Impact of Dietary Fats on Hormones: What Research Shows

Dietary fats affect hormones in two main ways. Your body makes steroid hormones such as estrogen, progesterone and testosterone from cholesterol, and it makes hormone-like signaling molecules called eicosanoids from the essential fatty acids you can only get from food [1][3][4]. In controlled diet studies, cutting fat sharply has produced modest drops in testosterone in men and estradiol in women, so both the amount and the type of fat you eat play a part, although the effects are small [5][6][7].

Key Takeaways

Steroid hormones are built from cholesterol, and your body makes all the cholesterol it needs, so eating more fat does not simply mean making more hormones [3][4].
Two fatty acids are essential: linoleic acid (an omega-6) and alpha-linolenic acid (an omega-3). Your body uses them and their longer-chain relatives to make eicosanoids, signaling molecules active in the endocrine, immune and cardiovascular systems [1][2].
A 2021 meta-analysis of 6 intervention studies (206 men) found that low-fat diets modestly lowered total and free testosterone compared with higher-fat diets [5].
A 1999 meta-analysis of 13 fat-reduction studies found serum estradiol fell about 7% in premenopausal women and 23% in postmenopausal women [7].
The reference range for adults is 20 to 35% of calories from fat, and current U.S. guidelines advise keeping saturated fat to no more than 10% of calories; artificial trans fat from partially hydrogenated oils can no longer be added to U.S. foods [9][10][11].

Evidence grade: Moderate. Controlled feeding studies and meta-analyses of small, short diet trials point the same way (very low-fat diets modestly lower sex hormones), but the trials are few and the changes are small.

An Overview of the Hormonal System

Hormones are chemical messengers. Glands release them into the blood, and they travel to other tissues to influence metabolism, body temperature, hunger, reproduction, mood and the stress response. For a broader look at how hormones such as insulin, cortisol and thyroid hormone steer the way you use nutrients, see our guide to hormonal effects on nutrient metabolism.

Fat connects to this system in two places: the cholesterol that steroid hormones are made from, and the fatty acids that become eicosanoids.

Why Dietary Fats Are Building Blocks for Hormones

Cholesterol: the starting point for steroid hormones

Estrogen, progesterone, testosterone, cortisol and aldosterone are steroid hormones. Every one of them starts as cholesterol. The first and rate-limiting step is the conversion of cholesterol to pregnenolone by a single enzyme (P450scc, also called CYP11A1); other enzymes in the adrenal glands, ovaries and testes then turn pregnenolone into specific hormones [4].

Your body needs some cholesterol to make hormones and vitamin D, but it makes all the cholesterol it needs. Cholesterol is also found in animal foods such as egg yolks, meat and cheese [3]. That is why the link between fat intake and hormone levels is indirect: diet seems to influence how much hormone is made and cleared, not whether the raw material is available.

Essential fatty acids and eicosanoids

The fats you eat supply two essential fatty acids, linoleic acid and alpha-linolenic acid. They are called essential because your body cannot make them, and it needs them for brain development, controlling inflammation and blood clotting [2].

Omega-3s and omega-6s are also used to form eicosanoids. These signaling molecules have wide-ranging functions in the cardiovascular, pulmonary, immune and endocrine systems. Eicosanoids made from omega-6s are generally more potent drivers of inflammation, blood vessel constriction and platelet clumping than those made from omega-3s [1].

Fat does other jobs as well. It supplies energy (9 calories per gram), and it helps you absorb vitamins A, D, E and K, the fat-soluble vitamins [2]. For a full rundown of fat types, see our guide to dietary fats.

What Research Shows About Fat Intake and Hormone Levels

Low-fat diets and testosterone in men

Whittaker and Wu (2021) pooled 6 intervention studies with 206 men that compared low-fat and higher-fat diets. On the low-fat diets, total testosterone, free testosterone, urinary testosterone and dihydrotestosterone were all modestly lower, with standardized mean differences of about -0.3 to -0.4. Luteinizing hormone and sex hormone-binding globulin did not change significantly. The drop was larger in a subgroup of European and North American men. The authors concluded that low-fat diets appear to lower testosterone but that more randomized trials are needed [5]. A correction to the paper was published in 2025; the figures here are from the original abstract.

