Hormonal contraceptives explained

Working out the hormone levels of different contraceptives is quite complicated, so we’re starting to put together some research for you.

This graph shows the amount of hormone (oestrogen and progestogen) contained in a pill, or released in a 24 hour period, for every brand of contraception The Lowdown features. The amount of hormone is in micrograms (mcg), which is one millionth of a gram.

All contraceptives – approximate daily hormonal release rates (micrograms)

As you can see it varies quite a lot. But this doesn’t mean that some types or brands are ‘better’ or ‘worse’ than others, because different types of hormones have different levels of ‘potency’. Potency is how much of a drug is needed to give a certain affect. A highly potent drug evokes a given response at low concentrations, while a drug of lower potency evokes the same response only at higher concentrations. For example, the hormone drospirenone (which is in the Yasmin combined pill and Lucette) needs a lot more than other pills (almost 3000 mcg) to work with he oestrogen component of the pill as a contraceptive.

Combined and progestogen only pills: micrograms of hormone in each tablet

Contraceptives also contain inactive ingredients – things like lactose, starch or saline solution that help to bind the pills together, or help inject or deliver the hormones into your blood supply or body. These can also impact the way you metabolise the hormones in the contraceptive – whether it acts quickly or slowly in your system.

If we break this up to just look at the combined and progesterone only pills, you can see that many different brands of pill contain exactly the same type and amount of hormones. (above)

Hormonal coil (IUS): approximate micrograms of hormone released every 24 hours (averaged over a 5 year period)

The hormonal coils (IUS) work differently. They sit within your womb and release tiny amounts of the hormone progestogen into your body over several years. Here is the amount of progestogen released every 24 hours for each brand of the hormonal coil.

Injections: total dose injected (every 8-12 weeks)

For the contraceptive injection it is not possible to work out the amount of hormone that is ‘released’ into you every day, so we can only give you the total amount injected every 8-12 weeks.

Implant, patch and vaginal ring: approximate micrograms of hormone released every 24 hours (over a 3 week and 3 year period

Finally, here are the daily hormone release rates for the implant, ring and patch. The patch and ring amounts are averaged over 3 weeks (the length of time you use one before taking a break) and the implant is averaged over its three year lifespan.