Sacred Lotus Chinese & Integrative Medicine

Relationship Graph

Sacred Lotus connections

Updated
Sep 2026

Mind: Meditation and Mindfulness

My Plan

Meditation is a family of simple attention practices, most often following the breath, and the evidence for it is solid but modest. The clearest benefits are for anxiety, low mood and stress, where a mindfulness course gives a small to moderate improvement over about eight weeks. Its single strongest result is preventing relapse in people with recurrent depression: an eight-week mindfulness course cut the chance of the depression returning by roughly a third.

Meditation costs nothing, needs only a few minutes a day, and builds as a skill over weeks. It is not a cure-all, and long or intense practice can cause trouble, so start short and gentle. The situations that call for care are gathered in one place below.

Cost
FreeFree · takes steady practice · modest anxiety and mood gains build over weeks to months
Effort
ModerateModerate
Results In
Weeks to MonthsWeeks to Months

Findings & Outcomes

What It Is

Meditation is a family of attention practices; the version behind most research is mindfulness, paying steady, unforced attention to the present, usually starting with the breath as an anchor. When the mind wanders, you notice and bring it back, again and again, that returning is the practice.

The three main forms differ in where attention rests. Focused attention holds one object, the breath or a word. Open monitoring watches whatever arises (thoughts, sounds, sensations) without following any of it. Loving-kindness turns attention toward warmth, wishing yourself and others well.

You can do any of these alone with a timer, with free recorded guidance, or through a paid course or app. A few minutes a day is a starting dose that counts.

What It Does

A structured mindfulness program eases anxiety, low mood and stress by a small to moderate amount. These are its clearest benefits. As a formal therapy it works about as well as talk therapy or medication for anxiety and depression.

Its single strongest result is preventing relapse. For people with recurrent depression who are currently well, an eight-week mindfulness-based cognitive therapy (MBCT) course lowers the odds that the depression comes back.

Beyond mood the effects are smaller and the evidence thinner. Meditation gives a small drop in the distress around long-standing pain, on weak evidence. For heart risk and blood pressure, the American Heart Association endorses meditation only as an add-on to standard care, not a substitute for it. For sleep, meditation beats doing nothing, but it does no better than a dedicated sleep program (CBT-I). For warmth and connection, loving-kindness practice has the best record.

It does little for everyday memory and focus, little for positive mood, and little for eating, weight or habit change. In short, it eases distress more than it builds well-being.

The Research & Studies

Everything here is based on the research we have collected and checked, sorted into groups and ordered with the strongest evidence first. Click any claim to open the studies behind it.

Mood & stress

Anxiety drops about 0.38 of a standard deviation at eight weeks, and 0.22 by six monthsModerate
In plain terms

In the studies with a fair comparison group, meditation gave a small to moderate drop in anxiety, about a third of a standard deviation at eight weeks. The effect is modest and dependable. It had faded a little by six months.

In detail

The review pooled 47 randomized trials with active controls covering 3,515 adults, so the comparison was against something that also asked for time and attention, not a waiting list. Mindfulness meditation programs showed moderate evidence of improved anxiety, SMD 0.38 (95% CI 0.12 to 0.64) at eight weeks and 0.22 (0.02 to 0.43) at three to six months. The authors graded the strength of evidence as moderate for anxiety.

How to use it

Expect a modest, useful reduction, and give a daily practice about eight weeks before judging it. If anxiety is severe or has a diagnosis behind it, meditation is studied as an addition to care, not a substitute for it.

The study · 1

Goyal et al., meditation programs for psychological stress and well-being, systematic review and meta-analysis · JAMA Intern Med 2014;174(3):357-368

Counts once: this finding and 2 others here come from the same source, so they are one body of evidence, not separate confirmations.

Depression symptoms ease about 0.30 of a standard deviation at eight weeks, holding at 0.23Moderate
In plain terms

Meditation also eased low mood by a small to moderate amount, about a third of a standard deviation at eight weeks, on the same fair comparison. The effect is modest, and it held at a smaller size out to six months.

In detail

In the same 47-trial review, mindfulness meditation programs showed moderate evidence of improved depression, SMD 0.30 (95% CI 0.00 to 0.59) at eight weeks and 0.23 (0.05 to 0.42) at three to six months. The lower bound touching zero at eight weeks is why the durable three-to-six-month estimate matters: the benefit was small but persisted.

