How to Increase Estrogen When Trying to Conceive: Do Supplements Actually Help?

If you're searching how to increase estrogen while trying to conceive, here is the short version: if your periods arrive every 21 to 35 days, your oestrogen is very likely already doing its job, and no supplement on a UK shelf has good evidence that it raises it. (Oestrogen and estrogen are the same hormone, by the way. We spell it with an "o" in the UK; most people search the American spelling.)

The picture I keep coming back to is a rollercoaster. Oestrogen climbs slowly after your period, bursts to a peak just before ovulation, dips, then makes a smaller second hump. It's a ride your body runs on its own, not a tank you top up. Strapping a rocket to a jar of capsules doesn't make the car go faster, and when oestrogen genuinely is low, something has stopped the ride. That something is what needs fixing.

Does your oestrogen actually need increasing?

Most of the time, no. If your periods come every 21 to 35 days, the hormones behind them are very likely working. The NHS defines irregular periods as a gap of "less than 21 days or more than 35 days", and anything inside that range counts as normal.

NICE's fertility guideline, NG257, tells GPs to "reassure them that if they have regular monthly menstrual cycles, they are likely to be ovulating." Ovulation needs a proper oestrogen rise, so a regular cycle is your body showing its working.

If your periods arrive every 21 to 35 days, your oestrogen is very likely already doing its job.

What oestrogen does across your cycle

Oestrogen (the main form in your blood is oestradiol, often written E2) is made by the follicles growing in your ovaries. It does three jobs that matter when you're trying:

• It builds the womb lining. The lining averages about 12 mm thick around ovulation in natural cycles (Bakos, 1993).
• It changes your cervical secretions. They turn wetter, then clear and stretchy around your fertile days, which you can read more about in our guide to egg white discharge.
• It triggers the LH surge. Oestrogen peaks and the brain answers with a burst of LH (Hoff, 1983). Ovulation follows about 24 to 36 hours after the surge starts.

Then oestrogen dips, and makes a second, gentler rise alongside progesterone in the second half of the cycle. Slow climb, big peak, dip, smaller hump. Same shape, roughly, every cycle.

Here is the whole ride on one page, if you'd rather see it than read it.

"Roughly" is doing real work there. In more than 600,000 app-tracked cycles, the first half of the cycle averaged 17 days, and in most cycles fell between about 10 and 30 days (Bull, 2019). Day 14 ovulation is a textbook example, not a rule.

When low oestrogen is completely normal

Right before your period and on the first few days of bleeding, oestrogen sits at the bottom of the ride. That low point is the signal that tells your brain to start growing a new egg, so a "low" result can be perfectly normal or a real problem depending on the day the blood was taken. Lab ranges differ too: one NHS lab gives a follicular range of 92 to 921 pmol/L (about 25 to 251 pg/mL), another gives 80 to 420 pmol/L. NICE confirms ovulation with a progesterone test in the second half of the cycle, and oestradiol isn't one of its routine fertility tests (NG257, 1.18.7).

If you're worried about specific signs, our companion guide to low oestrogen symptoms and what they mean for TTC covers those. This article picks up the next question: what actually raises oestrogen, and what doesn't.

From 2:53, for about a minute and a half, US fertility specialist Dr Natalie Crawford explains why oestrogen is naturally low on your period days, why the day of the test changes what the number means, and why a clear history of your cycles helps your doctor. Her "less than 20" is in US units (pg/mL), about 73 pmol/L on a UK lab report.

The cycle explorer below puts that ride on a slider, so you can check any day for yourself rather than take my word for it. Slide through the days to see how oestrogen rises and falls across a typical 28-day cycle, and where your fertile window sits.

What to take from it: the same number can be fine on one day and odd on another. A result that looks low on day 3 is exactly where the ride is supposed to start. The peak is also why the fertile window sits where it does: sperm can survive for up to about 5 days, and the fertile days are the six ending on the day of ovulation (Bigelow, 2004). One caveat: the curve is a typical shape drawn for illustration, not a target to match, and the ranges under it come from one NHS lab.

Low oestrogen on the first days of your period is the starting line of every cycle, not a sign that something is wrong.

Why does oestrogen run low when you're trying to conceive?

Genuinely low oestrogen almost always has a cause upstream. Your ovaries make oestrogen when the brain tells them to, by sending out FSH and LH. If the signal from the brain goes quiet, or the ovaries stop answering it, oestrogen falls. A supplement fixes neither end of that line.

