ME/CFS ist eine chronische körperliche Erkrankung, deren kennzeichnendes Merkmal die postexertielle Malignität (post-exertional malaise) ist, ein verzögertes Zusammenbrechen, das durch Anstrengung ausgelöst wird. Die gestufte Expositionstherapie, die früher Standard war, wurde 2021 zurückgezogen.
Im Vordergrund steht heute das Pacing: Das Erlernen, innerhalb der verfügbaren Energie zu leben, damit man seltener zusammenbricht. Die tägliche Pflege besteht aus einer konsequenten Symptomkontrolle für nicht erholsamen Schlaf, die Schwindel und Herzrasen bei orthostatischen Problemen sowie Schmerzen.
Practice Ranking
Every practice we track for Chronic Fatigue Syndrome (ME/CFS): What the Evidence Supports, ranked by how well the evidence supports it for this condition. Strength describes the evidence, not our endorsement.
3 practices · 1 to start with
| # | Practice | Evidence | Type | Cost | Effort | Results In | Add to plan |
|---|---|---|---|---|---|---|---|
| 1 | Pacing: How Staying Within Your Energy Envelope Prevents Crashes in ME/CFS and Long COVID The frontline approach: stay within your energy envelope to avoid post-exertional crashes. Management, not a cure. | Moderate | Self-Directed | – | – | – | |
| 2 | Cognitive Behavioral Therapy: What It Treats, How Strong the Evidence Is, and How to Start Supportive CBT can help some people cope, alongside pacing; it is not a cure and remains contested in the patient community. | Emerging | Self-Directed | Free to $$ | Moderate to Hard | Weeks | |
| 3 | Coenzyme Q10: What the Trials Show for Heart Failure, Migraine, and Statin Muscle Pain Coenzyme Q10 plus NADH lowered exercise heart rate and eased fatigue over 8 weeks in one 80-person trial. | Preliminary | Supplement | $ to $$ | Easy | Weeks to Months | |
Default order puts the best-supported practices first, with self-directed care ahead of clinical options. Click any row to open the practice.
ME/CFS turns on one feature: post-exertional malaise. Ordinary tiredness has dozens of causes and is covered on the Fatigue page. When the illness begins after a COVID infection, it overlaps with Long COVID.
What It Is
Myalgic encephalomyelitis, also called chronic fatigue syndrome, is a long-term physical illness marked by disabling fatigue that rest does not fix.
One feature sets it apart from ordinary tiredness: post-exertional malaise.
A small physical or mental effort triggers a delayed, disproportionate crash, often a day or two afterward, that can last for days or weeks.
There is no single blood test; a doctor recognizes ME/CFS by its pattern:
- months of fatigue that does not lift with rest,
- the crash after exertion,
- unrefreshing sleep,
- trouble with memory, concentration, or standing upright.
Those same symptoms also point to four treatable conditions: thyroid disease, sleep apnea, anemia, celiac disease. The diagnosis is settled only after each is ruled out, so an early, careful assessment matters.
Severity spans a wide range, and doctors group it in three bands:
- Mild: activity is cut by around half; many keep working or studying by giving up leisure, social life and rest margins, then crash after any overexertion.
- Moderate: most people are housebound, managing daily tasks only in short bursts with rest between.
- Severe and very severe: people are largely or entirely bed-bound, often unable to tolerate light, sound or being moved, and may need help with eating and washing. Trivial-looking exertions can cause a lasting setback. This most severely affected group is often under-recognized.
Many also feel worse upright: light-headed and unsteady, with palpitations that ease on lying down. This overlaps with postural tachycardia syndrome (POTS), one more form of orthostatic intolerance and treatable on its own. ME/CFS affects women more often than men.
How It Works
The crash has a measurable physical basis. On a maximal exercise test repeated on two consecutive days, people with ME/CFS look much like healthy but inactive people on day one. On day two they cannot repeat it, reaching lower oxygen consumption and workload at both peak effort and the anaerobic threshold. Healthy sedentary controls reproduce their day-one results. That day-one-to-day-two drop is a physical marker of post-exertional malaise, and only the two-day test reveals it. It points away from simple deconditioning: the control group was inactive too, yet recovered normally. A classification model detected the two-day drop with 95.1% accuracy.
