Balance hormones

The bigger effects reported in women, in people already diagnosed, and in Asian populations each rest on a handful of trials, few enough that ordinary chance could produce them. Doses and trial lengths varied widely, so 0.4 points is an average across regimens rather than the result of any one of them. Berberine caused more stomach and bowel upset than placebo in the large trial.

This is an absence of evidence, not evidence that D-chiro-inositol does nothing. Myo-inositol sat outside the review entirely, so nothing here describes the form most people actually take. The search closed in January 2017.

These figures are reported as background inside a guideline evidence review, not measured by a study designed for the question. That same review rated every comparison of different inositol ratios at the lowest certainty its framework offers.

The cycle-regularity interval's lower bound is 1.01, so one more small trial could take it to nothing. A one-point change on a hair-growth scale may not be visible to the person looking in the mirror. Six trials, 388 women, three to six months, and no fertility or pregnancy outcomes.

An umbrella review inherits the weaknesses of the trials underneath it, and counts the same small trials again each time they turn up in a different meta-analysis. Over half of the 13 meta-analyses it appraised were themselves rated low or very low quality.

A guideline synthesises trials rather than adding any, and only 3 of the 13 comparisons its evidence review assessed had enough studies to pool. The same guideline records that inositol's side effects and safety are not known, and that supplement regulation, dose and quality control differ from those for medicines.

Ovulation and a regular cycle are steps toward pregnancy, not pregnancy. The ovulation pooling was highly inconsistent between trials, and the whole analysis rests on ten small trials totalling 601 women. Neither pooling reported a live birth.

A null result is not proof of equivalence. Eight small trials, with moderate inconsistency on three of the five outcomes, are underpowered to rule out a real difference between the two. No risk-of-bias assessment or certainty grading is reported.

The shape comes from observational data, so it maps an association rather than a demonstrated causal curve. Nonlinearity cleared significance for recurrence only; for breast-cancer death and death from any cause it did not, and most of the reduction there sat between 20 and 40 mg a day.

Diet was self-reported, and soy eaters may differ from others in weight, diet quality and health behaviour that no adjustment removes. Only recurrence reached significance; both death-rate estimates crossed the line of no effect. Diagnoses ran from 1991 to 2006.

The tamoxifen-user estimate, unlike the non-user one, still includes no effect within its range of uncertainty, so the near-identity is between point estimates rather than between two equally firm results. Every study pooled is observational, with self-reported diet.

Forty-six of the 62 trials, three-quarters of them, carried a high risk of bias in three or more quality domains. Against a typical starting point of several flushes a day, four-fifths of one is a real change and a small one. The night-sweats interval is wide enough to rule out almost nothing.

The trials were too dissimilar to combine, so the review's only pooled estimate is of red clover, a different plant. Four trials of extracts delivering more than 30 mg of genistein a day did consistently reduce flushes, so the negative verdict is not uniform across preparations.

The rise in thyroid stimulating hormone only just cleared significance, its interval reaching down to 0.001. The pooled trials disagreed sharply with one another. Everyone studied was thyroid-healthy and presumed iodine-replete, so the worry that soy matters more when iodine is scarce goes untested.

The relative risk of 8.14 runs across an interval from 1.87 to 35.40, which reflects how few men had the event rather than a precise estimate. It rests on four trials, and those trials needed to run only twelve weeks, short against how long testosterone is actually taken.

The trial was powered for artery thickening rather than for sexual outcomes, so the null on sex is a secondary result rather than a definitive one. Its authors say plainly that it should not be read as establishing cardiovascular safety. Haematocrit and prostate-specific antigen both rose more on testosterone.

Men had to have a partner willing to attempt intercourse at least twice a month, which selects a particular and comparatively motivated group. Twelve outcomes were tested, so some of the ten significant ones may be the arithmetic of testing many things. And the missing threshold cuts both ways: it undercuts any single diagnostic cutoff, and it also means no reading identifies in advance who will benefit.

This is a snapshot, so it can say which symptoms travel with low testosterone and not whether raising it would relieve them. That fatigue and low mood failed to cluster is a statement about how symptoms group, not proof they have nothing to do with testosterone. Testosterone here was measured by mass spectrometry on morning samples, a stricter standard than much routine clinical testing, so the thresholds may not transfer to an ordinary lab result.