Not eating enough for what you're asking of your body

This is one of the most common reasons for genuinely low oestrogen in younger women, and it's often the hardest to spot in yourself. The Endocrine Society describes functional hypothalamic amenorrhoea (periods stopping because the brain has dialled things down) as "often associated with stress, weight loss, excessive exercise, or a combination thereof" (Gordon, 2017).

In a controlled study of 29 women, the brain's LH pulses held steady until the energy left over after exercise fell below a threshold, then became disrupted (Loucks and Thuma, 2003). Your body is careful, careful, careful about spending energy on reproduction when it thinks food is short.

NICE says people in this situation may improve their chance of ovulating and conceiving by "increasing their body weight to reach a healthy weight if they have a body mass index (BMI) of less than 18.5 kg/m2 and/or moderating their exercise levels if they undertake high levels of exercise" (NG257, 1.30.1). If you train hard, see our guide to overtraining and fertility.

In this 34-second TikTok, US fertility specialist Dr Natalie Crawford explains hypothalamic amenorrhoea in her own words: the brain shuts off the ovulation pathway, oestrogen runs low, and many women in this position are not being treated with oestrogen. The treatment she means is oestrogen prescribed and monitored by a doctor, not anything from a supplement shelf. Our text starts a step earlier than she does, with fuel and training, which is where NICE starts too.

Thyroid, prolactin and early menopause

• Thyroid problems. The NHS says "both an overactive thyroid gland and an underactive thyroid gland can prevent ovulation" (NHS, causes of infertility). The fix is treating the thyroid.
• High prolactin. Raised prolactin can stop ovulation, and NICE recommends a medicine called cabergoline for it (NG257, 1.32.1).
• Premature ovarian insufficiency (POI). Here the ovaries stop responding, oestrogen falls and FSH rises. The NHS calls it premature menopause "if this happens before the age of 40". The 2024 international guideline puts it at about 3.5% of women and says "there are no interventions that have been reliably shown to increase ovarian activity and natural conception rates" (Panay, 2024). Hormone therapy protects bones and heart, and donor eggs are the established route to pregnancy.

PCOS, breastfeeding and medicines

PCOS (now renamed PMOS in the UK) often makes ovulation irregular, but it isn't usually a problem of too little oestrogen. Breastfeeding and hormonal contraception are both on the NHS list of common reasons for missed or late periods. And the NHS lists some medicines and drugs, including chemotherapy, antipsychotics, long-term NSAIDs, spironolactone and cannabis, as affecting female fertility. Never stop a prescribed medicine on your own; ask your GP.

Causes of low oestrogen or missed ovulation, and the fix for each. Sources: NICE NG257 (2026), NHS, Gordon 2017, Panay 2024, Teede 2023.

How to increase estrogen naturally: what actually works

The honest answer to how to increase estrogen naturally is to remove whatever has stopped the ride. If your body is short of fuel, oestrogen usually comes back when energy intake goes up or training comes down. Nothing else on this page comes close.

• Eat enough, every day. Regular meals with enough energy for the exercise you do, which is where NICE's advice on weight and fertility points too. If eating feels hard to talk about, you can say so to your GP; it's a common reason periods stop.
• Ease off extreme training. NICE's word is "moderating", not stopping. Moving your body is good; running it on empty isn't.
• Be honest about stress and sleep. I haven't found a trial showing that more sleep raises oestrogen, so I won't pretend it does. Stress is part of the picture in functional hypothalamic amenorrhoea, though, and the Endocrine Society recommends "medical, dietary, and mental health support" together (Gordon, 2017). Our guide to stress and trying to conceive has practical ideas.
• Treat the cause. Thyroid, prolactin and POI need a diagnosis and real treatment, which starts with a GP appointment.

👉 Oestrogen comes back when the reason it left goes away. That is the whole trick, and it is not sold in a tub.

How long does that take? I'm not going to give you a number of weeks, because none of the sources behind this article gives one. What I can tell you is that if food and rest aren't enough on their own, that is not a personal failing, and there is a next step. NICE's committee notes that in some cases hormone treatment "is needed to induce ovulation" (NG257, rationale), and its recommendation is to offer gonadotrophins or gonadotrophin releasing hormone (NG257, 1.30.2). Clomifene and letrozole, the tablets further down this page, are not what NICE recommends for this group: they work through the brain's feedback loop, and here it is the brain's own signal that has gone quiet.

Which foods are high in estrogen?