ME/CFS often begins after an infection, so in many people it is a post-viral illness. COVID made the overlap plain. Among people still severely fatigued six months after a mild or moderate infection, 19 of 42 met the full 2003 Canadian consensus criteria for ME/CFS, post-exertional malaise included. They closely resembled patients whose illness had followed other infections. What triggers it in one person, and the immune and metabolic mechanisms behind the crash, are still being worked out.
What Helps
Pacing comes first. Also called energy management, it means learning where your limit sits and staying under it, so effort does not tip into a crash. Pacing keeps you as active as the illness allows without slipping into all-day bed rest. It does not cure ME/CFS; it lowers how often you crash and makes a fluctuating illness more livable. In patient surveys it is the approach people rate most helpful and least likely to set them back. That is why current guidance builds care around it. A large trial has not yet tested individualized pacing head to head, so for now it rests on patient experience and today's guidance. The PACE trial tested a separate, fixed pacing protocol, which did no better than usual specialist care; it is not the same as day-to-day energy management. The practical core is learning your own early warning signs and stopping before you reach the limit.
The exercise question needs the most care, because getting it wrong has harmed people. For years, graded exercise therapy, a program of steadily increasing activity, was the standard, built on the PACE trial. A Cochrane review still finds a small fatigue benefit on low-to-moderate-certainty evidence. Large patient surveys reported high rates of harm from graded exercise. When PACE was reanalyzed using the study's own original scoring rules, the recovery claims came out far smaller than first reported, and no better than the comparison group. Most trials showing a benefit used broad entry rules that did not require post-exertional malaise. So they may not apply to the people whose effort reliably triggers a crash. Weighing the harm reports against the deflated recovery claims, the 2021 UK national guideline withdrew graded exercise therapy, and it is no longer offered.
Talk therapy and brain-retraining are sometimes sold as treatments for the illness itself. In that same reanalysis, cognitive behavioral therapy did not change the illness, though it helps some people cope. Brain-retraining programs such as DNRS are marketed directly at ME/CFS. These programs are built around nervous-system sensitization, which is real, but no controlled trial has tested the program itself. Any claim that it reverses the illness is unconfirmed, the research to judge it has not been done.
No drug changes the course of ME/CFS. Rituximab, a B-cell-depleting drug, was the most-watched attempt and matched placebo in a well-run 151-patient trial: response rates ran 26.0% on the drug and 35.1% on placebo. That closed off a leading disease-modifying hope, though it speaks only to rituximab and leaves other immune approaches still under study. A small trial of coenzyme Q10 plus NADH is preliminary and industry-affiliated. In one 80-person study it eased fatigue and lowered the heart rate people reached on an exercise test over eight weeks. It did nothing for pain or sleep, and one author was affiliated with a nutrition company. Beyond these, chronic-fatigue supplement protocols and private tests are sold directly to consumers online. Most are unregulated and none has been tested in a controlled trial. That does not prove they do nothing, it means the evidence is not there yet.
Most care is steady, symptom-by-symptom work you largely run yourself, and four pieces matter most:
- Orthostatic intolerance and POTS, one of the more treatable pieces. Options include more fluids and salt where a doctor agrees, compression garments, standing up slowly, and medication a doctor may add.
- Unrefreshing sleep and pain, each treated as a problem in its own right.
- Aids, help at home and adjustments at work or school that suit a changing illness.
- Anything that adds to the load (thyroid disease, sleep apnea, low mood) found and treated.
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.
Energy And Fatigue
Rituximab wirkte nicht besser als Placebo (26.0 % vs. 35.1 % Ansprechen) in einer Studie mit 151 Patienten
Eine gut durchgeführte Studie mit Rituximab, einem Medikament, das B-Immunzellen erschöpft, fand, dass es bei ME/CFS nicht besser als Placebo wirkte, und schloss damit einen der meistbeobachteten Behandlungsversuche ab.
