Red Light Therapy to Promote Fertility and Conception

Cases of infertility and subfertility are on the rise among men and women worldwide. Infertility refers to a couple’s inability to conceive after 6 to 12 months of trying.
Subfertility refers to a lower probability of conception compared to other couples. It is estimated that 12% to 15% of couples who want children are unable to conceive.As a result, fertility treatments such as in vitro fertilization (IVF), intrauterine insemination (IUI), hormone or medication therapy, and surgery are rapidly gaining popularity.

Light therapy (sometimes referred to as photobiomodulation, low-level laser therapy, red light therapy, or cold laser therapy) shows great promise in improving health in various parts of the body and has been studied for its potential to enhance fertility in both women and men. Is light therapy an effective fertility treatment?

Infertility is a global crisis affecting both men and women, and birth rates are falling rapidly, with some countries experiencing even steeper declines than others. In Denmark, 10% of babies born today are conceived through in vitro fertilization (IVF) or other assisted reproductive technologies.

In Japan, one in six couples is infertile. The Japanese government recently introduced policies to cover IVF costs for couples in an effort to curb the worsening fertility crisis. To boost its sluggish birth rate, the Hungarian government has implemented a policy granting women who give birth to four or more children a lifetime exemption from income tax.In some European countries, the total fertility rate per woman is as low as 1.2, and in Singapore, it is even as low as 0.8.

Global birth rates have been declining since the 1950s, and in some regions, the decline began even earlier. Not only is human infertility becoming increasingly prevalent, but various animals, such as farm animals and livestock, are also facing fertility issues. The decline in birth rates is partly due to socioeconomic factors—couples are choosing to delay having children until their natural fertility has declined.Another contributing factor is environmental, dietary, and hormonal factors. For example, over the past 40 years, the average sperm count in men has dropped by 50%. Consequently, men today produce only half the number of sperm that their fathers and grandfathers did in their youth. Female reproductive disorders, such as polycystic ovary syndrome (PCOS), currently affect up to 10% of women.Endometriosis (a condition in which endometrial tissue grows in other parts of the reproductive system) affects another 10% of women, meaning nearly 200 million women worldwide are affected. Light therapy is a novel treatment for infertility. Although it falls under the category of assisted reproductive technology (ART) alongside in vitro fertilization (IVF), it is more affordable, non-invasive, and more accessible.Light therapy has been widely used to treat eye conditions, pain, and wound healing, and its efficacy for various diseases and body parts is currently being actively researched worldwide. Currently, most light therapy research for infertility comes from Japan and Denmark, particularly in the area of female fertility.

Female Fertility
Approximately half of all cases of infertility in couples are caused solely by female factors, while another 20% result from combined male and female fertility issues. Therefore, about seven out of ten conception problems can be resolved by improving female reproductive health.

Thyroid issues and polycystic ovary syndrome (PCOS) are among the leading causes of infertility, but both conditions are frequently misdiagnosed (click here to learn more about thyroid health and light therapy). Endometriosis, uterine fibroids, and other uterine growths are also significant causes of infertility.Among those struggling with infertility, over 30% have endometriosis to varying degrees. Other common causes of infertility include blocked fallopian tubes, internal scarring from surgery (including cesarean sections), and ovulation issues other than PCOS (such as anovulation or irregular ovulation).In many cases, the cause of infertility remains unknown. In some instances, conception and successful implantation occur, but a miscarriage occurs during the early to mid-pregnancy period. With the rapid rise in infertility issues, infertility treatment and research have correspondingly increased.

Japan is one of the countries facing the most severe fertility crisis in the world, and its IVF usage rate ranks among the highest globally. They are also pioneers in researching the effectiveness of light therapy in improving female fertility… Light Therapy and Female Fertility Light therapy utilizes red light, near-infrared light, or a combination of both. The ideal type of light for a specific application varies depending on the body part. In terms of female fertility, the primary target tissues are the uterus, ovaries, fallopian tubes, and related hormonal systems (such as the thyroid and brain).All of these tissues are located inside the body (unlike male reproductive organs), so light with the greatest penetration is required, as only a very small fraction of the light applied to the skin can penetrate to tissues such as the ovaries. Even when using wavelengths with optimal penetration, the amount of light that penetrates is still very small, so very high light intensity is also necessary.

Near-infrared light with wavelengths between 720 nm and 840 nm has the strongest penetration into biological tissues. Due to its unique penetration depth, this wavelength band is referred to as the “near-infrared window” (for penetration into biological tissues). In their exploration of using light therapy to improve female infertility, researchers have generally chosen the 830-nm near-infrared wavelength for their studies (1–6).Light at this 830-nanometer wavelength not only penetrates deeply but also has a significant stimulatory effect on cells, improving cellular function. The Neck Light Some early Japanese studies were based on the “proximal-priority theory.” The fundamental premise of this theory is that the brain is the body’s master control center, and all other organs and hormonal systems are regulated by it. Whether this view is correct or not, it holds some merit.Researchers used 830-nanometer near-infrared light to irradiate the necks of infertile Japanese women (1), hoping that the light’s direct and indirect (via the bloodstream) effects on the brain would ultimately improve systemic hormonal and metabolic conditions (3), particularly within the reproductive system.The results were encouraging: many women previously diagnosed with “severe infertility” not only successfully conceived but also gave birth without complications (1, 2, 4), welcoming their babies into the world.

