While many people are aware that men should avoid tight-fitting underwear if they and their partner are trying to get pregnant, most are less aware that the type of fabric too plays a serious role. Studies looking into this have shown a distressing correlation between polyester underwear and lower sperm count, decreased erectile funcion and reduced fertility in general.
The late Professor Ahmed Shafik from the Faculty of Medicine at Cairo University is one person that studied this subject intensively. The professor, famous among other things as a pelvic surgeon and personal physician to many dignitaries and world leaders, published around 500 studies and wrote over 1,000 articles in his career. These included several studying whether wearing polyester underwear could cause infertility and reduced sexual function.
Here’s a brief summary: in all studies the participants were divided into polyester and non-polyester underwear-wearing groups. In all cases the polyester underwear-wearing subjects fared worse.
STUDY ONE (1992): HOW WEARING POLYESTER UNDERWEAR CAN LOWER YOUR SPERM COUNT TO ZERO
The study name says it all: “The contraceptive efficacy of polyester-induced azoospermia in normal men”. Azoospermia means there is no sperm in the ejaculate. This was induced by the 14 men in the study wearing a polyester scrotal sling day and night for 12 months.
They became azoospermic after approximately 20 weeks and the volume of their testicles fell significantly. Their partners were able to stop taking oral contraceptives and non became pregnant during the study. Approximately 22 weeks after the study finished, sperm count and testicular volume went back to pre-study levels. All five couples that wanted to did eventually conceive.
So, wearing polyester underwear can actually serve as a contraceptive. In these cases it did cause temporary infertility. The study, reported in Science Direct, found that this was due to two factors: an electrostatic field effect and a thermoregulatory effect.
It’s true that most men don’t wear a polyester sling day and night, but many wear their underwear day and night so perhaps it’s not far off.
STUDY TWO (1993): THE EFFECT ON SPERM OF WEARING DIFFERENT TYPES OF FABRIC UNDERWEAR
In this study a group of 31 dogs were used. 12 wore polyester and 12 cotton underwear continuously for 2 years, while 7 control dogs wore nothing. The underwear was deliberately loose-fitting in the scrotal region to avoid the effect of the underwear causing heat.
After 2 years the underwear was removed and, while the cotton-wearing and control dogs showed no differences, the polyester-wearing dogs showed statistically significant reductions in sperm count, motile sperm, more abnormal forms and the testicles showed degenerative changes.
All effects were reversed 12 months after removing the underwear in 10 of the dogs while 2 continued to be “oligozoospermic” (meaning low sperm count). It was concluded that this was probably caused by the electrostatic potential of the polyester underwear.
STUDY THREE (1992): THE EFFECT ON THE SURFACE OF THE HUMAN SCROTUM OF DIFFERENT FABRIC TYPES
Here, 21 healthy men were split into three groups wearing either 100% polyester, 100% cotton or a 50:50 polycotton mix underpants for just one hour in the day and one hour at night (repeated four times).
The cotton wearing subjects showed none and the polyester wearing subjects had the highest electrostatic potentials with the polycotton wearing guys less than half that of the 100% polyester wearers. The effect was higher during the day which was thought to be because of the increased friction and heat caused during the day through movement.
It is thought that this electrostatic potential causes an electrostatic field across the “scrotal contents” which may lead to the abnormal development of sperm. This suggests that wearing polyester underwear could definitely cause some kind of infertility.
STUDY FOUR (1993): THE EFFECT OF DIFFERENT TYPES OF TEXTILES ON SEXUAL ACTIVITY
As much as unhealthy sperm can negatively affect fertility, outside of the clinic, the painful issue of sexual performance can too. This study looked into just that across a group of 75 rats.
These were split into 5 groups including one control and four groups wearing 100% cotton, 100% wool, 100% polyester or a 50:50 polycotton mix underwear. Their sexual behaviour was assessed after 6 and 12 months of wearing the garments and 6 months after removing them, plus electrostatic potential was measured.
All groups (apart from the control) showed a more marked reduction in “intromission to mounting ratio” after 12 rather than 6 months. At 6 months there was no notable difference in the cotton and wool wearing rats. The 100% polyester group showed the highest reduction followed by the polyester-cotton mix. Six months after removing the underwear all groups returned to normal. It was thought that the electrostatic fields generated in the intrapenile structures could explain the reduced sexual activity.
While this study was carried out 30 years ago and has not been repeated by other scientists, and on rats rather than humans, it gives you shocking food for thought.
STUDY FIVE (2008): THE EFFECT OF DIFFERENT TYPES OF TEXTILES ON CONCEPTION
After several years, it seems that Professor Shafik turned his attention to the female concern.
