If you’re trying to conceive, you may have been recommended—by a friend, family member, or even an ad online—a specific supplement or ingredient to boost your fertility. The market for fertility supplements is huge, with tablets, chews, and even teas available that claim to support natural fertility or improve outcomes from fertility treatments like IVF.
But do these fertility supplements really work, and are they worth the money? Here, we’ll review the most commonly sold fertility supplements for women to understand if (and how) they impact fertility and pregnancy rates, according to research.
Are fertility supplements evidence-based?
An evidence-based practice—whether it be a medication, intervention or therapy, complementary treatment, or even the way a provider communicates about care—is a practice that’s been thoroughly examined via appropriate research and found to make a significant difference in patient outcomes. “Evidence-based” is the gold standard in healthcare. Are fertility supplements evidence-based? Overwhelmingly, no.
Fertility supplements, like all nutritional supplements, are not regulated by the Food & Drug Administration (FDA) or any other regulating body. That means that no one is keeping track of what’s in these supplements, let alone checking that they actually do what they claim to do. Unlike over-the-counter or prescription medications, fertility supplements are not required to prove their effectiveness via clinical trials (or any other research).
In one review of 39 women’s fertility supplements available on the market, researchers found that not a single manufacturer “provided any reasonable scientific substantiation that its products help women become pregnant.” To quote those researchers:
“The products’ websites were no more helpful: four studies cited showed no increase in pregnancy rates, four others didn’t look at pregnancy rates, and one assessed its ingredient using a dose that was eight times the dose in the supplement. When CSPI pressed the 39 products’ manufacturers via email for scientific evidence, 11 did not reply and 16 cited no supportive studies. Four cited customer reviews as evidence and three cited studies that showed no increase in pregnancy rates.”
So, what’s a savvy consumer and hopeful parent to do? Remember that, when it comes to fertility supplements, you and/or your doctor will need to do your own research into the evidence to support the use of particular ingredients. This guide is a great place to start.
Adding fertility supplements to your regimen
Even if an ingredient is “natural” or “naturally occurring,” it may not be safe at certain doses, free from side effects or potential interactions with other medications you may be taking, or okay to take during pregnancy or while trying to get pregnant. Always talk to your doctor(s) before introducing a new supplement into your regimen.
Prenatal vitamins vs. fertility supplements
Prenatal vitamins are taken during pregnancy to support the growth and development of a fetus in the womb. Prenatal vitamins don’t improve fertility—that’s not what they’re intended to do. While prenatals are recommended for IVF patients, that’s because it’s best to start them about 3 months prior to pregnancy, and IVF patients are typically hoping to get pregnant within that time frame.
PS: The most important ingredient in prenatal vitamins is folic acid or folate, which has been shown in many, many studies to prevent fetal neural tube defects (failure of the spine or brain to form properly)—which can be devastating. The reason neural tube defects are so rare in the developed world is almost exclusively due to the widespread use of prenatal vitamins along with folate enrichment in foods like bread and cereal.
Common female fertility supplements & relevant scientific evidence
DHEA
Dehydroepiandrosterone, which is (thankfully) referred to in shorthand as DHEA, is what’s known as a “prohormone,” a hormone whose job is to help produce other hormones. DHEA—naturally produced in the brain, ovaries/testicles, and adrenal glands—helps the body produce estrogen and testosterone. DHEA levels in the body naturally peak around early adulthood and fall with age.
DHEA supplementation can increase levels of testosterone in the body, which may be helpful for female fertility in some cases. If this seems counterintuitive, remember that all bodies use both “male” and “female” hormones, but at different optimal levels. For people with ovaries, too much testosterone can result in ovulatory disorders like PCOS, but because testosterone helps drive the production of ovarian follicles (the small sacs that hold immature eggs), too little of this “male” hormone can also impact egg maturation and ovulation.
There’s evidence that DHEA fertility supplements can help improve pregnancy rates for women with a low ovarian reserve. According to a review of DHEA research, four of five studies analyzed reported increases in pregnancy rates for patients taking DHEA prior to IVF—in one trial, the pregnancy rate more than doubled. Other noted results included higher follicle counts, more eggs retrieved, and lower doses of medication required for IVF patients using DHEA before their cycles.