Foods don't contain human oestrogen. What some foods contain are phytoestrogens, plant compounds that bind weakly to oestrogen receptors. There are two main families:

• Isoflavones, found mainly in soya foods. Per typical portion: tempeh (100 g) about 61 mg, roasted soya nuts (30 g) about 45 mg, a pot of soya yoghurt (125 g) about 41 mg, firm tofu (100 g) about 30 mg, a glass of soya drink (200 ml) about 21 mg, edamame (80 g) about 14 mg (USDA Isoflavone Database, 2015).
• Lignans, found mainly in seeds. Ground flaxseed leads by a mile at about 21 mg per tablespoon of ground seed, with sesame seeds about 3.5 mg per tablespoon and a slice of flaxseed bread about 5 mg (Milder, 2005).

The chart below puts those numbers side by side, per normal UK portion rather than per 100 g, so you can see what a real plate adds up to. Sort it by amount or from A to Z.

What to take from it: there are only two tall groups of bars, soya foods for isoflavones and flaxseed for lignans, and everything else is close to a rounding error. The two families are measured differently, so compare soya with soya and seeds with seeds rather than adding them up. And these are averages. Real foods vary a lot: the firm tofu samples behind that 30 mg figure ran from about 3 mg to about 142 mg per 100 g.

The surprise is chickpeas: about 0.02 mg of isoflavones per 100 g, and hummus about 0.01 mg, against about 30 mg in firm tofu. Hummus is lovely. It is not an oestrogen food. In fact, "Most foods in the UK only contain small amounts of phytoestrogens" (Ward and Kuhnle, 2010).

So what does a normal week of these foods look like? Soya drink on your cereal, a tofu or edamame stir-fry once or twice, a tablespoon of miso stirred into soup (about 7 mg of isoflavones), a tablespoon of ground flaxseed on porridge, and seeded toast at about 2.7 mg of lignans a slice. Greens and fruit barely register: a portion of curly kale has about 1.9 mg of lignans, broccoli about 1.1 mg and seven strawberries about 0.3 mg. For scale, a glass of soya drink plus 100 g of firm tofu on the same day comes to about 51 mg of isoflavones, so two proper soya servings is already a lot by UK standards. And the main source of isoflavones in the UK diet isn't tofu at all. It's bread (Ward and Kuhnle, 2010).

Here's the bit that matters most for anyone searching estrogen rich foods: in premenopausal women, eating phytoestrogens doesn't meaningfully change blood oestradiol (Hooper, 2009; Frische, 2003). Eat these foods because they're good food, not because they'll move a blood test.

Is soya safe when you're trying to conceive?

Yes, at normal food amounts. Usual soy intake wasn't linked to hormone levels or missed ovulation in 259 women (Filiberto, 2013). In 7,778 women trying to conceive, the researchers "did not observe strong associations between phytoestrogen intake and prospectively-measured fecundability" (Wesselink, 2020). In an IVF clinic cohort, women who ate more soy actually had more live births (Vanegas, 2015).

The one caution is very high intake. In a large North American study of 11,688 women, those eating 40 mg of isoflavones a day or more (roughly two soya servings) had about a 3% lower chance of ever having a baby, though a snapshot study like this can't prove cause (Jacobsen, 2014). Tofu stir-fry on a Tuesday: fine. Soy isoflavone capsules on top of a soya-heavy diet: that's where I'd stop.

From 1:17, Australian fertility dietitian Melanie McGrice covers the same question: soya foods are fine for most people trying to conceive, and her advice is to avoid soy supplements unless you've been specifically told to take them. She is a little more relaxed on amounts than I am, suggesting a few serves a day, where our text flags one study's weak signal at about two servings a day. She also calls the research on soya and oestradiol conflicting; the pooled trials above found no change.

Do estrogen supplements actually help?

Not for raising oestrogen before menopause, and not for getting pregnant. NICE tells clinicians to explain that "the effectiveness of complementary therapies for fertility problems has not been properly evaluated, and that further research is needed before such interventions can be recommended" (NG257, 1.14.1). The NHS is shorter: "There's no evidence to suggest complementary therapies for fertility problems are effective."

We graded each supplement on two questions: does it raise oestradiol in premenopausal women, and does it help conception? A means consistent good trials in the right people. B means at least one reasonable trial, with gaps. C means small, indirect (often menopausal women) or compromised evidence. D means no human evidence in the right people at all. So a "no" with an A is strong evidence something doesn't work; a D just means nobody has properly checked.

The scoreboard below puts all 18 things we checked in one place, so you can go straight to the one you've been recommended. Tap any row to see the verdict and the studies behind it.

