An Early Phase 1 interventional study of Four-Chamber Tartrazine Patch across 3 Body Sites in Healthy, Dermoscopy and Optical Imaging, sponsored by Johns Hopkins University. Withdrawn at 1 site in United States. Open to participants aged 18 Years to 65 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-11-14.
Sponsored by Johns Hopkins University · Early Phase 1, Interventional, and Diagnostic
The goal of this clinical trial is to learn if the topical application of tartrazine, an FDA-approved food dye, can help improve the transparency of the skin in healthy volunteers. The main questions it aims to answer are:
Participants will:
Optical imaging of biological tissues is limited by unwanted scattering and absorption of light, which restricts both the depth of imaging and the spatial resolution. This scattering occurs due to refractive index (RI) mismatches between different tissue components, such as the low RI of water-rich cytosol and the high RI of lipid-based structures. Current methods to reduce light scattering, such as the use of optical clearing agents (OCAs), often involve toxic chemicals or removal of tissue components, making them unsuitable for live imaging.
A recently published study in Science demonstrated that tartrazine, a commonly utilized food dye, is a potent OCA that achieves temporary optical transparency in living tissues. In rodent models, tartrazine was topically administered in a 0.6 M solution and showed reversible transparency effects and rendered their skin, muscle and connective tissues transparent while also providing high-resolution imaging down to the micrometer level without causing tissue damage. Imaging techniques such as laser speckle contrast imaging revealed clear visualization of cerebral blood vessels and internal organs, without needing to surgically remove tissue. Topical application in rodents caused minimal inflammation as affirmed by histological analysis. Additionally, the dye was rapidly cleared via urine and feces without signs of systemic toxicity, and after application, the dye can be washed out to further reduce exposure.
Compared to additional OCAs, tartrazine diffused through tissues more rapidly and required lower concentrations to achieve the desired transparency, resulting in faster visualization. Unlike conventional agents, tartrazine did not cause side effects such as tissue shrinkage or dehydration, making it a promising alternative for non-invasive imaging. These studies established that tartrazine, a strongly absorbing molecule, can reduce the RI mismatch between water and lipids, effectively minimizing light scattering and improving optical transparency.
Tartrazine, also known as FD\&C Yellow No. 5, is a commonly utilized coloring agent found in food products, cosmetics, and medications with approved safety profiles across multiple regulatory bodies, including the US Food and Drug Administration (FDA), Joint Food and Agriculture Organization (FAO) and World Health Organization (WHO) Expert Committee on Food Additives (JECFA), and European Food Safety Authority (EFSA). Although tartrazine has been widely used in food and cosmetics, its clinical use for enhancing reversible skin transparency remains under-explored. The long-standing safety profile of tartrazine, in conjunction with the promising preclinical imaging modulation effects, justifies investigating its efficacy in humans.
Existing optical imaging techniques are limited by penetration depth and high scattering, particularly in vivo. This study aims to fill this gap by using tartrazine to improve visualization in human subjects. The potential benefits of this non-invasive technique for human applications are vast, particularly in dermatology, tumor imaging, and surgical planning. If successful, tartrazine could enable clearer, non-invasive imaging of tumors, vascular lesions, and other subcutaneous structures - providing real-time insights into disease progression and aiding in more accurate medical interventions. This clinical pilot study, with a primary focus on the feasibility of topical tartrazine for improving skin transparency, is built upon the promising results from rodent models and tartrazine's well-established safety profile in humans.
Johns Hopkins University is the lead sponsor of 1,783 studies on the registry; 313 are open to participants now.
Of its 203 completed or terminated interventional studies of FDA-regulated products, 140 (69%) have results posted.
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Exclusion Criteria:
A four-chamber patch will be loaded with 0.5militer (mL) of tartrazine and applied to 1 cm diameter areas on the skin. Each chamber will deliver one of four different concentrations of a tartrazine solution-0.15 molar concentration (M), 0.3M, 0.6M, and 1.2M-on three distinct skin regions: the anterior forearm (representing thin skin), the abdomen (representing medium-thickness skin), and the back (representing thicker skin). This method ensures consistent, standardized, and simultaneous applications across all skin types and participants, reducing variability in the application process.
Drug: Four-Chamber Tartrazine Patch across 3 Body Sites
This is a chamber patch comprising four increasing doses of tartrazine (0.15M, 0.3M, 0.6M, 1.2M). This will be applied on the forearm, abdomen, and back to represent different skin thicknesses.
Also known as: FD&C Yellow 5, E102
Optical Transparency as Assessed by Total Transmittance Percentage
To determine the optimal duration for maximum transparency, serial imaging will be conducted over the course of one 90 minute clinic visit (baseline, immediately post-application, and at 5-minute intervals until transparency plateaus). Imaging will be performed using non-invasive modalities. High-resolution dermoscopy will capture clear images of skin structures, and standardized high-quality photography will document the visible effects of transparency. These images will assess improvements in the resolution, depth, and overall image quality of subdermal structures, allowing the investigators to evaluate whether tartrazine significantly enhances visualization.
Time frame: Up to 90 minutes
Plan to share: No
This study is withdrawn, as verified in Nov 2025. You cannot join it, but the record below documents what was studied.
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