Ginkgo Biloba

• Symptomatic mild-to-moderate dementia, modest and contested (EGb 761, German S3 'kann')
• Intermittent claudication and peripheral arterial disease (older European data)
• Tinnitus, mixed and mostly tied to accompanying anxiety or cognitive symptoms
• Vertigo and dizziness (limited)
• Marketed for memory in healthy adults, where trials show no benefit

Ginkgo biloba occupies a unique evolutionary position, the last surviving species of the Ginkgoaceae family and the entire Ginkgophyta division, a plant lineage that emerged in the Permian period approximately 270 million years ago and dominated forests during the Jurassic period. The species has no close living relatives at any taxonomic level above species, Ginkgo biloba is the sole representative of its order, family, and genus. The "living fossil" characterization reflects this evolutionary isolation; the modern Ginkgo biloba is morphologically essentially identical to fossil specimens from the Jurassic period 170+ million years ago. The trees can live for thousands of years (the oldest documented specimens in China exceed 3000 years) and demonstrate remarkable resilience, the six ginkgo trees that survived the Hiroshima atomic bombing within 1-2 km of the hypocenter and continued to grow have become symbolic of the species' biological hardiness. Traditional Chinese medicine has used ginkgo seeds (the gametophytes within the foul-smelling fruit) for respiratory and digestive applications for centuries; the leaves have been used more recently in Chinese medicine. Modern Western use centers almost entirely on standardized leaf extracts. The pharmacology of standardized ginkgo leaf extract has been characterized primarily through EGb 761 (the trademark of Dr. Willmar Schwabe Pharmaceuticals, marketed as Tebonin in Europe and licensed to multiple supplement manufacturers globally), the dominant pharmaceutical-grade preparation used in essentially all major clinical trials. EGb 761 is standardized to 22-27% flavonoid glycosides (quercetin, kaempferol, isorhamnetin glycosides) and 5-7% terpene lactones (the ginkgolides A, B, C, J, and bilobalide, the latter being unique to Ginkgo biloba). Standardization also limits ginkgolic acids to ≤5 ppm, ginkgolic acids are allergenic compounds present in raw leaf material that pharmaceutical-grade processing removes. The active pharmacology centers on multiple mechanisms: platelet-activating factor (PAF) antagonism (the ginkgolides are among the most potent PAF antagonists characterized, relevant to bleeding risk concerns and possible cerebral microcirculation effects); modest cerebral vasodilation and improved cerebral blood flow; antioxidant activity in brain tissue (relevant to neuroprotective claims); MAO inhibition (modest, relevant to antidepressant claims that have not robustly translated to clinical efficacy); modulation of neurotransmitter systems including acetylcholine, dopamine, and serotonin; possible amyloid-beta interactions relevant to Alzheimer's disease research; mitochondrial protective effects in preclinical models. The modern ginkgo evidence story is one of substantial mechanism-translation evidence reversal. Through the 1980s-90s, ginkgo became among the most-studied and most-prescribed herbal medicines globally, with German LANI (Bundesinstitut für Arzneimittel) approval and substantial use in Germany and France as prescription pharmaceutical for cognitive impairment in dementia. Substantial clinical evidence accumulated supporting symptomatic improvement in mild-to-moderate dementia. The 2000s brought the major rigorous trials that substantially reshaped expectations: GEM (Ginkgo Evaluation of Memory, DeKosky 2008, JAMA) randomized 3069 older adults to EGb 761 240mg/day or placebo over ~6 years for primary prevention of dementia, null result. GuidAge (Vellas 2012, Lancet Neurology) randomized 2854 older adults with memory complaints to EGb 761 240mg/day or placebo over 5 years for dementia prevention, also null result. These two large rigorous trials substantially recalibrated expectations about ginkgo cognitive prevention claims. Modest evidence remains for symptomatic support in mild dementia (Janssen 2010 systematic review supports modest cognitive and behavioral improvements at 240mg/day), intermittent claudication, tinnitus, and select other applications, but the "prevent dementia with ginkgo" framing has been substantially recalibrated.

