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The Most Common Symptom of Menopause Isn't Hot Flashes

You eat well. You take your vitamins. And you still wake up tired, with nothing left by mid-afternoon that coffee can reach. Women your age are told this is just what happens. It isn't. The cause has a name. Finding it won the 1998 Nobel Prize, and a ten-second test reads your own level. You have almost certainly never seen yours.

Cathy Eason MS, BCHN, FNTP Chief Science Officer Last updated August 3, 2026
A woman in her early fifties sitting at her kitchen table in afternoon light, holding a mug in both hands, looking away in thought.
The 2pm wall. Four out of five women seeking menopause care report low energy.

Nobody told you this was the reason

When most of us picture menopause, we picture hot flashes. It is the version we were handed and the version most women still expect. So when the exhaustion arrives first, and the hot flashes either come later or never come at all, it does not get filed under menopause. It gets filed under stress, or poor sleep, or simply getting older.

The version we were handed is the part that is wrong. In an analysis of more than 100,000 intake assessments from women seeking menopause care, low energy was the most commonly reported symptom at 79 percent, followed by weight change and fatigue. Hot flashes came sixth, reported by 44 percent.

Those women were carrying an average of nine symptoms at once. More than three quarters had lived with them for over a year before saying anything to anyone.

Menopause symptoms Share of women reporting each
  • Low energy 79%
  • Weight change 75%
  • Fatigue 71%
  • Brain fog 70%
  • Sleep changes 69%
  • Hot flashes 44%
Data Winona, State of Menopause 2026. Intake assessments, May 2025 to February 2026. PR Newswire302807290 n = 100,000+ womenself-reported at intake

Low energy, fatigue and brain fog are all ways of saying the same thing. Not enough is getting where it needs to go. One delivery system serves all three. The rest of this page follows it down to its cause.

So the tiredness is not you failing to keep up. It is the symptom women in midlife report more than any other, and it has a mechanism behind it that almost nobody gets told about.

Estrogen was the on switch

Inside the lining of every blood vessel you have sits an enzyme with an unglamorous name, . Its job is to produce a gas called , which tells your blood vessels to relax and open so that more blood can get through.

Estrogen turns that enzyme on. Researchers at UT Southwestern showed the effect is almost immediate, with enzyme activity peaking within five minutes of estrogen reaching the cells that line a vessel. Then they blocked gene transcription altogether, and it still happened. Estrogen throws a switch that is already in place. It does not have to change your genes to do it.

As estrogen declines through your forties and fifties, the switch stops being thrown as often. The enzyme is still there. The instruction arriving at it is not.

Estrogen is one road to nitric oxide. It is not the only one, and the other one starts with food.

For most of your life this ran without your attention, because estrogen was doing it for you. Nobody is doing it now.

Nitric oxide won a Nobel Prize

Three American scientists shared the 1998 Nobel Prize in Physiology or Medicine for working out what nitric oxide does in the cardiovascular system. The journal Science had already named it Molecule of the Year. This is not an idea the supplement industry invented.

Stockholm, 1998 Robert Furchgott receiving the 1998 Nobel Prize in Physiology or Medicine from the King of Sweden in Stockholm.
Robert Furchgott accepts the Nobel Prize for the discovery of nitric oxide as a signalling molecule.
Record The Nobel Prize in Physiology or Medicine 1998: Robert F. Furchgott, Louis J. Ignarro and Ferid Murad. Archivenobelprize.org/medicine/1998

What has stayed in the journals is the part that concerns you. That research connects this pathway to how you feel in midlife. It has not made it into the conversation you had with your doctor.

How far circulation falls in midlife

In 2012 researchers measured blood vessel function in 132 healthy women at five different stages of the . They used a standard test called , which measures how well an artery widens when it needs to. Higher is better.

Blood vessel function Measured at five stages of menopause 10% 5% 0% 9.9 8.2 6.5 5.5 4.7 Pre Early peri Late peri Early post Late post
Source Moreau, Hildreth, Meditz, Deane & Kohrt. Journal of Clinical Endocrinology & Metabolism, 2012;97(12):4692–4700. PMCIDPMC3513538 n = 132 healthy womenp < 0.001

From premenopausal to late postmenopausal, the measurement falls from 9.9 percent to 4.7 percent, slightly more than half the function gone. It happens in healthy women, independent of the usual risk factors, and it tracked estrogen levels closely enough that the two fell together stage by stage.

Circulation is how oxygen and fuel reach every working cell you have. It is also how everything else you take gets there. Every vitamin and mineral in that cabinet arrives the same way. You feel a drop that size long before it shows up at a checkup.

Estrogen, nitric oxide, cardiovascular risk Across the same forty years Higher Lower MENOPAUSE Cardiovascular risk Nitric oxide Estrogen 30 40 50 60 70 AGE (YEARS)
An illustration of how these three change with age.

Can any of it come back?

In 2024 a trial set out to answer exactly that. Researchers gave 24 postmenopausal women either beet juice or a placebo for seven days. Nobody involved knew who was getting which. Then they measured the same thing the chart above plots.