23 samples, and the exposure is multiple sclerosis treatment at doses far above any hair supplement, so the blood levels here are an upper bound rather than what a shopper reaches. Two authors worked for the company developing that high-dose product, which had a commercial interest in characterising this interference. Roche assays only, and the removal step is not perfectly neutral: it shifts parathyroid hormone by about 8%.

A single case, paired with a review of other single cases: this shows that something can happen, never how often. The interference was inferred from how fast the results normalised rather than by measuring biotin in the sample. Assay formulations from 2016 have since been revised for biotin tolerance, and this patient's own dose is not a market-typical exposure.

Twenty-five percent of twelve people is three people, so the familiar claim that a quarter to a third of Westerners are producers is consistent with this study rather than established by it. Its lasting contribution is the test, not the prevalence, and the work was done at a company that sells soy.

A registry entry records that a trial was declared, not what it found, so none of these counts is evidence about how inositol works. Trials often publish in journals without ever posting back to the registry, so a raw non-posting count overstates true non-reporting. This registry is US-centred and under-covers the Italian and Indian trials that dominate this field.

This is a professional body's clinical report rather than primary data, and it is nearly two decades old. Its published abstract states that it reviews potential harms without saying what it concluded about them, so nothing about safety can be read off it. The market figure is United States only.

Only 190 of the 600 enrolled were still taking part at fourteen, and children who leave a study rarely do so at random. Families chose the feeding method, so whatever tracks with that choice tracks with these results. Heart-rate and autonomic differences between groups are reported and unexplained.

Twelve of the 18 studies are case-control, a design in which people recall their past diet after already knowing their diagnosis. The literature stops in 2004. Eight studies gave no menopause-specific result, and six of those did not support an association at all.

Most outcomes are synthesised narratively rather than pooled, so there are few numbers behind the verdict. The reassurance covers soy as food, not concentrated extracts, which is the distinction the 100 mg line marks. It was conducted at a naturopathic college, which has an interest in the answer.

Every included study is observational with self-reported intake, so soy eaters may simply differ from other patients. The authors describe their own overall-survival finding as limited evidence and confine it to postmenopausal patients. The search stops in January 2018.

The measurements are from 1999, and brands, formulations and processing have all changed since, so treat them as an order of magnitude rather than as current values. Composite samples were used, which averages out the brand-to-brand and batch-to-batch variation a shopper actually meets.

No pooled effect size was reported for these five trials, so the size of the null cannot be stated. The wider review they sit inside is a narrative synthesis rather than a meta-analysis for most of its outcomes. It was conducted at a naturopathic college, which has an interest in the answer.

A guideline is expert synthesis rather than primary evidence, and by its own grading many of its recommendations rest on low-quality evidence. It was published in 2018, before the large cardiovascular safety trial reported. It is a United States society position, and other specialist societies set different cutoffs.

The mechanism account is an expert review rather than a systematic synthesis, and it describes recovery as highly variable rather than putting numbers on it. Its suggestion that newer short-acting oral and nasal formulations partly spare sperm production is preliminary and rests on no fertility outcomes. The guideline is expert synthesis, and by its own grading many of its recommendations sit on low-quality evidence.

Twelve weeks is short against a process that takes years, so a slow thinning could begin after the trial ended. The 38 men who finished were all resistance-trained and aged 18 to 40, which leaves everyone else untested. And this was maintenance dosing at 5g a day; the older study that started the worry ran a 25g loading week first.

The creatine hair worry and the hair trial measured different things: a hormone shift during a week of 25g a day, and hair itself after twelve weeks of 5g a day, which showed nothing. Both may be right.

Eleven of the 13 trials in the Cochrane review gave inositol as preparation for in vitro fertilisation, so it does not describe ordinary supplement use. Cochrane translated its own estimate into absolute terms: against a 12% live birth rate without inositol, the rate with it would sit somewhere between 9% and 51%.

Whether inositol raises live births is unsettled. One umbrella review says it more than doubles them, Cochrane calls the outcome too uncertain to judge, and none of the 85 outcomes graded in this field reaches high quality.

These were women undergoing fertility treatment, so this describes a fertility-treatment add-on rather than everyday supplementation. Sixty were randomised and about 44 analysed, a thin base for a gap that wide. There was no plain myo-inositol arm, so it cannot say whether either blend beats myo-inositol on its own. Several of the authors are affiliated with a nutrition-sector company.

