What makes a woman want to have sex is complicated and not always totally hormonal, as it can be with men, according to a study published in the Journal of Clinical Endocrinology and Metabolism. While your loss of libido could be caused by a wide variety of things, here are four possible causes - some of which might surprise you.
See also: How to have more orgasms as you get older
1. Anxiety, stress and low mood
If you're worried, stressed or drop into bed exhausted each night, you're hardly going to be in the mood for love. Anxiety and low mood are both common causes of low sex drive in women.
If you have been suffering from fatigue, feel weepy or hopeless, and have lost interest in the things you once enjoyed, such as sex, it's worth talking things over with your doctor. One of the main symptoms of depression is loss of libido.
The female libido is strongly influenced by hormones. When these change - during the menopause, after childbirth or after a hysterectomy, for example - it can have a dramatic effect on arousal and libido. In fact, it's estimated that as many as 15% of menopausal women lose interest in sex.
Women need a certain level of the 'male' hormone testosterone in order to feel sexual desire and arousal. Production of the hormone starts to decline in women from the age of 40 onwards, which can reduce in loss of desire. Because some testosterone is produced in the ovaries, removal of these during surgery can reduce levels of testosterone by half.
Taking hormones in the form of the contraceptive pill can also have an effect on desire. Researchers in Germany studied 1,000 women and found that those who used a hormonal method of birth control, such as oral contraceptives, had lower levels of libido.
Some medical conditions can cause loss of sexual desire in women (such as thyroid disease, heart disease and diabetes), as can certain prescription medications, including drugs for epilepsy, high blood pressure and anti-depressants.
According to a review of blood pressure medication in the International Journal of Clinical Practice, the worst offenders are diuretics and beta-blockers, such as propranolol and atenolol. Speak to your doctor if you're concerned and never stop taking medication without consulting your GP first.
There's also some evidence to suggest that cold remedies and antihistamines might have a negative effect on sex drive. A study from the Cleveland Clinic in Ohio found that antihistamines might lead to loss of libido in both women and men, while cold remedies which contain diphenhydramine or pseudoephedrine were found to reduce sexual desire.
Certain chemicals found in cleaning products, food packaging and personal-care items like shampoo and cosmetics, have also been linked to low sex drive.
According to research presented at the American Society for Reproductive Medicine, phthalates (a softener which makes plastics bendy), are endocrine disruptors which interfere with hormones in the body – including testosterone and oestrogen.
If you're concerned, there are many phthalate-free alternative products available.