Standard ginkgo dosing centers on 120-240mg/day of standardized leaf extract (24% flavonoid glycosides, 6% terpene lactones, the EGb 761 specification). The 240mg/day dose is used in essentially all major dementia trials (GEM, GuidAge, Le Bars, Kanowski) and represents the symptomatic dementia evidence-based dose. The 120mg/day dose has substantial evidence for intermittent claudication and general cognitive support. Take in 1-3 divided doses, twice daily (120mg morning, 120mg evening) is common for 240mg total daily. Take with or without food; absorption is acceptable either way. Treatment duration matters, symptomatic dementia effects develop over 4-12 weeks; intermittent claudication walking distance improvements over 4-8 weeks. For acute mountain sickness prevention: 80-120mg twice daily starting 1-2 days before ascent. The Upper Limit (UL) is not formally established; doses above 240mg/day produce diminishing returns and increased bleeding risk concerns. The pre-surgical discontinuation guidance is critical, at least 2 weeks before elective procedures, longer if extensive surgery planned. Anticoagulant coordination is essential given documented case reports of serious bleeding events with concomitant use. The pharmaceutical preparations (EGb 761 / Tebonin in Germany; Tanakan in France; equivalent licensed products in other markets) carry the most rigorous clinical inheritance; generic standardized extracts at equivalent 24/6 specification provide cost-effective alternatives. The GEM and GuidAge trial results substantially recalibrate the dementia prevention framing, symptomatic mild dementia evidence remains supported (German LANI guidelines) but primary prevention claims are not supported by current evidence.

Standard daily dose

120-240mg/day standardized extract

Dementia symptomatic (EGb 761)

240mg/day in divided doses

Intermittent claudication

120-240mg/day

General cognitive support

120mg/day

Acute mountain sickness

80-120mg twice daily, start 1-2 days pre-ascent

EGb 761 standardization

24% flavonoid glycosides, 6% terpene lactones

Ginkgolic acid limit

≤5 ppm (pharmaceutical-grade)

Treatment duration (symptomatic dementia)

4-12 weeks for meaningful effects

• EGb 761 / Tebonin (Dr. Willmar Schwabe Pharmaceuticals)

  Rating: gold

  The foundational clinical-grade ginkgo standardization used in essentially all major modern clinical trials (Le Bars 1997, Kanowski 1996, GEM 2008, GuidAge 2012, multiple). Standardized to 22-27% flavonoid glycosides, 5-7% terpene lactones (ginkgolides A/B/C/J and bilobalide), ≤5 ppm ginkgolic acids. Prescription pharmaceutical in Germany, France, and several European countries (marketed as Tebonin, Tanakene, Tanakan). Licensed to multiple supplement manufacturers globally including Vitex (US), Nature's Bounty, and similar. Premium pricing justified by extensive clinical inheritance.

• Standardized Ginkgo Leaf Extract (24/6 standardization)

  Rating: gold

  Generic standardized ginkgo extracts matching the EGb 761 composition specification (24% flavonoid glycosides, 6% terpene lactones). Common standardization across major supplement manufacturers. Pharmacology essentially equivalent to EGb 761 at the molecular level; clinical trial inheritance technically belongs to EGb 761 specifically but standardized composition is the operative driver. Major manufacturers include NOW Foods, Thorne, Pure Encapsulations, Solgar, Nature's Way.

• Tanakan (Beaufour Ipsen, France)

  Rating: gold

  French pharmaceutical-grade ginkgo extract (EGb 761 licensed) with substantial French clinical inheritance. Used in GuidAge trial. Specialty pharmaceutical category in some European markets.

• Generic Ginkgo Extract (Variable Standardization)

  Rating: caution

  Generic ginkgo extracts without specific 24/6 or equivalent standardization disclosure. Quality variation is substantial; clinical effects unreliable due to active compound variation. The 22-27% flavonoid glycosides / 5-7% terpene lactones standardization is the operative pharmacological framework, products without explicit standardization disclosure may have substantially different composition.

• Whole Ginkgo Leaf Powder

  Rating: caution

  Whole dried leaf powder without extraction concentration. Active compound content is substantially lower than concentrated extracts; ginkgolic acid content may be higher (allergenic concern). Reasonable for traditional/tea use but substantially less reliable than standardized extracts for clinical applications. Ginkgolic acid content particularly concerning in unprocessed leaf material.