The 40:1 ratio the market is built on has been tested far less than the argument over it suggests. The only two trials comparing ratios head to head point opposite ways, and both sit at the lowest certainty rating.

Neither is a new trial: both are re-poolings of a literature made mostly of small studies. The earlier one stopped searching in October 2021, so it predates both the guideline's own review and the 2025 pregnancy trial. The later one could pool only 3 of the 13 comparisons it assessed.

Two reviews of the same inositol trials disagree on whether it works. The one calling it effective reports no live birth or pregnancy outcome, so the split is less about the trials than about what a reviewer calls enough.

This tested prevention during pregnancy in women who already had polycystic ovary syndrome, so it says nothing about inositol taken before conception for ovulation or cycles. All 13 sites were Dutch and 86.1% of participants reported White race. Baseline hyperandrogenism ran against the treated arm, 29.0% versus 18.5%.

Earlier, mostly Italian trials suggested myo-inositol in pregnancy roughly halved gestational diabetes; a later, adequately powered Dutch trial found no effect. The two are not of equal quality, which is why the null carries more weight.

Heterogeneity is high, 67 percent for frequency and 86 percent for severity, so the pooled figures sit on trials that contradict one another. The results are percentages, not flushes per day, which flatters a small absolute change. A co-author directs the industry-funded Soy Nutrition Institute.

Whether soy pills ease hot flushes is unsettled because the reviews disagree first about whether trials this varied can be combined at all, and only then about the answer. That is why more studies have not settled it.

Two of the five authors have soy-industry ties, one directing an institute funded by the United Soybean Board, and the same group produced the earlier analysis this one updates. Dihydrotestosterone was left out of the pooled outcomes, and it is the one androgen a soy effect has been reported for.

Soy's clean record on male hormones leaves out dihydrotestosterone, the one androgen a crossover trial saw fall by 9 to 15 percent. Both can be true because they measured different things; nobody has pooled the hormone that moved.

Noninferiority means testosterone was not worse than placebo by more than a preset margin, which is a different statement from safe. The three excess events were not adjusted for multiple comparisons and the trial was not powered to find them. Doses were titrated into the low-to-mid normal range, so nothing here speaks to higher amounts. The trial was funded by testosterone manufacturers.

Whether testosterone harms the arteries is unresolved. The largest trial found no rise in major cardiac events; an imaging trial found more non-calcified plaque after a year. Nobody has shown whether that plaque turns into events.

These were healthy men with normal testosterone taking defined, mostly short courses in contraception trials, not men on open-ended replacement or on the much larger doses used for physique. Recovery was faster with shorter treatment and shorter-acting preparations, both of which cut against long-term replacement. The endpoint is a sperm concentration of 20 million per millilitre, a fertility proxy rather than a pregnancy. The data stop in 2005.

Each man was his own comparison, which handles his fixed characteristics but not a new illness or hospital stay that could prompt both a prescription and a clot. Only 7.8% of the men had a hypogonadism diagnosis code at all. A prescription record shows the drug was dispensed, not that it was taken.

Whether testosterone raises clot risk is unsettled. Insurance claims show about double the odds and the randomised trial no overall excess, yet both point the same way on clots in the lung, the part of the signal that has not gone away.

Thirty-six people split between two drugs is small enough that an ordinary run of luck moves the number about as much as the drug does. With no placebo group, the fall also contains whatever three months of clinic visits and daily pill-taking do on their own. About a third of patients in the add-on arm had short-lived stomach upset.

Whether berberine lowers blood sugar is not the open question. The head-to-head with metformin everyone quotes came from a pilot with no placebo group, never built to size an effect, and no larger trial has repeated it.

This is the figure for all six interference types together, and the review does not break it down by cause, so it is not a biotin rate. The 150 patients come from published case reports, which select for cases that went wrong; how many people had an interference and came to no harm is unknowable from this design. It is not a probability that any given biotin user will be misdiagnosed.

This states what these two studies were built to measure, not that no such comparison exists anywhere in the wider literature. Both are small: 160 women in the trial, and 41 in the producer-status study, of whom 12 were non-vegetarians.

Everyone enrolled started low, at about three flushes a day, and one a day was enough to take part, so the percentage figures the trial reports describe small absolute movements. Thirty-four of the 160 randomised did not finish, and the reported analysis is of those who did. Japanese women only.

