Is it true that semen is an antidepressant?


Happy Friday Geeks,

Firstly, thank you for all the Questions. I have my work cut out for me, I have to say that some of the questions had me rolling on the floor with tears of laughter running down my face, so thank you to each and everyone of you that responded to last weeks Knock Knock request.

It was pretty difficult to pick which question to answer first and in all honesty I picked this one because I got asked it not once, or twice but thrice by three different people. This really intrigued me so I did a little background research and realised that the story was recently spun by our very own Daily Fail aka Daily Mail and The Burn aka The Sun. It didn’t stop here however, it got picked up by a number of chat shows and comedians hence the proliferation. I am going to scientifically BREAK this down for you ladies and gentleman.

The above newspapers claimed that scientific research has shown that semen acts as an antidepressant for women, they published this story towards the end of August 2012.  Right off the bat, the first thing to note is that these claims are actually based on a decade-old study that made the extraordinarily bold claim that semen has an antidepressant effect in women (Gallup, Burch & Platek, 2002). The fact that the study is 10 years old and has not been followed up by any other researchers testing whether this claim is actually valid is already a red flag.

Side-note; during my background research I discovered that the huge media attention was linked to the fact that the President of the American College of Surgeons lost his job over a very bad Valentines Day joke related to this particular paper. Of-course some dude just HAD to make THAT joke lol.

Back to the science, the study was a correlational in nature and provided no direct biological evidence for the claim that semen has an antidepressant effect. A well-known research principle is that correlation does not imply causation, and there are many plausible alternative explanations that the authors of the study did not take into consideration. Furthermore, close examination of the scientific literature shows that there is no basis at all for taking this claim seriously. What the study actually found was that women who did not use condoms during sex had lower levels of depressive symptoms compared to women who usually or always used them, and to women who abstained from sex altogether. The authors argued that vaginal exposure to semen was the causal mechanism underlying this effect, arguing that semen has components including various hormones, particularly prostaglandins, that are readily absorbed into the woman’s bloodstream and that these have an antidepressant effect.

This may seem like a valid conclusion to make when taken on it’s own but that is not how research and scientific enquiry works geeks. It is a rigorous process and ladder that has been established for hundreds of years, otherwise every Tom, Dick and Harry would prove his/her hypothesis. In this case, the authors’ source for the antidepressant hypothesis was a single case study (Ney, 1986) published in Medical Hypotheses which found that evening primrose oil apparently alleviated depression in a child-abusing mother (What the …??)

For the sake of our collective sanity, I am going to explain to you what I think Ney’s thought process was. Ney argued that evening primrose oil and semen have in common the fact that they contain prostaglandins, and claimed that the latter have an antidepressant effect. Ney even went so far as to argue that in the single case study mentioned above, the disruption to the woman’s sex life due to the birth of her child was a causative factor in her depression because of the lack of exposure to her husband’s semen. Oh, the story gets even better, Ney the goes on to admit that semen contains minute quantities of prostaglandins but still goes on to argue that even so “they have powerful direct effects”. I am going to give him a break here and say that he was talking about the effects on the mood otherwise his theory is flawed beyond recognition. To back up his theory Ney describes a review of the psychiatric implications of prostaglandins (Gross et al., 1977).

Wait it gets better, when I read this review by Gross et al I found that they reported that one study found that depressed patients had slightly elevated levels of prostaglandins, whereas another study found depressed patients had normal levels of prostaglandins. Furthermore, Gross et al. noted that antidepressant medications had an inhibitory effect on prostaglandins (they say they have done little research and clinical implications are yet unknown so props to them for being clear).

What does all this mean? It suggests that if absorption of prostaglandins in semen had an antidepressant effect, one would reasonably expect this to mean that depressed patients had low levels of these hormones or that antidepressant medications would actually increase not decrease their production, yet neither of these things appear to be true. Hence the claim that semen has any antidepressant properties at all does not appear to rest on any biological evidence.

Ok, let us go back to the paper from 2002 that caused the media storm and the poor man to lose his job by Gallup et al. I am going to bullet point the many other reasons why I am confidant in letting you know that NO semen is NOT an antidepressant.

