For millions of people who inject insulin every day, the idea of swapping needles for a simple skin gel sounds almost unreal. Researchers have spent years trying to push insulin through the skin’s outer barrier, and a recent thermosensitive gel from Zhejiang University is one of the most detailed efforts so far, but it remains at the animal‑testing stage. As of September 2024, there is no approved skin cream or gel that can replace insulin injections in people, and no completed human trials of this specific approach.
The scientific story behind this gel centers on solving a stubborn delivery problem: how to move a large, fragile protein through skin that is built to keep things out. This article focuses on what the peer‑reviewed research actually shows, how that work compares with other needle‑free tools, and what questions still need answers before anyone can trade syringes for a tube of cream. It also highlights where later media reports may have gone beyond the available evidence.
How the insulin skin gel works
The starting point is a thermosensitive gel that is liquid at room temperature and becomes a soft semi‑solid at body temperature. In preclinical tests, this gel was used to carry insulin across the outer skin layers in animals, and the researchers measured how much insulin reached the bloodstream compared with a standard injection, a value known as bioavailability. Rather than only tracking blood sugar changes, they also sampled blood for insulin itself, which helps separate real absorption from other effects such as stress or handling.
Because the gel thickens on warm skin, it can stay in place and release insulin over time rather than running off or evaporating. The study authors reported that the formulation improved insulin permeation through the skin barrier in animal models, but the absolute amount that entered the blood was still lower than with a shot, and the work did not include any human volunteers. An investigative feature that interviewed members of the team describes how they are now refining dosing plans, skin preparation steps and blood‑sampling schedules in preparation for possible clinical trials, yet it also makes clear that these trials have not started.
Polymer carrier slips past the skin barrier
Later news coverage has focused on a zwitterionic polymer, often referred to as OP‑I, that is linked to insulin in some experimental gels. A news summary describes this polymer as carrying both positive and negative charges, which may help it move between the tightly packed lipids of the stratum corneum without sticking too strongly to skin components. However, that summary is dated November 2025, so its detailed claims about OP‑I go beyond what is documented in the 2024 thermosensitive gel paper and cannot yet be confirmed from current peer‑reviewed sources.
An institutional article from Zhejiang University also appears with a 2025 date and states that this polymer can help insulin and other protein drugs cross skin that they “usually can’t get through.” Because these materials are future‑dated relative to the present, they should be treated as provisional and not as established scientific fact. What is firmly supported by the 2024 gel study is the broader concept that polymers can assist insulin in crossing the skin barrier, but the specific structure, name and performance of OP‑I remain uncertain until peer‑reviewed data are available.
Animal tests show rapid glucose control
Several media outlets have reported on animal experiments where insulin linked to a skin‑permeable polymer lowered blood sugar without needles. A piece in Science News describes tests in animals in which blood glucose fell over a time window similar to that seen after standard injections, suggesting relatively rapid onset of action. Another article in Inside Precision Medicine states that insulin conjugated to the polymer penetrated the stratum corneum, viable epidermis and dermis in animal skin without obvious short‑term damage or changes in liver and kidney function tests.
Coverage in the Times of India goes further, calling the approach a “groundbreaking” skin cream that could replace injections and reporting that early animal trials showed effective blood glucose control similar to traditional shots. Yet these media reports rely heavily on press materials and interviews rather than on a published animal‑study dataset that readers can inspect in detail. As of now, there is no peer‑reviewed paper describing mini pig experiments with OP‑I that shows rapid glucose normalization and a full panel of organ‑safety data, so such specific claims about mini pigs and long‑term safety should be viewed as unproven.
How it compares with current needle-free tools
Needle‑free insulin delivery is not a new idea, and some options already exist in practice. A 2023 clinical observation study compared a spring‑powered needle‑free injector with standard insulin pens for subcutaneous delivery of premixed insulin. In that study, 70 patients using the needle‑free device were matched with 70 patients using pens, and the researchers found similar blood sugar control but less reported pain at the injection site in the needle‑free group. These data show that hardware‑based needle‑free systems can work in real‑world diabetes care, even though they still break the skin.
The polymer gel aims to go a step further by keeping the skin surface intact and relying on chemistry rather than pressure. Reporting in ScienceAlert describes this as a possible “skin cream” that might one day deliver insulin or other peptide drugs, with early animal work suggesting blood glucose reductions that resemble those from injections. Still, all of these results come from controlled lab settings, not from daily life with variable temperatures, sweating, clothing friction and other factors that affect a topical product. Until human trials show that the gel can match existing tools on reliability and safety, jet injectors and pens will remain the standard for most people.
Interpreting the numbers behind the hype
Numbers from the published gel study help put the promise and limits of this approach into perspective. In the thermosensitive formulation, the researchers reported a relative bioavailability of about 15 percent compared with standard subcutaneous injection, meaning that for the same nominal dose, only around one‑seventh as much insulin reached the bloodstream. To compensate, they adjusted dosing in animals so that effective blood sugar control could still be seen, but this trade‑off would matter in humans, where insulin is expensive and dosing needs to be precise.
The same work and related summaries also mention that the gel can be stored for up to 306 hours at controlled temperatures without major loss of insulin activity, and that the formulation remained stable through at least 698 heating and cooling cycles in the lab. These figures suggest that the material could handle routine storage and shipping conditions, but they do not guarantee stability in every real‑world setting, such as a hot car or a humid bathroom. Nor do they answer key questions about long‑term skin exposure, such as whether repeated daily use over years might cause irritation, allergy or changes in barrier function.
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*This article was researched with the help of AI, with human editors creating the final content.
