Insulin Resistance and Hormones in Women: the Blood Sugar-Hormone Axis
Insulin is far more than a blood sugar hormone. In women it has a strong say in the hormone system. Once you understand this, you often see the same contributor behind acne, an irregular cycle and stubborn belly fat: blood sugar.
Many women come to me with skin, cycle or weight concerns and have never heard that their blood sugar might be involved. They think of diabetes as a condition of later years. Yet insulin reaches deep into the hormone system long before that. I find it relieving to know this. Because blood sugar is one of the levers you can move in everyday life. Not as a miracle, but as a calm, steady influence on a connected system.
Perhaps you know this. Your skin acts up, even though your teenage years are long gone. Your cycle comes whenever it wants. There is a pad of fat at your belly that barely moves, no matter how disciplined you eat. And in the afternoon you fall into a hole that only something sweet pulls you out of. These things seem unrelated. But they can be connected, through an axis that should not be missing from any standard conversation about hormones: the link between blood sugar and sex hormones.
In this article we look at what insulin resistance really means in women, why insulin is itself a hormone and how it can influence androgens, SHBG and therefore skin and cycle. We understand the link to polycystic ovary syndrome, clarify what the HOMA index can tell you and I show you the lifestyle levers that are best studied. All of this as an honest framing, not as a promise.
Insulin is a hormone, not a supporting act
Picture insulin as a door opener. After eating, blood sugar rises, the pancreas releases insulin, and insulin opens the cell doors so the sugar can come in. So far the familiar picture. With insulin resistance the cells react more sluggishly. The doors stick. To open them anyway, the pancreas releases more insulin. Blood sugar stays normal for a while, but the insulin in the blood rises. This persistently raised amount of insulin is called hyperinsulinemia.
And this is exactly where it gets interesting for women. Insulin acts not only on muscle, fat and liver. It also speaks to the ovaries and the liver in a way that shifts the sex hormone balance. Insulin is therefore not a pure metabolic hormone that stays neatly in its lane. It reaches right into the hormone system.
In women, insulin resistance is rarely just a weight or diabetes matter. It is often a quiet driver behind acne, hair growth and cycle problems, and that long before blood sugar shows up in the lab. This is not bad news. It means there is an early point where you can move something.
The blood sugar-hormone axis at the cellular level
How exactly does raised insulin shift the hormone balance? Four mechanisms interlock. Each of these KPNI lenses explains one part at the cellular level. Together they form the blood sugar-hormone axis.
Insulin drives the androgens
Raised insulin can directly prompt the theca cells of the ovaries to produce more androgens. It acts like an amplifier that turns up the signal of luteinizing hormone. More androgens from the ovary mean more drive for acne, hair growth and disturbed egg maturation. In this way the metabolism can push the ovary in a direction that has nothing to do with a defect of the ovaries themselves.
Insulin lowers SHBG in the liver
Sex hormone-binding globulin is made in the liver and catches androgens in the blood. Insulin and sugar dampen its production, among other things through new fat formation in the liver cell. If SHBG drops, more free, active androgens circulate. A low SHBG is therefore a sensitive early marker that visibly connects metabolism and hormones.
Ovulation falls out of rhythm
High androgens and a shifted signal from the brain can disturb egg maturation. If ovulation does not happen, no corpus luteum forms, and the calming progesterone of the second cycle half is missing. In this way insulin resistance can contribute to irregular or absent cycles, which in turn intensify the hormonal imbalance.
Silent inflammation as amplifier
Belly-centered fat tissue is metabolically active and can release inflammatory messengers. This silent inflammation can further worsen insulin action and so set off a loop: more insulin resistance, more androgens, more inflammation. This is exactly why calming this loop often acts on several levels at once.
These four lenses are not a theoretical model. They explain why some women find their skin settles and their cycle returns once blood sugar becomes steadier. And now you know why a look at the sex hormones alone can fall short.