In einer randomisierten, doppelblinden, placebokontrollierten multizentrischen Studie mit 151 Patienten, die kanadische Kriterien erfüllten, erzielte Rituximab eine Gesamt-Ansprechrate von 26.0 % gegenüber 35.1 % für Placebo (Differenz -9.2 Prozentpunkte, 95-%-KI -23.3 bis 5.5), und die Gruppen unterschieden sich über 24 Monate beim Müdigkeits-Score oder bei sekundären Maßen nicht. Schwere unerwünschte Ereignisse traten in der Rituximab-Gruppe bei 26 % und in der Placebogruppe bei 19 % auf. Measured in: 151 adults aged 18 to 65 with ME/CFS by Canadian consensus criteria, ill for 2 to 15 years, at five Norwegian hospitals. Dies war eine gut ausgestattete, verblindete Studie, sodass das Nullergebnis für Rituximab gesichert ist, gilt aber für dieses eine Medikament und schließt andere untersuchte Immunansätze nicht aus; der primäre Endpunkt war selbst berichtet.
Who this may not transfer to:Both sexes were enrolled with a female majority typical of ME/CFS; the trial did not report sex-stratified response rates.
The study · 1
Fluge et al., B-lymphocyte depletion in patients with myalgic encephalomyelitis/chronic fatigue syndrome: a randomized, double-blind, placebo-controlled trial · Ann Intern Med 2019;170(9):585-93
Across 8 trials in 1,518 adults, exercise therapy probably eased fatigue a little, on low-to-moderate certainty
Pooled trials found that graded exercise probably lowered fatigue a little compared with doing nothing, but the certainty was low, whether it caused harm was unclear, and most trials did not specifically enroll people with the crash-after-effort pattern.
A Cochrane review of 8 randomized trials in 1,518 adults found that exercise therapy, mostly graded aerobic activity, probably reduced fatigue at the end of treatment compared with passive control, on low-to-moderate certainty evidence. The review judged the effect on serious harms to be uncertain, and most included trials recruited under broad criteria that did not require post-exertional malaise. Measured in: 1,518 adults with a primary diagnosis of chronic fatigue syndrome across 8 randomized controlled trials, using a range of diagnostic criteria. Most trials used broad definitions that did not require post-exertional malaise, so the results may not describe the people for whom exertion reliably triggers a crash; the review flagged uncertainty about harms, and its own publisher has stated it is being updated.
Who this may not transfer to:Trials enrolled both sexes with a female majority typical of ME/CFS cohorts; the review did not report sex-stratified effects.
The study · 1
Larun et al., exercise therapy for chronic fatigue syndrome · Cochrane Database Syst Rev 2019;10:CD003200
Anhand ihres eigenen ursprünglichen Protokolls neu analysiert, schnitt die CBT und abgestufte Bewegungstherapie der PACE-Studie nicht besser ab als die Vergleichsgruppe
When the PACE trial data was analyzed the way its own plan had specified, the recovery and improvement numbers for CBT and graded exercise were far lower than first reported and no better than the comparison group, with any small gains limited to how people rated themselves.
Eine Neuanalyse der PACE-Studie mit ihrem eigens festgelegten Protokoll fand, dass nach Korrektur für die geplanten Vergleiche CBT und abgestufte Bewegungstherapie die Kontrollgruppe bei der Gesamtverbesserung nicht signifikant übertrafen, und die Genesungsraten waren durchgängig niedrig und unterschieden sich nicht zwischen den Gruppen. Signifikante Effekte lagen fast ausschließlich bei Selbstbericht-Maßen vor und hielten über zwei Jahre nicht an. Measured in: Reanalysis of data from the 641-patient PACE randomized trial (Oxford criteria), using protocol-specified outcomes obtained through a Freedom of Information request. Dies ist eine Neuanalyse einer bestehenden Studie, keine neue Studie, und übernimmt die Designgrenzen der ursprünglichen Studie, einschließlich einer breiten Falldefinition und unverblindeter, selbst berichteter primärer Endpunkte; eben diese Merkmale sind der Grund, warum die Autoren warnen, dass die bescheidenen Selbstbericht-Gewinne Berichtsbias widerspiegeln könnten.
Who this may not transfer to:The underlying PACE trial enrolled both sexes with a female majority; the reanalysis did not report sex-stratified outcomes.
