No significant effect on their psychological function, thoughts of self-harm, or body image

e BMJ:

Puberty blockers used to treat children aged 12 to 15 who have severe and persistent gender dysphoria had no significant effect on their psychological function, thoughts of self-harm, or body image, a study has found.

However, as expected, the children experienced reduced growth in height and bone strength by the time they finished their treatment at age 16.

So, no evidence of good effects, but plenty of evidence for some serious bad effects. And, as we've seen, once the puberty blockers are given, the course is set for the cross-sex hormone treatment. In practice it's a one-way street to transitioning.

From this BBC report:

The evidence for using puberty blocking drugs to treat young people struggling with their gender identity is "very low", an official review has found.

The National Institute of Health and Care Excellence (NICE) said existing studies of the drugs were small and "subject to bias and confounding". […]

The NICE evidence review looked at what impact puberty blockers had on gender dysphoria, mental health – such as depression, anger and anxiety – and quality of life.

NICE, which provides national guidance and advice to improve health and social care, said: "The quality of evidence for these outcomes was assessed as very low certainty." […]

NICE also reviewed the evidence base for gender-affirming hormones – sometimes known as cross-sex hormones.

These can be given to young people with gender dysphoria from age 16 in the NHS.

Oestrogen may be given to people who are registered or assigned male at birth, and testosterone to females, to start the development of the physical sex characteristics of the gender with which they identify.

The aim is to improve mental health, quality of life and body image.

The review found the evidence of clinical effectiveness and safety of gender-affirming hormones was also of "very low" quality.

"Any potential benefits of gender-affirming hormones must be weighed against the largely unknown long-term safety profile of these treatments in children and adolescents with gender dysphoria," NICE said.