1-No evidence that semen exposure explains the differences in depression between women who do not use condoms and those who do.
2- They did not properly consider a range of alternative explanations. For example; why some women choose not to use condoms in the first place and whether pre-existing differences between users and non-users might have affected their results?
3-They noted that non-users had the highest frequency of intercourse and in fact those who never used condoms had sex almost twice as frequently as those who always used condoms. However, when statistically controlling for condom use, frequency of intercourse did not predict depressive symptoms.
4- The fact that non condom users were not only less depressed but also had the most frequent intercourse suggests that non-users may be different from users in some important way. Gallup et al. argued that the “important” difference is their exposure to semen and frequency is suddenly not important.

5-This was a correlational study and hence statistically they are not justified in arguing that this is the underlying cause of the relationship between condom use and depression particularly when there are other plausible causal factors.

It is well known now that frequency of intercourse is positively correlated with both life satisfaction and good mental health. It has been suggested that sex with condoms for some women may be less satisfying where 40% of women surveyed reported decreased sensation with condoms. Therefore, it seems possible that sexual enjoyment has an antidepressant effect that may be reduced by condom usage. But ladies, please do not ditch the condoms without weighing up the consequences i.e sexually transmitted diseases and unwanted pregnancies.

In conclusion, the claim by Gallup et al. that semen has an antidepressant effect is not only lacking any direct evidence, there does not even appear to be any plausible biological reason to believe that the components of semen have a beneficial effect on even mood. The authors thankfully acknowledged that more definitive and direct evidence is needed, e.g. manipulation of the presence of semen or measures of seminal components in the bloodstream. However, no studies providing such evidence appear to have been done and there is probably little justification for investigating such a far-fetched hypothesis. There are plausible psychological mechanisms that could explain the relationship between condom use and depression, such as pre-existing depression, personality differences, or “turn-offs” associated with condom usage, that have not been adequately explored and seem more likely to yield informative results. Finally, sorry to disappoint any of you, click on the video below and enjoy one of my favourite SV songs, it will make you feel better I promise.

Until next time, have a great weekend all.

What’s up Doc?


Hello All,

Hope you have all had a great week.  The holy month of Ramadan falling in the summer months has meant that it has been a long and hard month of fasting, this hardest Ramadan I have fasted during my life-time so far.  This summer especially, London has been exceptionally hot (sods law of-course). Yesterday was Eid (yaaay) so Eid Mubarak to one and all. I am in the midst of celebrating the three days of Eid with family and friends so for this reason I have not had the time to finish working up the topic I wanted to share with you this Friday.

However, I have been meaning to ask you all to send me in some new questions for the Knock Knock section as it has been neglected of late and figured this is a good opportunity to do so. Please send me a message or post a comment with a question you would like me to research and/or ask my network of Dr’s to answer so we can keep sharing the knowledge.

Until next week, wishing you all a blessed and wonderful weekend. Here is some music to inspire you to think of some questions.



Q- Dr E, how do I know if I am lactose intolerant or not?


Happy Friday Geeks,

It has been a while since my last knock knock post and I’m excited to put this one out. I get asked this question all the time and it is not an easy one to answer scientifically but I am going to give it my best shot. It is science “thick” but I am going to do my best here to touch all bases and hopefully make the science easier for everyone to digest (like my little pun here?)

I hear people say they think they are lactose intolerant quite often and they usually go to the extreme of cutting out all dairy products. I can definitely understand why that would be the first point of action for many, but it has always worried me because dairy products are our main form of calcium intake (as well as good protein and carbohydrate sources). Calcium is a very important part of our diet and it is hard for many to grasp how important it is until they are at an age (50 and over) where they are prone to an increase in bone fractures and other calcium related dis-orders associated with calcium restriction.