Hyperinsulinemia as an amplifier of androgen production
Review Goudas and Dumesic summarized the mechanisms of polycystic ovary syndrome in the Endocrinology and Metabolism Clinics of North America. Their central observation: hyperinsulinemia from insulin resistance is an important regulator of ovarian androgen overproduction. Raised insulin strengthens LH release, increases the activity of certain enzymes of androgen production and suppresses SHBG capacity in the liver. With this the authors describe early on exactly the axis that today is regarded as the core of the blood sugar-hormone connection.
Goudas VT, Dumesic DA. Endocrinol Metab Clin North Am. 1997;26(4):893-912. doi:10.1016/s0889-8529(05)70286-3 · PMID: 9429864
Insulin resistance and PCOS: why blood sugar has a say
Polycystic ovary syndrome, PCOS for short, is the most common hormonal and metabolic disorder in women of reproductive age. Depending on the definition it affects roughly eight to thirteen out of a hundred women. PCOS shows impressively that hormones and metabolism cannot be separated. Many women with PCOS have irregular cycles, signs of raised androgens such as acne or increased hair growth, and very often insulin resistance.
Insulin resistance at the center of PCOS development
Review Goodarzi and colleagues framed the development of PCOS in Nature Reviews Endocrinology. Their description: in the majority of those affected there is insulin resistance, and the compensatory hyperinsulinemia contributes to hyperandrogenism by prompting ovarian androgen release and inhibiting the formation of sex hormone-binding globulin in the liver. The authors also name dysfunction of fat tissue as a contributor to insulin resistance. This shows that blood sugar is not a side topic in PCOS.
Goodarzi MO, Dumesic DA, Chazenbalk G, Azziz R. Nat Rev Endocrinol. 2011;7(4):219-231. doi:10.1038/nrendo.2010.217 · PMID: 21263450
The honest framing matters. Not every woman with PCOS has insulin resistance, and not every woman with insulin resistance develops PCOS. It is not a switch, but an interplay. But in many of those affected blood sugar is a central contributor. This is exactly why the international PCOS recommendations place nutrition and exercise first, ahead of medication. And now you know why a purely hormonal view of PCOS often falls short.
"I only have insulin resistance if I am overweight." That is not quite true. Excess weight raises the risk, but lean women can also have insulin resistance, especially in the context of PCOS. Conversely, a normal fasting blood sugar does not automatically mean everything is fine, because insulin can be raised for a long time before sugar becomes abnormal. So it pays to look at more than just the scale and the sugar value.
Symptoms and testing: how to recognize the axis
Insulin resistance shows up in women on two levels, the metabolic and the hormonal. On the metabolic side you may notice stubborn belly fat, strong sugar cravings, tiredness after eating and the afternoon dip. On the hormonal side there can be acne on the chin and jaw, increased hair growth, thinning scalp hair and irregular cycles. Some women notice dark, velvety skin changes in skin folds, the acanthosis nigricans. None of these signs proves anything on its own. Together they are a good reason to look more closely.
What the HOMA index can and cannot do
The most common estimate is HOMA-IR. It is calculated from fasting blood sugar and fasting insulin, both taken in the morning while fasting. A higher value points to stronger insulin resistance. HOMA-IR is practical and widely used in research. But it has limits. It is an estimate, not an exact measurement, and there is no globally uniform cut-off. An oral glucose tolerance test, the HbA1c and SHBG can be used in addition. Which test makes sense depends on the question and belongs in medical hands.
Low SHBG as an early sign of insulin resistance
Review Qu and Donnelly described in the International Journal of Molecular Sciences that the liver-made SHBG correlates negatively with markers of insulin resistance and non-alcoholic fatty liver disease. If hepatic SHBG production drops, the availability of androgens rises, which may promote the development of the PCOS picture. The authors discuss a low SHBG as a possible early diagnostic biomarker. This makes SHBG a lab value that is often underestimated when working up the blood sugar-hormone axis.