In this study, 35 female dogs were split into five groups and wore either pure polyester, pure cotton, pure wool, a 50:50 polyester-cotton mix underwear or no underwear for a year. Eight of the polyester wearing dogs had “diminished serum progesterone in the oestrus of the oestrous cycle” and did not get pregnant during the study either by mating or insemination. However after the study ended they were able to conceive.
It is thought that this is because the polyester causes an electrostatic potential on the skin and this inhibits the ovaries funcioning properly resulting in reduced progesterone.
STUDY SIX (2007): THE EFFECT OF DIFFERENT TYPES OF TEXTILES ON PREGNANCY
This study was less conclusive but in a group of 35 pregnant dogs, split like the study above, all went on to have successful pregnancies apart from two of the seven wearing 100% polyester underwear. They were found to have low serum progesterone levels and had miscarriages in the first month of pregnancy.
This could have been caused by the electrostatic effect of the polyester but the numbers were too small to be conclusive. The good news though is that both went on to have successful pregnancies once the polyester underwear was removed.
These studies are shocking no matter which way you look at them. They all suggest that wearing polyester underwear can cause infertility in some way or other.
But we must remember that they were carried out by one scientist and have not, until now, been replicated by others. They were also carried out on small groups and not on humans in all cases (which I am in no way advocating). We must take them with a pinch of salt and remember that the theories derived are just that, they are theories and not facts.
But I won’t forget them nonetheless.
THE ROLE OF CORE BODY TEMPERATURE
It’s not surprising when you think about it that the type of underwear you choose can make a difference. Electrostatic potential aside, cotton underwear and underwear made from natural fabrics tend to breathe better, helping to regulate testicular temperature and fostering higher sperm concentration.
The genital area, for optimal reproductive health, requires a slightly lower temperature than the rest of the body. Polyester, with its heat-retaining properties, can disrupt this delicate balance.
When opting for natural fabrics, organic cotton and other natural materials like hemp are even better as they’re not treated with any of the nasty chemicals traditional cotton is such as pesticides and insecticides.
CHEMICALS ASSOCIATED WITH POLYESTER AND THEIR EFFECTS ON FERTILITY
Polyester garments and those made from synthetic materials such as polyamide, nylon and acrylic might raise body temperature and even cause electrostatic potential, but they can harbor an array of toxic chemicals too.
THE DISTURBING EFFECTS OF FLAME RETARDANTS ON FERTILITY
Many synthetic materials, in addition to polyester, contain harmful fire retardants, which have also been linked to fertility problems. One study published in Scientific American suggested a link between flame retardants and reduced human fertility. The study found that women exposed to high levels of flame retardants took substantially longer to get pregnant.
The study also found that cushions, carpet padding, and other household items contain hormone-disrupting flame retardants called polybrominated diphenyl ethers (PBDEs). These are endocrine disruptors, known to cause adverse health effects.
A further study, published in Springerlink in 2020, show that they can disrupt the balance of sex hormones in the body and cause problems with the reproductive system.
OTHER FERTILITY-AFFECTING CHEMICALS USED IN POLYESTER CLOTHING
Phthalates, another chemical used in polyester production and to make plastics more durable and flexible are known to disrupt reproductive hormones.
According to the European Chemicals Agency, some phthalates can interfere with our hormonal systems and cause allergies. And a further article published in Science Direct linked phthalates to reduced testosterone production meaning lower sperm counts and increased fertility problems in men.
Meanwhile, Bisphenol A or BPA, commonly known to be found in plastic bottles, is also lurking in lycra or spandex in much of our polyester clothing. Studies have linked this to problems with the female reproductive system too.
Other chemicals used in the manufacture of clothes such as PFAs, heavy metals, NPEs and VOCs have also all been found to affect our fertilily in some way too. For more on this see our article on the toxic and dangerous chemicals in our clothes.
The list of chemicals in our wardrobe making it harder for us to mate just gets longer.
It’s a mammoth concern, particularly in an era where toxic exposure from industrial chemicals, personal care products, and even water bottles are all around us. These toxins are omnipresent in our daily lives, seeping into our bodies through multiple routes, including skin exposure.
SO DOES POLYESTER UNDERWEAR CAUSE INFERTILITY?
Given all of the evidence, including Shafik’s studies and other research on the toxins associated with polyester, it is hard to deny that wearing polyester underwear doesn’t affect our fertility in one way or another.
But reproductive health isn’t the only concern. Our hormone balance affects our overall well-being too.