Let me start by explaining to you what lactose actually does for us. Lactose is the main source of sugar from milk and milk products from all mammals except the sea lion. After ingestion, lactose passes into the small intestine where it comes into contact with lactase (a natural enzyme within our bodies) at the intestinal brush border where it is hydrolysed/converted into the monosaccharides glucose and galactose (sugars), which are easily absorbed. In-short, lactose is good for us because it can be converted to sugars by lactase which are then used by many bio-chemical processes in our systems. Remember sugars are not bad!, sugars are basically our human fuel or petrol, a car can’t run properly without a good supply of petrol and the same goes for our bodies. Over subscription to sugars is what is bad.


Now that is out of the way. What do we mean when we say someone is lactose intolerant? And this is where it can get a little confusing. Time for the hard-core science section.

Non-digested lactose can cause gastrointestinal symptoms such as diarrhoea and distending the intestines (bloating, cramps, abdominal discomfort) as well as psychological symptoms, events that are likely to lead to clinical symptoms.

Lactose malabsorption refers to inefficient digestion of lactose due to reduced expression or impaired activity of the enzyme lactase.

Lactose intolerance is when the gastrointestinal symptoms are clinically observed in an individual with lactose malabsorption.


What causes lactose malabsorption I hear you ask? The most common cause of lactose malabsorption is lactase non-persistence also known as lactase deficiency, a common condition in which lactase expression decreases during infancy. What this means is that we naturally start off needing lactose as it is our earliest form of providing our systems with the sugars/energy it needs to grow and develop to adults. But, as we get older we don’t need it as much. I am about to really go in on this, hope you are ready?

Lactase activity changes during development. In most humans, lactase activity reaches a maximum in late pregnancy but declines after 2–3 years of age and reaches a stable low level at age 5–10 (this is thought to be a process which might help weaning). However, a proportion of the human population, especially Caucasians from Northern Europe or Northern European descent, retain high lactase levels during adulthood. This is known as lactase persistence. Just to be clear, lactase persistence means you and lactose can be good friends, if you want to.

Therefore, lactase persistence and non-persistence are both “normal” human phenotypes. What is very interesting, is where lactase persistence is found and why?  The prevalence of lactase persistence is high  in most regions in Scandinavia, the British Islands, and Germany (80–95%); however, this condition is observed in only 20–40% of Indian adults, 30% of Mexicans, 30% of African Americans.

Lactase persistence is thought to be related to the development of farming during the last 10,000 years. Just in-case you really really wanted to know, the genetic polymorphism responsible for most cases of lactase persistence in Caucasian individuals is the13910C/T variant (it’s all very straight-froward :-), T at position 13910 upstream of the lactase gene within a putative regulatory DNA-region causes persistence; C leads to non-persistence). Basically if you are from any of these regions you are good and if you are mixed, then you are also good because lactose malabsorption is a recessive condition meaning you need a homozygous genotype as a heterozygous/mixed geneotype is considered clinically negative.

African tribes that herd cattle in Sudan, Kenya, Ethiopia and Tanzania also have high prevalence for lactase persistence. However, lactase persistence is mediated by a different polymorphism (gene/DNA change). Importantly, this tells us that lactase persistence developed several times independently in human evolution in different areas of the world. So again, if you are east African you and lactose can be good friends. Of-course exceptions to the rule do exist, as they do with everything. (for review, see Ingram et al Human Genet 2009; 124: 579–591)


Statistical calculations of genetic data estimated that selection for lactase persistence commenced relatively recently, during the last 10,000 years. Lactase persistence was beneficial for our ancestors by providing a clean source of fluid and a source of protein, fat, and carbohydrates  generating a selective advantage of 1.5–19% in each generation. This indicates a strong selection pressure comparable to malaria resistance genes (2–5% for G6PD deficiency, 5–18% for sickle-cell trait) in various parts of the world. That is a big deal by the way, selective advantages are hard to prove.

So those rumours that humans are not supposed to drink milk, especially cows milk are questionable for two reasons, two very different reasons, in my humble opinion. Firstly, no significant bio-chemical difference between lactose in breast milk and cows milk has been observed, they both get digested in the same way via the lactase enzyme, which is common and present a birth. It is very rare that you are born lactose intolerant (known as congenital lactase deficiency). Secondly, cows milk has been reported to be ingested by humans from times dating back to the father of man, The Prophet Abraham according Biblical and Quranic scriptures and that tells me something, whether you are spiritual or not, history should at least strike a cord here? or maybe be not? As a scientist, I personally believe all evidence should be taken into account, including historical, religious, spiritual evidences.

