Infertility and subfertility are on the rise, in both women and men, all across the world.
Being infertile is the inability, as a couple, to get pregnant after 6 – 12 months of trying. Subfertility refers to having a reduced chance of becoming pregnant, relative to other couples.
It is estimated that 12-15% of couples want, but are unable, to conceive. Due to this, fertility treatments such as IVF, IUI, hormonal or drug approaches, surgical procedures, and more, are rapidly increasing in popularity.
Light therapy (sometimes known as photobiomodulation, LLLT, red light therapy, cold laser, etc.) shows promise for improving the health of a lot of different body parts, and has been studied for both female fertility and male fertility. Is light therapy a valid fertility treatment? In this article we will discuss why light might be all you need…
Infertility is a worldwide crisis for both males and females, with fertility rates rapidly decreasing, in some countries more so than others. 10% of all babies currently born in Denmark were conceived through the help of IVF and similar reproductive technologies. 1 in 6 couples in Japan are infertile, with the Japanese government recently intervening to pay for couple’s IVF costs in order to stop the unfolding population crisis. The government in Hungary, desperate to increase low birth rates, has made it so women that have 4 children or more will be exempt for life from having to pay income tax. The births per woman in some European countries is as low as 1.2, and even as low as 0.8 in Singapore.
Birth rates have been declining worldwide, since at least the 1950s and in some regions before that. It’s not just human infertility that is on the rise, various species of animals are also having problems, such as farm and domestic animals. Part of this decline in birth rates is due to socioeconomic factors – couples are choosing to try for children later, when natural fertility has already declined. Another part of the decline is environmental, dietary and hormonal factors. For example sperm counts in the average male have decreased by 50% in the last 40 years. So men today are only producing half as many sperm cells as their fathers and grandfathers did back in their youth. Female reproductive disorders such as polycystic ovarian syndrome (PCOS) now affect up to 10% of women. Endometriosis (a condition where uterine tissue grows in other areas of the reproductive system) also affects another 1 in 10 women, so almost 200 million women worldwide.
Light therapy is a novel treatment idea for infertility, and although it falls under the same ‘ART’ (assisted reproductive technology) classification as IVF, it is a much cheaper, non-invasive, and easier to access treatment. Light therapy is very well established for the treatment of eye health issues, pain problems, would healing, etc., and is being vigorously studied across the world for a wide range of conditions and body parts. Most of the current light therapy for fertility research is coming out of 2 countries – Japan and Denmark – especially for research on female fertility.
50%, about half, of all infertile couples are due to solely female factors, with a further 20% being a combination of both female and male subfertility. So around 7 out of every 10 conception issue can be improved by addressing female reproductive health.
Thyroid problems and PCOS are among the leading causes of infertility, both being severely underdiagnosed (Read more about thyroid health and light therapy here). Endometriosis, fibroids and other unwanted internal growths account for another large percentage of infertility cases. When a woman is infertile, 30%+ of the time there will be some degree of endometriosis. Other common infertility causes are; fallopian tube blockages, internal scarring from surgery (including C-sections), and other ovulation problems besides pcos (anovulation, irregular, etc.). In many cases the cause of infertility is just unexplained – it’s not known why. In some cases conception and egg implantation occur, but at a later point in early pregnancy there is a miscarriage.
With the rapid rise of fertility problems, there has been a commensurate rise in infertility treatments and research. Japan as a country has one of the worst fertility crises in the world, with one of the highest rates of IVF use. They are also pioneers in studying the effects of light therapy on improving female fertility….
Light therapy and female fertility
Light therapy uses either red light, near infrared light, or a combination of both. The ideal type of light for a specific purpose varies based on the part of the body.
When looking at female fertility specifically, the primary targets are the uterus, ovaries, fallopian tubes and general hormonal systems (thyroid, brain, etc.). All of these tissues are inside the body (unlike male reproductive parts), and so the type of light with the best penetration is necessary, as only a small percentage of the light hitting the skin will penetrate down into tissues like ovaries. Even with the wavelength that gives the optimal penetration, the amount that penetrates is still very small, and so a very high intensity of light is required as well.