Following studies on light therapy applied to the neck, researchers became interested in whether light therapy could improve the success rates of both natural conception and in vitro fertilization (IVF). In vitro fertilization (IVF) is often viewed as a last resort after traditional methods of conception have failed.The cost of each cycle can be extremely high, often unaffordable for many couples, with some even taking out loans to cover the expenses.

IVF success rates can be low, particularly for women aged 35 and older. Given the high costs and low success rates, improving the success of IVF cycles is crucial for achieving pregnancy. It would be even more appealing if natural conception were possible after IVF failure, thereby avoiding the need for IVF. The rate of embryo implantation—which is critical for both IVF and natural conception—is believed to be linked to mitochondrial function (8). Impaired mitochondrial function can hinder the function of the egg cell. The mitochondria in the egg cell are inherited from the mother, and some women, particularly as they age, may have mitochondrial DNA mutations.

Red and near-infrared light therapy acts directly on mitochondria, improving their function and reducing issues such as DNA mutations. This explains why a Danish study showed that two-thirds of women who had previously failed IVF treatments successfully conceived (even naturally) through light therapy. Among them was even a 50-year-old woman who successfully conceived. Light on the Abdomen The protocol used in this Danish study (7) involved near-infrared light therapy three times a week, with light directed directly at the abdomen at a relatively high dose. If a woman did not conceive during a given menstrual cycle, treatment continued into the next cycle. Out of a sample of 400 women with a history of infertility, as many as 260 successfully conceived after receiving near-infrared light therapy.The decline in egg quality does not appear to be irreversible. This study has raised questions about assisted reproductive technology (ART), specifically the practice of removing a woman’s egg nucleus and transplanting it into a donor’s egg cell (known as mitochondrial transfer, or “three-parent babies”)—is such a procedure truly necessary when a woman’s own egg cells could potentially be restored through non-invasive therapies?

Direct light therapy applied to the abdomen (targeting the ovaries, uterus, fallopian tubes, oocytes, etc.) is believed to work in two ways. First, it optimizes the environment of the reproductive system, ensuring that oocytes are released during ovulation, pass smoothly through the fallopian tubes, and implant in a healthy uterine lining with good blood flow, thereby forming a healthy placenta, among other benefits (23).The second mechanism involves directly improving the health of the egg cell. Compared to other cells, egg cells (oocytes) require a significant amount of energy during cell division and growth. This energy is provided by mitochondria—the cellular structures targeted by phototherapy. Declining mitochondrial function is considered a key cellular cause of infertility(8).

This may explain the majority of “unexplained” infertility cases as well as the decline in fertility with age—the egg cell is unable to produce sufficient energy. Evidence that egg cells require and utilize more energy is that the number of mitochondria in an egg cell is 200 times that of other ordinary cells. This implies that, compared to other cells in the body, egg cells have 200 times the potential to benefit from phototherapy.Of all the cells in the human body, regardless of gender, egg cells may be the type that benefits most from red and near-infrared light therapy. The only challenge is how to get the light to penetrate the ovaries (discussed in detail below). The combined effects of these two light therapies, or “photobiomodulation,” create a healthy, youthful environment conducive to supporting embryo growth. Male Fertility Male factors account for approximately 30% of infertility cases in couples, while combined male and female factors account for another 20%.

Therefore, improving male reproductive health can often resolve a couple’s fertility issues. Male fertility problems are typically associated with declining testicular function, which leads to abnormal sperm.Additionally, other causes include retrograde ejaculation, dry ejaculation, anti-sperm antibodies, and various genetic and environmental factors. Cancer and infections can also permanently damage the testes’ ability to produce sperm. Behaviors such as smoking and frequent alcohol consumption have significant negative effects on sperm count and quality. A father’s smoking can even reduce the success rate of IVF cycles by half (17). However, environmental and dietary factors can improve sperm production and quality, such as optimizing zinc status and red light therapy (9–16, 18–22, 24). Light therapy is relatively unknown as a treatment for fertility issues, but a quick search on PubMed reveals hundreds of studies.

Light Therapy and Male Fertility

Light therapy (also known as photobiomodulation) involves applying visible red light or invisible near-infrared light to the human body, and there has been extensive research on its effects on sperm health. So which type of light is best? What is the specific wavelength? Is it red light or near-infrared light? Currently, red light with a wavelength of 670 nm is the most extensively studied and the most effective wavelength range for improving male reproductive health and sperm quality. Faster, Stronger Sperm Cells Research shows that even a single red light treatment can significantly improve sperm motility (swimming speed):

Sperm motility or speed is crucial for fertility because if the speed is insufficient, sperm cannot reach the egg and fertilize it.There is strong evidence that light therapy can improve sperm motility (9–16, 18–22); therefore, using the appropriate light therapy device is crucial for any couple facing infertility. Improved sperm motility through light therapy can even compensate for low sperm count, as sperm can still reach and fertilize the egg (even if only one) despite low concentration.