One of the best-controlled studies of this kind fed 43 healthy men two diets for 10 weeks each. The low-fat diet provided about 19% of calories from fat and the high-fat diet about 41%. Total testosterone was about 13% higher on the high-fat diet, though only the bound fraction differed significantly, and urinary testosterone was 13% higher. Urinary estrogens were 12 to 28% lower on the high-fat diet. Fiber also differed between the two diets, so the effect cannot be pinned on fat alone [6].

Fat intake and estrogen in women

Wu, Pike and Stram (1999) combined 13 studies in which women cut their fat intake. Serum estradiol fell by about 7.4% in premenopausal women and 23% in postmenopausal women. The largest drops came from two studies that cut fat to 10 to 12% of calories, a level far below typical diets [7].

In the BioCycle Study, 259 women with regular cycles recorded their diets for up to two cycles while their hormones were measured repeatedly. Women in the highest third for fat intake had total and free testosterone about 4% higher than the lowest third, which the authors called very small increases. Higher intake of docosapentaenoic acid (DPA), an omega-3, was linked to higher progesterone and a lower chance of a cycle without ovulation. Fat intake was not linked to other reproductive hormones [8]. This was an observational study, so it shows associations rather than cause and effect.

Study	Who	What changed	Hormone finding
Whittaker & Wu, 2021 [5]	206 men, 6 studies	Low-fat vs higher-fat diets	Total and free testosterone modestly lower on low-fat diets
Dorgan et al., 1996 [6]	43 men, 10 weeks per diet	19% vs 41% of calories from fat (fiber also differed)	Testosterone about 13% higher on the high-fat diet; urinary estrogens 12-28% lower
Wu, Pike & Stram, 1999 [7]	Women, 13 studies	Reduced fat intake	Estradiol down about 7% (premenopausal) and 23% (postmenopausal)
Mumford et al., 2016 [8]	259 women, observational	Usual fat intake	About 4% higher testosterone with the highest fat intake; DPA linked to higher progesterone

Taken together, these studies suggest that very low-fat eating shifts sex hormones modestly. They do not show that adding fat beyond a normal intake improves hormone levels, and none of them measured symptoms or long-term outcomes.

Fat Quality: The Right Types and Amounts

How much fat

The Dietary Guidelines for Americans 2020-2025, drawing on the Dietary Reference Intakes, list an acceptable range of 20 to 35% of calories from fat for adults [9]. The current 2025-2030 edition advises that saturated fat generally not exceed 10% of daily calories, and notes that more high-quality research is needed to determine which types of dietary fat best support long-term health [11]. On a 2,000-calorie day, the 20 to 35% range that range works out to roughly 44 to 78 grams of fat. Most of the diets that lowered hormone levels in the studies above went well below the bottom of this range.

Which fats to favor

Monounsaturated fats, such as olive and canola oil, and polyunsaturated fats, such as safflower, sunflower, corn and soybean oil. Eating unsaturated fats instead of saturated fats can help lower LDL cholesterol [2].
Omega-3 sources. Flaxseed oil (7.26 g ALA per tablespoon), chia seeds (5.06 g per ounce) and walnuts (2.57 g per ounce) are rich in ALA. Fatty fish supply the long-chain omega-3s EPA and DHA; 3 ounces of cooked farmed Atlantic salmon has about 1.24 g of DHA and 0.59 g of EPA [1]. The adequate intake for ALA is 1.6 g a day for men and 1.1 g for women [1].
Saturated fats, found in butter, cheese, whole milk, fatty meats and coconut and palm oils, are best kept to no more than 10% of calories because they raise LDL cholesterol [2][11].
Artificial trans fats are best avoided. The FDA determined that partially hydrogenated oils are no longer generally recognized as safe, and manufacturers could no longer add them to most foods after June 18, 2018, with a final compliance date of January 1, 2021. Small amounts of trans fat occur naturally in milk, butter, cheese and meat [10].

You may see claims that a specific omega-6 to omega-3 ratio balances hormones. The NIH Office of Dietary Supplements notes that the optimal ratio, if any, has not been defined [1]. A practical approach is simply to eat fish and plant omega-3 sources regularly. Fat is only one part of the picture; fiber also influences how estrogen is cleared, which we cover in the role of fiber in hormonal health.

