Injectable hydrogels for degenerated discs are a real and active field of research. The evidence splits cleanly into two categories, and the claim collapses them.

Laboratory and ex vivo evidence (strongest for "restoration"): The 2024 Acta Biomaterialia study tested NPgel in human cadaveric discs. Injection of NPgel resulted in a significant increase (up to 31%, mean 13%) in disc height of post-injected discs compared with their height before injection . Injection into cadaveric discs followed by culture under physiological loading increased MRI signal intensity, restored natural biomechanical properties and showed evidence of increased anabolism and decreased catabolism with tissue integration observed. The authors characterise this as "essential proof of concept data supporting the use of NPgel as an injectable therapy for disc regeneration" . This was dead donor tissue in a bioreactor, not living patients.

Animal evidence: Reviews describe disc height recovery in animal models. One review notes a hyaluronic acid hydrogel injection restored disc height to over 75% of the pre-punctured disc, improved water retention, and restored normal disc appearance in nearly 84% of experimental subjects . Another notes hydrogels partially restored damaged disc height, with the disc height index approaching that of the normal group within a few weeks after surgery, while the untreated group showed continued decline .

Human evidence (weakest for "restoration," moderate for pain relief): The first-in-human HYDRAFIL study reported that after six months, all participants in this small study reported significantly less low back pain, declining from an average self-reported pain level of 7.1 down to 2.0 on a zero to 10 scale, with average physical function scores falling from 48 to 6 . Hydrafil was injected into the discs of 20 people in Colombia with chronic degenerative disc disease . A larger company dataset reports more than 80% improvement in Oswestry Disability Index scores and greater than 70% reduction in Numeric Pain Rating Scale scores, sustained for two years in the 63 patients who completed two-year follow-up . These are pain and function outcomes, not demonstrated tissue regeneration.

Regulatory status: CE Mark for the HYDRAFIL System was granted based on a clinical study of 75 patients . In the US the device remains investigational: the FDA approved an Investigational Device Exemption for ReGelTec's pivotal study to support premarket approval of the HYDRAFIL System , and the company announced it had treated the first patient in its HYDRAFIL-D FDA IDE clinical trial in June 2025. The HYDRAFIL-D study is a 225-patient, multicenter, single-blinded, randomized, controlled trial. It is not FDA approved.

Mechanism distinction: HYDRAFIL is described by its developer as a disc augmentation device. A hydrogel that is heated prior to injection into the nucleus of a degenerated disc, the Hydrafil system forms a contiguous implant to augment the disc , and once in the disc it distributes the load and strain felt in that intervertebral segment to improve function and reduce the pain signaling to the brain . That is structural filling and load redistribution, not biological regeneration of disc tissue.

Field-level assessment: A 2026 review states that while current surgical and conservative treatments provide symptomatic relief, they fail to reverse ECM degradation or restore biomechanical function , and that despite promising animal results significant challenges remain for clinical translation .