The study · 1
Wilshire et al., rethinking the treatment of chronic fatigue syndrome: a reanalysis and evaluation of findings from a recent major trial of graded exercise and CBT · BMC Psychol 2018;6(1):6
Das strukturierte Pacing-Programm in PACE schnitt nach 52 Wochen nicht besser ab als Spezialistenversorgung
Das spezifische strukturierte Pacing-Programm, das in der Hauptstudie getestet wurde, schnitt nicht besser ab als die übliche Spezialistenversorgung, was eine separate Frage ist von der täglichen Energieverwaltung, die Patienten und aktuelle Leitlinien als Pacing beschreiben.
In der randomisierten PACE-Studie mit 641 Patienten verbesserte das als adaptive Pacing-Therapie getestete formale Protokoll, zur spezialisierten medizinischen Versorgung hinzugefügt, nach 52 Wochen weder Müdigkeit noch körperliche Funktion stärker als spezialisierte medizinische Versorgung allein. Measured in: 641 adults meeting Oxford criteria for chronic fatigue syndrome, recruited from six UK secondary-care clinics. Adaptive Pacing-Therapie, wie in dieser Studie manualisiert, ist nicht dasselbe wie das individualisierte Energiemanagement, das jetzt als Pacing bezeichnet wird, daher spricht dieses Nullergebnis für ein formales Protokoll, nicht den allgemeinen Ansatz; die Studie verwendete auch die breite Oxford-Definition, die keine post-exertionelle Malaise erfordert.
Who this may not transfer to:Both sexes were enrolled with a female majority; the trial did not report sex-stratified primary outcomes.
The study · 1
White et al., comparison of adaptive pacing therapy, cognitive behaviour therapy, graded exercise therapy, and specialist medical care for chronic fatigue syndrome (PACE): a randomised trial · Lancet 2011;377(9768):823-36
In einer 80-Personen-Studie senkten Coenzym Q10 plus NADH die Belastungsherzfrequenz und linderten über 8 Wochen die Müdigkeit
In einer kleinen Studie senkte ein Coenzym-Q10- und NADH-Supplement die Herzfrequenz, die Menschen während eines Belastungstests erreichten, und linderte über acht Wochen ihr Müdigkeitsgefühl, tat aber nichts für Schmerzen oder Schlaf.
In einer 8-wöchigen randomisierten, doppelblinden, placebokontrollierten Machbarkeits-Studie mit 80 Patienten senkten Coenzym Q10 plus NADH die maximale Herzfrequenz, die während eines Fahrrad-Belastungstests in Woche 8 erreicht wurde, signifikant (P=0.022) und reduzierten wahrgenommene Müdigkeit gegenüber Placebo (P=0.03). Schmerzen und Schlaf verbesserten sich nicht. Die Kombination wurde gut vertragen. Measured in: 80 adults with chronic fatigue syndrome in a single-center trial in Barcelona. Die Studie war klein, dauerte nur acht Wochen, und ihr Hauptendpunkt war ein Herzfrequenzmaß während des Sports, nicht die alltägliche Funktion, sodass der Befund vorläufig ist; ein Autor war mit einem Ernährungsunternehmen verbunden.
Who this may not transfer to:Both sexes were enrolled with a female majority; the trial did not report sex-stratified effects.
The study · 1
Castro-Marrero et al., effect of coenzyme Q10 plus nicotinamide adenine dinucleotide supplementation on maximum heart rate after exercise testing in chronic fatigue syndrome: a randomized, controlled, double-blind trial · Clin Nutr 2016;35(4):826-34
Measurement And Diagnosis
About 0.89% of people have ME/CFS, women 1.5 to 2 times as often as men
About 0.9 in 100 people are estimated to have ME/CFS under the usual criteria, and women are affected around one and a half to two times as often as men, though the figure shifts a lot depending on how it is counted.
A meta-analysis of 46 studies covering more than 1,085,000 people estimated the prevalence of ME/CFS at 0.89% under the most commonly used case definition (CDC-1994), with a random-effects meta-analysis estimate across all definitions of 0.68% (95% CI 0.48 to 0.97). Estimates varied widely by case definition and by how the diagnosis was ascertained, from 0.09% by physician diagnosis to 1.14% by interview. Women were affected roughly 1.5 to 2 times as often as men. Measured in: More than 1,085,000 participants from community-based surveys and primary care sites across 46 studies published from 1980 to 2018. The estimates ranged widely with the case definition and diagnostic method used, so no single prevalence figure is definitive; the authors note the lack of an objective diagnostic test as the main reason for the spread.