How to read what you've just seen: the grade is about the evidence, not the supplement. Soy's "no (A)" is the firmest answer on the board, because 11 trials looked and found nothing. A grade C means the studies were small, done in a different group (often women after menopause) or have question marks over them, so treat that verdict as provisional. A grade D means nobody has properly tested it in people like you, which is not the same as "might work". The one pattern that matters is how the board looks as a whole: one A, one B, and everything else a C or a D.

Not one of the 18 supplements on our scoreboard earns a "yes" for raising oestradiol before menopause.

The detail on the ones you're most likely to be sold is below, starting with the best studied.

Soy isoflavones

The best-studied of the lot, and the clearest answer. Across 11 trials in premenopausal women, soy didn't change oestradiol. It lowered FSH and LH by about 20% and lengthened cycles by about a day (Hooper, 2009). Raises oestradiol: no (A). Helps conception: unclear (C).

Flaxseed and seed cycling

Two small trials in premenopausal women found no change in oestradiol (Phipps, 1993; Frische, 2003). Seed cycling, the social media routine of flax and pumpkin seeds then sesame and sunflower, has only small, low-quality studies behind it, mostly in women with PCOS or PMS and mixed with diet changes or other herbs; a 2025 review called for proper randomised trials (Nagarajan, 2025). Seeds as food are fine. The routine is unproven.

Red clover

Barely studied before menopause, and never for fertility that I could find. The two trials that included premenopausal women were about breast cancer and found little or no change in hormones (Powles, 2008; Ferraris, 2020). In menopausal women, a 12-month trial found it no better than placebo for hot flushes (Geller, 2009). One UK red clover label states: "Not suitable for use during planned pregnancy, pregnancy or breast-feeding". Planned pregnancy. That's you.

Black cohosh

Forums recommend it because of a few small trials that tested it alongside, or instead of, clomifene. That evidence is shaky: one trial has been retracted (Kamel, 2013) and two more were placed under expressions of concern in 2026 (Shahin, 2008; Shahin, 2009). Of the two without a notice, a 2014 trial from the same research group reported more pregnancies (Shahin, 2014) and a 2022 trial found no difference in follicles or lining (Pourhoseini, 2022). The MHRA's experts also concluded that "the available evidence supports an association between black cohosh and risk of hepatotoxicity" (liver damage) (MHRA, 2006). In the UK it's registered for menopause symptoms, never fertility.

Vitex (agnus castus)

Vitex acts mainly on prolactin rather than oestrogen, and the UK registered products I checked are licensed for premenstrual symptoms. Its best fertility trial missed significance: 57.6% against 36.0% on a combined outcome, p = 0.069 (Gerhard, 1998). A review of side effects concluded it "should be avoided during pregnancy or lactation" (Daniele, 2005).

DHEA

In the UK, DHEA (prasterone) is a Class C controlled drug (Home Office), not a supplement. A 2024 Cochrane review of 28 trials found it "likely results in little to no difference" in live birth for IVF patients with a low egg response (Naik, 2024). Only under a fertility specialist, if at all.

Maca, dong quai, evening primrose oil and the rest

• Maca: no oestradiol trial in women of childbearing age that I could find; the hormone studies are small ones around or after menopause, and the "hormone balancing" paper often quoted is a rat study (Meissner, 2006).
• Dong quai: in its main trial, in 71 menopausal women, it did "not produce estrogen-like responses" (Hirata, 1997), and it can interact with warfarin (Page, 1999).
• Evening primrose oil, wild yam, hops, pueraria mirifica: no trials in people trying to conceive that I could find, and no good pregnancy safety data. Evening primrose oil has only been trialled at the very end of pregnancy, to soften the cervix before birth, and in one Singapore study, women taking it before pregnancy took longer to conceive, though that can't prove cause (Ku, 2022).

Can vitamins increase estrogen levels?

There's no good evidence that any vitamin raises oestrogen. Most vitamins to increase estrogen levels you'll see online trace back to one sentence: "Vitamin B6 contributes to the regulation of hormonal activity". That's a real, authorised UK claim, but any food that's a source of B6 can carry it, so it says nothing about oestrogen or fertility (GB nutrition and health claims register). The NHS also says: "Do not take more than 10mg of vitamin B6 a day in supplements unless advised to by a doctor."

Vitamin D is worth taking for its own sake, not for oestrogen. In five trials in IVF patients low in vitamin D, supplements gave more positive pregnancy tests but not significantly more clinical pregnancies (Zhou, 2022). Vitamin E thickened the lining in one trial without a significant change in pregnancy (Cicek, 2012).