How to use it

For low mood in the general run of life this is a reasonable free practice to add. For a diagnosed depressive episode, treat it as one part of a plan that includes clinical care, not a stand-in for it.

The study · 1

Goyal et al., meditation programs for psychological stress and well-being, systematic review and meta-analysis · JAMA Intern Med 2014;174(3):357-368

Counts once: this finding and 2 others here come from the same source, so they are one body of evidence, not separate confirmations.

Roughly level with CBT and medication (g -0.07 and 0.13), well above a waiting list (0.53)Moderate · mixed
In plain terms

As a structured therapy, mindfulness works about as well as standard talk therapy or medication for anxiety and depression, and clearly better than a waiting list. It is a peer of the established treatments, not better than them.

In detail

Across 209 studies (12,145 participants), effect sizes were g = 0.55 pre to post, 0.53 versus waitlist, and 0.33 versus other active treatments. Against cognitive behavioral or behavioral therapy the difference was g = -0.07, and against pharmacological treatment 0.13, neither meaningfully different from zero. The authors judged it especially useful for anxiety, depression and stress.

How to use it

If you already have a treatment that works, mindfulness is an alternative or an addition to it, not a clear improvement. Its advantages are cost, access and self-direction, so it is most compelling where those matter.

The study · 1

Khoury et al., mindfulness-based therapy, a comprehensive meta-analysis · Clin Psychol Rev 2013;33(6):763-771

MBCT cuts depression relapse about 31% versus usual care and 21% versus antidepressants over 60 weeksModerate
In plain terms

For people who have had depression more than once and are currently well, an eight-week mindfulness course lowered the chance of a relapse over the next year, by about a third compared with usual care and about a fifth compared with staying on antidepressants.

In detail

The individual-patient-data analysis covered 1,258 patients across nine randomized trials, 75% women, mean age 47. Mindfulness-based cognitive therapy reduced relapse risk over 60 weeks with a hazard ratio of 0.69 (95% CI 0.58 to 0.82) versus non-MBCT care and 0.79 (0.64 to 0.97) versus active treatments including maintenance antidepressants. Greater pre-treatment symptom severity predicted a larger benefit.

Who this may not transfer to:Three quarters of the participants were women, so the estimate is anchored in women; the analysis found no significant interaction of the effect with sex, which is some reassurance it applies to men too.

How to use it

This is the strongest reason on the page to consider a proper course, not a casual app: the evidence is for the structured MBCT program. If you have recurrent depression, raise it with your clinician as an addition to, or a discussed alternative within, your relapse-prevention plan, not a reason to stop treatment on your own.

The study · 1

Kuyken et al., efficacy of mindfulness-based cognitive therapy in prevention of depressive relapse, individual patient data meta-analysis · JAMA Psychiatry 2016;73(6):565-574

Loving-kindness practice moderately lowers depression (g 0.61) and lifts compassionEmerging
In plain terms

Loving-kindness and compassion practices, where you deliberately wish yourself and others well, lowered depression and lifted warmth, self-kindness and good feeling. The strong results were against doing nothing, and the studies were small.

In detail

The review pooled 22 RCTs. Against passive controls, kindness-based meditation reduced self-reported depression (g = -0.61, 95% CI -1.08 to -0.14) and increased mindfulness (0.63), compassion (0.61) and self-compassion (0.45); positive emotions rose against progressive relaxation (0.42). Results were inconclusive against active controls and imprecise because of small studies and low-to-moderate report quality. The authors note initial exposure may be challenging for some.

How to use it

If your aim is warmth, connection or being kinder to yourself, this is the branch to try, and it complements the focus-based practices, not replacing them. Give it a few sessions, since it can feel awkward before it feels natural.

The study · 1

Galante et al., effect of kindness-based meditation on health and well-being, systematic review and meta-analysis · J Consult Clin Psychol 2014;82(6):1101-1114

Little to no effect on positive mood, sleep, eating or weightPreliminary · no effect
In plain terms

For the more positive outcomes, meditation did less. In the same big review there was little or no clear effect on positive mood, attention, eating, sleep, substance use or weight. It eases distress better than it builds happiness or fixes habits.

