Firstly, this article outlines the European Commission’s Evaluation of the blood, tissues and cells (BTC) legislation that identified the shortcomings that have prompted the legislative initiative, being the publication of the proposal for a Regulation on the safety and quality of substances of human origin on the 14^th of July 2022. This allows for the analysis of SoHO’s riveting provisions in the second part of this paper and to assess whether the BTC’s drawbacks have been resolved. The discussion on the BTC’s shortcomings paves the way to eventually examine a few critical issues as it seems that some matters bring about some legal uncertainty. The challenging interplay of the proposal with adjacent legislative frameworks raises several questions, especially in the context of autologous advanced therapy medicinal products. The broad discretion left to Member States to take ‘more stringent national measures’ allowing them to decline to recognise SoHO establishment authorisations as well SoHO preparation authorisations granted by another Member State clearly opens the door to increased divergences between Member States. The particularly high level of transparency of SoHO preparation authorization dossiers and the absence of rules guaranteeing a sufficient level of protection of the data submitted in this context raise serious concerns and will create problems in the sector. Finally, the absence of a robust framework fixing clear principles for allocation and access to SoHOs and the lack of adequate and harmonised oversight in this regard create a risk of arbitrary allocation and unequal access to SoHOs. These concerns have been highlighted for the sake of identifying and anticipating future challenges which have not been addressed by the new SoHO proposal and should be kept in mind when studying the SoHO proposal.