A beginner’s guide to sex hormone replacement


Tim Cheetham, Paediatric Endocrinologist, Royal Victoria Infirmary, Newcastle, UK

Hormones are natural chemical messages in the blood that tell different parts of the body what to do. Hormone replacement therapy is therefore pretty much as it sounds – it involves replacing hormones that the body isn’t making in normal amounts. Young people require hormone replacement for lots of different reasons. Here we will be focusing on sex hormone replacement – replacing the hormones oestrogen and testosterone that are usually made by the ovaries and testes. These hormones are responsible for the bust, hair and genital development that is typically seen in young people as they grow up. Hormone replacement may be required because the gonads (ovaries or testes) are not present or it may be because they have been removed because they weren’t very healthy. It may also be because the gonads have not formed properly or perhaps they have formed but simply cannot make enough hormone (oestrogen and / or testosterone).

The aim of hormone replacement is to put back what nature isn’t making in a way that is as easy and natural as possible. This frequently means building up the level of sex hormones with time in the same way that nature increases hormone production as a young person develops. Although this involves taking medicine it is usually a very natural and logical thing to do. It is very different to taking (for example) paracetamol or an antibiotic which are not normally present in the body.

Sex hormone replacement can be divided into two main categories – oestrogens and testosterone (androgen). Oestrogen is usually administered to girls who aren’t making female hormone in the usual way whilst testosterone is usually given to boys who are not making male hormones in the usual way. As well as ‘replacement’ therapy these hormones are sometimes given to boys or girls to speed up development and growth. In this setting they can be used to ‘kick-start’ the changes of puberty (such as hair and genital development).

What about starting hormone replacement? Well, there is no perfect time that fits everybody but many people start the medicine at a time when the young persons’ friends or classmates are starting to show signs of making oestrogen or testosterone. For many girls (but not all) this will mean starting oestrogen at around 10 to 12 years of age and in boys this means starting testosterone at around 11 to 13 years.

There are a number of different ways that these hormones can be given. The obvious and frequently the easiest way is to take them by mouth as a pill. However there are potential advantages in using gels or patches that are applied to the skin. For example, oestrogen and testosterone are not normally released from the intestines (which is what happens when you take a pill by mouth) and by absorbing oestrogen or testosterone through the skin - which is what happens with a patch or gel – you mimic the way they are normally released (in the peripheral tissues) more closely. Testosterone can also be given by injection as well as by patch, gel or pill. However, the fact that the injection can be administered every few weeks or even every few months has to be balanced against the fact that an injection can be uncomfortable and usually has to be given at the surgery and hence can be a bit inconvenient. For many people the decision to take injections, tablets, patches / gels or other ‘skin’ preparations is a balance between ease of use versus other considerations such as theoretical benefits on overall well-being.

So what are the effects of hormones in the body? Well oestrogen will tend to result in bust development and testosterone will tend to increase the size of the genitals (penis and scrotum). The sex hormones will have other important effects as well. For example, both types of hormone are good for your bones and heart and they are frequently good for the way you feel as well. People can associate these hormones with moodiness and being short tempered - ‘typical teenager’ they may say!! - but it is important to remember that people of all ages are grumpy from time to time. Some young people who are grumpy can have very little sex hormone in the body or they may have had sex hormones inside the body for quite a while and still be grumpy!! Helping a young lady to develop a bust or helping a young man to develop more mature genitals may actually boost confidence and have a positive impact on how someone feels and behaves.

Some people wonder if being on sex hormone replacement can make them put on weight. The sex hormones can certainly make you grow quickly in terms of height (this is a normal part of development in the teenage years) but hormone replacement (mimicking what the body normally does) shouldn’t make people overweight. People on the higher doses of oestrogen (for example in the contraceptive or birth control pill) may report changes in body weight but millions of people take this without being overweight. Healthy, sensible eating will help to ensure that weight change is not a significant issue for people on oestrogen and testosterone replacement.

So how is treatment monitored? – well, most importantly, how does the person feel that things are developing? Are they happy with the changes to their body? The doctor or nurse may want to examine the young person from time to time to make sure that they too are happy with the changes. It is also possible to measure hormone levels in blood and this is something else that the team may want to do at some point during treatment. It is also possible to look at the effects of the treatment on the skeleton as well, and at some point during treatment an assessment of bone health may be suggested as a way of ensuring that the right dose of hormone replacement is being used.

In summary, it is quite common for young people to need sex hormone replacement. Sex hormones have many important health benefits and are generally pretty easy to give. There is frequently more than one option available and your doctors / nurses will be very happy to talk to you about the different preparations and the different ways that they can be given.