In detail

In the 47-trial review, alongside the moderate benefits for anxiety, depression and pain, the authors found low evidence of no effect or insufficient evidence for positive mood, attention, substance use, eating habits, sleep and weight. They concluded meditation programs can produce small to moderate reductions in multiple negative dimensions of psychological stress, and that stronger study designs are needed to determine effects on the positive dimensions of mental health and on stress-related behavior.

How to use it

Choose meditation to take the edge off stress and low mood, where the evidence is strongest. If the goal is better sleep, weight loss or breaking a habit, reach first for the practice with direct evidence for that goal and let meditation support it.

The study · 1

Goyal et al., meditation programs for psychological stress and well-being, systematic review and meta-analysis · JAMA Intern Med 2014;174(3):357-368

Counts once: this finding and 2 others here come from the same source, so they are one body of evidence, not separate confirmations.

Pain

A small drop in chronic pain across 38 trials, on low-quality evidenceEmerging
In plain terms

For long-standing pain, meditation gave a small drop in how much pain people felt, and it lifted mood and quality of life alongside. The studies were not strong, so treat this as help with living around pain, not a painkiller.

In detail

The review found 38 RCTs; 30 contributed to the pain meta-analysis. It reported low-quality evidence of a small decrease in pain versus all control types, with statistically significant effects also on depression symptoms and quality of life. Seven trials reported on safety. The authors called for larger, more rigorous trials before the effect size can be trusted precisely.

How to use it

Pair it with the rest of a pain plan, not in place of it. Its most reliable contribution is to the distress and disability around pain, so judge it by whether daily life gets easier, not by whether the pain score alone falls.

The study · 1

Hilton et al., mindfulness meditation for chronic pain, systematic review and meta-analysis · Ann Behav Med 2017;51(2):199-213

Heart And Vascular

The American Heart Association rates it only a possible add-on for heart riskEmerging
In plain terms

The American Heart Association looked at all of it and said meditation might modestly help heart risk, including blood pressure, but the studies are not strong enough to promise it. Given the low cost and low risk, they say it is reasonable as an add-on to standard care.

In detail

The 2017 AHA scientific statement systematically reviewed meditation against stress physiology, smoking cessation, blood pressure, insulin resistance and metabolic syndrome, endothelial function, myocardial ischemia, and cardiovascular events. Overall it judged a possible benefit on cardiovascular risk, with the overall quality and in some cases quantity of data modest. It concluded meditation may be considered as an adjunct to guideline-directed risk reduction, with benefits that remain to be better established, and called for larger, well-powered, unbiased trials.

How to use it

Keep any prescribed blood-pressure treatment and use meditation as an inexpensive addition, not a swap. For blood pressure specifically, slow paced breathing has a more direct mechanism, covered separately.

The study · 1

Levine et al., meditation and cardiovascular risk reduction, a scientific statement from the American Heart Association · J Am Heart Assoc 2017;6(10):e002218

Sleep

Better sleep than a matched comparison (ES 0.33 to 0.54), no better than established sleep treatmentEmerging
In plain terms

Meditation improved sleep quality when compared with a matched but inactive comparison, and the gain grew a little by follow-up. Compared with actual sleep treatments it was no better. So it helps sleep more than doing nothing structured, and it does not beat a proper sleep program.

In detail

Eighteen trials with 1,654 participants were split by comparator. Versus specific active controls (such as evidence-based sleep treatments) there was low-strength evidence of no effect: ES 0.03 (95% CI -0.43 to 0.49) at post-treatment and -0.14 (-0.62 to 0.34) at follow-up. Versus nonspecific active controls there was moderate-strength evidence of benefit: ES 0.33 (0.17 to 0.48) at post-treatment and 0.54 (0.24 to 0.84) at follow-up.

How to use it

If sleep is the main problem, the first-line evidence-based treatment (cognitive behavioral therapy for insomnia) outperforms meditation and is the thing to reach for. Meditation is a fair general aid and a reasonable addition, not the strongest single tool for insomnia.

The study · 1

Rusch et al., the effect of mindfulness meditation on sleep quality, systematic review and meta-analysis of randomized controlled trials · Ann N Y Acad Sci 2019;1445(1):5-16

Cognition

Three months of five-hour-a-day retreat practice sharpened sustained attentionEmerging
In plain terms

People who did an intense three-month meditation retreat, meditating about five hours a day, got measurably better at seeing fine differences and at holding attention on a boring, demanding task. It shows attention can be trained, at a dose almost nobody will do.