Near infrared light at wavelengths between 720nm and 840nm have the best penetration into biological tissue. This range of light is known as the ‘Near Infrared Window (into biological tissue)” because of the unique properties of passing deep into the body. Researchers looking at improving female infertility with light have overwhelmingly selected the 830nm near infrared wavelength for study(1-6). This 830nm wavelength not only penetrates well, but also has potent effects on our cells, improving their function.
Light on the neck
Some of the early research out of Japan was based on ‘The Proximal Priority Theory’. The basic idea is that the brain is the master organ of the body and all other organs and hormonal systems are downstream from the brain. Whether or not this idea is correct, there is some truth to it. Researchers used 830nm near infrared light on the neck of infertile Japanese women(1), hoping that the direct and indirect (via the blood) effects on the brain would ultimately lead to better hormonal and metabolic situations across the entire body(3), especially the reproductive system. The results were great, with a high percentage of women previously deemed ‘severely infertile’ not only getting pregnant, but also achieving live births(1,2,4) – welcoming their baby into the world.
Following on from the studies using light on the neck, researchers were interested in whether or not light therapy might improve the success rates of natural pregnancies and IVF.
In vitro fertilization is known as a last resort when traditional methods of conception have failed. The cost per cycle can be very high, even unfeasible for many couples, with others taking out loans as a gamble to fund it. The success rates of IVF can be very low, especially in women aged 35 years or more. Given the high cost and low success rate, improving the chances of an IVF cycle is critical to achieve the goal of pregnancy. Eliminating the need for IVF and getting pregnant naturally after failed cycles is even more appealing.
Implantation rates of the fertilised egg (critical for both IVF and regular pregnancy) are thought to be related to mitochondrial function(8). Lower performing mitochondria hinder the functioning of the egg cell. The mitochondria found in egg cells are inherited from the mother, and can have DNA mutations in certain women, especially as age advances. Red and near infrared light therapy work directly on the mitochondria, improving the function and reducing issues like DNA mutations. This explains why a study from Denmark showed that two-thirds of women who previously had failed IVF cycles achieved a successful pregnancy (even natural pregnancies) with light therapy. There was even a case of a 50 year old woman getting pregnant.
Light on the abdomen
The protocol used in this study from Denmark(7) involved 3 near infrared light therapy sessions per week, with the light being directly applied to the abdomen, at quite a large dose. If the woman did not conceive during the current menstrual cycle, treatments continued into the next. Out of a sample of 400 previously infertile women, a whopping 260 of them were able to conceive following near infrared light treatments. Declining egg quality is not an irreversible process, it would seem. This research raises questions over the ART process of removing a woman’s egg nucleus and inserting it into the egg cells of a donor (known as mitochondrial transfer, or 3-person/parent babies) – is it really necessary when a woman’s own egg cells can be potentially restored with a non-invasive therapy.
Using light therapy directly on the abdomen (to target the ovaries, uterus, fallopian tubes, egg cells, etc.) is thought to work in 2 ways. Firstly is optimises the environment of the reproductive system, ensuring egg cells are released during ovulation, can travel down the fallopian tubes, and can implant into a healthy uterus wall with good blood flow, a healthy placenta can form, etc(23). The other mechanism involves improving the health of the egg cell directly. Oocyte cells, or egg cells, require huge amounts of energy compared to other cells for the processes related to cell division and growth. This energy is provided by mitochondria – the part of a cell affected by light therapy. Declining mitochondrial function can be seen as the key cellular cause of infertility(8). This may be the key explanation for most cases of ‘unexplained’ fertility and why fertility declines with advancing age – the egg cells just can’t make enough energy. Evidence that they require and use so much more energy is found by the fact that there are 200 times more mitochondria in egg cells when compared to other regular cells. That’s 200 times more potential for effects and benefits from light therapy relative to other cells in the body. Of every cell in the entire human body, male or female, the egg cell may be the type that receives the most drastic enhancements from red and near infrared light therapy. The only problem is getting the light to penetrate down to the ovaries (more on that below).
Both of these light therapy or ‘photobiomodulation’ effects together create a healthy and youthful environment, suitable to support a growing embryo.
Males are the cause of around 30% of infertile couples, with a combination of male and female factors accounting for another 20% on top of that. So half of the time, improving the male reproductive health will resolve a couple’s fertility issues. Fertility problems in males typically correspond with lowered testicular function, leading to a problem with the sperm. There are various other causes too, like; retrograde ejaculation, dry ejaculate, antibodies that attack sperm, and a myriad of genetic and environmental factors. Cancers and infections can permanently damage the ability of the testes to produce sperm.