What the NHS actually advises when you're trying to get pregnant is simple. Take "400 micrograms of folic acid every day", ideally from 3 months before, and 10 micrograms of vitamin D a day, especially between October and March (NHS). Some people need a higher dose of folic acid that a GP prescribes, for example if you have diabetes, take medicine for epilepsy or HIV, or there's a neural tube defect in your or your partner's family, so ask your GP if that's you. For everyone else, that's the list.

So if you have a supplement budget, that is where it goes: folic acid, vitamin D, and the rest on food you actually enjoy eating. One thing to leave out rather than add: the NHS says "Do not take cod liver oil or supplements containing vitamin A (sometimes called retinol) when you're pregnant" (NHS), so check any multivitamin for it.

What is actually in an "oestrogen support" supplement?

Many estrogen supplements in the UK are a mix of plant extracts and vitamins, sold as food rather than medicine. Food supplements "are required to be regulated as food", and their use "is not intended to treat or prevent diseases in humans or to modify physiological functions" (GOV.UK). Nobody checks that a food supplement works before it goes on sale.

Some herbal products carry a Traditional Herbal Registration (THR) instead, which needs at least 30 years of traditional use. A THR "is only granted if the medicine is used for minor health conditions where medical supervision is not required" (MHRA). The registered products I found are for premenstrual symptoms (agnus castus) and menopause symptoms (black cohosh), not fertility, low oestrogen or "hormone balance".

A few things jump out when you read the backs of these tubs:

• The B6 line is the hormone claim you'll see most. The other authorised GB claims that touch hormones or fertility are just as general: pantothenic acid "contributes to normal synthesis and metabolism of steroid hormones", iodine to "the normal production of thyroid hormones" and zinc "to normal fertility and reproduction", and any food that's a source of the nutrient can carry them. No authorised UK claim mentions oestrogen, ovulation or the menstrual cycle.
• B6 doses stack up. Some products contain 10 mg or more per daily dose, so a "hormone" product plus a conception multivitamin can take you over the NHS 10 mg limit.
• "Balance" can mean the opposite of what you want. Some oestrogen balance products contain broccoli extract, calcium-D-glucarate or DIM, which are marketed to help clear oestrogen, not raise it.
• Pregnancy warnings are everywhere. The NHS says "You should not take herbal medicines if: you're pregnant or breastfeeding". An egg can be fertilised up to about two weeks before a pregnancy test can pick it up, so "not suitable in pregnancy" really means "not suitable while trying".

How to read a supplement label in 30 seconds

You don't need a science degree in the shop aisle. Turn the tub over and look for five things, in this order:

1. The words "food supplement". The law says "The product label must be labelled as 'food supplement'" (GOV.UK). If you see them, the product is regulated as food, and nobody had to show it works.
2. A THR mark. The NHS says to check that any herbal medicine has one (NHS). It shows "the product meets the required standards of quality, safety and evidence of traditional use" (MHRA), for a named minor condition. Traditional use is not the same as a trial.
3. The hormone sentence. If the only one is the B6 line, it tells you nothing about oestrogen.
4. The B6 amount. Add it to whatever else you take, and compare the total with the NHS limit of 10 mg a day from supplements.
5. The pregnancy line. If it says not to use it in pregnancy, it wasn't made for the two-week wait.

Now try it on a tub. Ours is invented, but its ingredients are typical of what's on UK shelves. Tap each ingredient on our made-up label to see what it is and how the evidence stacks up.

What to take from it: the front of a tub is where the promises live, and the back is where the required wording and the warnings live. On our made-up label, the only authorised claim is the B6 sentence, and its 10 mg of B6 is the whole NHS daily limit before you've taken anything else.

A supplement that is "not suitable in pregnancy" is not suitable while you're trying to get pregnant either.

Why do fertility pills block oestrogen?

Because the goal isn't more oestrogen, it's a stronger signal from the brain. The two tablets most used to bring on ovulation both make the brain think oestrogen is low, so it releases more FSH, which grows a follicle.

Clomifene (Clomid) blocks oestrogen's message in the brain. Its UK product information says it works "by binding to oestrogen receptors in the hypothalamus", which increases the pituitary's output of the hormones that grow follicles (Clomifene SmPC). It's licensed for proven ovulation problems, for up to about six cycles, and one listed side effect is a thinner womb lining.

Letrozole lowers oestrogen on purpose. Its UK product information says: "In premenopausal women, the inhibition of oestrogen synthesis leads to feedback increases in gonadotropin (LH, FSH) levels. Increased FSH levels in turn stimulate follicular growth, and can induce ovulation" (Femara SmPC). In the UK it's licensed only for breast cancer, so using it for ovulation is off-label.