Some caveats: DHEA certainly isn’t a fertility “silver bullet.” None of these studies were able to identify exactly why DHEA increased pregnancy rates. The improvement was only seen in women with diminished ovarian reserve; DHEA has never been shown to be helpful for women with normal ovarian reserve, and has never been shown to increase egg count or success rates for women who are freezing eggs.
Coenzyme Q10
CoQ10 is an antioxidant. What does that mean?
As your body uses food, heals wounds, and reacts to its environment, it naturally creates waste products called “free radicals.” These unstable atoms can damage cells; this damage is also known as oxidative stress, and it’s what leads to aging and some illnesses. Antioxidants are substances—both created within the body and consumed via food and supplements—that help neutralize free radicals to prevent cell damage.
CoQ10 is a compound that’s produced naturally by the body and stored in the mitochondria (the powerhouse of the cell, if you recall high school biology class). It’s used for cell growth and maintenance, and also has antioxidant properties. Naturally occurring levels of CoQ10 decrease with age, and it’s difficult to consume a significant amount via food.
There’s some evidence that, for women with low ovarian reserve, CoQ10 fertility supplements (often along with DHEA) can improve outcomes. In one study, treating with CoQ10 prior to an IVF cycle resulted in a higher chance of producing healthy embryos, lower doses of required medication, and a slightly higher pregnancy rate than untreated IVF cycles. In another study, CoQ10 plus DHEA fertility supplements were shown to increase antral follicle count and the ovaries’ response to medication during an IUI or IVF cycle. (CoQ10 has never been studied as a supplement for women who are freezing their eggs.)
What’s the mechanism here? Studies of mice suggest that CoQ10 may support the mitochondria within the egg cells, potentially slowing reproductive aging. CoQ10 certainly isn’t an infertility cure-all, but it’s generally safe and is one of the few fertility supplements, along with DHEA, with evidence to support its use.
Ubiquinol vs. CoQ10
When searching for CoQ10 fertility supplements, you may also come across the term “ubiquinol.” Ubiquinol is a different form—the “active” form—of CoQ10. To put it simply, your body must convert CoQ10 to ubiquinol before use. So if you take ubiquinol, your body may be able to absorb more of the active compound from the same dose, studies suggest.
Evening primrose oil
Evening primrose is a flowering plant native to North America; the oil extracted from this plant contains omega-6 and omega-3 fatty acids. There are several purported ways that evening primrose oil supports fertility:
Some proponents of evening primrose oil (EPO) as a fertility supplement say it works because the fatty acids it contains are anti-inflammatory substances. But there’s mixed evidence as to whether or not, and how much, inflammation contributes to infertility. One study found no association between levels of C-reactive protein (CRP), a substance produced in response to infection and inflammation in the body, and IVF outcomes.
Another theory says that the fatty acids in EPO help improve the cervical mucus, the viscous fluid released by the cervix that can be protective for sperm at certain times in the menstrual cycle. But the relationship between fatty acids and cervical mucus has not been demonstrated in any large, well-designed studies.
Finally, some point to the idea that EPO can help regulate female reproductive hormones, improving PMS symptoms and supporting regular ovulation. While a study of obese female rats suggest EPO may have an impact on the menstrual cycle regularity of rats, there’s no evidence this impact holds true for humans as well, and studies of its impact on PMS have concluded that it’s “of little value” in the management of symptoms.
No high-quality studies have been done on the specific impact of EPO on pregnancy rates, but there has been research on fatty acids and fertility—and results are mixed. While one study found that women with high levels of fatty acids (including those found in evening primrose oil) in their blood had higher pregnancy rates during IVF, another concluded that women with higher fatty acid levels were no more likely to conceive naturally than women with lower levels, nor did they have lower miscarriage rates or higher AMH levels.
The bottom line on this fertility supplement is that, as it stands, there’s not enough evidence to support its use for any reproductive or menstrual issues, and most studies evaluating the use of EPO for hormone-related conditions have concluded it’s not helpful.