Things like cigarette smoking and regular alcohol consumption have a dramatically negative effect on sperm counts and sperm quality. Paternal smoking even reduces the success rate of IVF cycles by half(17).
However, there are environmental and dietary factors that can improve sperm production and quality, such as improved zinc status and red light therapy(9-16, 18-22, 24).
Light therapy is relatively unknown for treating fertility issues, but a quick search on pubmed reveals hundreds of studies.
Light Therapy and male fertility
Light therapy (a.k.a. photobiomodulation) involves the application of visible red, or non-visible near infrared, light to the body and is very well studied for sperm health.
So which type of light is best and which specific wavelength? Red, or near infrared?
Red light at 670nm is currently the most well researched and effective range for improving male reproductive health and sperm quality.
Faster, stronger sperm cells
Studies show that even after just a single session of red light therapy, sperm motility (swim speed) improves significantly:
Motility or speed of the sperm cells is of critical importance for fertility, as without sufficient speed, the sperm will never make the journey to reach the female’s egg cell and fertilise it. With strong, clear evidence that light therapy improves motility(9-16, 18-22), using an appropriate light therapy device seems essential for any infertile couple. The improved motility from light therapy can even overcome the issue the low sperm counts, because the low concentration of sperm will still be able to reach and (one of them) fertilise the egg cell.
Millions more sperm cells
Light therapy doesn’t just improve motility, various studies show how it can also improve sperm counts/concentration, giving not just faster sperm, but more of them(7,13,15).
Almost every cell in our body has mitochondria – the target of red light therapy – including Sertoli Cells. These are the sperm producing cells of the testes – the place where sperm is manufactured. Proper functioning of these cells is essential for all aspects of male fertility, including sperm counts.
Studies point to light therapy improving the quantity of Sertoli Cells in the male testicles, their performance (and so the amount of sperm cells/count that they produce), and also decreasing the production of abnormal sperm cells. Overall sperm counts have been shown to improve by 2-5 times in males with previously low counts. In one study from Denmark(7), sperms counts increased from 2 million per ml to over 40 million per ml with only one treatment to the testicles.
Higher sperm counts, faster sperm motility, and less abnormal sperm are some of the key reasons why light therapy is an essential part of improving any male fertility issue.
Avoid heat at all costs
An important note on light therapy for the testes:
Human testes descend from the body into the scrotum for an important reason – they require a lower temperature to operate at(25). At the normal body temperature of 37°C (98.6°F) they can’t produce sperm. The process of spermatogenesis requires a temperature drop of between 2 and 5 degrees from core body temperature. It is important to consider this temperature requirement when selecting a light therapy device for male fertility – the most energy efficient type of lighting must be used – LEDs. Even with LEDs, there is a mild warming effect felt after long sessions. Applying the appropriate dose with the appropriate wavelength of energy efficient red light is key to improving male fertility. More info below.
Read more about red light therapy and male reproductive health:
The mechanism – what red/infrared light does
To properly understand why red/IR light helps with both male and female fertility, we need to know how it works on a cellular level.
The effects of red and near infrared light therapy are thought to come from the interaction with our cells’ mitochondria. This ‘photobiomodulation’ happens when the appropriate wavelengths of light, between 600nm and 850nm, are absorbed by a mitochondrion, and ultimately lead to better energy production and less inflammation in the cell.
One of the key targets of light therapy is an enzyme called Cytochrome C Oxidase – part of the electron transport chain process of energy metabolism. It is understood that there are several other parts of the mitochondria that are also affected. These mitochondria are extremely prevalent in egg and sperm cells.
Shortly after a light therapy session, it is possible to see the release of a molecule called Nitric Oxide from cells. This NO molecule actively inhibits respiration, blocking energy production and oxygen consumption. So, removing it from the cell restores the normal healthy function. Red and near infrared light are thought to dissociate this stress molecule from the Cytochrome C Oxidase enzyme, restoring the healthy level of oxygen utilisation and energy production.
Light therapy also has an effect on the water inside our cells, structuring it with more space between each molecule. This changes the chemical and physical properties of the cell, meaning that nutrients and resources can enter more readily, toxins can be expelled with less resistance, enzymes and proteins work more efficiently. This effect on cellular water applies not just directly inside the cells, but also outside it, in the extracellular space and tissues like blood.