From 4:03, for about 45 seconds, US reproductive endocrinologist Dr Lora Shahine explains the same mechanism out loud: Clomid blocks oestrogen receptors in the brain, "tricking the body into thinking that estrogen levels are low", while letrozole lowers oestrogen by blocking the enzyme aromatase. She is describing US practice, so the UK licensing points above are ours, not hers, and after 4:46 she moves on to doses, which are for your own doctor to set.

The diagram below is the same explanation as a picture. Switch between the three tabs to see how clomifene and letrozole change the conversation between your brain and your ovaries.

What to take from it: in all three tabs, the brain is reading oestrogen and answering with FSH. Both tablets work by making that reading look low, one by blocking the message and one by making less of the hormone for a few days. Nowhere in the loop does adding more oestrogen push a follicle to grow, which is why a "booster" was never going to do the job these medicines do.

And here's the twist. In a trial of 750 women with PCOS, the oestrogen-lowering pill won: 27.5% had a live birth with letrozole against 19.1% with clomifene (Legro, 2014). A Cochrane review of 41 trials backed it up: across the 11 that measured live births after timed sex, letrozole came out ahead (odds ratio 1.72) (Franik, 2022). The 2023 international PCOS guideline now says: "Letrozole should be the first-line pharmacological treatment for ovulation induction in infertile anovulatory women with PCOS, with no other infertility factors" (rec 5.3.1, Teede, 2023).

In women with PCOS, the fertility pill that lowers oestrogen gave more live births than the one that blocks it: 27.5% against 19.1%.

NICE's own PCOS advice is in transition. NG257 has removed its PCOS ovulation-induction section "because NICE is developing a guideline on polycystic ovary syndrome" (NG257, 1.31), and the new PMOS guideline is expected on 27 January 2027.

One practical point: letrozole's product information says oestrogen-containing therapies "should be avoided" alongside it. I couldn't find a study of whether plant oestrogen supplements interfere in the same way in fertility treatment, only lab and breast cancer studies, so the risk is theoretical, but tell your clinic about every supplement anyway.

When do clinics prescribe oestrogen?

Clinics do prescribe real oestrogen, at measured doses with scans, when your own ovaries aren't doing the job:

• Frozen embryo transfer. In a "medicated" cycle, the lining is built with oestrogen and then progesterone. For people with regular cycles, NICE says live birth is "similar for embryos replaced during natural cycles and hormone-supplemented cycles" (NG257, 1.49.12).
• Donor egg cycles. The recipient's lining is prepared with oestrogen and then progesterone (Glujovsky, 2020).
• POI and early menopause. Hormone therapy replaces missing oestrogen for bones and heart (Panay, 2024).

In this 83-second TikTok, Dr Natalie Crawford, the US fertility specialist from the video near the top of this page, describes oestrogen before a frozen embryo transfer: approximately two weeks of it, given as a pill, a patch or vaginally, to build the lining. That is a general description from a US clinic, so your own clinic's routine and timings may differ.

Even in IVF, more isn't automatically better: in a Cochrane review, adding oestrogen to progesterone support after egg collection "does not seem to improve outcomes" (16 trials compared the two) (van der Linden, 2015).

Should you try an oestrogen supplement?

For most people trying to conceive, no. If your cycles are regular, your oestrogen is very likely fine and a supplement adds cost and, often, a pregnancy warning. If your cycles are irregular or missing, a supplement can delay finding the real cause. And if you're already having fertility treatment, tell your clinic about everything you take, because some of these medicines lower oestrogen on purpose.

If you'd like that answer fitted to your age, your cycle and how long you've been trying, use the checker. Answer five quick questions below to see what makes sense for you next. It's signposting, not a diagnosis, and it can't replace your GP.

What to take from your result: there are four possible answers, and three of the four point you towards your GP rather than a product. "See your GP first" always wins over everything else, so if that's your result, don't talk yourself out of it because the rest of your answers looked fine. And if you get the quiet one, regular cycles and no warning signs, the instructions are nicely dull: eat normally, take folic acid and vitamin D, keep your money.

When should you see your GP about low oestrogen?

See your GP rather than a supplement aisle if any of these apply. The NHS says to see a GP if:

• You've missed your period 3 times in a row and you're not pregnant (NHS).
• Your periods are irregular (under 21 or over 35 days apart) and you're struggling to get pregnant (NHS).
• You bleed between periods or your periods last longer than 7 days.
• You're under 45 and think you have menopause symptoms, such as your periods stopping, hot flushes or night sweats (NHS).
• You take prescribed or over-the-counter medicines or herbal remedies and want to get pregnant (NHS).