Saying all the above, I do appreciate that many people are experiencing discomfort when ingesting milk and dairy products. So what do you do if you are one of them?

Treatment of lactose intolerance should not be aimed at reducing malabsorption but rather at improving digestive symptoms. Reduction of lactose intake rather than exclusion is recommended because long-term effects of lactose restriction may help improve gastrointestinal complaints but can lead to other damages. For example, the long-term effects of a diet free of dairy products may be a concern as you are significantly decreasing the amount of calcium. Low calcium levels are leading to an increase in fractures and orthopaedic problems. Adolescents require approximately 1300mg and over 50’s approximately 1200mg of calcium, which is roughly equal to 3 cups of milk per day. Furthermore, in blinded studies results indicate that most patients with self-reported lactose intolerance can ingest at least 12g lactose (equivalent to 250ml milk) without experiencing symptoms and taken with other foods, up to 18g lactose can often be tolerated (Suarez FL, Savaiano DA and Levitt MD, N Engl J Med1995; 333: 1–4).

I know I took you all through the paces with this one, but I really wanted to flesh this one out. As with everything all food groups are important and good for you as long as it is taken with moderation, completely cutting out a good source of calcium because you think you may be lactose intolerant is not recommended. But, if you are then you should take all necessary steps to make sure you are providing your body with the healthy amount of nutrients it requires. Many lactose supplements and calcium supplements produced as “drugs” are available that can be taken to supplement your diet, but I hope you go the foodie route, it is much more colourful, fun and tastes all so wonderful.


Hope you enjoyed the read and if the science was too “thick” for you ( ha, not sure why I like that word today, but like I do) click play and relax to this brilliant song by James Blake.

Have a great weekend all.


Q- To Caffeine or Not To Caffeine?

I am a self-confessed Tea addict, everyone that knows me, KNOWS I’m a tea addict, and a tea snob, in-fact if you can’t make a good cup of tea, I am either never going to accept another cup from you or I will have to teach you myself.  This cartoon says it all.

I keep hearing things like:

“You shouldn’t drink too much tea, it is not good for you”

“Let’s switch to de-caffeinated coffee or tea, it is better for you”

Conjuring images like this in peoples head!!!

I mean, it is really not that bad and not to be rude but do you actually know what tea and caffeine do? or why it is not good for you? Sometimes…ofttimes, I am pretty sure most people don’t, so I am going to break it down for you here (even tho I am biased, but this is my blog so I choose pro-tea lol).

Caffeine actually stops the breakdown of energy so you have a surplus! In simple terms, ATP is what gives your body energy. Food is broken down and stored as ATP which is used as energy. When you start to feel yourself dragging, it is because you’ve used up all the ATP, because ATP cannot be stored for long term (hence why you need to eat more than once during the day, especially if what you are doing requires the use of energy)

So basically, it helps you “save” up some energy for things like, a evening run post work, or playing with the kids after-work, or a night on the dance floor or bedroom floor, as long as you don’t wait too long to get home…do I need to go on?

What’s even better is that, say you do run out of energy or ATP because, maybe you didn’t have breakfast or you are having back to back meetings/high-workload and missed lunch? Caffeine blocks the signal in your body, Adenosine, from binding and letting the body know you are out of energy. It tricks your body into thinking that there is energy there. The effects of the caffeine can kick in within 10 minutes and last up to 4-6 hours! Much faster than waiting for food to be broken down and stored as ATP. That’s why you crash from caffeine, when the effect runs out, your body tries to use ATP and there’s none there! Something like what’s happening below

Final thoughts: Caffeine can be your friend when ATP has failed you, saving you from that fatal crash. So its not all bad, it has a purpose in life and its purpose works in 10mins, much quicker than that super smoothie! LOL.

I rest my case, with the help of this BRILLIANT British parody song and video by Elemental.  Please, put the kettle on and press play.

