MEDICAL DISCLAIMER: Educational research guidelines only. Lyophilized peptides are investigational chemical compounds and are NOT approved for human consumption, diagnosis, or therapy. Consult a licensed physician before any research application.
CT-388 Dosage Chart, Schedule & Reconstitution Protocol
Quickstart Highlights
CT-388 (RO7795068; proposed INN enicepatide) is an investigational once-weekly subcutaneous dual GLP-1/GIP receptor agonist for obesity and type 2 diabetes, originally from Carmot Therapeutics and developed by Roche/Genentech. It is a unimolecular peptide engineered to be cAMP signaling-biased at both receptors, activating G-protein signaling while minimizing beta-arrestin recruitment and receptor internalization (PMID 41319798). Its long half-life of about 5 to 6 days supports once-weekly dosing, and trials titrate slowly from roughly 5 mg toward maintenance doses as high as 24 mg weekly. Phase II reported a 22.5% placebo-adjusted weight loss at 48 weeks at the 24 mg dose, with predominantly mild-to-moderate gastrointestinal side effects. CT-388 is not approved by the FDA or EMA and is presented here for educational reference only, not as medical advice.
Reconstitute: Add 1.5 mL bacteriostatic water → 20 mg/mL concentration.
Typical dose: 5-24 mg SC once weekly (investigational; titrated over ~4 months)
Easy measuring: At 20 mg/mL, 1 unit = 0.01 mL = 0.2 mg (200 mcg) on a U-100 insulin syringe.
Storage: Lyophilized powder stored frozen at −20 °C; reconstituted solution refrigerated at 2-8 °C and used within ~4 weeks. Protect from light and avoid freeze-thaw of the reconstituted solution.
Half-life: Approximately 123-139 hours (about 5-6 days), supporting once-weekly subcutaneous dosing [1].
Route: Subcutaneous injection (abdomen, thigh, or upper arm), once weekly; titrated from ~5 mg up to ~24 mg [1][2].
Status: Investigational; NOT approved by the FDA or EMA. Phase III obesity program planned. Research/educational use only [2].
About CT-388
CT-388 (RO7795068; proposed INN enicepatide) is an investigational once-weekly subcutaneous peptide that acts as a signaling-biased dual GLP-1/GIP receptor agonist for obesity and type 2 diabetes [1]. Unlike many oral or topical compounds modeled on this site, CT-388 is genuinely administered by subcutaneous injection in clinical trials, so the reconstitution figures below reflect its real-world route rather than an educational substitution.\n\nThis guide models a 30 mg vial reconstituted with 1.5 mL of bacteriostatic water (20 mg/mL, or 200 mcg per insulin-syringe unit) so the studied CT-388 dosage maps cleanly onto a U-100 insulin syringe: 5 mg ≈ 25 units, 7.5 mg ≈ 37.5 units, 12 mg ≈ 60 units, and 24 mg ≈ 120 units (split into two 60-unit injections). Trial protocols always titrate slowly to limit gastrointestinal effects, beginning around 5 mg weekly and stepping up over several weeks toward the maintenance dose [1][2].\n\nFrequency: Inject once weekly subcutaneously into the abdomen, thigh, or upper arm, rotating sites [1][2]. CT-388 is not approved by the FDA or EMA and is presented here for educational purposes only, not as medical advice.
Quick Protocol Navigation
Reconstitution Instruction & Mixing Step-by-Step
Lyophilized powder must be reconstituted carefully. Agitating peptide chains can shear disulfide bonds and render the peptide biologically inert.
Draw 1.5 mL of bacteriostatic water into a sterile syringe.
Inject the water slowly down the inner wall of the 30 mg CT-388 vial; do not spray the stream directly onto the lyophilized powder, and never shake the vial.
Gently swirl or roll the vial until the solution is completely clear; the result is a 20 mg/mL concentration (200 mcg per insulin-syringe unit).
Store refrigerated at 2-8 °C and draw the units for your titration step: 5 mg ≈ 25 units, 7.5 mg ≈ 37.5 units, 12 mg ≈ 60 units, and 24 mg ≈ 120 units (split into two 60-unit injections).
Inject subcutaneously into the abdomen, thigh, or upper arm, rotating sites between weeks; do not aspirate, and wait a few seconds before withdrawing the needle to ensure full delivery.
Interactive CT-388 Syringe Calculator
Currently visualizing the 30 mg vial reconstituted with 1.5 mL bacteriostatic water. Adjust the target dose to dynamically render syringe units.
Reconstitution Calculation: 30mg dry powder in 1.5mL water yields 20.00 mg/mL. To evaluate a 250mcg dose, pull to 1.3 units (1 syringe ticks).
U-100 Syringe Representation
Educational reference visual. Assumes standard U-100 insulin syringe where 1.0 mL volume = 100 units.