NICE also sets out when to ask for fertility investigations (NG257): after 12 months of trying through sex, after 6 cycles of insemination, or straight away if you're 36 or over or there's a known reason for fertility problems. If you're inseminating at home, our guide to home insemination covers timing and when to get help.

What happens at the appointment

Expect questions before blood tests: how long your cycles are, what has changed and when, how long you've been trying, and what you take. As Dr Crawford says in the video near the top of this page, a doctor can only work with the information you give them. So bring your cycle dates for the last few months, a list of every medicine, supplement and herbal remedy, and, if it applies, an honest note about training and eating. NICE asks clinicians to check prescription, over-the-counter and recreational drugs as part of fertility advice (NG257, 1.13.1).

The standard NHS check is a progesterone blood test in the second half of your cycle, about 7 days before your next period is due (day 21 of a 28-day cycle, later if your cycles are longer), to confirm you ovulated (NG257, 1.18.7 and 1.18.8). FSH and LH are checked if your cycles are irregular, prolactin if you have an ovulation problem or milky nipple discharge, and thyroid tests if you have thyroid symptoms. Oestradiol isn't a routine NICE fertility test; many clinics take early-cycle bloods on days 2 to 5, so let your GP or clinic tell you which day.

Don't expect anyone to ask for your temperature charts. NICE tells clinicians not to use them to confirm ovulation "because they do not reliably predict ovulation" (NG257, 1.18.9).

Here are ten questions to take in with you, written so you can read them straight off your phone. Copy the questions below into your phone notes before your appointment, and take your cycle dates with you.

If you only get to ask three, make them the first, the third and the sixth. Between them they cover whether you're ovulating, whether any oestradiol number was read against the right day and the right range, and whether anything you already take is a problem. The rest can wait for a follow-up.

When a blood result can mislead

A perfectly accurate number can still send you the wrong way. Three things to watch for:

• The wrong day. Oestradiol taken on your period days is meant to be low. Progesterone only tells you about ovulation if it's timed to your cycle: for a 35-day cycle, NICE's example is day 28, "repeated weekly thereafter until the next menstrual cycle starts" (NG257, 1.18.8). So tell whoever takes the blood how long your cycles usually are.
• The wrong range or unit. Ranges differ between labs, and US websites quote pg/mL where UK reports use pmol/L. Multiply pg/mL by 3.671 before you compare anything you read online with your own report.
• The wrong test for the question. If the worry is early menopause, the diagnosis rests on at least 4 months of irregular or missing periods plus a raised FSH (above 25 IU/l), and that FSH test "does not have to be timed to a specific day of the menstrual cycle" (Panay, 2024). One oestradiol number doesn't settle it.

How a partner can help

If you have a partner, there is real work for them here, and none of it involves forwarding you adverts.

• Keep the dates. A clear record of period dates is the first thing to take to an appointment, and it's an easy job to share.
• Come to the appointment. When NICE recommends investigations after a year of trying, it says to offer them to "both partners" (NG257, 1.16.5).
• Check their own medicines. The NHS says to speak to a GP if "you or your partner take prescribed or over-the-counter medicine, or any herbal remedies" (NHS).

Oestrogen myths, quickly

Seven claims that do the rounds on forums and social media, each with the short answer. All of them are covered, with their sources, in the sections above.

If those seven have one thing in common, it's that each treats oestrogen as an amount to push up. Everything in this article says it's a signal to get right: cycles of 21 to 35 days are the sign it's working, the real fixes are for causes, and no tub changes that. Here is the whole thing on one page, for your phone or your fridge.

And if a whole page is more than someone will read, the cards below are one number each. Three things worth sending to your partner, or anyone else who keeps forwarding you supplement adverts:

Why these three? Each one undoes a different assumption: that plant oestrogens raise oestrogen, that more oestrogen means more fertility, and that lists of "oestrogen foods" can be trusted.

Oestrogen and fertility: frequently asked questions

Do estrogen pills help you get pregnant?

Not if you're buying them yourself. Over-the-counter "oestrogen" products are plant extracts and vitamins, and none has good evidence that it raises oestradiol before menopause or improves pregnancy rates. Real oestrogen is a prescription medicine that clinics use for specific jobs, such as building the lining for a frozen embryo transfer or replacing hormones in early menopause. The tablets most used to bring on ovulation, clomifene and letrozole, actually block or lower oestrogen.

