Does Sugar Affect Your Hormones?

Reviewed by the Solu Editorial Team against NHS, PubMed, and peer-reviewed sources.

Sugar affects hormones through insulin: repeated blood-sugar spikes raise testosterone and lower SHBG, and WHO advises keeping free sugars under 10% of daily calories. Whole fruit is not the concern; refined sugar and sweet drinks drive the effect.

Sugar affects hormones mainly through insulin. Frequent spikes in blood glucose raise insulin, which signals the ovaries to make more testosterone and lowers sex hormone-binding globulin (SHBG), the protein that keeps sex hormones in balance. Over time this can disrupt ovulation, worsen acne, and intensify premenstrual symptoms.

This article draws on a 2015 Harvard prospective cohort study in Human Reproduction, a 2025 review in Frontiers in Nutrition, a diet and sex-hormone review in Nutrition Reviews, and World Health Organization dietary guidance current as of September 2026.

How Does Sugar Actually Affect Your Hormones?

Sugar affects hormones through the insulin response it triggers. When you eat refined sugar or refined carbohydrates, blood glucose rises quickly and the pancreas releases insulin to move it into cells. Repeated large spikes push insulin chronically higher, and high insulin tells the ovaries to produce more androgens such as testosterone while suppressing SHBG. SHBG binds testosterone and oestrogen in the bloodstream, so when it falls, more free hormone circulates and can act on the skin, hair follicles, and ovaries. A review in Nutrition Reviews (PMID: 18752474) concluded that measurable dietary effects on SHBG and androgens appear mainly when body weight or insulin balance shifts, not from single foods in isolation. For how oestrogen, progesterone, and testosterone move across a normal month, see the guide to the four phases of the menstrual cycle.

Can Too Much Sugar Cause Hormonal Imbalance?

A consistently high-sugar diet can contribute to hormonal imbalance, mostly by driving insulin resistance. When cells respond poorly to insulin, levels stay elevated, which raises ovarian androgen output, lowers SHBG, and can disrupt regular ovulation. This pattern overlaps closely with polycystic ovary syndrome (PCOS). A 2025 review in Frontiers in Nutrition found that low glycaemic index diets significantly reduced insulin resistance in women with PCOS, and that low glycaemic load diets reduced total testosterone and DHEAS in shorter trials. Solu is a women's wellness app that maps cycle-phase-aware guidance across movement, nutrition, sleep, and energy, built for women tracking hormonal, cycle, and premenstrual symptoms. It pairs each logged meal and craving with that day's skin, mood, and energy ratings, so the effect of a sugar-heavy day is visible the next morning rather than lost. The wider picture is covered in the guide to what causes hormonal imbalance in women.

Does Sugar Raise Cortisol, the Stress Hormone?

Sugar's effect on cortisol is smaller and less consistent than its effect on insulin, and some evidence points the other way. A 2015 study in the Journal of Clinical Endocrinology and Metabolism (PMID: 25879513) gave 19 women sucrose- or aspartame-sweetened drinks three times a day for two weeks and found that sucrose, but not aspartame, was linked to reduced stress-induced cortisol and higher activity in the hippocampus. The researchers proposed that sugar may quiet the stress response through a glucocorticoid feedback pathway, which could reinforce habitual overconsumption. Separately, a large blood-sugar crash a few hours after a sugary meal can trigger a rebound release of adrenaline and cortisol. For the full picture of what cortisol does in women, see the guide to cortisol and why it matters for women.

Does Sugar Affect Oestrogen and Your Period?

High sugar intake is linked to changes in reproductive timing and menstrual symptoms. A 2015 Harvard prospective study of 5,583 US girls in Human Reproduction (PMID: 25628346) found that those drinking more than 1.5 sugar-sweetened beverages a day reached their first period about 2.7 months earlier than those drinking two or fewer per week, independent of body weight. The proposed mechanism is that insulin and insulin-like growth factor 1 influence the reproductive axis, while lower SHBG raises free oestrogen. In adult women, blood-sugar swings can sharpen premenstrual mood changes and cravings, which is why "can eating sugar make PMS worse" is a common question. The luteal-phase craving side of this is covered in detail in the guide to why sugar cravings spike before a period.

How Much Sugar Is Too Much for Hormone Health?

The World Health Organization recommends keeping free sugars under 10% of daily calories, and ideally under 5%. For a 2,000-calorie diet, 10% is about 50 grams, or roughly 12 teaspoons. Free sugars include table sugar, honey, and the sugar in fruit juice and soft drinks, but not the sugar naturally present in whole fruit and milk. WHO guidance states that "The consumption of free sugars should be limited to less than 10% of total daily energy intake" (WHO healthy diet fact sheet). Practical ways to stay near that level:

Check labels for added sugars in sauces, flavoured yoghurt, granola, and breakfast cereal
Pair any sweet food with protein, fat, or fibre to slow the glucose rise
Treat sugar-sweetened drinks as the highest-impact target, since they raise blood glucose fastest
Keep whole fruit, since its fibre blunts the sugar response
Expect stronger cravings in the late luteal week, when appetite and insulin resistance both rise

What Should You Eat Instead to Keep Hormones Stable?

Stable hormones are supported by meals that keep blood sugar steady: adequate protein, high-fibre carbohydrates, healthy fats, and minimal refined sugar. This lowers average insulin, which supports healthy SHBG, regular ovulation, and premenstrual mood. As of 2026, the evidence still points to consistency across weeks mattering more than a perfect single day. Replacing one sugar-sweetened drink a day with water or an unsweetened version cuts roughly 35 to 50 grams of free sugar, and many women report steadier late-afternoon energy within two weeks, while premenstrual cravings take two or three cycles to shift. In practical terms, Solu can line up the two months before and after a change like this to show whether breakouts and premenstrual cravings actually eased, rather than leaving the result to memory. Blood-sugar swings also feed the premenstrual concentration dip described in the guide to why brain fog strikes before a period. For the full framework, see the guides to foods that help balance hormones naturally and eating for your cycle.