The importance of The Advisory Committee on Borderline Substances (ACBS)

30 Nov 2023
by Alison Smith

Alison Smith explains the work of the ACBS and discusses how as dietitians we consider prescribed nutritional borderline substances.

The Advisory Committee on Borderline Substances (ACBS) is an independent scientific committee supported by the Department for Health and Social Care (DHSC) and is responsible for advising on whether borderline substances should be approved for prescribing at NHS expense in primary care. ACBS listing is not applicable to products used in an acute setting.

‘Borderline substances’ are defined as nutritional or dermatological products that have been specially formulated to manage certain medical conditions.

The vast majority of borderline substances are nutritional products (often called Nutrition Borderline Substances (NBS)), which is why the bulk of the ACBS committee is made up of dietitians.

It can be easy to think of the ACBS as a group of bureaucrats in the DHSC, but it’s actually a group of dietitians (plus a geriatrician, a gastroenterologist, a dermatologist and a pharmacist) who are committed to ensuring that products approved are appropriate prescribing at NHS expense. If you want to find out who we are, you can view all our names on the ACBS website. Committee members have a huge range of clinical knowledge and expertise and include dietitians who are specialists in inherited metabolic disorders, paediatrics, tube feeding and oral nutrition support. The ACBS committee members are all volunteers and are not paid for undertaking this role.

How does the ACBS approval process work?

The ACBS approval process starts with a company choosing to submit an application for ACBS approval for a product. The application process itself is completely free.

Over the last three years, working in partnership with the British Specialist Nutrition Association (BSNA) (the organisation that represents the majority of manufacturers which produce NBS for the UK market), the ACBS has created a new standardised and detailed application form.

Applications can be one of three types:

  • Type 1 – a completely new type of product
  • Type 2 – a new product which is broadly similar to a product which is already ACBS-listed
  • Type 3 – a change to an existing ACBS-listed product

The committee is responsible for reviewing all Type 1, 2 and 3 applications and does this as part of three meetings per year. If the committee approves an NBS product for prescription at NHS expense, the committee is very aware that it is committing the NHS to paying for that product to be prescribed, in addition to all the other already ACBS-listed products on the Drug Tariff. For that reason, the committee thoroughly reviews every aspect of each application, including considering whether each new product is something that is needed by patients and therefore that the NHS should be paying for.

The committee therefore questions manufacturers about anything within the application that is unclear or where additional information is needed to enable a decision to be made. The process from receipt of an application to a final decision can take some time, but by working in this way the committee is able to support both safe patient care and NHS finances.

The Drug Tariff

All ACBS-approved NBS have one or more indications for which the ACBS deems that they are appropriate to be requested for prescription at NHS expense. As a dietitian you may have heard the term ‘standard ACBS indications’ but, surprising as it might seem, there are no standard indications!

Being clear on the specific ACBS indication/s for the exact NBS that you are requesting is a key starting point when requesting a prescription, and the only way to be absolutely sure of a product’s ACBS indication/s is to check the product entry in the Drug Tariff.

Every ACBS-listed NBS is included in Part XV of the Drug Tariff. The Drug Tariff is a freely available resource online (just search ‘Drug Tariff’) and it is updated every month – for that reason, you should always go to the website to check, rather than trying to download and save the document anywhere. Also be sure to select the PDF version to search for a product – at over 1,000 pages long you do not want to have to scroll through the Drug Tariff looking for a single product!

As with many things to do with NBS, there are some things that are not entirely up to date in the Drug Tariff. However, the one part that is up to date is Part XV, so you can be confident that if a product is there, it is ACBS-listed for the specific indication/s stated. Equally, if the NBS isn’t in Part XV you can be equally confident that it isn’t ACBS-listed.

Odd as it sounds, an independent prescriber (e.g. a GP) can prescribe just about anything whether it is listed in the Drug Tariff or not. However, it’s important to remember that any NBS that does not appear in Part XV of the Drug Tariff has either not been through  scrutiny to ensure it is a product that should be available for prescription at NHS expense, or it has been through that process and has not been deemed appropriate for ACBS approval. Such a product is therefore unlikely to be appropriate to request for prescription at NHS expense and a prescriber may decline to prescribe it.

Local NHS formularies

Many Medicines Optimisation Teams around the country have produced formularies to try to rationalise which NBS products are most cost effective for prescribing for their populations. When you consider that there are nearly 700 ACBSlisted NBS you can see why some rationalisation can be helpful.

Adult oral nutrition supplements (ONS) are a good example to consider, not least as local formularies usually include these products. There are currently about 70 NBS which can be categorised as adult ONS products. Interestingly, in the community in England in 2022/23, nearly £180million was spent on prescribing just these products (representing about 35% of the total spend on all NBS) and that spend is rising year on year.

Those adult ONS products can be divided into about 20 different types of adult ONS, where all the products within each ‘type’ are nutritionally similar to all the others within that ‘type’. Formularies can help prescribers to make sense of this sort of information, especially where multiple manufacturers produce an ONS which is broadly nutritionally equivalent to another manufacturers ONS but at a different cost to the NHS.

It can be challenging to find cost information to enable you to compare like-for-like products with each other, but you can find this information in the Dictionary of Medicines and Devices (dm+d) (another free-to-access website).


Prescribing any product is a serious responsibility. As dietitians, we don’t currently have access to independent prescribing rights, but even without them we still have responsibilities relating to appropriate prescribing whenever we request an NBS prescription to be either initiated or continued by someone else.

Perhaps the easiest way to think of this is that by requesting/advising someone else to prescribe a specific product or type of product, we are effectively prescribing by proxy. This means that, even though the person who signs the prescription is ultimately responsible, if you are the person who has recommended that product to be prescribed then you also hold a level of responsibility for ensuring that the prescription you have requested is appropriate for that patient and is appropriate to be prescribed at NHS expense.

The HCPC requires us to “engage in evidence-based practice” and to “recognise the need to manage … resources safely and effectively”. In addition, our BDA Code of Professional Conduct states we must “Provide high-quality, cost-efficient services based on the needs of the population and service users” and “Be accountable for [our] decision making, given that [we] have a moral and legal obligation for the provision of safe and competent service delivery”.

A Competency Framework for all Prescribers, written by the Royal Pharmaceutical Society and endorsed by the BDA, is a really helpful resource for supporting even non prescribers to understand what good prescribing looks like and how we can all support it.

Sadly, as we all know, the NHS is constantly facing cost pressures but never more severe than now, so we all have to remember that every pound spent on something that might not be needed is a pound that can’t be spent on something that is. Many community dietitians see frequent examples of products being neither prescribed nor taken as recommended, which I believe demonstrates how essential it is for us as dietitians to measure and record meaningful outcomes for our patients. After all, if the NHS is going to spend a lot of money on NBS, we as NHS employees and users of the system need to be sure that this expense is achieving a meaningful outcome for the patients for whom they are prescribed.

Useful resources


BDA Code of Professional Conduct

British Dietetic Association, Older People Specialist Group and Optimising Nutrition Prescribing Specialist Group Outcome Indicators 2023 *Coming soon to the BDA website*


Drug Tariff

HCPC Standards of Proficiency 

Royal Pharmaceutical Society – A Competency Framework for all Prescribers