What foods are high in estrogen?

No food contains human oestrogen, but soya foods are the richest source of plant oestrogens called isoflavones. Per typical portion, tempeh has about 61 mg, roasted soya nuts about 45 mg, firm tofu about 30 mg and a glass of soya drink about 21 mg. Ground flaxseed leads for lignans at about 21 mg per tablespoon of ground seed. Chickpeas and hummus contain almost none, and eating these foods doesn't meaningfully change blood oestradiol in premenopausal women.

Can vitamins increase estrogen levels?

There's no good evidence that any vitamin raises oestrogen. Vitamin B6 carries an authorised UK claim that it "contributes to the regulation of hormonal activity", but that's a general statement, not evidence about oestrogen or fertility, and the NHS says not to take more than 10 mg a day from supplements. The NHS advice for anyone trying to conceive is 400 micrograms of folic acid a day and 10 micrograms of vitamin D, especially from October to March. Some people, for example those with diabetes or taking epilepsy medicine, need a higher dose of folic acid prescribed by a GP.

Are estrogen supplements safe in the UK?

Some aren't a good idea while trying. Black cohosh carries an MHRA liver warning, red clover products can carry a warning against use during planned pregnancy, and vitex should be avoided in pregnancy. Because an egg can be fertilised up to about two weeks before a pregnancy test can pick it up, a product with a pregnancy warning effectively covers the whole cycle. Check anything you take with your GP, pharmacist or fertility clinic.

How can I increase my oestrogen levels quickly?

There's no safe quick fix you can buy. If low oestrogen is caused by under-eating or heavy training, NICE says reaching a healthy weight and moderating exercise may improve your chance of ovulating regularly, but that takes time. Prescribed oestrogen does raise oestrogen levels, which is exactly why doctors only use it for specific reasons, at measured doses, with monitoring.

Can you buy oestrogen over the counter in the UK?

Not for fertility. Oestrogen medicines need a prescription, with one exception: low-dose vaginal oestradiol tablets that pharmacists can sell to women aged 50 and over who haven't had a period for at least a year, to treat vaginal dryness after menopause (MHRA). They aren't for anyone trying to conceive. What's sold as "oestrogen support" is food supplements, or traditional herbal medicines registered for PMS or menopause symptoms. DHEA, sometimes sold online as a fertility booster, is a Class C controlled drug in the UK (Home Office).

What is oestradiol?

Oestradiol (estradiol, or E2) is the main oestrogen your ovaries make during your reproductive years, and it's the one measured in a blood test. It builds the womb lining in the first half of the cycle and triggers the LH surge that leads to ovulation. UK labs report it in pmol/L; to convert from the US unit pg/mL, multiply by 3.671.

Should I take agnus castus (vitex) while trying to conceive?

It isn't an oestrogen booster. Vitex acts mainly on prolactin, the UK registered products I checked are licensed for premenstrual symptoms, and its best fertility trial didn't reach significance. A review of side effects concluded it should be avoided in pregnancy, so if you're thinking about it, talk to your GP first, especially if your cycles are already regular.

Does a thin womb lining mean I need more oestrogen?

Not necessarily, and it's a question for your clinic rather than a supplement. NICE says transferring an embryo into a lining under 5 mm is unlikely to result in pregnancy, while a study of over 40,000 transfers found live births fell below 8 mm in fresh transfers and below 7 mm in frozen ones, but "reasonable outcomes were obtained even with lower endometrial thickness measurements" (Liu, 2018). Vitamin E thickened the lining in one trial without significantly changing pregnancy rates, and in IVF, adding oestrogen to luteal support didn't improve outcomes.

I'm using donor sperm at home. Does any of this change?

Not the oestrogen part. Your cycle, your oestrogen and what raises it work the same however sperm gets there. What does differ is when to ask for help: NICE says to offer fertility investigations after 6 cycles of insemination without a pregnancy, or straight away if you're 36 or over or there's a known reason for fertility problems.

Keep Reading: Helpful TTC Guides

Want to go further on hormones, cycles and timing? These guides pick up where this one leaves off:

• Low Oestrogen Symptoms: What They Actually Mean for TTC
• Exercise and Fertility: Could Overtraining Affect Your Cycle?
• Foods to Eat When Trying to Conceive: The Ultimate Fertility Diet Guide
• Positive Ovulation Test: What It Means and What to Do Next
• Luteal Phase Symptoms: What's Normal After Ovulation

References

Last reviewed: 11 November 2026