• Ginkgo Seeds (Yin Xing, Traditional Chinese Medicine)

  Rating: caution

  The seeds (gametophytes within the foul-smelling fruit) have been used in traditional Chinese medicine for respiratory and digestive applications. The seeds contain neurotoxic ginkgotoxin (4-O-methylpyridoxine, a vitamin B6 antagonist), sufficient consumption can cause seizures, particularly in children. This is fundamentally different chemistry from leaf extract pharmacology. Modern Western use of leaf extract should NOT include seed consumption.

• Combination Cognitive Formulations

  Rating: good

  Ginkgo commonly included in multi-herb cognitive formulations alongside bacopa, gotu kola, lion's mane, B vitamins, and other cognitive cofactors. Mechanistically reasonable; verify ginkgo dose specifically rather than relying on category positioning. Most premium cognitive supplements use 24/6 standardized extract.

• Liquid Ginkgo Tincture

  Rating: good

  Ethanolic or glycerin-based liquid extracts. Traditional herbal preparation form with reasonable absorption. Standardization varies more across tincture products; reputable manufacturers specify flavonoid and terpene lactone content per dose.

• Mild-to-moderate dementia (symptomatic)

  Strength of evidence for this group: modest

  Janssen 2010 systematic review and substantial prior evidence base (Le Bars 1997, Kanowski 1996, multiple) support EGb 761 240mg/day for modest symptomatic improvements in mild-to-moderate dementia (cognitive function, behavioral symptoms, activities of daily living). German LANI guidelines support this use. Reasonable adjunct to standard dementia management; not substitute for acetylcholinesterase inhibitors or memantine in established Alzheimer's disease. Coordinate with neurology.

• Dementia prevention (NULL evidence)

  Strength of evidence for this group: avoid

  GEM trial (DeKosky 2008) and GuidAge trial (Vellas 2012) both demonstrated NULL results for dementia prevention with EGb 761 240mg/day over 5-6 years. Substantial mechanism-translation failure; not supported for primary prevention of cognitive decline or dementia in cognitively normal older adults. Reasonable to abandon dementia prevention claims; modest symptomatic evidence in established dementia is a separate (and weaker) framework.

• Intermittent claudication / peripheral vascular disease

  Strength of evidence for this group: modest

  Pittler 2000 meta-analysis and subsequent work support ginkgo at 120-240mg/day for modest improvements in walking distance and symptom severity in intermittent claudication. Effect sizes modest versus pharmaceutical alternatives (cilostazol, pentoxifylline); reasonable adjunct to established vascular medicine management. Coordinate with vascular specialist.

• Tinnitus (mixed evidence)

  Strength of evidence for this group: cautious

  Hilton 2013 Cochrane review and subsequent work show mixed evidence for ginkgo in tinnitus. Some users experience modest improvements; many do not respond. Reasonable trial in chronic tinnitus given limited treatment alternatives; if no improvement after 8-12 weeks, likely not effective in that user.

• Vertigo and dizziness

  Strength of evidence for this group: modest

  European pharmaceutical use for vertigo and dizziness has substantial clinical inheritance. Modern Western evidence is more limited but consistent with the European pharmaceutical positioning. Reasonable specialist consideration; coordinate with ENT for established vestibular disease.

• Age-related macular degeneration (preliminary)

  Strength of evidence for this group: cautious

  Preliminary evidence for ginkgo in age-related macular degeneration through possible retinal vascular effects. Reasonable component of comprehensive AMD nutrition (AREDS framework primary); not standalone intervention. Coordinate with ophthalmology.

• Acute mountain sickness (mixed evidence)

  Strength of evidence for this group: cautious

  Mixed evidence for ginkgo in acute mountain sickness prevention. Reasonable preventive consideration for users planning high-altitude activities but acetazolamide remains gold standard.

• Healthy adults (general cognitive support)

  Strength of evidence for this group: cautious

  Mixed evidence for cognitive enhancement in healthy adults. Some preliminary studies support modest acute cognitive effects; chronic effects in cognitively normal adults are limited. Reasonable component of comprehensive cognitive nutrition but with realistic expectation calibration post-GEM/GuidAge.

• Anticoagulant users (BLEEDING RISK)

  Strength of evidence for this group: avoid

  Substantial bleeding risk through PAF antagonism in users on warfarin, DOACs (apixaban, rivaroxaban), or antiplatelet agents (aspirin, clopidogrel). Documented case reports of subdural hematoma and serious hemorrhagic events. Generally avoid in anticoagulated users without prescribing physician coordination; clinical evidence does not support routine use in this population.

