For women, the menopause typically starts between the ages of 45 and 55.
It can be extremely debilitating and can cause anything from hot flushes to depression to decreased sex drive - in fact one quarter of women over 40 say their sex life is non-existent thanks to menopause.
The symptoms can last between two and five years, which means it's really important to seek out treatment if you're finding the experience unbearable.
To help you on your way, we spoke to Dr Helen Webberley from Oxford Online Pharmacy about what treatments are available. She also gave her verdict on whether hormone replacement therapy (HRT) is safe.
The end of a woman’s reproductive life is marked by a reduction in the function of the ovaries. When this finally stops, the menopause begins.
"Generally speaking, for a woman over the age of fifty, the menopause can be said to have taken place one year after the last period, or two years after the last period in the under fifties," explains Dr Webberley.
"This is the guide used when considering stopping contraception."
The period of time before the menopause starts, when the end of fertility approaches but may not yet have been reached, is known as the perimenopause.
All women will go through this stage, but their experiences and symptoms will often be different.
"Some women don't notice it and some suffer terribly," explains Dr Webberley.
Symptoms can include irregular periods, bleeding between periods, heavier or lighter periods, a gradual decline in periods or a sudden stop in periods altogether.
"The reduction in oestrogen also causes ‘vasomotor instability’ which means the tiny blood vessels don’t know whether they are coming or going and can cause temperature changes on the skin," explains Dr Webberley.
This leads to the characteristic hot flushes and night sweats, which many women come to know (and hate).
During this transition, changes in mood are very common. Women may experience mood swings, tearfulness, anxiety, depression and emotional lability, which means you cry one minute and laugh the next.
Changes in the body also happen as a result of lack of oestrogen.
Some women experience vaginal dryness, while others might suffer from atrophy, where the skin around the lips and vagina shrink. This can cause painful sex and irritation of the bladder and urethra.
The perimenopause can affect a woman's sex life dramatically and Dr Webberley says that communication with your partner is key to getting through it.
"Talk about the changes in your sex-drive, body image, moods, pain, sexual enjoyment and try and understand the changes that life throws your way with the help of your partner," she advises.
Other symptoms include thinning and dryness of the skin and hair in general, as well as changes to the bones and tendons which can lead to joint pain.
It might sound pretty horrendous all in all, but thankfully there are various treatment options to help you through it.
Hormone replacement therapy (or HRT) became the subject of debate for many years after a study suggested there was a strong link between HRT and the development of breast cancer.
The treatment works by replacing oestrogen and other hormones which have been reduced in the body. These hormones help prevent premature ageing of bones, the cardiovascular system and skin.
"The current advice is very clear," says Dr Webberley. "If the benefits outweigh the risks then women who want to have HRT should have it."
New guidance issued at the end of 2015 suggested that more than one million women could benefit from the treatment.
The National Institute for Health and Care Excellence (NICE) advised doctors to consider offering HRT to more women because it can be extremely effective for symptoms including hot flushes, mood swings and depression.
Women are advised to hold out for HRT until they reach 50 years old. There are some known risks surrounding the treatment, including an increased risk of breast cancer and blood clots in the venous system, however that's not to say it should be ruled out because of it.
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"No woman should be denied HRT just because of her age or risk profile," says Dr Webberley. "It should be a fully consenting decision between the woman and her doctor."
To cope with hot flushes and night sweats, women should: wear light clothing, keep their bedroom cool at night, take a cool shower or have a cold drink, avoid potential triggers (like spicy food, caffeine, smoking and alcohol), and do regular exercise.
If the flushes and sweats are frequent or severe, it might be worth asking your GP about HRT.
To cope with fluctuations in mood you should get plenty of rest, exercise regularly and do relaxing activities such as yoga or tai chi, the NHS suggests.
Medication and other treatments are also available, including cognitive behavioural therapy (CBT), a type of talking therapy that can improve low mood and feelings of anxiety.
Finally, if you're experiencing vaginal dryness your GP can prescribe an oestrogen treatment, often available as a pessary, cream or vaginal ring.
Over-the-counter vaginal moisturisers or lubricants may also help.