Blood vessel function, in two studies The decline, and one week of beet juice
  • Lost across the whole transition Between women, premenopausal to late postmenopausal 5.2
  • Regained on seven days of dietary nitrate Within the same women, against placebo 2.21
Both numbers are percentage points of flow-mediated dilation, the measurement charted above. They come from two different studies, and are set side by side to show scale, not to predict a result.
Sources

The nitrate group's vessels responded measurably better than the same women's did on the placebo. The trial tested dietary nitrate, not any particular product, and seven days is seven days. But it answers the question the chart above raises. The decline is not permanent, and what moves it is the molecule your body was already using estrogen to reach.

Measuring blood vessel function takes a cuff and an ultrasound. Your nitric oxide level takes a strip on your tongue and about ten seconds, and I'll show you how further down.

How much you would have to eat

is in leafy greens and beets, so the obvious response is to eat more of them. Two things get in the way. A meaningful daily amount from food alone means about 7oz of beetroot, every single day, prepared the right way. And the nitrate content of any given bunch of spinach varies enormously with soil and season.

Nitrate: food or capsules Roughly equivalent
A plate of cooked beets and spinach. Two Berkeley Life Nitric Oxide Support capsules.
7oz of beetroot, every day 2 Berkeley Life Capsules

Keep eating the vegetables. They are doing other work for you. But nothing on a plate arrives with a number on it, and if the amount is what matters, a number is the thing you are missing.

So we put it in a capsule

This is what we make. Two capsules a day, standardised so that every dose carries the same amount of nitrate as the one before it.

That formulation is made by Berkeley Life. Two capsules a day, and this is what is in them.

A dish of Berkeley Life Nitric Oxide Support capsules, cream coloured, seen from above.
Supplement facts Two capsules, per serving
  • Vitamin C as ascorbic acid 290 mg
  • Thiamin as thiamin mononitrate 90 mg
  • Vitamin B12 as methylcobalamin 200 mcg
  • Magnesium as magnesium citrate 75 mg
  • Potassium as potassium nitrate 189 mg
  • Proprietary blend Potassium nitrate, beet root extract standardised to 25% betaine nitrate, organic fermented beet root powder 500 mg
The blend is listed by weight and not broken out into its three parts.
Our label Supplement Facts, Nitric Oxide Support. full panel with the offer

The reason for the beet extract being standardised is the whole argument of the section above. A beet grown in one field and a beet grown in another are not the same beet, and neither are two spinach leaves from the same bag. An extract made to 25% is made to a number, so the second capsule you take is the same as the first, and so is the two-hundredth. Four of the seven ingredients carry nitrate, including the vitamin B1.

Then we had it tested. Three times, on this formula. The largest of the three ran for twelve weeks at the Lundquist Institute at Harbor-UCLA Medical Center. Sixty-seven adults, randomised, double-blind, against a placebo, measuring endothelial function and how much nitric oxide the body had available.

Forty-one of those sixty-seven were women, at an average age of fifty-nine.

Source Cherukuri, Birudaraju, Kinninger, Chaganti, Shekar et al. Clinical Nutrition ESPEN, 2020;40:327–335. PMID33183558 n = 67, 41 of them womenmean age 59.3 ± 9.0

What that trial dosed was beetroot extract, thiamin nitrate and potassium nitrate in the presence of ascorbic acid. All four are on the panel above.

You can read your own number today

Every kit ships with saliva test strips. You touch one to your tongue, wait about ten seconds, and read the colour against the scale on the box. Pale pink means your level is low. Deep magenta means you are in the target band.

Nitric oxide test strips Before, and two hours after
Colours shown are representative of the printed scale. Individual readings vary.
Source Stahl, Grammer, Allen & Weltman. Journal of Clinical Medicine, 2025;14(13):4581. PMCIDPMC12250075 n = 12strip vs. laboratory assay, p < 0.01 Funded by Berkeley Life.

A colour scale is not a laboratory instrument, so it has been checked against one. In a 2025 study the same readings were taken by strip and by the analytical method a lab would use, and the two tracked each other closely enough to tell a high reading from a low one.

Test first thing, before anything else touches your mouth, and write the result down. Take your two capsules. Test again two hours later, which is where the published measurements put the peak. Whatever the second strip says, you now know something about your own body that you did not know this morning, and you did not have to take anyone's word for it.

Then keep testing across the following weeks. One reading tells you the conversion is working. A run of them tells you where your level actually sits, which is a different thing from a supplement you hope is working.

Why you haven’t heard of us

For most of the time this company has existed, you could not buy it. Berkeley Life was sold through practitioners — you got it from a clinic, from someone who already knew what nitric oxide was and why it mattered to you. Today more than three thousand healthcare providers recommend it.

Selling it directly, to the person actually taking it, is recent. That is the whole reason this is the first time you are reading about us, and it is also why the research came first and the advertising came second.

I always talk about how important it is for us to be healthy hosts for our hormones — and that means good blood flow.
Dr. Mariza Snyder, D.C.Women's hormone practitioner
The body works best when we support it from the inside out. Berkeley Life helps restore nitric oxide naturally, so you feel more vibrant, energetic, and ready for whatever your day brings.
Dr. Debra Durst, MDFounder, RevitalyzeMD

Estrogen is not coming back

The switch that ran this quietly for thirty years is not going to start being thrown again. What was handled for you is now something you do on purpose, or do not. From here, this is maintenance.