This is not my normal Knock Knock but I do often get asked if caffeine is good for you or not. Some say it is good, some say it is bad for you but it does have a purpose and people have been consuming tea and coffee throughout the ages for this purpose.

Thank you for reading and please share the post if you enjoyed it.

Until next time.


Q-E, Is it true that having sex before a job interview will increase my chances? LOL

The truth is, I got this Q a while back but kept putting it off know :-/ but actually it is a valid scientific question. I figured now would be the right time, it is the beginning of the year and new beginnings for some, so here it goes geeks

As SV would say, I know, I know you like the art of sex…  Press play for some background music and read on

The answer to your question is a no boner..uhm I mean brainer…(sorry, I just couldn’t resist ha!)

….going to a job interview can be one of most stressful events and sex is one of the most natural ways as humans we can regulate our anxiety levels.

But how can we prove this scientifically?

In one study, using rats, researchers found daily intercourse for two weeks led to cell growth in the hippocampus, the part of the brain that keeps stress levels under control. This paper actually caused quite a stir when it was published (Sex makes your brain grow wooo hooo!!! etc etc absolutely ridiculous tabloids in the papers). Click here for the full article and hardcore science.

I know what you are thinking, E, we are not the same as rats! Right? so I dug a little deeper and came across another study to support the theory;

This research group stated that people who had daily intercourse for two weeks showed lower stress-related blood pressure than those who chose to fool around in other ways or abstain from sex altogether. (Solo sessions didn’t cut it either, I’m just saying!) Click here for the full article and hardcore science

But wait, it gets better 🙂

They also found that the body releases oxytocin (aka the love hormone) during penis-vaginal sex which acts as a natural sedative and can trigger feelings of compassion (everybody say aaaaaaaaahhhhh)

However, before we go lookin’ for love every time those stress signals go off, know that too much sex can also let loose glucocorticoids, molecules the body produces during the stress response. (Less really is more, huh? so don’t go overboard aight!)


Dr E does not take any responsibility for any failures in job interviews, relationships or marriages related to this post.

Q- E, why do I get bitten by moquitoes but my partner doesn’t?











Hah, Ok so first I have to confess that I am a bit off a mozzy (mosquitoe) geek as I have a soft spot for this area of research, for two reasons;

1-My first ever real research project that I designed myself as a undergraduate was on Malaria and mozzy’s

2-Sudan is full of them and has both the species that carry malaria in abundance and they like to bite me, lots, whenever I go home ggggrrrrhhh!

Side note/Trivia: Did you know that mosques (Islamic house of prayer) are called mosques in England instead of Masjid (which is the correct word) because when the English landed in countries which contained Masjid’s and they heard the call to prayer, the soldiers described the sound as the buzzing of mosquitoes, hence the term mosque instead of Masjid.

Anyhoo, back to the topic at hand, due to the above reasons, I am still a member of a number of web journals all about mozzys’ and malaria and it just so happens that only yesterday I read this paper.

Click here if you feel up-to the hard-core science (I hope some of you do 🙂 otherwise play this live ensemble by Seun Kuti feat Manu Dibango whilst I try and break it down.

I always used to say to my dad ” it really is not fair, how come you never get bitten and I always get bitten” and he used to come at me with an African proverb that translates to “My old skin/blood is dry and your young skin/blood is sweet my dear”.LOL

So I looked it up and it turns out he was kinda right. Firstly, I thought a mozzy was just looking for blood, so what does it matter who’s blood it has for dinner, right? I was wrong.

Actually, the mosquito that carries malaria aka Anopheles gambiae, tracks its victims with an acute sense of smell.

Now when I say acute, I really mean it, as the smells they are attracted to come from the billions of tiny bacteria that live on our skin. Skin bacteria gives us all our own “scent” if you will, and we need them as they help convert chemicals on our skin into those that can easily rise into the air.

So here is the answer to your question. We all have different types of bacteria on our skin or different concentrations of a particular type. Therefore, our scent will be different, your scent must be far more attractive than your partners.

