Peptide LibraryTrofinetide dosage in published studies and labels
These are the doses used for Trofinetide in FDA labelling and published clinical studies, reported as each source states them, one row per regimen. They describe what was studied or approved for a specific population. They are not a recommendation, and none of them is a dose for any individual.
Research and educational reference only. This is not medical advice, and no figure on this page is a dosing recommendation.
Last checked against primary sources:
Studied regimens and sources
Trofinetide has an FDA-approved human dosage. As Daybue (oral solution) and Daybue Stix (powder packets), it is taken twice daily by weight, from 5,000 mg at 9 kg to under 12 kg up to 12,000 mg at 50 kg and above, for Rett syndrome in adults and children aged 2 and older. The label halves these doses in moderate kidney impairment and does not recommend use in severe impairment.
FDA Approved
| Human dosing established | Yes |
|---|---|
| Studied dose range | 5,000–12,000 mg twice daily, by body weight |
| Route | Oral · Gastrostomy tube |
| Frequency | Twice daily, morning and evening |
| Duration studied | Continuous |
| Titration | None. The dose is set by weight band: 5,000 mg at 9 to under 12 kg, 6,000 mg at 12 to under 20 kg, 8,000 mg at 20 to under 35 kg, 10,000 mg at 35 to under 50 kg, and 12,000 mg at 50 kg and above. Severe diarrhea, suspected dehydration, significant weight loss or severe vomiting can mean interrupting, reducing or stopping treatment. |
| Half-life | Effective half-life about 1.5 hours |
| Evidence level | FDA Approved |
| Last reviewed | 2026-10-30 |
Research-reported dosing
Doses as studied, one row per regimen. Different trials used different regimens; they are listed separately rather than averaged.
| Study / context | Population | Dose | Route | Frequency | Duration | Outcome studied | Source |
|---|---|---|---|---|---|---|---|
| FDA label — Daybue and Daybue StixFDA-approved label · FDA prescribing information | Adults and children aged 2 and older with Rett syndrome | 5,000 to 12,000 mg by body weight; 2,500 to 6,000 mg in moderate kidney impairment | Oral or gastrostomy tube | Twice daily | Continuous | Treatment of Rett syndrome | DAYBUE (trofinetide) oral solution and DAYBUE STIX for oral solution — FDA prescribing information, DailyMed |
| Neul et al., 2023 — LAVENDER, phase 3Clinical trial · Randomised, double-blind, placebo-controlled phase 3 | Girls and women aged 5 to 20 with Rett syndrome and a MECP2 mutation (93 on trofinetide, 94 on placebo) | By body weight | Oral or gastrostomy tube | Twice daily | 12 weeks | RSBQ score improved by 4.9 points versus 1.7 on placebo; CGI-I at week 12 was 3.5 versus 3.8 | Neul JL et al. Trofinetide for the treatment of Rett syndrome: a randomized phase 3 study. Nat Med. 2023. |
| Percy et al., 2024 — LILAC, open-label extensionClinical trial · Open-label extension | Girls and women aged 5 to 21 from LAVENDER (n=154) | By body weight | Oral or gastrostomy tube | Twice daily | 40 weeks | Symptom scores continued to improve; diarrhea led 21.4% of participants to withdraw | Percy AK et al. Trofinetide for the treatment of Rett syndrome: Results from the open-label extension LILAC study. Med. 2024. |
| Percy et al., 2025 — DAFFODIL, phase 2/3Clinical trial · Open-label phase 2/3 | Girls aged 2 to 4 with Rett syndrome (n=15) | By body weight | Oral or gastrostomy tube | Twice daily | 12 weeks, then about 21 months | Weight-based dosing reached the target exposure; diarrhea in 80% and vomiting in 53.3% | Percy AK et al. Results from the phase 2/3 DAFFODIL study of trofinetide in girls aged 2-4 years with Rett syndrome. Med. 2025. |