Titration & Dose Escalation Schedules
| Phase | Dose per injection | Units (per injection) |
|---|---|---|
| Initiation (weeks 1-4) | 5000 mcg (5 mg) | 25 units (0.25 mL) |
| Titration (weeks 5-8) | 7500 mcg (7.5 mg) | 38 units (0.38 mL) |
| Mid-dose (weeks 9-16) | 12000 mcg (12 mg) | 60 units (0.60 mL) |
| Maximum studied (weeks 17+) | 24000 mcg (24 mg) | 120 units (1.20 mL) |
Administration guidelines: Refer to guidelines | 1.5 mL Reconstitution
Research Supplies Quantity Planner
Scientific mathematical planning of syringes, bacteriostatic water and dry vials needed for extended research blocks using the 30 mg vial.
Peptide Vials (CT-388, 30 mg each):
- check8-week titration course (5 to 7.5 mg weekly): approximately 2-3 vials.
- check12-week course (escalating to ~12 mg weekly): approximately 4-5 vials.
- check16-week course (escalating to ~24 mg weekly maintenance): approximately 8-9 vials.
Insulin Syringes (U-100):
- check8-week course: about 8-10 syringes (one per weekly injection plus spares).
- check12-week course: about 12-16 syringes.
- check16-week course: about 20-28 syringes (24 mg doses are split into two injections).
Bacteriostatic Water (30 mL bottles): Use 1.5 mL per vial for reconstitution.
- check8-week course (~3 vials): roughly 4.5 mL, well within one 30 mL bottle.
- check12-week course (~5 vials): roughly 7.5 mL, one 30 mL bottle.
- check16-week course (~9 vials): roughly 13.5 mL, one 30 mL bottle.
Alcohol Swabs: clean the vial stopper and injection site before each use.
- check8-week course: about 20-30 swabs.
- check12-week course: about 30-45 swabs.
- check16-week course: about 50-70 swabs (extra for split-dose injections).
Mechanism of Action (MOA)
CT-388 is a synthetic, peptide-based unimolecular agonist that simultaneously activates the glucagon-like peptide-1 receptor (GLP-1R) and the glucose-dependent insulinotropic polypeptide receptor (GIPR). Its defining feature is cAMP signaling bias: in vitro it stimulates strong Gs/cAMP signaling (cAMP EC50 of approximately 0.087 nM at GLP-1R with ~99% efficacy and 2.47 nM at GIPR with ~92% efficacy) while recruiting minimal beta-arrestin-2 (GIPR beta-arrestin Emax only around 28%) and producing little receptor internalization compared with the native incretin ligands [1]. Potency is skewed toward the GLP-1 receptor. The design rationale is that preserving cell-surface receptor signaling rather than driving internalization may sustain responsiveness and improve tolerability over a long dosing interval [1].\n\nDownstream, GLP-1R activation in hypothalamic and brainstem appetite centers and in pancreatic beta-cells reduces food intake, slows gastric emptying, and enhances glucose-dependent insulin secretion, while GIPR co-agonism complements satiety signaling and postprandial glucose and lipid handling. Together these actions produce marked appetite suppression, body-weight reduction, and improved glycemic control, the same complementary mechanism exploited by tirzepatide but achieved here with an explicitly signaling-biased pharmacology [1].\n\nPharmacokinetics support once-weekly dosing. After subcutaneous injection the median time to peak concentration (Tmax) is roughly 24 hours, and the mean elimination half-life is consistent across the studied dose range at approximately 123 to 139 hours (about 5 to 6 days) [1]. Exposure (Cmax and AUC) increased with dose across single doses of 0.5 to 7.5 mg, and concentrations accumulated as expected toward steady state over four weekly multiple-ascending doses [1].\n\nIn the Phase 1 program (NCT04838405), single ascending doses were 0.5, 2.0, 5.0, 6.0, and 7.5 mg, and the multiple-ascending-dose cohorts used weekly titration schemes such as 5.0 mg on days 1, 8, and 15 followed by 7.5 mg on day 22, or 5.0 mg escalating to 8.0 and 12.0 mg [1]. Over just four weekly doses this produced placebo-adjusted weight reductions of −4.7% to −8.0% versus −0.5% with placebo [1]. A longer Phase Ib study reported an 18.8% placebo-adjusted reduction at 24 weeks [3], and Phase II titrated up to 24 mg weekly, yielding a 22.5% placebo-adjusted reduction at 48 weeks with no apparent plateau [2].\n\nUnlike oral or topical compounds elsewhere on this site, CT-388's clinical route is genuinely subcutaneous, so the reconstitution figures here reflect real practice. CT-388 remains investigational, is not approved by any major regulator, and a Phase III obesity program (Enith1 and Enith2) was slated to begin in early 2026 [2].
