necessarily co dependence. In any event, this study looked at whether or not people have high levels of self expansion through the actions or statements of their significant other and how that influences their perception of people outside the relationship, Meaning how attractive they perceive people outside the relationship to be. Turns out to be strongly influenced by a whether or not their self expansion is very strongly driven by the other person that they are involved with, that they're in the romantic relationship with and whether or not that's being expressed to them. So here's how the study went. First of all, they rated or categorized individuals on the basis of the self expansion metric. Some people have more of a potential to experience self expansion through others, right? Some of us feel great about ourselves and we're kind of topped off at the others don't feel so great about themselves, but they can feel much better in response to praise. In particular praise or self expansion type behaviors or statements from people that we really care about. And still other people are a mixture of the two. The kind of moderate levels of both. So they rated them on this scale. And then they had people experience self expansion narratives. They heard their significant other say really terrific things about them and about the relationship in particular, that the relationship that they have was exciting, novel and challenging. So that was one form of self expansion. And they went into some detail as to why that was the case. In their particular relationship or they heard a narrative from their significant other about strong feelings of love between the two that had been experienced previously in the relationship. So in the one case it's sort of directed more towards them and in the other case it's more about the relationship itself. And then they did brain imaging of one person in the relationship While that person assessed the attractiveness of of people outside the relationship. And what they found was that people who were primed for this self expansion had lower activation of brain areas associated with assessing others attractiveness than did the people who experienced a lot of self expansion. Now the takeaway from that, at least the way I read this study, Is if you're with somebody who really benefits from or experiences a lot of self expansion, Unless you really want them to pay attention to the attractiveness of other people, it stands to reason that they would benefit from more self expansion type gestures or statements. Okay, not so much centered on the relationship. We have such a great relationship. There's so much love. It's so great. That too. But in the context of this study and these findings, that the person is really terrific, that the relationship that they've created together is really exciting, novel and challenging, that there's a narrative around the relationship that really has a lot to do with the dynamics between the individuals in particular, that the person who really likes self expansion is vital to that dynamic. Okay, so it's not looking down at the relationship as a set of equals. There is sort of this bias written into this of that this person is really essential for the relationship. I'm not saying this is something that anyone has to do. I'm not saying this is right or wrong. This is just what the data say. But what's remarkable is that in the absence of those statements, People who have or that rate high on this scale of self expansion Rate attractive alternative partners as more attractive. Now that's interesting to me because it means that their actual perception of others is changing. They're still seeing all these attractive people. It's just that if they're feeling filled up in air quotes, psychologically filled up, emotionally filled up, autonomically filled, enhanced in the language that we're using today by this self expansion narrative, well then the same set of attractive faces appear less attractive to a given individual. Now whether or not this predicts cheating or loyalty, I certainly can't say. That would be very hard to assess in neuroimaging. But I find this study, again, the title manipulation of self expansion alters responses to attractive alternative partners to be absolutely fascinating. Because again, it points to the fact that the interactions with our significant others shapes our autonomic arousal, shapes our perception of self, and thereby shapes our perception of other potential partners in the outside world, or shuts us down to the potential of other people in the outside world. And so this really does point to the idea that while it is important to link our autonomic nervous systems to establish desire, love and attachment, that we want to have a stable internal representation of ourselves, a stable autonomic nervous system to some degree or another, so that we can be in stable romantic partnership with another individual if that's what we're really trying to do. If you're a regular listener of the Huberman Lab Podcast, you've no doubt heard me talk about the vitamin mineral probiotic drink AG1. And if you've been on the fence about it, now's an awesome time to give it a try. For the next few weeks, AG1 is giving away a full supplement package. With your first subscription to AG1, they're giving away a free bottle of vitamin D3K2, a bottle of Omega 3 fish oil capsules, and a sample pack of the new sleep formula agz, which by the way is now the only sleep supplement I take. It's fantastic. My sleep on AgZ is out of this world. Good AgZ is a drink, so it eliminates the need to take a lot of pills. It tastes great and like I said, it has me sleeping incredibly well, waking up more refreshed than ever. I absolutely love it. Again, this is a limited time offer, so make sure to go to drink ag1.com/huberman to get started Today in the Huberman Lab podcast, I discuss both science and science based tools and so I'd be remiss if I didn't actually cover some of the tools that relate to those deeper biological mechanisms. Now the hormones testosterone and estrogen are almost always the first biological chemicals and hormones that are mentioned and described and explored when thinking about desire and love and attachment too for that matter, since love and attachment stem from desire. The simple stereotyped version of the hormones testosterone and estrogen are that testosterone drives libido or increases it, AKA sex drive, and that estrogen somehow blunts it or is not involved in libido and sex drive and that is simply not the case. Yes, testosterone and some of its other forms like dihydrotestosterone are strongly related to libido and sex drive in the pursuit and ability to mate. However, the hormone estrogen is also strongly associated with with libido and mating behavior. So much so that for people that either chemically or for some other reason have very low estrogen, libido can severely suffer. So it's a coordinated dance of estrogen and testosterone in both males and females that leads to libido or sex drive. With that said, there are things that can shift libido in both men and women in the direction of more desire or more desire to mate, either to seek mates or to mate with existing partners. Now, a common misconception is that because dopamine is involved in motivation and drive, that simply increasing dopamine through any number of different mechanisms or tools will increase libido and sex drive. And that's simply not the case either. It is true that some level of dopamine or increase in dopamine is required for increases in libido. However, because of dopamine's relationship to the autonomic nervous system, and because the