Qu X, Donnelly R. Int J Mol Sci. 2020;21(21):8191. doi:10.3390/ijms21218191 · PMID: 33139661
Why insulin and sugar can lower SHBG at all has been described at the cellular level in a review by Pugeat and colleagues in Molecular and Cellular Endocrinology. According to it, simple sugars such as glucose and fructose throttle SHBG production by stimulating new fat formation in the liver cell and thereby down-regulating an important control factor of the SHBG gene (doi:10.1016/j.mce.2009.09.020, PMID: 19786070). This provides the biological explanation for why a low SHBG is such a sensitive marker for insulin resistance. And now you know why this single value can reveal more than expected in a hormone check.
Lifestyle levers: what the research best supports
Before turning the dial on individual hormones or medications, it pays to look at the basics. With insulin resistance they are especially well studied. These three levers are a start, not a treatment plan. You will find the individual path with medical guidance.
Steady your blood sugar across the day
A fiber-rich and vegetable-rich diet with fewer fast sugars keeps blood sugar steadier and eases insulin. It can help to combine carbohydrates with protein and healthy fat and to start with the vegetables. You do not have to eat perfectly. Even steadier rather than rollercoaster meals can do the whole system good and ease a low SHBG.
Move regularly, and feel free to make it more intense
Muscle work improves insulin action, because working muscles can take up sugar even without much insulin. Studies suggest that sufficiently intense exercise across the week can favorably influence insulin resistance. A mix of endurance and strength training makes sense, because muscle mass enlarges the metabolic buffer. What matters is regularity, not perfection.
Have the whole axis checked
If skin, cycle or weight stay stubbornly abnormal, the workup should look at cycle phase, androgens, fasting insulin, blood sugar, SHBG and the thyroid, not just one value. This way treatable causes can be found and it can be decided whether further steps beyond lifestyle make sense. A good workup takes your complaints seriously.
A lifestyle program improves metabolic health in PCOS
RCT Dietz de Loos and colleagues followed 183 women with PCOS and a BMI above 25 in the European Journal of Endocrinology. Over one year they compared a three-part lifestyle program of behavioral therapy, nutrition and exercise, partly with an additional reminder by text message, against usual care. Result: the lifestyle program improved metabolic health more clearly than the standard advice, and a clinically relevant weight loss had a favorable effect on all metabolic parameters. The authors recommend such a program in PCOS with excess weight.
Dietz de Loos A, Jiskoot G, Beerthuizen A, et al. Eur J Endocrinol. 2021;186(1):53-64. doi:10.1530/EJE-21-0669 · PMID: 34714771
DASH nutrition lowers HOMA-IR in PCOS
RCT Asemi and Esmaillzadeh tested a DASH diet against a control diet over eight weeks in 48 overweight women with PCOS, published in Hormone and Metabolic Research. The DASH group ate rich in vegetables, fruit, whole grains and low-fat dairy and low in saturated fats, refined grains and sweets. Result: in the DASH group fasting insulin, HOMA-IR and an inflammation marker dropped more clearly than in the control group, as did waist and hip circumference. This suggests that the composition of nutrition, not only the amount of calories, could act on insulin resistance.
Asemi Z, Esmaillzadeh A. Horm Metab Res. 2014;47(3):232-238. doi:10.1055/s-0034-1376990 · PMID: 24956415
The breadth of the evidence supports this direction. A Cochrane review by Lim and colleagues found that lifestyle measures can improve the free androgen index, weight and BMI in PCOS, but urged caution because of low study quality (doi:10.1002/14651858.CD007506.pub4, PMID: 30921477). A meta-analysis by Patten and colleagues on exercise suggested that more intense training in particular can lower HOMA-IR (doi:10.3389/fphys.2020.00606, PMID: 32733258). A small study by Li and colleagues on eight-hour time-restricted eating observed improvements in weight, free androgen index and HOMA-IR in anovulatory PCOS, as well as a more regular period in some of the women, but only in fifteen participants over a few weeks (doi:10.1186/s12967-021-02817-2, PMID: 33849562).
