Does progesterone cause weight gain? What you need to know

Progesterone is a sex hormone best known for its role in helping to regulate the female reproductive system. But beyond its reproductive functions, progesterone can also influence other aspects of health — including body weight. 

Weight fluctuations are common during times of hormonal changes, such as pregnancy, perimenopause, or while using hormonal contraceptives. This often leads women to wonder: “does progesterone cause weight gain?” To answer this question, we need to take a closer look at what progesterone is, how it affects the body, and the crucial role hormones play in maintaining weight balance. 

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Understanding Progesterone

What is progesterone?

Progesterone is a steroid hormone that helps regulate the menstrual cycle, prepare the body for pregnancy, and support a pregnancy. It’s produced by:

• Ovaries (corpus luteum): The majority of progesterone is produced after ovulation (release of an egg by the ovaries) by the corpus luteum. The corpus luteum is formed by the follicle after the release of an egg and it secretes progesterone. If the egg is not fertilized the corpus luteum will break down around 10 days after ovulation and progesterone levels will drop.
• Placenta: When you’re pregnant your placenta becomes the main producer of progesterone from around the second trimester. 
• Adrenal glands: These small glands, found above the kidneys are responsible for the production of a number of hormones, including a small amount of progesterone as well as cortisol and aldosterone.

Functions of progesterone 

Progesterone levels rise and fall during the menstrual cycle. Progesterone levels surge after ovulation, this prepares the endometrium (lining of the uterus) for a potential pregnancy by thickening it and making it rich in blood vessels and nutrients. 

• If pregnancy does not occur, progesterone levels fall, leading to the breakdown of the uterine lining — and menstruation begins.
• If pregnancy does occur, progesterone levels stay high to help maintain the uterine lining and prevent miscarriage. 

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Progesterone not only has an effect on the menstrual cycle and pregnancy, it also influences

• Mood
• Sleep
• Bone formation
• Fluid balance
• Hormonal regulation 
• Metabolism
• Libido

Sources of progesterone

Your body naturally produces progesterone, but it can also come from external sources, such as:

• Hormonal contraceptives (progestin—only pills, combined oral contraceptive pill)
• Hormone replacement therapy (HRT)
• Certain fertility treatments

How Progesterone Affects Weight

Progesterone itself does not directly cause weight gain, however as it interacts with many other hormones and systems, having levels that are too high or too low can contribute to changes in weight.

Progesterone and appetite 

Progesterone may influence appetite by interacting with other hormones involved in hunger and satiety. Although the evidence is mixed, many women report a higher appetite or increased cravings during the second half of their menstrual cycle (luteal phase) when progesterone levels peak. 

Progesterone also affects insulin sensitivity. When progesterone levels are high, they may reduce the body’s sensitivity to insulin, leading to increased insulin secretion. Elevated insulin levels can promote fat storage, increase appetite, and trigger food cravings — particularly for sugary foods.

Progesterone and fluid retention

Progesterone plays a role in fluid balance, a change in progesterone and estrogen levels can cause sodium retention which leads to water retention and bloating. This buildup of water can make you feel like you’ve gained weight, even though there’s no increase in body fat.

Progesterone and Estrogen

Progesterone and estrogen work closely together to maintain hormonal balance, so a disruption in one often affects the other. When progesterone levels are too low, estrogen can become dominant — a state known as estrogen dominance. Elevated estrogen levels are associated with weight gain, increased fat storage in the hips and thighs, and a higher risk of insulin resistance.

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Natural Progesterone Fluctuations and Weight

Progesterone levels fluctuate and change both month to month as a part of the menstrual cycle, but also during different phases of life, like pregnancy and menopause. 

During perimenopause and menopause, many women notice they gain weight even though they haven’t changed their diet or activity levels. Hormonal changes alongside other factors like aging, genetics, and a reduction in metabolism all contribute to weight gain at this time. 

