If you're looking for a way to reduce hot flashes, night sweats or other menopause symptoms, chances are you've heard of hormone replacement therapy. But what is it exactly? And when might it help?

"We're actually calling it hormone therapy now, rather than hormone replacement therapy," explains Dr. Erin Manning, a gynecologist at Houston Methodist specializing in menopausal medicine. "The decline of hormone levels during menopause is a natural, physiologic process. We use hormone therapy to treat menopausal symptoms, not to replace the natural loss of hormones."

The average age of the final menstrual period is 51.5 years old, but the final menstrual period can occur anywhere between the ages of 40 and 55. (Related: When Does Menopause Usually Start?)

"The symptoms of menopause, however, can begin anywhere between one and seven years before a woman's final menstrual period," says Dr. Manning. "And they can persist for a number of years after the final menstrual period as well."

Dr. Manning reports that the average number of years of symptoms is 7.4 years. So buckle up! Here's what you need to know about hormone therapy for menopause symptoms:

What is hormone therapy?

Hormone therapy is a low dose of estrogen and progesterone — or just estrogen, if a woman has had a hysterectomy — given around the time of perimenopausal transition to help relieve the classic menopause symptoms.

It can be administered via a few different formulations, from oral pills to patches, sprays, creams and gels.

"Estrogen helps with the symptoms, but the reason we also often include progesterone is for protection of the endometrium, the tissue lining the uterus," explains Dr. Manning. "If you give a woman who still has a uterus — hasn't had a hysterectomy — estrogen only, it can cause the uterus lining to grow out of control and lead to uterine cancer."

If you're thinking that hormone therapy sounds fairly similar to birth control, you're right.

"Birth control also has estrogen and progesterone in it, though at a slightly higher dose," explains Dr. Manning. "It's why, for a woman in her 40s already on the pill, I typically recommend staying on it — even if she doesn't necessarily need it for birth control — since it's a good way to get through the perimenopausal transition with hormonal support to help alleviate symptoms."

Dr. Manning says it's safe for non-smokers to take birth control through age 55.

"Once a woman is 55, we take her off the pill," says Dr. Manning. "And, in some cases, menopause symptoms are in the rearview mirror and the person doesn't need any further hormonal support. But this isn't the case for everyone. Some women go off the pill and begin experiencing menopause symptoms and that's when we start talking about hormone therapy."

What are the signs you need hormone therapy?

Whether it's appropriate to start hormone therapy depends on the severity of menopause symptoms, particularly hot flashes and night sweats.

"The question really becomes about how bad your symptoms are," says Dr. Manning. "I can't answer that for you. So I usually follow up by asking, 'Are these symptoms affecting your ability to function in your daily life?'"

Dr. Manning says having, say, 20 hot flashes a day is a lot. But it's not just the amount of hot flashes, it's how they impact your day, too.

"If you're a professional trying to lead a meeting and you're soaking through your blouse, I would say we should certainly start a conversation about treating that," adds Dr. Manning. "If you're talking to your boss and all of a sudden your face is bright red and you're sweating, that might be something you feel affects your quality of life."

Night sweats are another classic menopause symptom that can be particularly disruptive.

"Sweating at night can really impact a person's sleep, but that's not all," says Dr. Manning. "If you are waking up with soaking wet bedsheets every single night and having to change them every morning — and it takes 10 minutes, not to mention starting a load of laundry — over time that can affect your sleep patterns, your professional life, your parenting responsibilities and more."

Such are the kinds of situations for which Dr. Manning recommends considering hormone therapy.

Which menopause symptoms does hormone therapy help with most?

The lengthy list of menopause symptoms includes:

• Hot flashes
• Night sweats
• Sleep disturbances
• Cognitive changes, including brain fog
• Joint pain
• Weight gain
• Fatigue
• Depression
• Anxiety
• Irritability

Hot flashes and night sweats are the most classic — not to mention some of the most bothersome — menopause symptoms we often think about. Fortunately, they're also the ones hormone therapy best treats.