Vitex or chasteberry
This supplement is called by many names, but the two most common are “vitex,” from the scientific name of the tree (Vitex agnus-castus), and “chasteberry,” a reference to the fact that, historically, the plant was used by monks to decrease sexual desire and promote chastity. Today, it’s been rebranded as a fertility supplement that lowers prolactin levels—more on that below—and a treatment for menstrual period irregularity.
Prolactin is a hormone that helps the body produce breast milk; it also inhibits the hormones that trigger ovulation, which is why people who are breastfeeding are less likely to get pregnant. Abnormally high levels of prolactin may also lead to luteal phase defect, a condition in which the luteal phase (the section of the menstrual cycle between ovulation and the next period) is too short, not enough progesterone is produced, and the uterine lining doesn’t develop enough to support a fertilized egg for pregnancy.
There’s some evidence that using vitex as a fertility supplement can help lower unnecessarily high prolactin levels and treat luteal phase defects. In one small study, after 3 months of daily treatment with vitex, prolactin release was reduced, short luteal phases were normalized, and deficits in progesterone production during the luteal phase were corrected. These changes were significant and occurred only in the experimental group.
Other studies have shown that products containing chasteberry have a slight positive impact on pregnancy rates, but because these products contain multiple ingredients—and in some cases are “proprietary” (secret) formulations—we can’t say for certain that it’s the chasteberry that’s working. In one study, a supplement called FertilityBlend, which contains chasteberry as well as green tea, L-arginine, and other vitamins and minerals, was tested in a small group of infertile women. Of the 53 women in the FertilityBlend group, 14 (26%) became pregnant after three months, compared to just 10% of the women taking a placebo.
Another study investigated the efficacy of Phyto Hypophyson, another fertility supplement that contains vitex. Researchers found that there was an increase in pregnancy rates among women taking the fertility supplement vs. those taking a placebo—but the increase was not statistically significant. And in a study of the effects of Mastodynon, another supplement containing vitex, on women with fertility disorders, pregnancy rates were twice as high for women with luteal defects or amenorrhea (absence of a menstrual period) taking the fertility supplement than they were for women taking a placebo. But once again, the study was quite small, with only 15 pregnancies total.
What can we conclude from this about using vitex as a fertility supplement? There’s a possibility that this plant has a real impact on certain aspects of fertility, but there aren’t any robust studies just yet—more research is required.
Inositol
Inositol is sometimes called “vitamin B8,” but that’s strictly a marketing term; it’s not a vitamin at all, it’s a type of sugar. Found in foods such as nuts and beans, fresh fruits and vegetables, and grains, inositol plays several important roles in the body: in addition to being a major component of cell membranes, it influences the action of neurotransmitters serotonin and dopamine in the brain, and mediates the way insulin—a hormone produced by the pancreas that helps the body utilize sugar from food—works inside cells. It’s this final role that holds the most promise for inositol’s use as a fertility supplement for people with PCOS.
PCOS, or polycystic ovary syndrome, is a hormone disorder that affects ovulation. A quick overview: ovaries contain immature eggs, stored in sacs called “follicles,” and in a normal cycle, they mature and release one egg. For patients with PCOS, this process is disrupted, resulting in irregular or no periods (indicating irregular or no ovulation), higher-than-normal androgen (“male” hormone) levels, and cysts in the ovaries from multiple cycles without ovulation. Without regular ovulation, it’s difficult to get pregnant naturally, so PCOS is a common cause of fertility issues.
While doctors and researchers aren’t 100% sure what causes PCOS, we do know that it’s closely tied to insulin resistance and obesity. If your body is resistant to insulin, you need higher levels of insulin to keep your blood sugar normal. Extra insulin in the bloodstream can impact the delicate balance of hormones required for ovulation. Because inositol is known to reduce blood sugar and excess insulin, it may be effective at improving insulin resistance and the symptoms of PCOS.