Pregnancy is another common time women find themselves gaining weight. A dramatic increase in progesterone levels, along with a change in other hormones, can slow digestion, increase appetite, and cause fluid retention, all of which lead to weight gain. 

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Does Taking Progesterone Cause Weight Gain

A large 2019 systematic review found no link between synthetic progesterone and weight gain in women. However, many women report weight gain while taking progesterone-containing contraceptives, hormone replacement, or fertility treatment medications. This could be due to:

• Fluid retention
• Increased appetite 
• Shifts in fat distribution

Tips for Managing Weight 

While hormonal shifts can influence your weight, they don’t mean that weight gain is inevitable. With the right strategies, you can support your body through these changes and maintain a healthy weight. Here are some top tips to help you maintain a healthy weight:

1. Focus on whole, nutrient-dense foods

A balanced diet consists of one that is high in fibre, lean proteins, and healthy fats. It also consists of plenty of fruit and vegetables and limits highly processed foods and added sugar. A healthy diet helps weight maintenance, regulates blood sugar, reduces the chances of developing insulin resistance, and supports hormonal balance. 

2. Stay active

It can be difficult to stay active, especially as you age or when you have young children. However, regular physical activity is one of the best ways to maintain weight, stay healthy, and support hormonal balance. The CDC recommends doing at least:

• 150 mins (2.5 hours) of moderate-intensity physical activity per week or 75 mins of vigorous-intensity activity a week.
• 2 sessions of muscle-strengthening activity a week 

Examples of moderate-intensity activity include; brisk walking, doubles tennis, cycling, and swimming.

3. Prioritize sleep and stress management

Poor sleep and chronic stress can disrupt hormonal levels and make it harder to manage weight.

• Aim for 7-9 hours of sleep per night
• Practice stress-reducing habits like mindfulness, deep breathing, or yoga.

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Myths About Progesterone and Weight 

Myth 1: Progesterone always causes weight gain

Fact: While some women may experience temporary bloating or changes to their appetite, progesterone doesn’t cause significant weight gain in most women. Weight gain is influenced by many different factors, and while hormones play a role, factors like age, lifestyle, and genetics are important.

Myth 2: Natural progesterone and synthetic progestins have the same effect

Fact: Bioidentical progesterone and synthetic progestins are not identical. Some women find that they tolerate bioidentical progesterone better than progestin and experience fewer side effects. 

Myth 3: You can’t lose weight if you’re taking progesterone

Fact: Hormonal therapy doesn’t automatically prevent weight loss. With a balanced diet, regular exercise, and good sleep, many women can manage their weight effectively while on progesterone, or even lose weight, if needed.

When to Seek Medical Advice

Mild, temporary weight changes during your menstrual cycle or at different stages of life are common and normally nothing to worry about. However, persistent weight gain can be a sign of an underlying issue. Consult with your healthcare provider if you notice any of the following:

• Sudden or unexplained weight gain: If you’re significantly gaining weight without any changes to your diet or exercise regimen it could be a sign of an underlying hormonal imbalance, thyroid dysfunction, or metabolic issue that needs further evaluation. 
• Difficulty losing weight despite efforts: If you’ve made consistent changes to your diet and activity but still struggle to lose weight then this may be a sign of an underlying hormonal imbalance.
• Other symptoms of hormonal imbalance:
  
  • Irregular or missed periods
  • Fatigue
  • Mood swings or anxiety
  • Hair or skin changes
  • Difficulty getting pregnant if you’re trying

Key Takeaways

• Progesterone is a key hormone involved in the menstrual cycle and pregnancy. 
• Hormonal changes, including fluctuations in progesterone, can affect appetite, fluid retention, and fat distribution — all of which can influence weight gain.
• Progesterone alone has not been found to significantly increase weight gain in women, however, some women taking progesterone-containing birth control, HRT, and fertility medications do experience an increase in weight.
• Healthy lifestyle habits—including a balanced diet and regular exercise, can help maintain a healthy weight.

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