In detail

Sixty participants were randomly assigned to receive training first or to a waitlist that trained later. The intervention was roughly 5 hours a day for 3 months of focused-attention practice on a chosen object such as the breath. Training improved visual discrimination through increased perceptual sensitivity and reduced the vigilance decrement, the normal fall-off in accuracy as time on a task increases. The mechanism proposed is that easier perception frees up the resources needed to keep attention going.

How to use it

Read this as proof of principle, not a home protocol. For attention in ordinary life, short daily practice has not clearly moved lab attention measures, so meditate for the mood and stress benefits and treat any focus gains as a bonus.

The study · 1

MacLean et al., intensive meditation training improves perceptual discrimination and sustained attention · Psychol Sci 2010;21(6):829-839

Mixed, unsettled evidence for everyday memory and focus across 23 studiesPreliminary · mixed
In plain terms

On tests of memory and attention the picture is mixed. Early practice, which is mostly about focusing, seemed to sharpen selective attention, and some studies found gains in working memory, but others found nothing, and the studies were not strong.

In detail

The review included 23 studies (15 controlled or randomized, 8 case-control) using objective neuropsychological measures. It suggested early phases of mindfulness training, centered on focused attention, could improve selective and executive attention, while later open-monitoring phases were linked more to sustained attention; working memory and some executive functions might also improve. The authors stressed methodological limitations and reported negative results, concluding the evidence is preliminary and should be treated with caution.

How to use it

Do not take up meditation expecting a memory or focus upgrade. The evidence for that is unsettled, so let it be a possible side benefit, not the reason you practice.

The study · 1

Chiesa, Calati & Serretti, does mindfulness training improve cognitive abilities? A systematic review of neuropsychological findings · Clin Psychol Rev 2011;31(3):449-464

Anxiety And Stress

A meditation app cut stress in 88 students over eight weeks, holding at 12Emerging
In plain terms

A meditation app cut stress and raised self-kindness in stressed college students over eight weeks, and the gains held at twelve. It is one small study against a waiting list, and people used the app only about half an hour a week.

In detail

This randomized waitlist-controlled trial enrolled 88 students scoring high on the Perceived Stress Scale, asked to meditate at least 10 minutes a day with Calm. All outcomes (perceived stress, mindfulness, self-compassion) differed significantly between groups after the intervention (all P < .04) and at 12-week follow-up (all P < .03), with effect sizes from moderate (0.59) to large (1.24). Actual use averaged 38 minutes a week during the intervention and 20 during follow-up. As a single small trial against a waitlist, it establishes feasibility more than a firm effect size.

How to use it

An app is a convenient way to start, not a requirement. If a subscription is the difference between practicing and skipping it, pay for it; otherwise the same practice is free with recorded guidance or a timer.

The study · 1

Huberty et al., efficacy of the mindfulness meditation mobile app Calm to reduce stress among college students, randomized controlled trial · JMIR Mhealth Uhealth 2019;7(6):e14273

How It Works

The core is training attention: choosing where it rests, noticing when it has drifted into planning or rumination, and bringing it back without judgment. Repeated over weeks, this loosens the pull of repetitive negative thinking. That is part of why the clearest benefits show up in anxiety and low mood, and why the effects on memory and willpower stay slight.

Focused-attention practice also tends to slow and deepen the breath. That overlaps with the mechanism behind slow breathing, a separate practice with a more direct effect on the body.

How big the effect looks depends heavily on the comparison. Against a waiting list, meditation looks powerful, because a waiting list matches the treatment group on nothing it shares, the time spent, the attention given, the expectation of improving. Against an active control, another practice that also asks for time and attention, the effect shrinks to a modest size. The strongest reviews use active controls on purpose, so the numbers here are smaller than the ones often quoted.

Against a waiting list the numbers balloon, since the people waiting spend no time and expect nothing. Matched practice for practice, the gain settles to a small-to-moderate size that still holds months later.

What To Expect

The first session may feel calm or restless; either way, practice follows a predictable arc over weeks.

Anatomy of the Practice

1The first sessions

You sit, rest attention on the breath, and within seconds the mind wanders. You notice and return. Most beginners take this wandering as proof they cannot meditate, when it is the exercise itself: the noticing and the return are the repetitions. Some people feel calmer at once, others feel restless, and both are normal early on.