• Pre-surgical patients (BLEEDING RISK)

  Strength of evidence for this group: avoid

  Pre-surgical discontinuation at least 2 weeks before elective procedures is standard guidance. Documented case reports of postoperative bleeding with ginkgo continuation. Coordinate with surgical and anesthesia teams.

• Epilepsy / Seizure disorders

  Strength of evidence for this group: cautious

  Theoretical seizure risk, particularly with ginkgo seed consumption (ginkgotoxin neurotoxicity). Modern leaf extracts have reduced concern but limited safety data in established epilepsy. Coordinate with neurology.

• Pregnancy and lactation

  Strength of evidence for this group: cautious

  Limited systematic safety data. Bleeding risk concerns reasonable around delivery. Generally avoid during pregnancy without OB-GYN coordination; lactation safety data limited.

• Pediatric use

  Strength of evidence for this group: cautious

  Limited safety data in pediatric populations. Ginkgo seed neurotoxicity particularly concerning in children. Routine pediatric supplementation outside specific clinical indication not warranted.

• Acetylcholinesterase Inhibitors (Donepezil, Rivastigmine)

  Interaction: synergy

  Mechanistically complementary in dementia symptomatic management, ginkgo through cerebral microcirculation and PAF antagonism; AChE inhibitors through synaptic acetylcholine preservation. Common combination in specialist dementia practice; coordinate with neurology.

• Memantine

  Interaction: synergy

  NMDA antagonist mechanistically complementary to ginkgo. Common combination in moderate dementia management. Specialist coordination.

• Warfarin

  Interaction: avoid

  Substantial bleeding risk through PAF antagonism plus anticoagulation. Documented case reports of serious bleeding events. Generally avoid combination; coordinate with prescribing physician if both clinically necessary.

• DOACs (Apixaban, Rivaroxaban, Dabigatran, Edoxaban)

  Interaction: avoid

  Similar bleeding risk concern as with warfarin. Generally avoid combination; coordinate with prescribing physician.

• Antiplatelet Agents (Aspirin, Clopidogrel)

  Interaction: caution

  Additive bleeding risk concern. Coordinate with prescribing physician; consider monitoring for bleeding signs if combined use clinically necessary.

• SSRIs and Other Serotonergic Medications

  Interaction: caution

  Theoretical MAO inhibition effects from ginkgo could interact with serotonergic medications. Clinical relevance modest at typical doses but coordinate with prescribing psychiatrist.

• Anticonvulsants

  Interaction: caution

  Theoretical seizure threshold concerns with ginkgo (particularly seed consumption). Coordinate with neurology for users on anticonvulsant therapy.

• NSAIDs

  Interaction: caution

  Additive bleeding risk through different mechanisms. Modest practical concern at standard doses; coordinate for chronic high-dose NSAID users.

• Surgery

  Interaction: avoid

  Pre-surgical discontinuation 2+ weeks before elective procedures. Documented postoperative bleeding case reports. Critical perioperative guidance.

• Diuretics

  Interaction: caution

  Limited evidence for blood pressure interaction effects. Coordinate with prescribing physician for users on antihypertensive therapy.

• Bacopa, Lion's Mane, Other Cognitive Herbs

  Interaction: synergy

  Common combinations in cognitive supplementation. Mechanistically distinct; reasonable comprehensive cognitive protocols. Verify individual ginkgo dose given bleeding risk awareness.

Look for: explicit Ginkgo biloba leaf extract specification (not seeds or whole leaf); standardization to 24% flavonoid glycosides and 6% terpene lactones (24/6 the EGb 761 specification); ginkgolic acid limit disclosed (≤5 ppm pharmaceutical-grade); EGb 761 or equivalent branded licensing for clinical-grade applications; HPLC verification of active compound content; reputable manufacturer with quality control disclosure; USP or NSF third-party verification. Avoid: whole leaf or unstandardized products (ginkgolic acid concern, variable potency); ginkgo seed products (neurotoxicity concern, especially in children); products without standardization disclosure; products at unusually low cost (likely quality compromise); aggressive dementia prevention claims (NOT supported post-GEM/GuidAge); products marketed for pediatric use; combination products that obscure ginkgo dose given bleeding risk awareness.

Research published from: China.