One trial found equol beat placebo on hot flushes in women who cannot make it, yet a menopause society later declined to recommend it. It stays unsettled because one trial of one product, in one country, is thin ground for a recommendation.

A network meta-analysis mostly compares treatments that were never tested against each other directly, so this is an indirect estimate. Twenty-two trials and 1079 women spread across four classes of treatment leaves each comparison thin. Nothing here goes beyond a surrogate: no pregnancy, no live birth.

The label states the interaction without citing the studies behind it or saying how much absorption is lost. It is one manufacturer's label for one brand, and generic levothyroxine carries its own separate labelling. A drug label is a regulatory summary rather than a study.

The label names soybean flour and soy formula but gives no figure for how much absorption they cost and cites no study, so it cannot say how much a soy meal matters to the dose.

Thirty-five men at one centre, all young and healthy, so nothing here reaches older men or any clinical outcome. Other hormones moved in inconsistent directions across timepoints, which is what measuring several hormones at three timepoints tends to produce.

This one trial shows dihydrotestosterone falling in 35 young men on soy, with or without isoflavones. It cannot show the fall holds across trials or matters for health; that needs the hormone pooled, which nobody has done.

The remit was peri- and postmenopausal women taking isolated isoflavone supplements, so it says nothing about men, children, premenopausal women or soy as a food. The opinion is ten years old.

The lead author directs the Soy Nutrition Institute, funded by the United Soybean Board and its member companies; that is the largest declared conflict in this evidence base and it points toward the review's conclusion. Its verdicts are narrative judgments, not pooled effect estimates.

Twelve women, a single dose, no blinding, and the trial was funded and run by the company that makes the supplement tested. One dose cannot detect anything that builds up over weeks of taking the two together. Everyone enrolled was healthy and stably treated, not newly diagnosed.

A single isoflavone supplement dose left levothyroxine absorption untouched, yet the drug's label warns against soybean flour and soy formula. What separates the two is the form of soy, protein against isolated isoflavones.

A position statement inherits whatever its panel weighted, and produces no new estimates of its own. The recommendation covers hot flushes and night sweats only, and says nothing about soy for bone, cholesterol or cancer outcomes.

A menopause society declining to recommend soy is not the same as soy failing: its Level II grade means the evidence is limited or inconsistent. The listing cannot say whether soy eases hot flushes, only that the panel would not back it.

Normal here means the middle third of the men surveyed, a statistical convention rather than a line anchored to symptoms or outcomes. Each man gave one measurement, where guidelines require two confirmatory morning readings. And knowing the range shifts with age does not show that treating young men against the higher number would help them; it would mainly widen who counts as deficient.

This compares whole markets rather than individual men, so it cannot show that any particular man was moved by an advert. Per exposure the effect is tiny, on the order of 0.05 extra initiations per 10,000 men per monthly exposure, even though the ratios are statistically significant. Advertising clustered in the southeastern states, which may differ in ways nobody measured. The data run to 2013, before direct-to-consumer telemedicine.

This reads what clinics say on their own websites, not what care they deliver or what happens to patients. The clinics were found by internet search, so the sample is neither exhaustive nor random. Website content changes, which dates the snapshot. And it describes the market around testosterone rather than saying anything about the drug itself.

The zinc came with 5 mg of folic acid a day and there was no zinc-only arm, so neither result can be pinned on the zinc by itself. The men were fertile and subfertile patients at a fertility clinic, not chosen for their zinc status, so this shows what happens when you supplement a mixed group rather than a group known to have enough. Eighty-seven men across four arms is thin enough that this is an effect not detected rather than an effect ruled out.

Eleven men, and every arm of the study sat at or below the 11 mg of zinc a day a man is meant to get, so it compares degrees of going short and never tests giving anyone extra. Thirty-five days at each intake says nothing about years at one. Nothing here shows that a man who already has enough zinc gains anything from more.

How far zinc shortage lowers testosterone is unsettled. An uncontrolled study of four men reported a 73% fall; a controlled feeding study that cut zinc far lower saw 19%. The weaker design produced the figure that travelled.

The restriction arm reported a 73% fall in testosterone from what the paper itself calls marginal restriction, larger than the controlled feeding study found at a far lower intake, which is an anomaly rather than a detail. The supplementation arm recruited men already identified as zinc deficient, so it cannot speak to anyone else. Alongside both sits a correlation measured in 40 men, and a correlation in 40 people is where this began.