Exosome Evidence Index

Studies / COVID-19 lung disease and inhaled use

Bone marrow stem cell exosomes (ExoFlo) for severe COVID-19

Sengupta V et al., Stem Cells and Development, 2020

Improvement reported, no control groupStrength of design, level 2 of 5: Study without a control group

Improvement reported, no control group: Patients improved, but without a comparison group there is no way to tell whether the treatment caused it.

Level 2 of 5: A group was treated and followed, but nobody was left untreated for comparison. Improvement may come from time, other care, or the placebo effect.

See the full key
Design
Single-center, no control group
People
24 people
Made from
Bone marrow
How it was given
One IV infusion

What they found

Oxygen levels, clinical status, and lab markers improved, survival was 83%, and no adverse events were seen within 72 hours.

What limits it

No comparison group during a period when COVID-19 care was changing quickly. The later randomized trial of the same product is listed separately.

Read the study

Reviewed by Tomaz Mesar, MD. Last reviewed October 2026. No exosome product is FDA-approved for any use. Before you book a treatment

Other studies of covid-19 lung disease and inhaled use

  1. Mixed or short-lived resultStrength of design, level 3 of 5: Controlled trial

    Bone marrow stem cell vesicles (ExoFlo) for respiratory failure from COVID-19

    Lightner AL et al., CHEST, 2023. 102 people. Made from: bone marrow.

    No treatment-related adverse events. Lower 60-day mortality was seen in the higher-dose group and in a subgroup of patients aged 18 to 65.

  2. No benefit over controlStrength of design, level 3 of 5: Controlled trial

    Stem cells with or without added vesicles for COVID-19 ARDS

    Zarrabi M et al., Stem Cell Research & Therapy, 2023. 43 analyzed (8 got cells plus vesicles). Made from: umbilical cord.

    Both treated groups had lower inflammatory markers than the control group, with no serious adverse events. A 2025 review of the trial reports no significant difference between cells alone and cells plus vesicles.

  3. Safety onlyStrength of design, level 2 of 5: Study without a control group

    Inhaled adipose stem cell vesicles in healthy volunteers

    Shi M et al., Journal of Extracellular Vesicles, 2021. 24 healthy volunteers. Made from: fat (adipose) stem cells.

    All doses were well tolerated. Two people had a brief, mild slowing of heart rate that was not linked to dose.

  4. Improvement reported, no control groupStrength of design, level 2 of 5: Study without a control group

    Inhaled adipose stem cell exosomes for severe COVID-19

    Zhu Y et al., Stem Cell Research & Therapy, 2022. 7 people. Made from: fat (adipose) stem cells.

    All patients tolerated treatment. Lymphocyte counts rose slightly, and lung lesions on CT regressed to varying degrees.