Ginkgo biloba's evolutionary lineage extends approximately 270 million years to the Permian period, the species exists today essentially morphologically unchanged from Jurassic-era fossils, earning the "living fossil" designation popularized by Charles Darwin. The species likely came close to extinction during the Pleistocene; surviving wild populations may exist only in specific Chinese mountain valleys (with most current Chinese ginkgo populations descended from temple plantings that maintained the species through cultivation). The cultural-medical use in China extends thousands of years, the seeds (gametophytes in the foul-smelling fruit) have been used in traditional Chinese medicine for respiratory, digestive, and urinary applications, with documentation in classical TCM texts. The leaves have been used more recently in Chinese medicine, though traditional Chinese leaf use is more limited than modern Western extract use. The species reached Europe in the 18th century through trade with China and Japan; Linnaeus formally classified the species in 1771 with the name Ginkgo biloba reflecting the Japanese "ginkyo" (the Japanese pronunciation of the Chinese "yin-xing" meaning silver apricot, referring to the silvery seeds) and "biloba" indicating the characteristic two-lobed leaf shape. The species was planted as ornamental tree across European botanical gardens and city plantings throughout the 19th and 20th centuries. The symbolic resilience of ginkgo gained substantial attention through the Hiroshima atomic bombing, six ginkgo trees within 1-2 km of the August 6, 1945 hypocenter survived the bombing and continued to grow. These "A-bombed ginkgos" (hibaku jumoku in Japanese) became enduring symbols of resilience and hope; cuttings and seeds from these trees have been distributed globally as living memorials. The modern Western pharmaceutical era began with Dr. Willmar Schwabe Pharmaceuticals (Germany) developing EGb 761 in the 1960s, proprietary extraction methodology producing the standardized 24% flavonoid glycoside / 6% terpene lactone preparation with controlled ginkgolic acid limits. Tebonin was launched as German pharmaceutical product. The pharmacology was characterized substantially through the 1970s-90s including the foundational PAF antagonism characterization (ginkgolides are among the most potent PAF antagonists known); the cerebral microcirculation effects; the antioxidant activity; the modest MAO inhibition. The German LANI (Bundesinstitut für Arzneimittel) approval of ginkgo for cognitive impairment in dementia established the European pharmaceutical positioning. Kanowski 1996 Pharmacopsychiatry German trial and Le Bars 1997 JAMA US trial established the modern Western RCT evidence for symptomatic dementia improvement. The 1990s-early 2000s saw substantial growth of ginkgo as both pharmaceutical (in Europe) and supplement (globally), ginkgo became among the most-prescribed and most-supplemented herbal medicines worldwide. The major mechanism-translation reversal came with the large rigorous prevention trials. The GEM (Ginkgo Evaluation of Memory) trial by DeKosky and colleagues, published in JAMA 2008, randomized 3069 older adults (mean age 79) to EGb 761 240mg/day or placebo over approximately 6 years for primary prevention of dementia, null result. The GuidAge trial by Vellas and colleagues, published in Lancet Neurology 2012, randomized 2854 older adults with memory complaints to EGb 761 240mg/day or placebo over 5 years, also null for dementia prevention. These two large rigorous trials substantially recalibrated expectations and have informed clinical guidance ever since. The NTP (National Toxicology Program) 2013 bioassay raised concerns about hepatocellular and thyroid follicular cell tumors in rodents with very high-dose chronic ginkgo extract administration, though human extrapolation has been debated given the substantially supraphysiologic doses studied. The modern consumer market has matured substantially with the dementia prevention claims appropriately recalibrated. Modest evidence remains for symptomatic support in mild dementia (German LANI guidelines), intermittent claudication, tinnitus (mixed), and select other applications. The pharmaceutical-grade EGb 761 inheritance continues to anchor premium positioning; generic standardized extracts at equivalent 24/6 specification provide cost-effective alternatives.