Who this may not transfer to:Both sexes were included; the review found women affected about 1.5 to 2 times as often as men across every subgroup analyzed.
The study · 1
Lim et al., systematic review and meta-analysis of the prevalence of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) · J Transl Med 2020;18(1):100
19 von 42 Menschen mit anhaltender Post-COVID-Müdigkeit erfüllten die vollen ME/CFS-Kriterien
In einer Studie mit Menschen, die sechs Monate nach einer leichten oder mäßigen COVID-Infektion noch erschöpft waren, erfüllten fast die Hälfte die vollen Kriterien für ME/CFS, einschließlich des Einbruchs nach Anstrengung, was zeigt, dass die Erkrankung durch COVID ausgelöst werden kann, ähnlich wie sie anderen Infektionen folgen kann.
In einer prospektiven Kohorte von 42 Menschen mit anhaltender mäßiger bis schwerer Müdigkeit und Belastungsintoleranz sechs Monate nach leichtem bis mäßigem COVID-19 erfüllten 19 die kanadischen Konsensus-Kriterien 2003 für ME/CFS, einschließlich post-exertioneller Malaise. Die Post-COVID-ME/CFS-Gruppe ähnelte einer gematchten Kohorte, deren ME/CFS anderen Infektionen gefolgt war. Measured in: 42 adults (29 women, 13 men, median age 36.5) with persistent post-COVID fatigue, compared with an age- and sex-matched post-infectious non-COVID ME/CFS cohort. What could explain it instead: People who volunteer for a post-COVID fatigue study are selected for severity, so the share meeting ME/CFS criteria here is likely higher than among all people who catch COVID; unmeasured prior health differences could also shape who develops lasting symptoms.. Dies ist eine kleine Beobachtungskohorte aus der ersten Pandemiewelle, sodass der Anteil, der nach COVID ME/CFS entwickelt, daraus nicht verallgemeinert werden kann; es belegt, dass die Überschneidung real ist, misst aber nicht, wie häufig sie ist.
Who this may not transfer to:Both sexes were included (29 women, 13 men); the cohort was too small for reliable sex-stratified analysis.
The study · 1
Kedor et al., a prospective observational study of post-COVID-19 chronic fatigue syndrome following the first pandemic wave in Germany and biomarkers associated with symptom severity · Nat Commun 2022;13(1):5104
How it works
A second exercise test a day later exposes a drop that sorts ME/CFS from controls with 95.1% accuracy
People with ME/CFS did as well as healthy but inactive people on an exercise test the first day, but a day later their bodies could not repeat it, a measurable drop that gives the crash after exertion a physical marker a single test would miss.
In a two-day cardiopulmonary exercise test, 51 women with ME/CFS and 10 sedentary control women performed alike on day one, but on day two the ME/CFS group reached significantly lower oxygen consumption and workload at both peak effort and the anaerobic threshold, while controls reproduced their results. A classification model separated the groups with 95.1% accuracy on the second test. A separate study likewise found ME/CFS patients unable to reproduce their peak oxygen uptake on the second day. Measured in: 51 women with ME/CFS and 10 sedentary control women, each completing two maximal exercise tests 24 hours apart. What could explain it instead: Deconditioning from inactivity could in principle lower exercise capacity, but the control group was also sedentary and reproduced their day-one results, which points away from deconditioning alone as the explanation for the day-two drop.. Only patients well enough to complete two maximal exercise tests were included, so this cannot describe the more severely affected, and the control group was small. It documents a physiological pattern, not establishing a cause of the illness.
Who this may not transfer to:The Snell cohort was all women; the companion study by Keller included men and women and found the same failure to reproduce peak oxygen uptake on the second day, so the pattern is not thought to be specific to women.