Recently, Neils Verhulst et al (2011) discovered that the bacteria on our skin does affect the odds of being bitten by a malarial mosquito and they have even managed to identify which of the different types of skin bacteria are more attractive.This has exciting implications for malaria research.

What can you do?

There are a few things that you can do to make yourself less “attractive” to mozzys

1-We know from past experiments that human sweat becomes more enticing to A.gambiae, therefore a shower before sundown might help.

2-Your diet matters, for example we know that drinking bear can give a attractive odour

3-Cover up as much as possible during the evenings when the mozzy’s come out to play

Hope that helps.


Q E, I want to know if red wine is good for the heart or not, once and for all please?

The good ol’ red wine and heart Question! aaah yes, I do get asked this frequently and actually it’s my area of “expertise” as I worked in the cardiovascular arena for 5 years.

So here it goes, I hope you’re all ready for this? I promise to try and keep it simple 🙂 but just in-case click play for some background music

Yes, red wine (or white) is good for the heart, IF you drink it moderately and you are generally “healthy”! That means if you are unhealthy or “at Risk” don’t be fooled into thinking that wine is your savior, it will do you more harm than good if you go over moderate!

Right, now that’s out of the way, I’ll explain why?

1- The reason red wine is quoted more than white is because the types of grapes that red wine is made from contain a higher concentration of Flavonoids. Flavonoids are polyphenolic antioxidants found in many plants and vegetables but are especially abundant in red grapes.

2- Now here is the Science bit; Low Density Lipoprotein (LDL) the “bad” cholesterol/fat that you hear about on TV is the stuff that undergoes oxidation and initiates the process of atherogenesis (fat deposits in your arteries/heart), which can lead to heart disease.

3- Put 1 and 2 together and you can see why red wine is good as the higher concentration of flavonoids following wine consumption act as an ANTI-oxidant, hindering that process.

4-Wine also contains alcohol, and prospective epidemiological studies have suggested that alcohol, in all of its forms, increases plasma High Density Lipoprotein and it’s major apolipoprotein, Apo A1. HDL is the good protein, which protects against heart disease and a increase in HDL concentration is inversely related to a 50% reduction in atherosclerosis.


5-Studies DO NOT show these benefits to be highly-significant especially as the fitness, diet and honesty of cohorts varies so much in studies. But studies DO show absolutely that alcohol, especially in excess, does have detrimental effects, in most groups and outweigh its benefits. Other interventions, including dietary modification, are far more effective at reducing the risk of cardiovascular disease. Hence the confusion!

To Conclude:

regular light-to-moderate alcohol intake, especially in those at risk, whose diet is steadfastly Western will, at the very least, do no harm and almost certainly lead to benefit. For those who have a healthy diet and lifestyle, you can probably push it a little more? I’m just saying tho, disclaimer!!

Now you gotta decide what light-to-moderate is in relation to your personal level of fitness and make an educated guess LOL

Click here for one of the best reviews I have read for further details, history and info

Hope that helps, if you have any more questions leave me a comment and I will do my best to reply.

Happy light-to-moderate drinking



Q- E, my son insists that music helps him learn better? Is this true?

Even Books Need A Little Music: LOVE

oh yes, I remember telling my mother and farther the same thing while I was studying for exams. They complained a lot, I ignored them a lot and eventually they stopped telling me, a lot.

The simple answer, is yes and no lol

Yes, it is true when it comes to memory recall. It has been proven that if you associate a concept to a song and/or the word within a song or the melody of a song it helps you recall the concept from memory much easier. This is good for subjects like history, humanities, geography, Biology, Psychology etc

No, it is not true when it comes to learning figures or facts. So subjects like maths, physics, charts, tables etc. However, converting equations into song-form has been proven to increase grades in students.

What is important to understand is that music has lots of benefits, including making you feel better and surely a happy student will do better than a less happy student without his music. You can then advise him on how to use his music to help him study better by suggesting he links some of it to his subjects or pay careful attention and see if you can make the links for him? then suggest them in that way that only a parent can do 🙂

Have a read of this link and see for yourself how music affects the Brain and how you can use it to your advantage.

Hope that helps