Additional approaches are also being studied. A prospective study by Pustotina and colleagues on inositol in PCOS observed a lower HOMA-IR, fewer free androgens and a higher SHBG after three months, but without a control group and in only 34 women (doi:10.1159/000536163, PMID: 38295772). On medication, a meta-analysis by Melin and colleagues for the international PCOS guidelines showed that metformin lowers insulin more than the pill, while the pill dampens androgens more (doi:10.1210/clinem/dgad465, PMID: 37554096). Such steps belong in medical hands. And now you know why lifestyle here is a foundation, not an accessory.
Blood sugar is a lever, not a fate
Insulin resistance is not a moral judgment on your discipline. It is a regulatory state that affects many women and that reaches early into the hormone system. That is precisely the good news. Because blood sugar is so closely tied to your hormones, steadier blood sugar can ease things in several places at once. Your body is allowed to find its rhythm again.
Frequently asked questions about insulin resistance and hormones in women
What is insulin resistance in women?
Insulin resistance means the body cells respond less well to the hormone insulin. Insulin is the key that moves sugar from the blood into the cells. If the cells react more sluggishly, the pancreas releases more insulin to achieve the same effect. This leads to hyperinsulinemia, meaning persistently raised insulin in the blood. In women this is not only a metabolic matter. Raised insulin reaches directly into the sex hormone balance, can prompt the ovaries to produce more androgens and can lower sex hormone-binding globulin in the liver. In this way blood sugar and hormones connect into an axis that may promote acne, cycle disorders and polycystic ovary syndrome.
Which symptoms can point to insulin resistance in women?
Typical clues can be: stubborn belly fat despite your efforts, strong sugar cravings, a slump in energy and tiredness after carbohydrate-rich meals, fluctuating focus and the well-known afternoon dip. On the hormonal side you may also notice: acne especially on the chin and jaw, increased hair growth on the face or body, thinning scalp hair, irregular or absent cycles and difficulty becoming pregnant. Some women notice velvety, dark skin changes in skin folds, known as acanthosis nigricans. These signs are nonspecific and prove nothing on their own. They are a reason to have the blood sugar-hormone axis checked medically, rather than to interpret them yourself.
How are insulin resistance and PCOS connected?
In polycystic ovary syndrome, raised insulin is considered one of the central drivers. Hyperinsulinemia can act in two ways. First, it prompts the ovaries and the control center in the brain to produce more androgens. Second, it lowers the liver's production of sex hormone-binding globulin, so that more free, biologically active androgens circulate. Together this intensifies acne, increased hair growth and cycle disorders that belong to the PCOS picture. Not every woman with PCOS has insulin resistance, and not every woman with insulin resistance develops PCOS. But in many of those affected, blood sugar is an important contributor. That is why nutrition and exercise rank highly in the international PCOS recommendations.
What is the HOMA index and how is insulin resistance measured?
The HOMA index, more precisely HOMA-IR, is a simple calculated value from fasting blood sugar and fasting insulin. It estimates how pronounced insulin resistance is. Both values are taken in the morning while fasting and entered into a formula. A higher value points to stronger insulin resistance. HOMA-IR is practical and widely used in research, but it has limits: it is an estimate, not an exact measurement, and there is no globally uniform cut-off. An oral glucose tolerance test, the HbA1c value and SHBG can be used in addition. Which test makes sense in an individual case, and how the value should be read, belongs in medical hands, because a single value without context says little.
Why do I get acne and more body hair from insulin resistance?