This is just a quick summary of 2 potential mechanisms of action. There are possibly more, not fully understood, beneficial effects that happen on a cellular level to explain the results from light therapy.
All of life interacts with light – plants need light for food, humans need ultraviolet light for vitamin D, and as all the studies show, red and near infrared light are essential to humans and various animals for a healthy metabolism and even reproduction.
The effects of light therapy are not just seen in the target area of the session, but also systemically. For example a session of light therapy on your hand can provide benefits to the heart. A session of light therapy on the neck can provide benefits to the brain, which can in turn improve hormone production/status and lead to dramatic whole body health improvements. Light therapy is essential for removing cellular stress and enabling your cells to function normally again and the cells of the reproductive system are no different.
- Light therapy has been studied for human/animal fertility for decades
- Near Infrared light studied to improve fertility status in females
- Improves energy production in egg cells – critical for pregnancy
- Red Light therapy is shown to improve energy production in Sertoli cells and sperm cells, which leads to increased sperm counts and quality
- All aspects of reproduction (male and female) require large amounts of cellular energy
- Light therapy helps cells to meet the energy demands
- LEDs and lasers are the only devices that are well studied.
- Red wavelengths between 620nm and 670nm are ideal for males.
- Near Infrared light around the 830nm range seems best for female fertility.
- Personal Overview of the Application of LLLT in Severely Infertile Japanese Females. Ohshiro. 2012
- Treatment Of Female Infertility Incorporating Low-Reactive Laser Therapy (LLLT): An Initial Report. Iwahata et al. 2005
- The Proximal Priority Theory: An Updated Technique in Low Level Laser Therapy with an 830 nm GaAlAs Laser. Ohshiro. 2012
- Analysis of the curative effect of GaAlAs diode laser therapy in female infertility. Taniguchi et al. 2010
- Proximal Priority Treatment Using The Neck Irradiator For Adjunctive Treatment of Female Infertility. Fujii et al. 2007
- A case where low reactive level laser therapy was thought to be extremely effective in the treatment of female infertility. Fujii et al. 2004
- PhotoBioModulation for Infertility. EC Gynaecology 8.9. 2019
- Why do older women have poor implantation rates? A possible role of the mitochondria. Bartmann et al. 2004
- Sperm motility enhancement with low level laser therapy. Harrison et al. 2008
- Effect of 830-nm diode laser irradiation on human sperm motility. Yazdi et al. 2014
- Photobiomodulation with light-emitting diodes improves sperm motility in men with asthenozoospermia. Frangez et al. 2015
- Photobiomodulation with 810 nm Wavelengths Improves Human Sperms’ Motility and Viability In Vitro. Safian et al. 2020
- Effectiveness of low level laser therapy for treating male infertility. Moskvin et al. 2018
- Red light improves spermatozoa motility and does not induce oxidative DNA damage. Preece et al. 2017
- Photobiomodulation therapy for male infertility. Zupin et al. 2020
- The Possible Application of low Reactive-Level Laser Therapy (Lllt) in the Treatment of Male Infertility. Hasan et al. 1989.
- The Effects of Cigarette Smoking on Male Fertility. Kovac et al. 2016
- Effect of 655-nm diode laser on dog sperm motility. Corral-Baqués et al. 2005
- The effect of low-level laser irradiation on dog spermatozoa motility is dependent on laser output power. Corral-Baqués et al. 2009
- The Effects of Red Light on Mammalian Sperm Rely upon the Color of the Straw and the Medium Used. Catalán et al. 2021
- Red-Light Irradiation of Horse Spermatozoa Increases Mitochondrial Activity and Motility through Changes in the Motile Sperm Subpopulation Structure. Catalán et al. 2020
- Photobiomodulation improved stereological parameters and sperm analysis factors in streptozotocin-induced type 1 diabetes mellitus. Dadras et al.2018
- Low level laser therapy (LLLT) modulates ovarian function in mature female mice. Oubiña et al. 2019
- Red LED Light Acts on the Mitochondrial Electron Chain of Donkey Sperm and Its Effects Depend on the Time of Exposure to Light. Catalán et al. 2020
- Amelioration of heat stress-induced damage to testes and sperm quality. Shahat et al. 2020