A Phase 2 interventional study of Sucralose and Placebo in Healthy Volunteers and Overweight, sponsored by National Institute on Alcohol Abuse and Alcoholism (NIAAA). Recruiting at 1 site in United States. Open to female participants aged 18 Years to 60 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-11-09.
Sponsored by National Institute on Alcohol Abuse and Alcoholism (NIAAA) · Phase 2, Interventional, and Other
Background:
Artificial sweeteners like sucralose are found in many foods and drinks. Sucralose might affect hormones and cause health changes.
Objective:
To see if sucralose changes how medicines are absorbed and processed, how hormones are secreted, gut bacteria, and how fat cells are metabolized.
Eligibility:
People ages 18-60 who:
Design:
Participants will be screened with:
Participants must not eat or drink anything with artificial sweeteners throughout the study.
Over 7 days, Participants will answer questions, and give daily urine samples and 1 stool sample. Participants will repeat these throughout the study.
Overnight Visit 1: participants will fast starting the night before. They will get breakfast at the visit. The visit includes:
Then participants will be randomly assigned to take either a sucralose capsule or placebo. They will take it twice a day for 2 weeks. They will complete two 24-hour food diaries.
Overnight Visit 2 repeats Visit 1 except the biopsy.
Then participants will take the capsules for another 2 weeks.
Overnight Visit 3 repeats Visit 1.
Participants may be contacted by phone within 4 weeks after they finish....
Background:
Consumption of non-nutritive sweeteners (NNS) has dramatically increased worldwide and is more prevalent in women than men. Similarly, obesity rates have continued to rise, most notably in minorities. Since NNS consumption has been linked to obesity, we propose studying NNS effects specifically in minority women.
NNS are frequently consumed in combination with prescription medications. This necessitates the study of possible NNS-drug interactions. The hypothesis that NNS may affect drug absorption and metabolism is based on a rodent study. In 2008, Abou-Donia et al reported that sucralose increased the activity of P-glycoprotein (P-gp), a membrane transporter involved in absorption and distribution of a wide range of pharmacologic compounds, and CYP3A, a cytochrome P-450 enzyme important to the first-pass metabolism of many drugs.
So far, NNS effects in clinical studies were mostly observed after acute (one time) or short term exposure. For example, we and others found increased incretin and insulin concentrations in response to sucralose alone or in combination with acesulfame-potassium prior to a glucose load. The effects were most pronounced in obese African American women. We also found upregulation of inflammatory cytokines in subcutaneous fat biopsies of obese individuals who reported consumption of NNS compared to non-consumers. Whether these hormonal and tissue responses persist after prolonged exposure needs to be investigated. NNS have also been shown to influence the microbial composition of the oral cavity and the gut. However, most data were generated in mice and do not exist in humans.
Aims:
Primary Aim: To determine the effects of sucralose (4 mg/kg/day) administered to overweight and obese minority women for 28 days on drug metabolism using digoxin and midazolam as probes for P-glycoprotein and CYP3A, respectively.
Secondary Aims: To investigate the effects of sucralose on
Methods:
The study consists of 3 periods. In the first period (run-in, 7 days), participants will be instructed to avoid all NNS (including NNS in cosmetics or health care products). During the second and third periods (14 days each), participants will be randomized to consume either sucralose containing capsules (4 mg/kg/day) or placebo. At the end of each period, the following measurements will be obtained during an overnight hospitalization:
At the end of P1 (run-in, no intervention) and after P3 (sucralose exposure x 4 weeks), subcutaneous fat biopsies will be performed. Stool samples will be obtained throughout.
3,599 studies on the registry are indexed under Overweight; 852 are open to participants now.
This study's planned enrollment of 150 is above the median of 78 across 3,120 interventional studies indexed under Overweight.
Browse Overweight studies →National Institute on Alcohol Abuse and Alcoholism (NIAAA) is the lead sponsor of 102 studies on the registry; 14 are open to participants now.
Of its 13 completed or terminated interventional studies of FDA-regulated products, 9 (69%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Age: between 18 and 60 years
4 weeks
8. Able and willing to avoid eating grapefruit, parsnips, celery, drinking grapefruit juice or sodas containing quinine (e.g. tonic water) during the study
9. Able and willing to collect stool specimens
10. Able and willing to consume digoxin and midazolam during study visits
EXCLUSION CRITERIA:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ALT and AST (liver enzymes)
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ULN (upper limit of normal)
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants will receive sucralose capsules (approximately 4mg/kg/day) by mouth for 28 days.
Other: Sucralose
Participants will receive placebo capsules by mouth for 28 days.
Other: Placebo
Sucralose is an organochlorine and is approximately 600 times sweeter than sucrose. Participants will receive sucralose (approximately 4mg/kg/day) or placebo by mouth in a capsule for 28 days. This dose corresponds to the amount of sucralose contained in approximately 3 or 4 twelve ounce cans of commercially-available diet soda for a 70 kg adult.
Placebo capsules will be taken orally for 28 days
To explore the effects of sucralose (approx 4 mg/kg x 28 days) on pharmacokinetics of digoxin and midazolam, which are representative examples of P-gp and CYP3A dependent medications.
To determine the effects of sucralose (4 mg/kg/day) administered to overweight and obese minority women for 28 days on drug metabolism using digoxin and midazolam as probes for P-glycoprotein and CYP3A, respectively.
Time frame: 28 days
To investigate the effects of sucralose on glucose metabolism and incretin secretion, lipid metabolism, and intestinal microbiome
We also aim to determine if consumption of approximately 4mg/kg sucralose over a 28-day period leads to: 1)changes in glycemia and glucose stimulated secretion of GLP-1 and other gut hormones during an oral glucose tolerance test (OGTT) 2)changes in lipid metabolism (in vitro (adipose tissue) and in vivo (fasting and during OGTT) 3)alterations in the intestinal microflora
Time frame: 28 days
Started Apr 2018 (actual). Primary completion is estimated for Dec 2027, 116 months after the start.
Of 46 non-industry phase 2 interventional studies under Overweight, half reached primary completion within 35 months of starting (the median), counting those still running; a quarter within 12 and three quarters within 69. This study's planned 116 months is above that.
Counting every sponsor, half of 148 studies reached it within 13 months; a quarter within 8 and three quarters within 21.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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