| Glaze et al., 2019 — pediatric Rett syndrome, phase 2Clinical trial · Randomised, double-blind, placebo-controlled phase 2 | Girls aged 5 to 15 with Rett syndrome (n=82) | 50, 100 or 200 mg/kg | Oral | Twice daily | 42 days after a 14-day placebo lead-in | Improvement over placebo at 200 mg/kg on RSBQ, a clinician scale and CGI-I | Glaze DG et al. Double-blind, randomized, placebo-controlled study of trofinetide in pediatric Rett syndrome. Neurology. 2019. |
| Glaze et al., 2017 — adolescent and adult Rett syndrome, phase 2Clinical trial · Exploratory, randomised, double-blind, placebo-controlled phase 2 | Adolescent and adult females with Rett syndrome (n=56) | 35 or 70 mg/kg | Oral | Twice daily | 14 or 28 days | Efficacy trends at 70 mg/kg by prespecified criteria | Glaze DG et al. A Double-Blind, Randomized, Placebo-Controlled Clinical Study of Trofinetide in the Treatment of Rett Syndrome. Pediatr Neurol. 2017. |
| Berry-Kravis et al., 2020 — fragile X syndrome, phase 2 (not an approved use)Clinical trial · Exploratory, randomised, double-blind, placebo-controlled phase 2 | Adolescent and adult males with fragile X syndrome (n=72) | 35 or 70 mg/kg | Oral | Twice daily | 28 days | A signal of efficacy at 70 mg/kg on a composite analysis | Berry-Kravis E et al. A Double-Blind, Randomized, Placebo-Controlled Clinical Study of Trofinetide in the Treatment of Fragile X Syndrome. Pediatr Neurol. 2020. |
| NCT00805818 — traumatic brain injury, phase 2 (not an approved use)Clinical trial · Phase 2 trial, registry record | Patients with traumatic brain injury (n=261) | 20 mg/kg bolus, then 1, 3 or 6 mg/kg/h | Intravenous | — | 72 hours | Completed; no results posted on the registry | NCT00805818 — Study of NNZ-2566 in Patients With Traumatic Brain Injury |
Preclinical and analog research
Not human dosing evidence. Listed for completeness and never extrapolated to a human dose.
| Study / context | Population | Dose | Route | Frequency | Duration | Outcome studied | Source |
|---|---|---|---|---|---|---|---|
| Preclinical — focal stroke in ratsPreclinical · Rodent study | Rats | 3 to 10 mg/kg/h for 4 hours intravenously, or 30 to 60 mg/kg by mouth; not convertible to a human dose | Intravenous or oral | — | — | Smaller infarct area after induced stroke | Bickerdike MJ et al. NNZ-2566: a Gly-Pro-Glu analogue with neuroprotective efficacy in a rat model of acute focal stroke. J Neurol Sci. 2009. |
Where sources disagree
- The label says the mechanism in Rett syndrome is unknown. Trofinetide is an analog of glycine-proline-glutamate, the N-terminal tripeptide of IGF-1, but it is not IGF-1, and IGF-1 doses and data do not apply to it.
- The phase 3 effect was statistically significant but modest: a 3.2-point difference from placebo on the 90-point RSBQ, and 0.3 points on the 7-point CGI-I.
- LAVENDER enrolled girls and women aged 5 to 20. Use from age 2 rests on that trial plus pharmacokinetic and safety data in 15 children, and the label has no data in people aged 65 and older.
- Phase 2 trials used mg/kg doses. The weight bands on the label were designed to give similar exposure across patients, so the two sets of numbers are not directly comparable.
- Tolerability shapes real use. In LAVENDER, the label reports diarrhea in 82% (80.6% in the published paper), and 19% withdrew because of adverse reactions, most often diarrhea (15%).
- DAFFODIL shows as terminated on the registry because the sponsor ended it after the 2023 approval to switch participants to the commercial product.