The path runs through the androgens, the male-acting hormones that also play a role in the female body. Raised insulin can prompt the ovaries to produce more androgens and at the same time lower sex hormone-binding globulin in the liver. This binding protein catches androgens in the blood. If it drops, more free androgens circulate that can act on the sebaceous glands and hair follicles. More free androgen may promote more sebum, clogged pores and acne on the chin and jaw, as well as increased hair growth on the face or body. This explains why stabilizing blood sugar can do more for some women with hormonal acne than skin care alone. The evidence here is promising, but very individual.
Can I influence insulin resistance through nutrition and exercise?
Yes, lifestyle is the best-studied lever. Studies suggest that a combination of nutrition, exercise and behavior change can improve insulin sensitivity and favorably influence metabolic values. A fiber-rich and vegetable-rich diet with fewer fast sugars, such as the DASH pattern, may lower HOMA-IR. Regular exercise, especially at sufficient intensity, can improve insulin action. Even a moderate weight reduction with excess weight can have a favorable effect on the whole metabolism. The honest framing matters: these measures are not a promise of cure, and not every woman responds the same way. But they are a sensible starting point, ideally with medical guidance rather than internet tips alone.
Is insulin resistance the same as diabetes?
No, but they are related. Insulin resistance is an early stage in which the cells respond less well to insulin, while blood sugar is often still kept normal because the pancreas compensates with more insulin. If this persists over years and insulin production becomes exhausted, it can develop into impaired glucose tolerance and later type 2 diabetes. For women the hormonal dimension is important: insulin resistance can cause complaints long before blood sugar becomes abnormal, for example through androgens, acne and cycle disorders. That is exactly why it pays to look early, rather than to react only once blood sugar derails.
What role does SHBG play in the blood sugar-hormone axis?
Sex hormone-binding globulin, SHBG for short, is a transport protein made in the liver that binds sex hormones in the blood and thus regulates how much of them is freely available. Research suggests that insulin and sugar dampen SHBG production in the liver, among other things through new fat formation in the liver cell. A low SHBG is therefore considered a sensitive biomarker for insulin resistance and the metabolic syndrome. For women this means: if SHBG drops, more free androgens circulate, which may promote acne, hair growth and cycle problems. SHBG is thus a link that visibly connects metabolism and the hormone system, and a lab value that often reveals more than expected during a workup.
When should I see a doctor about insulin resistance or a suspicion of it?
A medical workup makes sense when several signs come together: irregular or absent cycles, stubborn acne on the chin and jaw, increased hair growth, stubborn belly fat, strong sugar cravings or an unfulfilled wish for children. A family history of type 2 diabetes, a history of gestational diabetes or dark skin changes in skin folds are also reasons to look at the blood sugar-hormone axis. No online text replaces an examination. A good workup looks at the whole picture, meaning the cycle, androgens, fasting insulin, blood sugar, SHBG and the thyroid, rather than treating a single value in isolation. This way treatable causes can be found and an individual path can be planned.
All topics in the cluster "Hormone Guide"
This article is a spoke. It belongs to the bigger picture of hormonal imbalance. Here you can reach all topics in the cluster.
- Hormonal Imbalance in Women (overview/pillar)
- Estrogen dominance: recognizing symptoms and addressing them naturally
- Xenoestrogens: hormone disruptors in everyday life
- Coming off the pill: what happens in the body
- Progesterone deficiency: symptoms and testing
- PMS: symptoms and what helps
- PMDD: when PMS hits the mind
- Perimenopause: symptoms and when it begins
- Menopause: symptoms and what helps
- PCOS: causes and symptoms
- Hormonal acne from within
- Endometriosis: an integrative view
- Hormone-free contraception compared
- Loss of libido in women
- Testing hormones: which test, when
- Lowering estrogen naturally (the liver)
- Cycle-based nutrition
- The thyroid and female hormones
- Insulin resistance and hormones
- Cortisol, stress and female hormones
- Chasteberry and herbal hormone helpers
Connections to other topics
A sluggish thyroid can slow metabolism and intensify signs that look like pure insulin resistance.
