How to Boost Fertility Naturally: What Actually Has Evidence

Three things have measured numbers behind them: timing intercourse to the fertile window using urine ovulation tests, stopping tobacco, and not drinking daily. Almost everything else sold as natural fertility support — herbal remedies, detoxes, fertility diets, hydration targets — has either been tested and failed, or never been tested at all.

That is not this page's opinion. It is what the guideline written for exactly this question says. The American Society for Reproductive Medicine's 2022 committee opinion, Optimizing Natural Fertility, states: "In general, robust evidence is lacking that dietary and lifestyle interventions improve natural fertility, although dietary and lifestyle modifications may be recommended to improve overall health."

Read that carefully, because it is doing two things at once. It is not saying eating well is pointless. It is saying the reason to eat well is your health, and that the extra promise attached to it — that it will get you pregnant — is not supported. Those are different claims, and the second one is the one being sold.

Four items on the usual list have effect sizes attached. They are not equivalent to each other, and none of them is large.

Timing. ASRM 2022 defines the fertile window, for counselling purposes, as the six-day interval ending on the day of ovulation, with peak fecundability when intercourse occurs within two days before ovulation. The 2023 Cochrane review of timed intercourse pooled 7 randomised trials and 2,464 women or couples. Using urine ovulation tests probably increases live birth, risk ratio 1.36 (95% CI 1.02 to 1.81). Fertility-awareness methods — temperature charting, mucus monitoring, calendar and app tracking — showed no such benefit, risk ratio 0.95 (95% CI 0.76 to 1.20). Whether an app is enough is covered separately in how reliable fertility apps actually are.

Tobacco. ASRM 2022 reports that women who smoke were significantly more likely to be infertile, odds ratio 1.60 (95% CI 1.34 to 1.91). ASRM issued a new committee opinion in 2024 covering tobacco, nicotine and marijuana, which replaces its 2018 smoking opinion — so if you are reading older advice on this, it has been superseded.

There is an India-specific problem with the word smoking. WHO India reports tobacco use prevalence at nearly 267 million adults, about 29% of all adults, and states that the most prevalent form of tobacco use in India is smokeless — khaini, gutkha, betel quid with tobacco, zarda. Advice framed only around cigarettes misses most Indian tobacco users. The honest position is that the measured association is with tobacco and nicotine, and that quitting is worth doing whichever form you use.

Alcohol. ASRM 2022 reports that among women who consumed two alcoholic drinks per day, the risk of infertility was significantly increased, relative risk 1.59 (95% CI 1.09 to 2.31). That is a threshold, not a statement about any drinking at all.

Caffeine. ASRM 2022 associates high caffeine consumption — 500 mg, more than five cups of coffee per day — with decreased fertility, odds ratio 1.45 (95% CI 1.03 to 2.04). This matters in the other direction from how it is usually presented: the threshold is high. Ordinary tea drinking is nowhere near it, and there is no retrieved basis for telling someone trying to conceive to give up chai.

This one has been randomised, and the answer surprised the people who ran it.

The LIFEstyle trial, published in the New England Journal of Medicine in 2016, took 577 infertile women with a body mass index of 29 or higher. One group did a six-month lifestyle programme first and then had up to 18 months of infertility treatment. The other went straight to 24 months of treatment. The programme worked on the thing it was aiming at: mean weight loss was 4.4 kg against 1.1 kg in the control group.

The birth outcome went the other way. A healthy singleton born vaginally at term within 24 months occurred for 27.1% of the lifestyle-first group versus 35.2% of the prompt-treatment group, a rate ratio of 0.77 (95% CI 0.60 to 0.99). Fewer healthy babies, not more.

Be careful what you take from that. The trial did not test whether weight affects fertility; it tested a strategy of spending six months on weight before starting treatment. What it establishes is that the delay has a cost, and that the cost can exceed the benefit. If a clinic asks you to lose weight before it will treat you, this is the trial to ask them about.

ASRM 2022 answers this directly, and names the categories: "there is little evidence that dietary variations, such as vegetarian diets, low-fat diets, vitamin-enriched diets, antioxidants, or herbal remedies, improve fertility in women without ovulatory dysfunction."

The two Cochrane reviews are worth reading past their headlines. For women, the 2020 review covered 63 trials and 7,760 women; the live birth odds ratio was 1.81 (95% CI 1.36 to 2.43), but the certainty was graded very low and the reviewers' own wording is "we are uncertain whether antioxidants improve live birth rate". An impressive odds ratio at very low certainty is not a finding you can act on.