1. ~270 million years agoGinkgophyta lineage emerges in Permian period
2. ~170 million years agoJurassic ginkgo trees morphologically similar to modern Ginkgo biloba
3. AntiquityTraditional Chinese medicine uses ginkgo seeds and leaves
4. 1771Linnaeus formally classifies Ginkgo biloba
5. 18th centurySpecies reaches Europe through Asian trade
6. August 1945Six Hiroshima ginkgo trees survive atomic bombing
7. 1960sDr. Willmar Schwabe Pharmaceuticals develops EGb 761
8. 1970s-90sPharmacology characterization including PAF antagonism
9. German LANI approvalPrescription pharmaceutical for cognitive impairment
10. 1996Kanowski German dementia trial (Pharmacopsychiatry)
11. 1997Le Bars US dementia trial (JAMA)
12. 2000Pittler intermittent claudication meta-analysis
13. 2008GEM trial NULL result for dementia prevention (DeKosky, JAMA)
14. 2010Janssen mild dementia systematic review
15. 2012GuidAge trial NULL for dementia prevention (Vellas, Lancet Neurol)
16. 2013NTP rodent carcinogenicity findings (human relevance debated); Hilton tinnitus Cochrane review
17. 2010s-2020sModern consumer market with recalibrated dementia prevention expectations

• Whether the substantial mechanism-translation failure for dementia prevention (GEM 2008, GuidAge 2012) generalizes to other proposed cognitive prevention applications or remains specific to dementia outcomes.
• Whether ginkgo retains specific value in symptomatic mild dementia management as German LANI guidelines support, or whether modern dementia treatments (acetylcholinesterase inhibitors, memantine, monoclonal antibodies) make ginkgo redundant in established dementia practice.
• Whether subgroup analyses of GEM and GuidAge data identify specific populations that might benefit from ginkgo despite the overall null prevention results, early evidence for ApoE4 carrier subgroups exists but is preliminary.
• Whether the NTP 2013 rodent carcinogenicity findings have clinical relevance at human supplementation doses, the doses studied were substantially above human use and human extrapolation remains debated.
• Whether ginkgo has specific applications in mild cognitive impairment (MCI), between healthy aging and dementia, where evidence base is limited.
• Whether ginkgo has specific applications in psychiatric conditions (depression, anxiety) beyond the preliminary evidence available.
• How best to address the substantial pharmaceutical-grade vs supplement-grade quality differential in commercial markets, generic standardized extracts at 24/6 are pharmaceutically equivalent but consumer markets vary substantially in quality.
• Whether the tinnitus evidence will mature into actionable clinical guidance, current evidence is mixed and recommendation patterns vary substantially.

Widely available globally as dietary supplement and (in some European markets) pharmaceutical product. Legal under DSHEA in the United States and equivalent supplement regulations in most jurisdictions. Not on WADA prohibited list. Pharmaceutical preparations: EGb 761 / Tebonin (Dr. Willmar Schwabe, Germany) is prescription pharmaceutical in Germany, France, and several European countries for cognitive impairment; Tanakan (Beaufour Ipsen, France) is French pharmaceutical license of EGb 761; Tanakene (Spain) similar pharmaceutical preparation. German LANI (Bundesinstitut für Arzneimittel und Medizinprodukte) supports prescription pharmaceutical use for dementia. Major retail supplement brands include NOW Foods, Thorne, Pure Encapsulations, Solgar, Nature's Way, Nature's Bounty, Vitex Pharmaceuticals (US licensee of EGb 761), and many others. Production of ginkgo leaf is concentrated in China (largest producer), United States (substantial commercial cultivation in South Carolina and other regions), and select other locations. Quality variation across consumer supplements is substantial, standardization to 24/6 (24% flavonoid glycosides, 6% terpene lactones) and ginkgolic acid limits (<5 ppm) matters substantially. Third-party testing (USP, NSF) provides standard quality verification.

Status current as of July 2026. Regulatory positions change, sometimes quickly.

Species

Ginkgo biloba (sole surviving Ginkgophyta species)

Lineage age

~270 million years (Permian period origin)

"Living fossil" status

Morphologically essentially unchanged since Jurassic

Active compounds

Flavonoid glycosides + terpene lactones (ginkgolides A/B/C/J + bilobalide)

Standard EGb 761 specification

24% flavonoid glycosides, 6% terpene lactones, ≤5 ppm ginkgolic acids

Standard daily dose

120-240mg/day standardized extract

What follows is unfinished work on our side, not a finding about Ginkgo Biloba. A short entry is not a safe entry.

• Cost and market. We have not documented what it sells for or who sells it.
• Supply chain. We have not mapped where it is made.
• Who uses it. We have not documented the user groups.
• What could change. No forward-looking summary yet.
• How it compares. We have not set it against the alternatives.
• Children and teenagers. We have not checked what is known about younger people.
• Where we land. We have not taken a position on this yet.