Chronic stress keeps cortisol high, and cortisol can drive blood sugar. This is how the stress system and insulin resistance intertwine.
The gut flora influences inflammation and metabolism and can thereby act on insulin action and the hormone balance.
Time-restricted eating is discussed in insulin resistance, yet women respond differently. Why the cycle plays a role here.
Tiredness and exhaustion have many causes. An iron deficiency can intensify complaints that feel purely hormonal.
Insulin is only one contributor. How the ratio of estrogen and progesterone shapes the overall hormonal picture.
Sources and further reading
- Goudas VT, Dumesic DA. Polycystic ovary syndrome. Endocrinol Metab Clin North Am. 1997;26(4):893-912. doi:10.1016/s0889-8529(05)70286-3 · PMID: 9429864 [Review]
- Goodarzi MO, Dumesic DA, Chazenbalk G, Azziz R. Polycystic ovary syndrome: etiology, pathogenesis and diagnosis. Nat Rev Endocrinol. 2011;7(4):219-231. doi:10.1038/nrendo.2010.217 · PMID: 21263450 [Review]
- Pugeat M, Nader N, Hogeveen K, et al. Sex hormone-binding globulin gene expression in the liver: drugs and the metabolic syndrome. Mol Cell Endocrinol. 2009;316(1):53-59. doi:10.1016/j.mce.2009.09.020 · PMID: 19786070 [Review]
- Qu X, Donnelly R. Sex Hormone-Binding Globulin (SHBG) as an Early Biomarker and Therapeutic Target in Polycystic Ovary Syndrome. Int J Mol Sci. 2020;21(21):8191. doi:10.3390/ijms21218191 · PMID: 33139661 [Review]
- Melin J, Forslund M, Alesi S, et al. Metformin and Combined Oral Contraceptive Pills in the Management of Polycystic Ovary Syndrome: A Systematic Review and Meta-analysis. J Clin Endocrinol Metab. 2024;109(2):e817-e836. doi:10.1210/clinem/dgad465 · PMID: 37554096 [Meta-analysis]
- Dietz de Loos A, Jiskoot G, Beerthuizen A, et al. Metabolic health during a randomized controlled lifestyle intervention in women with PCOS. Eur J Endocrinol. 2021;186(1):53-64. doi:10.1530/EJE-21-0669 · PMID: 34714771 [RCT]
- Asemi Z, Esmaillzadeh A. DASH diet, insulin resistance, and serum hs-CRP in polycystic ovary syndrome: a randomized controlled clinical trial. Horm Metab Res. 2014;47(3):232-238. doi:10.1055/s-0034-1376990 · PMID: 24956415 [RCT]
- Lim SS, Hutchison SK, Van Ryswyk E, et al. Lifestyle changes in women with polycystic ovary syndrome. Cochrane Database Syst Rev. 2019;3(3):CD007506. doi:10.1002/14651858.CD007506.pub4 · PMID: 30921477 [Meta-analysis]
- Patten RK, Boyle RA, Moholdt T, et al. Exercise Interventions in Polycystic Ovary Syndrome: A Systematic Review and Meta-Analysis. Front Physiol. 2020;11:606. doi:10.3389/fphys.2020.00606 · PMID: 32733258 [Meta-analysis]
- Li C, Xing C, Zhang J, et al. Eight-hour time-restricted feeding improves endocrine and metabolic profiles in women with anovulatory polycystic ovary syndrome. J Transl Med. 2021;19(1):148. doi:10.1186/s12967-021-02817-2 · PMID: 33849562 [Clinical trial, n=15]
- Pustotina O, Myers SH, Unfer V, Rasulova I. The Effects of Myo-Inositol and D-Chiro-Inositol in a Ratio 40:1 on Hormonal and Metabolic Profile in Women with Polycystic Ovary Syndrome. Gynecol Obstet Invest. 2024;89(2):131-139. doi:10.1159/000536163 · PMID: 38295772 [Cohort, n=34]