"Hormone therapy can significantly reduce hot flashes and night sweats," says Dr. Manning. "As for the other symptoms associated with perimenopause, these can sometimes improve with therapy, but not always."

For instance, mood-related symptoms, sleep disturbances and joint pain can sometimes improve with hormone therapy, but the effect isn't always as strong as with hot flashes and night sweats.

"A symptom like joint pain needs to be evaluated by a primary care physician as well, so we can first rule out other causes," says Dr. Manning. "But if there's no other cause, and you're still having joint pain, we can see if hormone therapy helps relieve it."

The one symptom of menopause that hormone therapy isn't proven to help is weight gain. Dr. Manning points out that the therapy is weight neutral, though, meaning it's not going to make you gain weight either.

"We do know that weight management is affected by sleep patterns, though," adds Dr. Manning. "So if the therapy is reducing night sweats and improving sleep, it might secondarily help with weight loss. There's just no direct impact on weight."

Are there risks associated with hormone therapy?

A well-designed, randomized, placebo-controlled study of hormone therapy, part of the Women's Health Initiative (WHI), was published in 2002. It's what most experts, including Dr. Manning, reference when talking about the safety of this therapy.

"From this study, we know there are risks associated with long-term hormone therapy, including a slightly increased risk of breast cancer and heart disease, heart attack and stroke," says Dr. Manning. "There were nine more cases of breast cancer per 10,000 women in the study. That's low, but statistically significant. Additionally, there were 11 more cases of cardiovascular issues and events per 10,000 women. Again, a low number, but statistically significant."

It's why hormone therapy isn't used to treat menopause symptoms long-term, something the majority of women rarely require anyway.

Estrogen-only hormone therapy can also increase a person's risk of uterine cancer if they still have an intact uterus — though, as mentioned, the addition of progesterone for these women mitigates this risk.

You might have also heard claims that hormone therapy increases dementia risk, but Dr. Manning notes that while some studies show there might be a slightly increased risk, other studies show a slightly decreased risk — meaning a link between hormone therapy and dementia isn't clear, and is unlikely to be strong if it does even exist.

"Another important message is in regard to the off-label use of injectable, compounded formulations of hormone therapy," warns Dr. Manning. "These aren't FDA-approved, and safety concerns certainly arise when untested formulations are being made in compounding pharmacies and prescribed to patients."

These off-label prescriptions often entail expensive blood work ups, aren't covered by insurance, and are only available at compounding pharmacies — so women should think twice before considering this form of hormone therapy. Conversely, the FDA-approved hormone therapy options don't require blood work, are covered by insurance, and prescriptions can be picked up from your local, big-name drug store.

How long is a person typically on hormone therapy?

"The thing about the perimenopausal transition is that every woman traverses it differently," says Dr. Manning. "A small percentage of women — about 10%-20% — never notice symptoms at all. Another small subset of women has symptoms all the way into their 70s and 80s. But the average number of years women experience symptoms is 7.4."

Menopause isn't a disease; instead, it's a natural process. And the purpose of hormone therapy is to simply treat menopause symptoms. This means that it's no longer needed once these symptoms subside. Your doctor will require a yearly check-up to review your symptoms and determine whether hormone therapy is still needed.

"Generally speaking, I usually try to get my symptomatic patients through the decade of their 50s on hormone therapy and then sometime in the early 60s start talking about lowering the dose, with the eventual plan of weaning the person off the medication entirely," explains Dr. Manning. "And this is really because of the cardiac risk associated with long-term use of this therapy."

Heart attack risk increases with age, independent of hormone therapy. For instance, the risk of heart attack and stroke is higher at age 68 than 58. Dr. Manning says that there comes an age where the added risk of hormone therapy — though low — warrants stopping the medication.

"By this time, many women are beyond their menopause symptoms anyway," says Dr. Manning. "And for those women still experiencing symptoms, there are non-hormonal options we can try. And there are always lifestyle factors that can help alleviate symptoms."

Alcohol intake is known to increase the chance of night sweats, so it helps to avoid it, especially before bedtime. Also, a few small studies have shown that exercise — yoga, in particular — can help relieve menopause symptoms.