Where OPA Omega 3 Gummies Fit

OPA Omega 3 Gummies are an orange-flavored gummy made with fish oil powder, designed to support daily omega-3 intake and overall wellness. A serving of two gummies lists 100 mg of fish oil powder with 13.2 mg of DHA and 2.8 mg of EPA, and each bottle is a 30-day supply.

To be clear about the numbers: that is about 16 mg of EPA and DHA per serving, while a 3-ounce serving of farmed salmon provides about 1,830 mg [1]. The gummies are a convenient way to add a little omega-3, not a replacement for fish, and they have not been studied for effects on hormone levels. Each serving also contains 2.8 g of added sugar, and the label lists tuna fish as an ingredient allergen.

For more on how EPA, DHA and ALA differ, see our omega-3 fatty acids guide.

Safety and Interactions

Very low-fat diets. The trials above show that cutting fat to well under 20% of calories can lower sex hormones modestly. If you are considering a very low-fat or otherwise restrictive diet, talk with your healthcare provider or a registered dietitian first.
Saturated and trans fats raise LDL cholesterol, and trans fats also lower HDL cholesterol [2].
Calories. All fats provide 9 calories per gram, more than twice as much as carbohydrate or protein [2].
Fish oil and blood thinners. Fish oil can have antiplatelet effects at high doses and might prolong clotting times when taken with warfarin, although most research suggests doses of 3 to 6 g a day do not significantly change anticoagulant status [1]. Talk to your doctor or pharmacist if you take warfarin or another anticoagulant before adding a fish oil supplement.
Allergies. Anyone with a fish allergy should avoid fish oil products, including OPA Omega 3 Gummies, which contain tuna.
If you take hormone therapy or have been told you have a hormone-related condition, ask your healthcare provider before making major changes to your fat intake.

Frequently Asked Questions

How do dietary fats affect hormone production?

Steroid hormones are made from cholesterol, which your body produces on its own, and essential fatty acids from food are used to make eicosanoids that act in the endocrine and immune systems [1][3][4]. Diet trials show that very low-fat diets modestly lower testosterone in men and estradiol in women [5][7].

Does a low-fat diet lower testosterone?

A 2021 meta-analysis of 6 intervention studies in 206 men found that low-fat diets lowered total and free testosterone modestly compared with higher-fat diets. The studies were small, and the authors called for more randomized trials [5].

Can consuming saturated fats lead to hormonal imbalances?

There is no good evidence that saturated fat is needed for hormone production, because your body makes its own cholesterol [3]. Guidelines advise keeping saturated fat to no more than 10% of calories, and it raises LDL cholesterol [2][11].

What are the benefits of unsaturated fats for hormone health?

Unsaturated fats supply the essential fatty acids your body uses to make eicosanoids, and swapping them for saturated fats helps lower LDL cholesterol [1][2]. In the BioCycle Study, higher polyunsaturated fat intake was linked to very small increases in testosterone in women, and higher DPA to higher progesterone [8].

How do trans fats impact hormone regulation?

Direct research on trans fats and sex hormones is limited. What is well established is that artificial trans fats raise LDL and lower HDL cholesterol, which is why the FDA removed partially hydrogenated oils from the U.S. food supply [2][10].

How much fat should I eat for hormone health?

The reference range for adults is 20 to 35% of calories from fat, with saturated fat at no more than 10% of calories [9][11]. Favoring unsaturated sources such as olive oil, nuts, seeds and fish is a sensible default. The hormone drops seen in studies came mainly from diets well below that range [7].

Sources

Disclosure: OPA Nutrition sells supplements, including products mentioned in this article. This content is for education only and is not medical advice. Statements about dietary supplements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease. Talk to your healthcare provider before using any supplement, especially if you take medication or have a medical condition.

Written and reviewed by Michael Gonzales, Founder, OPA Nutrition · Last reviewed: October 17, 2026 · How OPA researches and writes

Impact of Dietary Fats on Hormones: What the Research Shows

Key Takeaways

An Overview of the Hormonal System

Why Dietary Fats Are Building Blocks for Hormones