Great Britain follows the UK Cosmetics Regulation, which is identified within Schedule 34 of the Product Safety and Metrology etc. (Amendment etc.) (EU Exit) Regulations 2019 Statutory Instrument (SI) and its amendments.  There is not a consolidated version of the Regulation yet. 

Northern Ireland is part of the UK.  However, the Northern Ireland Protocol to the EU/UK Withdrawal Agreement stipulates that NI follows the EU Regulations listed in Annex II to the Protocol.  Therefore, cosmetic products sold in Northern Ireland must comply with the EU Cosmetics Regulation. 

If you are aiming to sell cosmetics in both GB and NI, you must comply with both the UK and EU Cosmetics Regulations.

If you sell your own brand of products, you are more likely identified as the Responsible Person.  You must have an EU or NI based RP to sell cosmetics in NI and a UK based RP to sell in GB; an RP in NI is accepted under both the UK and EU Cosmetics Regulations. As such, you have the responsibility for full compliance of the cosmetic product, including compliance with the formulation, safety, manufacturing, notification, documentation, labelling, claims and market surveillance requirements.  For more information, please check the CTPA Guide ‘Supplying Cosmetic Products on the EU and NI Market’ and the CTPA Guide ‘Supplying Cosmetic Products on the UK Market’.