Clinical Trial Efficacy Highlights
- starIn the first-in-human Phase 1 trial (Chakravarthy et al., Molecular Metabolism 2026; NCT04838405), single subcutaneous doses of 0.5 to 7.5 mg and four once-weekly multiple-ascending doses (5 to 12 mg) were studied in adults with overweight or obesity; over just four weekly doses, placebo-adjusted weight reductions ranged from −4.7% to −8.0% versus −0.5% with placebo, with the 7.5 mg single dose already producing a 3.1% placebo-adjusted drop by day 8 [1].
- starPharmacokinetic analysis confirmed a mean elimination half-life of approximately 123 to 139 hours that was consistent across the dose range, with a median Tmax near 24 hours, providing the rationale for once-weekly subcutaneous dosing [1].
- starIn a Phase Ib study, higher doses of CT-388 over 24 weeks produced a statistically significant and clinically meaningful placebo-adjusted weight loss of 18.8% (p < 0.001), with effectively all treated participants achieving at least 5% weight loss [3].
- starPhase II results (Genentech/Roche, January 2026) in 469 people with obesity or overweight without type 2 diabetes showed a placebo-adjusted weight reduction of 22.5% (p < 0.001) at 48 weeks at the highest dose tested (24 mg), administered once weekly without reaching a weight-loss plateau [2].
- starAt the 24 mg dose at week 48, the proportions of CT-388 participants achieving categorical weight loss were 95.7% for at least 5%, 87% for at least 10%, 47.8% for at least 20%, and 26.1% for at least 30% of body weight [2].
- starGlycemic benefit was substantial in the Phase II population: 73% of participants who were prediabetic at baseline achieved normal blood-glucose levels by week 48, compared with 7.5% in the placebo group [2].
- starIn the Phase 1 multiple-ascending-dose cohorts, an oral glucose tolerance test showed mean glucose reductions of −37 to −39 mg/dL with CT-388 versus a 10 mg/dL rise with placebo, alongside fasting-glucose improvements of −5.2 to −7.8 mg/dL [1].
- starTolerability supported continued development: in Phase II, treatment discontinuation due to adverse events was low at 5.9% across CT-388 arms versus 1.3% with placebo, with gastrointestinal events predominantly mild to moderate [2].
Side Effects & Tolerability Profile
Clinical subjects transiently report mild side effects. Slowly escalating the titration dose represents the single most effective intervention to limit side effects.
- warningGastrointestinal effects were the most common adverse events and a class effect of incretin agonists: in the Phase 1 multiple-dose cohorts, GI-related events affected about 83% of CT-388 participants, most often decreased appetite (reported in 100% of CT-388 recipients), nausea, vomiting, and diarrhea; events were generally mild to moderate and transient [1].
- warningSlow titration is used specifically to limit nausea and vomiting; one Phase 1 single-dose participant experienced moderate intractable vomiting considered probably related to study drug, underscoring the importance of dose escalation [1].
- warningTransient increases in heart rate were observed, consistent with the mechanism of action, without clinically significant abnormal heart-rate values; modest decreases in systolic blood pressure also occurred [1].
- warningDecreased appetite and reduced food intake can lead to dehydration or inadequate nutrient and protein intake if fluids and protein are not maintained during titration, a recognized concern across the GLP-1/GIP class.
- warningAs with other incretin therapies, class-level risks such as pancreatitis, gallbladder events, and hypoglycemia (particularly when combined with insulin or sulfonylureas) should be considered, although CT-388-specific long-term safety data remain limited.
- warningIn Phase II, treatment discontinuation due to adverse events was low (5.9% on CT-388 versus 1.3% on placebo), but long-term safety beyond the trial periods is not yet established [2].
- warningNo clinically significant changes in routine biochemistry parameters were reported in the Phase 1 study, but the overall safety database is still small and early-phase [1].
- warningRegulatory and research status: CT-388 is NOT approved by the FDA, EMA, or any other regulator; it is an investigational compound restricted to clinical-trial and research use, and the figures on this page are educational only, not medical advice [1][2].
Subcutaneous Injection Technique
Most research peptides require subcutaneous injection into fatty tissue. Never inject directly into a blood vessel or deep muscle tissue unless clinically detailed.
1. Site Selection
Common locations include the abdomen (2 inches from navel), outer upper arms, or thighs.
2. Sanitization
Thoroughly clean the selected site, stopper and vial top using 70% isopropyl alcohol prep swabs.
3. Angle & Push
Pinch the skin and insert the needle at a 45 to 90-degree angle. Depress plunger smoothly.
4. Site Rotation
Rotate injection sites continuously to avoid lipodystrophy or tissue scarring.