2Over the first weeks

Practiced a few minutes most days, the returning gets easier and quicker, and the small measured effects on mood and stress start to appear. A daily habit does more here than an occasional long sit, because regularity matters more than the length of any one session.

3Over weeks to months

Kept up, the benefit builds to its modest size and then holds steady months later. It stays a skill: how much it helps tracks how much you practice. More time keeps the benefit steady; it does not make it much larger.

How To Do It

Each rung below names its time and effort, from a three-minute sit to a structured eight-week course.

Ways to Do It

Meditation is free to start: attention, the breath, a few minutes. Begin at the first rung and add the others as they suit you. If sitting still brings up strong difficult feelings, keep sessions short and consider a guided or trauma-sensitive setting instead of pushing through alone.

1
A few minutes on the breathFreeEasy

Sit comfortably, rest attention on the feeling of the breath, and when you notice it has wandered, bring it back. Start with three to five minutes. Count a session full of returns as a session done well.

2
A guided session, most daysFreeEasy

Free recorded guidance, a focused-attention practice or a body scan, makes the early weeks easier. Aim for about 10 minutes on most days. Give it eight weeks before judging it, the span over which the trial effects appear.

3
Try open monitoring or loving-kindnessFreeModerate

Once holding the breath feels steadier, widen the practice. Open monitoring watches thoughts and sensations come and go without chasing them. Loving-kindness repeats simple phrases of goodwill toward yourself and others, and has the best evidence for warmth, connection and low mood. Give it several sessions.

4
A structured course or an app$ to $$Moderate

An eight-week mindfulness-based course (MBSR, or MBCT for recurrent depression) is the version behind the strongest clinical evidence, taught by a trained instructor. A subscription app is another paid option. The app adds guided sessions and a set schedule; the course adds a trained teacher and the exact format used in the strongest trials.

Go Deeper

The stress axis explains what repeated stress does to the body that these attention practices help unwind. Breathwork and HRV is the body-first cousin, with a more direct effect on the nervous system. Meditation is studied as an addition to care for Depression and Anxiety. For sleep, a structured CBT for insomnia program does more. Nature exposure and Yoga nidra sit beside it as low-cost, low-risk practices.

The Chinese Medicine View

In Chinese medicine the Heart houses the Shen, 心藏神, the spirit or consciousness. A settled Shen shows as a clear, calm, well-rested mind. Stilling the attention is understood to calm the Shen and let it return to its home in the Heart.

The classical practices of quiet sitting (靜坐) and entering stillness (入靜) belong to the quiescent side of internal cultivation. They are the counterpart to the moving practices of tai chi and qi gong.

The opening chapter of the Su Wen puts it in one line: 恬惔虛無,真氣從之, when one is tranquil and empty of striving, the true Qi follows. Stillness here means letting go of striving. Held that way, the Qi settles and gathers instead of scattering.

The whole frame belongs to Yang Sheng, nourishing life, the preventive tradition that aims to keep a person well before illness sets in.

Tradition holds that stillness does not suit every person and state the same way. Someone very depleted or deeply agitated may find that forcing long, intense concentration spends the reserve instead of settling it. The classical instruction is to practice briefly, gently and often.

The qi gong literature describes practice going wrong, 走火入魔, when the breath is forced, the concentration driven too hard, or someone practices while distressed. The reported results are chest tightness, headache, palpitations and agitation. This maps onto the modern finding that difficult experiences cluster around intensive practice.

Two descriptive languages, developed independently, name the same experience from different sides; neither is a translation of the other.

Cautions

Most of the risk in meditation sits at one end: intensity. Three situations call for a gentler approach.

Cautions For This Practice

Extra restraint

Everything to be aware of is here, in one place. This practice suits most healthy people; a few situations call for real care.

Adverse effects in about 8.3% of practitioners across 83 studies

The review searched five databases to October 2019 and found 83 eligible studies (6,703 participants); 55 of them (65%) reported at least one type of adverse event. Total prevalence was 8.3% (95% CI 0.05 to 0.12), but 3.7% in experimental studies versus 33.2% in observational studies, a gap that reflects how much harder observational work looks for harms. The most common events were anxiety (33% of studies reporting AEs), depression (27%) and cognitive anomalies (25%); gastrointestinal problems and suicidal behaviors were least frequent (both 11%). Events occurred in some individuals with no previous mental-health history.Farias et al., adverse events in meditation practices and meditation-based therapies, a systematic review

Intensity is where most difficulty clusters

Higher rates of difficult experiences show up around long or intensive practice, especially silent retreats of days or weeks. That is a reason to build up gradually, not a reason to avoid meditation. If practice reliably brings on anxiety, low mood, or a sense of yourself or the world feeling unreal, ease off and speak to a teacher or clinician.

