An interventional study of Normobaric hypoxia (NH) and Normobaric normoxia (NN) in Obesity (Disorder), sponsored by Pennington Biomedical Research Center. Completed at 1 site in United States. Open to participants aged 22 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-10-05.
Sponsored by Pennington Biomedical Research Center · Not applicable, Interventional, and Treatment
Among 67 studies in Obesity by Pennington Biomedical Research Center — 9 open to participants now, 13 under way, none of them phase 3. Obesity · Pennington Biomedical Research Center.
Among the 67 studies in Obesity by Pennington Biomedical Research Center, this one is the 35th largest by enrollment of the 45 interventional ones that give a count, is one of 5 that started in 2025, is one of 36 with no phase, and was the 65th registered.
11,522 studies on the registry are indexed under Obesity; 2,033 are open to participants now.
Browse Obesity studies →9 of the 67 studies in Obesity by Pennington Biomedical Research Center are open now, in 1 country. Recruiting first, the newest first:
Pennington Biomedical Research Center · Sites in United States
Pennington Biomedical Research Center · Sites in United States
Pennington Biomedical Research Center · Sites in United States
Pennington Biomedical Research Center · Sites in United States
Pennington Biomedical Research Center · Sites in United States
By country, each count listing its studies:
Of the 1,336 Obesity studies recruiting now, 377 (28%) set no upper age limit and 856 (64%) stop at 75 or younger; 168 take children under 18; 491 take healthy volunteers.
This study: 22 Years to 65 Years · all sexes · no healthy volunteers.
The full table on the hub →This tab as a report to print or save as PDF → With an account.
67 studies; the count open now beside each. This study's row is marked.
A study in two phases is counted once above. Listed by phase, each with its combined phases: Phase 1 5 · Phase 2 4 · Phase 4 3
First in 1999; this study’s year is marked. 5 started in 2025.
This study's enrollment of 16 is below the median of 67 across 9,006 interventional studies indexed under Obesity.
Median enrollment 42 across the 45 interventional studies, 47 across the 22 observational. Of the 49 that completed or were terminated, 13 (27%) have results posted.
This tab as a report to print or save as PDF → With an account.
Pennington Biomedical Research Center is the lead sponsor of 284 studies on the registry; 31 are open to participants now.
5 of the studies in Obesity by Pennington Biomedical Research Center that are under way reach primary completion within a year, 0 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT05958368Pennington Biomedical Research CenterAssessing the Value of Avocados on Glycemic Control in Type 2 Diabetes | 2026-11-30 |
| NCT04583514Pennington Biomedical Research CenterTesting the Adipose Expandability Hypothesis In Vivo During Overfeeding | 2026-12-31 |
| NCT07154719Pennington Biomedical Research CenterGLP-1R Actions on Muscle and the Skeleton | 2027-02-01 |
| NCT07530718Pennington Biomedical Research CenterBody Composition Outcomes in MS Patients | 2027-02-01 |
| NCT07095972Pennington Biomedical Research CenterContinuous Glucose Monitoring in Metabolic Surgery | 2027-06-30 |
Among the 67 studies in Obesity by Pennington Biomedical Research Center, from their registry updates:
This tab as a report to print or save as PDF → With an account.
Declines in iron status are common in those with obesity and may be due to obesity-related chronic inflammation; however, the effects of reducing inflammation following diet-induced weight loss on iron metabolism are poorly understood. Low environmental oxygen exposure increases dietary iron absorption and availability to supply iron for erythropoiesis but has not yet been tested in the context of weight loss. This study is designed to investigate diet-induced weight loss (inflammation reduction) and overnight low oxygen exposure (erythropoiesis stimulating agent) as strategies to improve dietary iron absorption in obesity.
Those with obesity are at increased risk for iron deficiency, which can worsen obesity-related comorbidities and add considerably to national health-care budgets. Declines in iron status in those with obesity may be due to adiposity-related inflammation. Adipokines, such as interleukin 6, increase hepcidin, an iron regulatory hormone secreted by the liver that functions to reduce iron absorption and iron availability. Elevated hepcidin and reduced dietary iron absorption may explain why those with obesity are more susceptible to iron deficiency and more resistant to treatment with iron supplements. However, the effects of reducing inflammation on iron absorption in those with obesity are poorly understood. In addition, low environmental oxygen exposure may be an alternative to optimize iron metabolism in obesity since hypoxia stimulates the synthesis of erythropoietin, which strongly suppresses hepcidin and increases iron absorption. The proposed study aims to capitalize on the ongoing Low Oxygen and Weight Status (LOWS) randomized, double-blind, parallel-arm, controlled-feeding trial (R01DK127162; Berryman) to understand the mechanism by which obesity increases risk for iron deficiency and potential countermeasures. In LOWS, adults with obesity are randomized to 8 weeks of controlled-feeding energy restriction (-500 kcal/day) plus intermittent exposure to normobaric hypoxia (8 h/night, 15% FiO2) or normoxia (8 h/night, 21% FiO2) using a commercially available, in-home tent system. This study aims at assessing dietary iron absorption at baseline and following 8 weeks of energy restriction in normoxia or intermittent hypoxia. Results of this project will serve as a foundation to the development of interventions to prevent and treat declines in iron status in obesity.
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.
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.
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
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.
Hemoglobin (Hb)
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
8 weeks of overnight exposure (8 hrs/night) to NH conditions (\~15% oxygen; achieved with nitrogen dilution, equivalent to \~8500 feet elevation) using a commercially available tent and generator system (Hypoxico, Inc., New York, NY).
Other: Normobaric hypoxia (NH)
8 weeks of overnight exposure (8 hrs/night) to NN conditions (\~21% oxygen; sea level) using a commercially available tent and generator system (Hypoxico, Inc., New York, NY).
Other: Normobaric normoxia (NN)
Low oxygen exposure to mimic \~8500 feet elevation (experimental)
Normal oxygen exposure to mimic sea level conditions (sham comparator).
Change in iron absorption
Fractional iron absorption will be measured during the baseline weight maintenance phase (day -7) and at the end of the study (day 42). Change in fractional iron absorption will be calculated as: fractional iron absorption on day 42 - fractional iron absorption on day -7.
Time frame: 7 weeks
Plan to share: No
Ran from Apr 2025 to primary completion in Sep 2026, 16 months.
Of 3,680 non-industry interventional studies with no phase under Obesity, half reached primary completion within 23 months of starting (the median), counting those still running; a quarter within 10 and three quarters within 43. This study's 16 months is below that.
Counting every sponsor, half of 3,843 studies reached it within 22 months; a quarter within 10 and three quarters within 42.
Since we started tracking on Sep 25, 2026, the dates moved once, on Oct 5, 2026: primary completion Jun 2026 → Sep 2026 and completion Jun 2026 → Sep 2026.
Earlier changes are on the record history on ClinicalTrials.gov ↗
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 ↗
This study is completed, as verified in Apr 2026. You cannot join it, but the record below documents what was studied.
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