autonomic nervous system is so intimately involved, no pun intended, in sexual activity, in seeking an actual mating behavior, as I described earlier, it's actually the case that if people drive their dopamine system too high, they will be in states of arousal that are high enough such that they seek and want sexual activity, but they can't actually engage the parasympathetic arm of the autonomic nervous system sufficient to become physically aroused. So this is an important point to make because I think that a lot of people are under the impression that if they just drive up testosterone, increase dopamine, and generally get themselves into high states of autonomic arousal, that that's going to increase their libido. But that's simply not the way the system works. It's that seesaw and that seesawing back and forth. That is the arc of arousal that we talked about earlier. Now, there are substances legal over the counter, substances that fall under the categorization of supplements that do indeed increase libido and arousal. I want to be clear, however, that these are by no means required. Many people have healthy libidos or have libidos that are healthy for their life and what they need and want. And as always, in any discussion about supplementation, you absolutely have to check with your physician. I don't just say that to protect us. I say that to protect you. Your health and wellbeing is dependent on you doing certain things and not doing others. And everybody is different. Nonetheless, there are studies that point to specific substances that are sold over the counter that, at least in the United States, are legal and that have been shown to be statistically significant in increasing measures of libido. There are many such substances, but three that in particular have good peer reviewed research to support them are maca. Maca, which is actually a root tongat ali, also sometimes called long Jack, I didn't name them, forgive me. And tribulus or tribulus, it's sometimes called. I'm going to talk about each of these in sequence. But on the whole, the studies on maca are quite convincing. That consumption of 2 to 3 grams per day of maca, which generally is sold as a powder or a capsule, typically consumed early in the day because it can be somewhat of a stimulant, meaning it can increase alertness and you wouldn't want it to interfere with sleep by taking it too late in the day. But in studies that include both men and women of durations anywhere from 8 to 12 weeks of athletes and non athletes and different variations of maca, turns out there's black maca, red maca, yellow maca, There are a bunch of different forms of maca, but that they can increase subjective reports of sexual desire independent of hormone systems. Meaning it does not seem, at least based on the existing literature that maca increases testosterone or changes estrogen, at least not on the timescales that these studies were done or with the measures that were performed in these studies. Another substance that has been shown to increase libido across a range of human populations is so called Tongat ali. This is an herb, there's a Malaysian version and an Indonesian version. My understanding is that the Indonesian variety of Tonga Ali is the one that is most potent for its effects on libido. Previously I've talked about Tonga ali taken in 400 milligram per day capsules as a means to increase the amount of free meaning unbound testosterone. So testosterone has a both bound form and an unbound form. Very briefly, the bound form is bound to albumin in the blood or to so called sex hormone binding globulin. When it's bound, it can't be biologically active at many cells. It is important that some of it be bound in order to get a sort of time release and proper distribution of testosterone through the body. But is the unbound free testosterone that can really have its most potent effects? And there's some evidence that Tonga Ali can increase the amount of unbound so called free testosterone by lowering sex hormone binding globulin, Although it is almost certain that it has other routes of mechanism as well. Nonetheless, there are some reports of Tonga Ali increasing libido. The Question always comes up around discussion of supplements. Do you need to cycle these things? The only way to determine that is really to do your blood work, monitor liver enzymes, monitor hormone levels and so forth. So I simply can't say whether or not you need to or you don't need to cycle them. Typically Tonga Ali and Maca are not cycled in any regular kind of way that I'm aware of. But again, you really need to check with your doctor if you're going to initiate taking any of these things. And you certainly should do your best to monitor your blood work as well as subjective measures in evaluating whether or not they're working for you, say for you and so forth. The third and final substance supplement that I want to touch on as it relates to libido is called Tribulus terrestis. So that's T R I B U L U S Tourestus T E R R E S T R I S. This is a commonly sold over the counter supplement for increasing testosterone for, you know, fitness purposes and so on. Whether or not it actually does that to a meaningful degree isn't clear. But I'm aware of four peer reviewed studies that were focused on both males and females ranging anywhere from 18 years old all the way up to 65 plus a fairly broad age range where people took anywhere from 750mg per day divided into three equal doses. So 750 total per day divided into three equal doses of Tribulus or placebo for 120 days. This particular study was focused on females and according to the Female Sexual Function Index Questionnaire, no significant difference between any of the groups. However, free and bioavailable testosterone increased in the group taking Tribulus terrestis. Total testosterone did not reach statistical significance. So this is sort of the inverse of what we see with Maca, where there do seem to be increases in testosterone which would predict that there would be increase in libido in this case, in this was postmenopausal women, there was no increase in libido, there was an increase in testosterone. I mention it only because there might be instances in which people want to increase their testosterone. It does seem that tribulus, at least in that population, is capable of doing that. Now there's a separate study that was done, a double blind study lasting anywhere from one to six months that had a clear and significant increase in libido. Now this was taking 6 grams, so that's 6,000 milligrams of Tribulus root for 60 days. And it did seem to increase various aspects of sexual function. I think more studies are certainly needed but these three substances, supplements, Maca, Tonga Ali in particular Indonesian Tonga Ali and tribulus can indeed create significant increases in sexual desire and in some cases by adjusting the testosterone and estrogen system, in some cases not by adjusting the testosterone and estrogen system. Again pointing to the complexity of neurochemicals and features that adjust things like libido AKA desire. So we covered a lot of material today related to desire, love and attachment and yet I acknowledge that it is not exhaustive of the vast landscape that is the psychology and biology of desire, love and attachment. Nonetheless, I hope that you found the information interesting and hopefully actionable in some cases toward the relationships of your past, of present and potentially for the relationships of your future. Thank you for joining me for today's discussion about desire, love and attachment. And last but certainly not least, thank you for your interest in science.

0:00