What does the research say? It’s overall positive, though most studies are small: inositol fertility supplements have been shown to prompt ovulation, improve hormonal profiles, and increase pregnancy and delivery rates for women with PCOS. In one study of 25 PCOS patients with irregular or absent periods, 88% had at least one spontaneous menstrual cycle after treatment with inositol, and 72% maintained normal ovulation after treatment.
In another small study of overweight patients with PCOS, inositol supplementation reduced insulin levels and restored menstrual cycle regularity for patients with irregular cycles. Another small study of PCOS patients with insulin resistance concluded that inositol induced ovulation in 61% of patients, resulting in pregnancy for over one-third of subjects. And several studies (1, 2) have demonstrated that inositol could be nearly as, if not more, effective for those hoping to conceive with PCOS than metformin, the common drug of choice for insulin resistance.
While inositol isn’t appropriate for everyone, for the sub-group of women dealing with fertility issues as a result of PCOS, it has promise as a way to improve menstrual cycles and increase pregnancy chances. We look forward to more large-scale studies on this fertility supplement.
Vitamin D
Vitamin D is a prohormone and an essential substance for the human body. It’s commonly known as the vitamin that helps our bodies absorb calcium for bone health, but it also plays a part in cell growth, muscular function, immune response, and inflammation. You may be familiar with vitamin D because it’s known as the “sunshine vitamin”; our skin actually produces this vitamin itself as a result of exposure to ultraviolet (UV) rays from the sun.
Because our lifestyles and environments have changed—we spend more time inside, wear sunscreen more often, and live with higher air pollution that blocks UVs—we are less able to create the vitamin D necessary for ideal body function. Today, nearly 50% of people worldwide have less-than-optimal levels of vitamin D. Blood vitamin D levels of 30–60 ng/mL are considered sufficient, levels of 20–30 ng/mL are considered insufficient, levels of 12–20 ng/mL are considered deficient, and levels below 12 ng/mL are considered severely deficient.
Vitamin D is an interesting case, because, while the mechanism by which it affects fertility is still unclear, the correlations between blood vitamin D levels and conception rates are well established. In one review of 2,700 subjects, researchers found that women with sufficient levels of vitamin D had higher pregnancy and live birth rates than insufficient and deficient women. Another analysis of 1,191 women also concluded that women with sufficient concentrations of vitamin D in their blood were more likely to achieve clinical pregnancy than women with insufficient concentrations.
This association holds true for women undergoing IVF, as well. One study of 132 IVF patients revealed that pregnancy and live birth rates were significantly higher among women with sufficient levels of vitamin D and who met the recommended daily intake (pregnancy rate of 67.5% and live birth rate of 59%), compared with those who did not (who had a pregnancy rate of 49% and a live birth rate of 40%). Another study of 173 Canadian IVF patients also concluded that women with sufficient levels of vitamin D have significantly higher rates of pregnancy per IVF cycle (52.5%) compared with women with insufficient levels (34.7%).
Additionally, emerging research suggests vitamin D has a role in miscarriage and recurrent pregnancy loss. One review of over 10,000 pregnancy outcomes determined that very low vitamin D levels (<20 ng/mL) were associated with first-trimester pregnancy loss, suggesting that vitamin D deficiency could be detrimental to early embryo development.
So, we know that insufficient levels of vitamin D are not ideal for conception or pregnancy. But large clinical trials to assess the impact of vitamin D supplementation on pregnancy rates are still mostly absent. That being said, most experts agree that supplements containing up to 2,000 IU of vitamin D, along with sun exposure, can help maintain adequate levels in the blood (though higher levels may be required to treat deficiencies). While many prenatal vitamins contain about 400 IU of vitamin D, that may not be sufficient for all people, especially those starting with lower vitamin D levels prior to treatment.
It’s very, very important to note that there is such a thing as too much vitamin D. Levels of over 150–200 ng/mL in the blood is considered vitamin D toxicity, and can lead to problems in the heart, blood vessels, and kidneys. It’s highly unlikely to experience this toxicity from sun exposure, as your body is able to self-regulate; the most common cause of vitamin D toxicity is high intake of dietary supplements. Please consult your doctor about your baseline levels and potential dosages before taking vitamin D as a fertility supplement.
