Which fertility dietary supplements have the most scientific validation, the best track record, and the most effective mechanism of action?
Fertility problems are quite common for couples of various ages. According to the United States Department of Health and Human Services (HHS), roughly 12%-13% of American couples have trouble getting pregnant. Moreover, infertility is both a female and a male problem. HHS data show that male and female fertility problems each account for one-third of infertility cases, with the remaining third the result of either a combination of male and female fertility problems or an undetermined cause.1
Fertility problems can also be a source of significant stress, particularly if they are prolonged in nature. Those struggling to conceive are looking for an effective solution to an emotionally charged problem, and the stamp of approval offered by clinical trials can help build consumer confidence. Here are some of the most promising fertility health supplements on the market—and the studies demonstrating their efficacy.
Beta-Carotene Shortens Time-to-Pregnancy
One of the key factors influencing fertility is oxidative stress. Lisa Dispensa, RD, medical director at family-wellness brand UpSpring (Austin, TX), says oxidative stress contributes to difficulty conceiving for both women and men. In addition to affecting the rate at which ova age and the quantity and quality of sperm, oxidation, Dispensa says, has other far-reaching effects.
“Oxidation impacts cell survival and ovum maturation and is well known to play a key role in male and female infertility,” Dispensa says. “That’s why the most-studied ingredients that show fertility benefits are antioxidants like beta-carotene.”
One 2014 secondary data analysis of the Fast Track and Standard Treatment trial, a 2010 randomized clinical trial involving over 500 women between the ages of 21 and 39 with unexplained infertility, found that increased intake of antioxidants was associated with a shorter time to pregnancy in certain groups of women. More specifically, the analysis found that among women with a BMI over 25 and among women under 35 years of age, consumption of beta-carotene supplements was associated with a reduction in the amount of time it took to become pregnant. In women over 35, however, beta-carotene was associated with an increase in time-to-pregnancy.2
In June 2020, UpSpring launched HeNatal, a preconception fertility health vitamin for men. HeNatal is a combination product that includes vitamin C, vitamin E, folate, selenium, antioxidants, and other ingredients designed to reduce oxidative stress and improve sperm health.
L-carnitine Boosts Fertility in Men
L-carnitine is another compound with fertility-increasing properties, Dispensa says. One 2016 literature review found that L-carnitine increased sperm motility and concentration in infertile men.3
One of the studies included in this literature review was a randomized, double-blind clinical trial involving 325 men between the ages of 27 and 40 who were experiencing either varicocele-associated or idiopathic oligoasthenospermia. All participants were in committed relationships with healthy fertile partners, and all participants had been actively trying to get pregnant for at least 12 months.
All participants followed a standard control diet. Participants were randomized to receive either: 1) a placebo (n=118), 2) 2 g of L-carnitine and 1 g of acetyl L-carnitine per day (n=101), or 3) 2 g of L-carnitine and 1 g of acetyl L-carnitine per day plus 30 mg of cinnoxicam once every four days (n=106). Participants were assessed for sperm concentration, bilateral testicular volume, percentage of class-A motile sperm, and natural pregnancies achieved at baseline, after three and six months of supplementation.
After six months of supplementation, 38% of participants receiving L-carnitine, acetyl L-carnitine, and cinnoxicam reported they had successfully conceived. In contrast, roughly 22% of participants who received L-carnitine and acetyl L-carnitine without cinnoxicam reported having successfully conceived, while the placebo group saw a mere 1.7% conception rate.4
B Vitamins Promote Healthy DNA Replication
Leah Hechtman, ND, founder of The Natural Health and Fertility Centre (Sydney, Australia), says B vitamins impact both male and female fertility health in various ways. She says the two most important B vitamins for promoting conception are the methylation co-factors folate (vitamin B9) and vitamin B12.
“Methylation regulates the healthy replication of DNA for all cells, especially eggs, and enables the embryo to grow and replicate,” Hechtman says. “A deficiency of either vitamin B12 or folate affects development of the embryo and the health of the child.”
One 2015 analysis of a prospective cohort study involving 100 women of childbearing age found that women who had higher serum folate concentrations and higher serum vitamin B12 concentrations were more likely to conceive and give birth. Specifically, women with more than 701 pg/ml of serum vitamin B12 were 43% more likely to become pregnant and twice as likely to experience a live birth relative to women with less than 439 pg/ml of vitamin B12.5
Vitamin B12 and folate also impact male reproductive health. Hechtman explains that these compounds regulate DNA replication in sperm. B vitamins play an important role in both male and female fertility. Consumers are also already largely familiar with B vitamins as a result of their other functional applications and high profile in workout supplements, making B vitamins an appealing compound to include in fertility formulations.
Fertility Supplements Set for Growth
The fertility products market is expanding rapidly. Data from Zion Market Research indicates the segment will grow by 7.2% CAGR through to 2026, when the global fertility supplement market will be worth $2.49 billion USD.6 As more consumers seek out natural options to help them conceive, clinical validation will become more important. Fertility ingredients with several robust clinical trials behind them will be well positioned to capitalize on this opportunity.