The studies · 2
Snell et al., discriminative validity of metabolic and workload measurements for identifying people with chronic fatigue syndrome · Phys Ther 2013;93(11):1484-92
Keller et al., inability of myalgic encephalomyelitis/chronic fatigue syndrome patients to reproduce VO2peak indicates functional impairment · J Transl Med 2014;12:104
A caution on exercise
Extra restraintEverything to be aware of is here, in one place. This practice suits most healthy people; a few situations call for real care.
Graded exercise worsened symptoms for 54% to 74% of patients surveyed, while pacing helped 44% to 82%
Across a primary survey of 1,428 patients and comparison surveys totaling 16,665 more, graded exercise therapy was followed by a worsening of symptoms in 54% to 74% of respondents. Cognitive behavioral therapy helped a small share (8% to 35%). Pacing was the most favored approach, with the lowest rate of reported harm and the highest reported benefit (44% to 82%). Survey data captures what patients report after the fact, not a controlled comparison, so it cannot measure effect size precisely; even so, the size and consistency of the harm signal for graded exercise across independent surveys is what current guidance weighed.Geraghty et al., ME/CFS patients' reports of symptom changes following CBT, GET and pacing treatments: analysis of a primary survey compared with secondary surveys
Do not push through the fatigue
The instinct to exercise your way back to fitness is the one that backfires here. In ME/CFS, structured graded exercise made a large share of people worse, and current guidance no longer recommends it as a treatment. Pacing to avoid post-exertional crashes is the approach that holds up. The advice that helps ordinary deconditioning is the opposite of what helps here.
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.
When to Get Checked
When to See Someone
Most of living with ME/CFS is steady, day-to-day energy management. A few situations call for a professional. One comes first: a doctor should make this diagnosis after ruling out other causes. These are the signs to get seen about:
- A first assessment: months of these symptoms need a doctor to rule out the treatable causes above before settling on ME/CFS
- Fatigue alongside unexplained weight loss, a fever that will not settle, drenching night sweats, or a new lump, which points toward a cause that needs looking into promptly(seek urgent care)
- A steep, lasting deterioration, or very severe illness where someone cannot take in enough food or fluid, which needs prompt medical help(seek urgent care)
- Fainting, chest pain, or a new or severe pounding or racing heart, which should be assessed(seek urgent care)
- New or worsening neurological symptoms: weakness in a limb, loss of coordination, double vision or trouble speaking, not part of ME/CFS, and needing review(seek urgent care)
- Thoughts of harming yourself or ending your life: contact your local emergency number or crisis line now, and tell someone nearby(seek urgent care)
- Low mood or anxiety: common alongside a disabling illness, and deserving care in its own right
- Any plan to start or stop a prescribed medicine, those changes belong with whoever prescribed it
ME/CFS is a serious illness, and much of what steadies it is self-directed, once a doctor has confirmed the diagnosis and ruled out other causes.
The Chinese Medicine View
The Chinese Medicine View
Chinese medicine reads a long, depleting illness like this as a vacuity pattern, the body drained of its resources. It centers on the Spleen, held responsible for making qi from food, and the Kidney. These patterns come from a system used to steady depleted people for well over a thousand years. Not everything that helps a fatigued person shows up in a trial. The tradition holds back too. A depleted person is not given strong draining, purging or stimulating methods; those deepen the exhaustion. The idea that vigorous exercise can restore a depleted person runs against the same caution that modern pacing teaches. The herb choice follows the pattern, so a formula that suits one person can be wrong for the next. Any herbs belong with a qualified practitioner.
Heavy, tired limbs, poor appetite, loose stools, bloating after eating, and a foggy head that worsens with effort. The classical direction is to strengthen the Spleen and build qi gently, so the person is not pushed past what they can hold.
A deep, bone-level exhaustion, low back and knee weakness, feeling cold, poor stamina and low drive. The tradition sees the Kidney as the root of reserve energy, and this pattern points to supporting it slowly.
The picture that often follows a viral illness: low-grade feverishness or night sweats, a dry throat, restless unrefreshing sleep, and a crash after exertion. The direction is to clear what lingers while rebuilding qi and yin, and to avoid overtreating a person who is already depleted.
Explore Related
Other pages this one connects to, by the evidence they share, the outcomes they touch, and the ground they cover.
All 10 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.
Evidence strength
How confidently the research supports a claim. Strength describes the evidence, not our endorsement.