Two capsules, and a strip on the mornings you want to know where you stand.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

Claimed 20% off the Starter Kit $48.00 $59.99 Yours for developing the strip. Applied at checkout.

The Berkeley Life Starter Kit: a box of Nitric Oxide Indicator Test Strips beside a 60-capsule bottle of Nitric Oxide Support, a halved beet and two capsules. A 180-capsule bottle of Berkeley Life Nitric Oxide Support, labelled 90-day supply, beside a halved beet and two capsules.

The Nitric Oxide Starter Kit

★★★★★ 351 reviews, jump to them

This is the simplest way to start. Run the test, take the dose, and watch your number move.

The Nitric Oxide Support Plan

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This is the one you stay on. It is also the lowest monthly price.

Supplement Facts panel. Serving size two capsules. Per serving: vitamin C 290mg, thiamin 90mg, vitamin B12 200mcg, magnesium 75mg, potassium 189mg, and a 500mg proprietary blend of potassium nitrate, beet root extract and organic fermented beet root powder.

Every order is covered for thirty days. The strips mean you will know where you stand well inside that window.

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Questions women ask before they start

Does this contain hormones?

No. There are no hormones of any kind in this formula. It works on a different pathway entirely, supporting your body's own nitric oxide production through dietary nitrate.

I already take several supplements. Does this replace them?

No, and it is not meant to. Keep taking what you take. This addresses one specific pathway that most routines do not cover.

How soon will I see something on the strip?

Most people see a colour change on the same day, about two hours after the first dose. That tells you the conversion is working in your body. Where your level settles over the following weeks is the more useful number.

What if my strip doesn't change colour?

The most common reason is antiseptic mouthwash, which removes the tongue bacteria the conversion depends on. Switch to a non-antiseptic rinse for a few days and test again.

When should I take it?

Two capsules once a day with water, after food. Most people take them in the morning.

What if it doesn't work for me?

Every order is covered by a 30-day money-back guarantee. The strips mean you will know where you stand well inside that window.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

A strip from the kit, two hours after the first dose

Develop it

Swipe down the strip About ten seconds, on your tongue

In the target band.

In the 2025 trial, two capsules moved the strip this far in two hours. Colours are representative of the printed scale; individual readings vary.

20% off the Starter Kit $48.00 $59.99 Yours for developing the strip. It is applied at checkout.

Endothelial nitric oxide synthase Usually shortened to eNOS The enzyme that makes nitric oxide. It sits in the endothelium, the single layer of cells lining the inside of every blood vessel you have. Estrogen is one of the signals that switches it on. Nitric oxide Not nitrous oxide, which is unrelated A gas your body makes on demand inside the lining of your blood vessels. It signals the vessel wall to relax so blood moves through more easily. Working out what it does in the cardiovascular system won the 1998 Nobel Prize in Physiology or Medicine. The menopause transition Perimenopause and postmenopause Not a single day, but the arc of hormonal change around your last period. Perimenopause is the run-up, when cycles start becoming irregular. Postmenopause begins twelve months after your final period. The whole transition commonly runs for years, not months, which is why the chart above has five stages instead of two. Flow-mediated dilation Usually shortened to FMD The standard non-invasive way to measure how well a blood vessel is working. A cuff briefly restricts blood flow in the arm. When it releases, a healthy artery widens to let the blood surge through, and ultrasound measures how much wider it gets. The result is a percentage. Higher means the vessel responded better. The three trials Run on this formulation, not on the category 2020 Randomized, double-blind, placebo-controlled, 12 weeks. 67 adults, 41 of them women, mean age 59. Measured endothelial function and nitric oxide availability. Run at the Lundquist Institute at Harbor-UCLA Medical Center. PMID33183558 2024 A 60-day pilot study in women. Unpublished. 2025 Open-label Phase 1, 12 adults. Measured how long a single dose stays available in saliva and blood, and read the saliva strips against a laboratory assay at every timepoint. This is the study behind the test-strip figure above. PMCIDPMC12250075 The two studies Figure 5 sets one beside the other 5.2 Moreau, Hildreth, Meditz, Deane & Kohrt. Journal of Clinical Endocrinology & Metabolism, 2012;97(12):4692–4700. Cross-sectional: blood vessel function compared between women at five stages of the transition. PMCIDPMC3513538 n = 132 healthy womenp < 0.001 2.21 Delgado Spicuzza, Gosalia, Zhong et al. Frontiers in Nutrition, 2024;11:1359671. Randomized, placebo-controlled, double-blind crossover: a change measured within the same women, on dietary nitrate rather than on any product. PMCIDPMC11194363 n = 24 postmenopausal womenp = 0.042 Dietary nitrate Found in leafy greens and beets A compound plants pull up from the soil. Bacteria living on your tongue convert it to nitrite, which your body can then convert onward into nitric oxide. That route runs entirely separately from the enzyme, which is why what you eat still matters even when the estrogen signal has faded.