It’s time to acknowledge that our supposedly innocent style of underwear, the choice of fabric, and the presence of synthetic materials in our clothing are not just mundane choices; they can significantly impact our health.
The late Professor Ahmed Shafik from the Faculty of Medicine at Cairo University is one person that studied this subject intensively. The professor, famous among other things as a pelvic surgeon and personal physician to many dignitaries and world leaders, published around 500 studies and wrote over 1,000 articles in his career. These included several studying whether wearing polyester underwear could cause infertility and reduced sexual function.
Here’s a brief summary: in all studies the participants were divided into polyester and non-polyester underwear-wearing groups. In all cases the polyester underwear-wearing subjects fared worse.
STUDY ONE (1992): HOW WEARING POLYESTER UNDERWEAR CAN LOWER YOUR SPERM COUNT TO ZERO
The study name says it all: “The contraceptive efficacy of polyester-induced azoospermia in normal men”. Azoospermia means there is no sperm in the ejaculate. This was induced by the 14 men in the study wearing a polyester scrotal sling day and night for 12 months.
They became azoospermic after approximately 20 weeks and the volume of their testicles fell significantly. Their partners were able to stop taking oral contraceptives and non became pregnant during the study. Approximately 22 weeks after the study finished, sperm count and testicular volume went back to pre-study levels. All five couples that wanted to did eventually conceive.
So, wearing polyester underwear can actually serve as a contraceptive. In these cases it did cause temporary infertility. The study, reported in Science Direct, found that this was due to two factors: an electrostatic field effect and a thermoregulatory effect.
It’s true that most men don’t wear a polyester sling day and night, but many wear their underwear day and night so perhaps it’s not far off.
STUDY TWO (1993): THE EFFECT ON SPERM OF WEARING DIFFERENT TYPES OF FABRIC UNDERWEAR
In this study a group of 31 dogs were used. 12 wore polyester and 12 cotton underwear continuously for 2 years, while 7 control dogs wore nothing. The underwear was deliberately loose-fitting in the scrotal region to avoid the effect of the underwear causing heat.
After 2 years the underwear was removed and, while the cotton-wearing and control dogs showed no differences, the polyester-wearing dogs showed statistically significant reductions in sperm count, motile sperm, more abnormal forms and the testicles showed degenerative changes.
All effects were reversed 12 months after removing the underwear in 10 of the dogs while 2 continued to be “oligozoospermic” (meaning low sperm count). It was concluded that this was probably caused by the electrostatic potential of the polyester underwear.
STUDY THREE (1992): THE EFFECT ON THE SURFACE OF THE HUMAN SCROTUM OF DIFFERENT FABRIC TYPES
Here, 21 healthy men were split into three groups wearing either 100% polyester, 100% cotton or a 50:50 polycotton mix underpants for just one hour in the day and one hour at night (repeated four times).
The cotton wearing subjects showed none and the polyester wearing subjects had the highest electrostatic potentials with the polycotton wearing guys less than half that of the 100% polyester wearers. The effect was higher during the day which was thought to be because of the increased friction and heat caused during the day through movement.
It is thought that this electrostatic potential causes an electrostatic field across the “scrotal contents” which may lead to the abnormal development of sperm. This suggests that wearing polyester underwear could definitely cause some kind of infertility.
STUDY FOUR (1993): THE EFFECT OF DIFFERENT TYPES OF TEXTILES ON SEXUAL ACTIVITY
As much as unhealthy sperm can negatively affect fertility, outside of the clinic, the painful issue of sexual performance can too. This study looked into just that across a group of 75 rats.
These were split into 5 groups including one control and four groups wearing 100% cotton, 100% wool, 100% polyester or a 50:50 polycotton mix underwear. Their sexual behaviour was assessed after 6 and 12 months of wearing the garments and 6 months after removing them, plus electrostatic potential was measured.
All groups (apart from the control) showed a more marked reduction in “intromission to mounting ratio” after 12 rather than 6 months. At 6 months there was no notable difference in the cotton and wool wearing rats. The 100% polyester group showed the highest reduction followed by the polyester-cotton mix. Six months after removing the underwear all groups returned to normal. It was thought that the electrostatic fields generated in the intrapenile structures could explain the reduced sexual activity.
While this study was carried out 30 years ago and has not been repeated by other scientists, and on rats rather than humans, it gives you shocking food for thought.
STUDY FIVE (2008): THE EFFECT OF DIFFERENT TYPES OF TEXTILES ON CONCEPTION
After several years, it seems that Professor Shafik turned his attention to the female concern.
