The NHS will stop prescribing powerful cross-sex hormones to trans-identifying children under the age of 18 after a review found the evidence did not support its continued use.

Oestrogen and testosterone have been available on the NHS for 16 and 17-year-olds with a diagnosis of gender dysphoria and who meet certain criteria.

However, from Monday, new referrals will be paused while a short consultation is launched on whether to remove the treatment as a routine procedure.

It is understood that medical experts are firmly behind the ban on the roll-out to new patients.

A recent internal NHS document, seen by the Mail on Sunday, acknowledged that injecting oestrogen and testosterone can cause blood clots, breast cancer, heart disease, stroke and ‘impaired sexual function’.

It also stated that the long term effects of these powerful hormones on teenage brain development are still unknown.

In the 2024 Cass Review into children’s gender care, Baroness Hilary Cass recommended ‘extreme caution’ in providing such treatment, and a ‘clear clinical rationale for providing hormones at this stage rather than waiting until an individual reaches 18’.

A review by NHS England has since found that the evidence is too weak to show whether such treatment is either beneficial or harmful to children with gender dysphoria.

It is understood that the NHS is continuing to examine evidence for masculinising and feminising hormones for adults.

The NHS will stop prescribing powerful cross-sex hormones to trans-identifying children under the age of 18 

NHS England said 16 and 17-year-old patients currently receiving cross-sex hormones can continue to receive treatment, but it said each case must be reviewed individually by clinicians.

A consultation on plans to remove the treatment will last 90 days as the health body expects to review thousands of responses.

A clinical trial into the impacts of puberty blockers on children as young as 10 was paused last month amid concerns over the ‘unquantified risk’ of ‘long-term biological harms’.

Use of drugs to delay or prevent puberty was banned for under-18s in 2024.

Professor James Palmer, national medical director for specialised services at NHS England, said: ‘Following the Cass Review, NHS England commissioned an in-depth review of all available clinical evidence for using oestrogen or testosterone either alone or with other medications to treat gender incongruence and dysphoria.

‘This review has established that the available evidence does not support the continued use of masculinising or feminising hormones to treat gender incongruence or dysphoria for young people under 18.

‘We are now launching a public consultation on a revised policy which would see the NHS remove this treatment as a routine intervention for young people under 18. As part of the consultation NHS England will want to determine whether any key evidence may need to be reviewed before a final policy is published.

‘The NHS has exercised extreme caution when considering starting young people on this treatment – in accordance with the advice from Dr Cass – and as part of this action will now be pausing any new referrals for this treatment for 16 and 17-year-olds.

‘Patients currently receiving these treatments on the NHS can continue but this will need to be reviewed individually with their clinical team.

‘The NHS continues to offer specialist support for under-18s managing gender incongruence, including mental health support and referral to specialist children and young people’s gender services where appropriate.’

Over the last decade, the number of children claiming to be trans has skyrocketed. 

Any ban will be seen as a victory for campaigners who believe the harms caused by the drugs outweigh any benefits.

Dr Alice Hodkinson, a GP from the campaign group Biology in Medicine, said: ‘This has been a long time coming given the evidence of the harms these hormones cause.’

Boys taking oestrogen typically report smoother skin, thicker hair and softening facial features, along with a redistribution of body fat. Girls on testosterone grow facial hair, develop deeper voices and some are affected by male-pattern baldness.

Some of the physical changes caused by injecting hormones over a long period of time are permanent, especially for girls and young women.

Testosterone can cause incontinence and vaginal atrophy – a thinning of the walls of the vagina, which leads to bleeding and discomfort. Other side effects of the drugs include dyslipidaemia, polycythaemia, hypercalcaemia, and elevated liver enzymes.