For men, the 2022 review covered 90 trials and 10,303 subfertile men. Live birth odds ratio 1.43 (95% CI 1.07 to 1.91), very low certainty. When the trials at high risk of bias were removed, the effect disappeared: Peto odds ratio 1.22 (95% CI 0.85 to 1.75), across 827 men in 8 trials. The same review found antioxidants may increase mild gastrointestinal discomfort, odds ratio 2.70 (95% CI 1.46 to 4.99).

The largest properly randomised test of the two nutrients sold hardest for male fertility found nothing. In the FAZST trial, 2,370 men took 5 mg folic acid with 30 mg zinc or placebo for six months. Live birth occurred for 34% versus 35% of couples, risk difference -0.9% (95% CI -4.7% to 2.8%). No semen parameter improved. Sperm DNA fragmentation was significantly higher on supplementation, 29.7% versus 27.2%, mean difference 2.4% (95% CI 0.5% to 4.4%).

One supplement recommendation is real and is routinely misdescribed. ASRM 2022 advises women attempting conception to take at least 400 micrograms of folic acid daily. That is to reduce the risk of neural tube defects in a pregnancy, not to help you get pregnant. Take it; do not expect it to shorten the wait. The supplement question in more depth is covered in what couple-friendly fertility supplements actually do, and the herbal and Ayurvedic side of it in whether Ayurveda has been tested for infertility.

On the male side there is a real biological clock on this, and it is about three months. A cycle of human spermatogenesis was estimated at roughly 64 days in the classic 1963 measurement, and with transit through the epididymis on top, the sperm in any given sample were made some ten to twelve weeks ago. So a man who stops tobacco today cannot expect a different semen analysis next month. Repeat the test at three months or do not repeat it at all.

On the female side there is no equivalent measured lag, and you should be suspicious of anyone who gives you one. Nothing retrieved here establishes how long a dietary or activity change takes to alter the chance of conceiving, because no trial has shown that such a change alters it in the first place.

What does have a timescale is the decision. ASRM's cumulative figure of approximately 80% of couples conceiving within the first six months is the honest anchor: if six months of well-timed attempts have passed, the useful next step is testing, not another supplement. The sequence of decisions is set out in how to build a fertility plan that commits to something.

Sometimes the answer is testing, timing or a simpler treatment, and sometimes lifestyle is not the lever at all.

Notice the qualifier in the ASRM sentence quoted above: little evidence of benefit in women without ovulatory dysfunction. It cuts both ways. Where ovulation is genuinely disordered, ASRM allows that a healthy lifestyle may help — so irregular or absent periods are a reason to be investigated, not a reason to try harder at diet.

Blocked tubes, severe male factor and age are not lifestyle problems and do not respond to lifestyle answers. Neither does an undiagnosed cause. The cost of natural-first is always time, and the LIFEstyle result is the measured version of what that time can cost.

Two adjacent questions have their own pages, both with the figures attached: which male lifestyle factors have measured effect sizes and whether stress actually stops you getting pregnant.

This is the most useful section on a page like this, so it is stated plainly rather than buried.

• That any diet improves fertility. ASRM 2022 states robust evidence is lacking for dietary and lifestyle interventions improving natural fertility. No retrieved trial shows a fertility diet raising the chance of a live birth.
• That herbal remedies do anything. Not one of the seven herbs named on the earlier version of this page had retrievable trial evidence for a fertility outcome. Absence of evidence is not proof they fail — it means nobody knows, which is not what the label implies.
• That hydration matters. No retrieved source supports a water target for fertility, cervical mucus, egg quality or semen volume. The claim has been removed rather than softened.
• That antioxidants raise live births. Both Cochrane reviews are graded very low certainty, and the male signal disappears once high risk-of-bias trials are excluded.
• That losing weight raises your own chance of a baby. The LIFEstyle trial tested a strategy in women with a BMI of 29 or higher and found the lifestyle-first arm did worse on healthy term births. It cannot tell an individual what her own weight change would do.
• That the alcohol, caffeine and smoking figures are causal. They are associations reported in a guideline, drawn from observational work. They are strong enough to act on and not strong enough to call proof.
• Indian applicability. Every effect size on this page comes from North American or European populations. No Indian trial of any of these interventions was retrieved, and the smokeless tobacco point is an inference from WHO India prevalence data rather than a measured Indian fertility outcome.

Almost everything in the natural fertility market is sold on the idea that there is something you have not done yet. For most people reading this there is not, and the waiting is the hard part rather than a sign you are getting it wrong. Timing well, stopping tobacco, drinking little, and getting tested at six months is close to the whole evidence-backed list, and it is short on purpose.