Not a replacement for treatment of a serious condition

For a diagnosed depressive, anxiety, trauma or psychotic condition, meditation is studied as an addition to care, not a replacement. The strong relapse-prevention result was for a structured eight-week program delivered alongside clinical care, in people already in remission. Keep any prescribed treatment, and change it only in consultation with whoever prescribed it.

Trauma and serious mental illness: choose the setting

Sitting quietly with your own attention can surface difficult material, and that is more likely for people with a trauma history or a serious mental-health condition. A guided, trauma-sensitive class, or a teacher who can adjust the practice, is a safer way in than long unguided sitting alone.

Start slow, be smart, read the research, and consult a professional if you have any concerns. This is here to inform your choice, not make it for you.

Common Questions

Does meditation actually work, or is it overhyped?

The benefits are dependable and modest. The strongest reviews compare meditation against an active control: another real practice, matched for time and attention. On that fair test it gave a small to moderate reduction in anxiety, low mood and the distress around pain, holding at a smaller size months later. As a formal therapy it roughly matches talk therapy or medication for those conditions, and beats doing nothing. It shows little clear effect on positive mood, sleep, eating or weight.

How long before I notice anything?

Trial benefits appear over about eight weeks of near-daily practice. It behaves like a skill: how much it helps follows how consistently you sit, more than the length of any single session. Frequency beats duration. If nothing has shifted after a couple of months of steady practice, it may not be your tool.

Do I need an app or a paid course?

The practice underneath costs nothing, your attention, the breath, a little time each day. A subscription app brings guided sessions and structure. An eight-week MBSR/MBCT course brings a trained teacher and the trial-tested format used in the best clinical studies.

I can't stop thinking. Am I doing it wrong?

No, this is the most common misunderstanding. The goal was never a blank, silent mind. Thoughts arriving is normal. The practice is noticing that a thought has carried you off, then gently returning attention to the breath. A session where that happens 50 times is 50 repetitions of the actual skill.

Is one kind of meditation better than another?

For anxiety, low mood and stress, focused attention and open monitoring, the practices in most mindfulness programs, carry most of the evidence. For warmth, connection and being kinder to yourself, loving-kindness has the better record. Research does not strongly favor one style, so pick the one you will actually practice. Consistency does more than the choice of technique.

Explore Related

Other pages this one connects to, by the evidence they share, the outcomes they touch, and the ground they cover.

Shares a source · 2 shared Slow breathing near six breaths a minute, the mechanism that makes that rate work, what a heart-rate-variability reading can and cannot tell you, and a protocol to follow.
Related evidence Two breathwork styles with opposite goals: slow coherent breathing near six a minute calms and lowers blood pressure; Wim Hof's fast breathing plus cold raises adrenaline. How to choose.
Related evidence L-theanine, an amino acid found almost only in tea, works best for calm, focused attention, clearest taken with caffeine, and for blunting the stress response to a task. Anxiety and sleep signals are smaller.
Related evidence What yoga nidra (NSDR) does for stress, mood and sleep, on modest, preliminary evidence, plus how to start free and when to be careful.
Related evidence Posture, breath and attention, with randomized trials behind much of it: back pain, mood, blood pressure, balance in older adults, and lately sleep, blood sugar in diabetes, and breast-cancer recovery.
Related evidence Tai chi and qi gong, the Chinese movement practices with the most randomized evidence: about 20% fewer falls in older adults, relief in fibromyalgia and knee arthritis, steadier balance in Parkinson's.

All 13 sources on this page independently checked and cross-referenced.

Thomas Dehli, Founder & Editor, Sacred Lotus

Sacred Lotus has published Chinese medicine reference material since 2001. Integrative pages are held to the same standard as the herb and formula library: cite the source, grade the claim at its real strength, and say where the research has not looked. This page is educational and it is not medical advice. Last reviewed and updated August 9, 2026.