In this study, 35 female dogs were split into five groups and wore either pure polyester, pure cotton, pure wool, a 50:50 polyester-cotton mix underwear or no underwear for a year. Eight of the polyester wearing dogs had “diminished serum progesterone in the oestrus of the oestrous cycle” and did not get pregnant during the study either by mating or insemination. However after the study ended they were able to conceive.
It is thought that this is because the polyester causes an electrostatic potential on the skin and this inhibits the ovaries funcioning properly resulting in reduced progesterone.
STUDY SIX (2007): THE EFFECT OF DIFFERENT TYPES OF TEXTILES ON PREGNANCY
This study was less conclusive but in a group of 35 pregnant dogs, split like the study above, all went on to have successful pregnancies apart from two of the seven wearing 100% polyester underwear. They were found to have low serum progesterone levels and had miscarriages in the first month of pregnancy.
This could have been caused by the electrostatic effect of the polyester but the numbers were too small to be conclusive. The good news though is that both went on to have successful pregnancies once the polyester underwear was removed.
These studies are shocking no matter which way you look at them. They all suggest that wearing polyester underwear can cause infertility in some way or other.
But we must remember that they were carried out by one scientist and have not, until now, been replicated by others. They were also carried out on small groups and not on humans in all cases (which I am in no way advocating). We must take them with a pinch of salt and remember that the theories derived are just that, they are theories and not facts.
But I won’t forget them nonetheless.
THE ROLE OF CORE BODY TEMPERATURE
It’s not surprising when you think about it that the type of underwear you choose can make a difference. Electrostatic potential aside, cotton underwear and underwear made from natural fabrics tend to breathe better, helping to regulate testicular temperature and fostering higher sperm concentration.
The genital area, for optimal reproductive health, requires a slightly lower temperature than the rest of the body. Polyester, with its heat-retaining properties, can disrupt this delicate balance.
When opting for natural fabrics, organic cotton and other natural materials like hemp are even better as they’re not treated with any of the nasty chemicals traditional cotton is such as pesticides and insecticides.
CHEMICALS ASSOCIATED WITH POLYESTER AND THEIR EFFECTS ON FERTILITY
Polyester garments and those made from synthetic materials such as polyamide, nylon and acrylic might raise body temperature and even cause electrostatic potential, but they can harbor an array of toxic chemicals too.
THE DISTURBING EFFECTS OF FLAME RETARDANTS ON FERTILITY
Many synthetic materials, in addition to polyester, contain harmful fire retardants, which have also been linked to fertility problems. One study published in Scientific American suggested a link between flame retardants and reduced human fertility. The study found that women exposed to high levels of flame retardants took substantially longer to get pregnant.
The study also found that cushions, carpet padding, and other household items contain hormone-disrupting flame retardants called polybrominated diphenyl ethers (PBDEs). These are endocrine disruptors, known to cause adverse health effects.
A further study, published in Springerlink in 2020, show that they can disrupt the balance of sex hormones in the body and cause problems with the reproductive system.
OTHER FERTILITY-AFFECTING CHEMICALS USED IN POLYESTER CLOTHING
Phthalates, another chemical used in polyester production and to make plastics more durable and flexible are known to disrupt reproductive hormones.
According to the European Chemicals Agency, some phthalates can interfere with our hormonal systems and cause allergies. And a further article published in Science Direct linked phthalates to reduced testosterone production meaning lower sperm counts and increased fertility problems in men.
Meanwhile, Bisphenol A or BPA, commonly known to be found in plastic bottles, is also lurking in lycra or spandex in much of our polyester clothing. Studies have linked this to problems with the female reproductive system too.
Other chemicals used in the manufacture of clothes such as PFAs, heavy metals, NPEs and VOCs have also all been found to affect our fertilily in some way too. For more on this see our article on the toxic and dangerous chemicals in our clothes.
The list of chemicals in our wardrobe making it harder for us to mate just gets longer.
It’s a mammoth concern, particularly in an era where toxic exposure from industrial chemicals, personal care products, and even water bottles are all around us. These toxins are omnipresent in our daily lives, seeping into our bodies through multiple routes, including skin exposure.
SO DOES POLYESTER UNDERWEAR CAUSE INFERTILITY?
Given all of the evidence, including Shafik’s studies and other research on the toxins associated with polyester, it is hard to deny that wearing polyester underwear doesn’t affect our fertility in one way or another.
But reproductive health isn’t the only concern. Our hormone balance affects our overall well-being too.
It’s time to acknowledge that our supposedly innocent style of underwear, the choice of fabric, and the presence of synthetic materials in our clothing are not just mundane choices; they can significantly impact our health.