Frequently Asked Questions
What is the typical CT-388 dosage?expand_more
In clinical trials CT-388 is given once weekly by subcutaneous injection and is always titrated. The Phase 1 program studied single doses of 0.5 to 7.5 mg and weekly multiple-ascending doses from 5 mg up to 12 mg, while Phase II titrated up to 24 mg weekly, which produced the headline 22.5% placebo-adjusted weight loss at 48 weeks [1][2]. A representative educational titration is 5 mg weekly to start, stepping up to 7.5 mg, 12 mg, and a maintenance dose as high as 24 mg over roughly four months. There is no established consumer dose because CT-388 is investigational; these figures are educational only.
Is CT-388 FDA approved?expand_more
No. CT-388 (RO7795068; proposed INN enicepatide) is not approved by the FDA, the EMA, or any other regulatory agency for any indication. It is an investigational dual GLP-1/GIP receptor agonist that has completed Phase 1 and Phase 2 studies, with a Phase III obesity program (Enith1 and Enith2) planned to begin in early 2026 [2]. All information here is for research and educational purposes only and is not medical advice.
What is the half-life of CT-388?expand_more
CT-388 has a long elimination half-life of approximately 123 to 139 hours, or about 5 to 6 days, which was consistent across the studied dose range. Combined with a median time to peak concentration of roughly 24 hours after subcutaneous injection, this long half-life is what allows true once-weekly dosing and steady-state accumulation over several weeks [1].
How do you reconstitute CT-388 for a subcutaneous protocol?expand_more
In this educational model a 30 mg vial is reconstituted with 1.5 mL of bacteriostatic water, giving 20 mg/mL, or 200 mcg per unit on a U-100 insulin syringe. Add the water slowly down the vial wall, swirl gently until clear (never shake), and refrigerate at 2-8 °C. At that concentration, 5 mg is about 25 units, 7.5 mg about 37.5 units, 12 mg about 60 units, and 24 mg about 120 units, which is split into two 60-unit injections.
Can CT-388 be stacked with other peptides?expand_more
CT-388 is already a dual GLP-1/GIP agonist that drives strong appetite suppression and gastrointestinal effects on its own, so combining it with other incretin agonists (such as semaglutide, tirzepatide, or retatrutide) would compound nausea, vomiting, hypoglycemia, and dehydration risk and is not supported by any trial data. Because CT-388 is investigational and unapproved, no stacking protocol has been clinically validated; this page does not recommend combining it with other agents.
Related Guides & Tools
Step-by-step references for reconstituting, measuring, and storing CT-388, plus the universal dosing calculator.
Academic References & Study Citations
Chakravarthy MV, Rodriguez R, Hergarden A, et al. (2026) Mol Metab. 'Effects of CT-388, a once-weekly signaling-biased dual GLP-1/GIP receptor agonist, on weight loss and glycemic control in preclinical models and participants with obesity.' Vol 103:102291. PMID 41319798; DOI 10.1016/j.molmet.2025.102291. Phase 1 SAD/MAD pharmacology, PK (t1/2 ~123-139 h), and dosing. View Scientific Paper →
Genentech (Roche) Press Release, 26 January 2026. 'Genentech Announces Positive Phase II Results for Its Dual GLP-1/GIP Receptor Agonist CT-388 in People Living With Obesity.' 22.5% placebo-adjusted weight loss at 48 weeks at 24 mg; 469 participants without type 2 diabetes. View Scientific Paper →
Roche Media Release, 16 May 2024. 'Roche reports positive Phase Ib results for its dual GLP-1/GIP receptor agonist CT-388 in people with obesity.' 18.8% placebo-adjusted weight loss at 24 weeks. View Scientific Paper →
ClinicalTrials.gov NCT04838405 — 'A Study of CT-388 in Otherwise Healthy Overweight and Obese Adults and Patients With Type 2 Diabetes Mellitus' (Phase 1 SAD/MAD and Phase 1b). View Scientific Paper →
ClinicalTrials.gov NCT06525935 — 'A Study of Enicepatide (CT-388) in Participants With Obesity or Overweight With at Least One Weight-Related Comorbidity' (Phase 2, 48 weeks, once-weekly subcutaneous). View Scientific Paper →
ClinicalTrials.gov NCT06628362 — 'A Study of Enicepatide (CT-388) in Participants Who Are Overweight or Obese With Type 2 Diabetes Mellitus' (Phase 2). View Scientific Paper →
Drugs.com MedNews (26 January 2026). 'Genentech Announces Positive Phase II Results for Dual GLP-1/GIP Receptor Agonist CT-388 in People Living With Obesity.' View Scientific Paper →
Applied Clinical Trials Online. 'Roche's Novel Dual GLP-1/GIP Receptor Agonist Produces Clinically Meaningful Weight Loss in Phase Ib Trial.' View Scientific Paper →