Inositol is a carbocyclic sugar, which refers to a group of molecules (isomers) that are structurally similar to glucose. Inositol is involved in cellular signaling in response to a variety of hormones, neurotransmitters and growth factors and participates in the regulation of osmosis (flow of water molecules across a semipermeable membrane). Inositol is synthesized in the human body, but is also obtained in the diet from foods like citrus fruits, bran, beans, nuts, and seeds, but is also taken as a dietary supplement. The majority of inositol supplements contain the myo-inositol form, as it is the most plentiful type of inositol found in the brain, body, and other mammalian tissues.
Inositol can improve insulin sensitivity and glycemic control, and may help manage polycystic ovary syndrome (PCOS) and prevent gestational diabetes. The most commonly supplemented forms of inositol are myo-inositol and D-chiro-inositol, but all forms are interchangeably referred to as inositol.
Inositol can improve insulin sensitivity and glycemic control, and may help manage polycystic ovary syndrome (PCOS) and prevent gestational diabetes. The most commonly supplemented forms of inositol are myo-inositol and D-chiro-inositol, but all forms are interchangeably referred to as inositol.
Benefits
Researchers have found a relationship between the consumption of inositol and a positive clinical outcome with the following health conditions:
- Blood glucose regulation/Insulin sensitivity
- Gestational diabetes
- Polycystic Ovary Syndrome (PCOS)
- Hypertension
- Intraventricular hemorrhage
- Lung Cancer
- Metabolic Syndrome
- Obsessive-Compulsive Disorder
- Oligomenorrhea
- Respiratory Distress Syndrome: Newborn
- Retinopathy of Prematurity
- Diabetic Neuropathies
- Bronchopulmonary Dysplasia
- Liver Cancer
- Liver Cirrhosis
- Inflammatory bowel disease and irritable bowel syndrome
- Anxiety
- Depression
Supplementation
Because supplementation with inositol can increase insulin sensitivity and help improve fasting glucose and postprandial glycemic control, inositol might help prevent and/or treat diabetes. One type of diabetes for which the role of inositol has been widely studied is gestational diabetes, a condition characterized by abnormal glucose tolerance and high blood sugar during pregnancy. Meta-analyses show that supplementation with inositol during pregnancy might reduce the incidence of gestational diabetes and related birth complications. However, further high-quality randomized controlled trials are needed to determine whether inositol is efficacious in the treatment of gestational diabetes.
Inositol shows promise for the management of polycystic ovary syndrome (PCOS), a condition characterized by high androgen levels, infertility, and abnormalities in glucose metabolism in women. However, given the small number of studies, the small sample sizes of these studies, and the general low quality of the evidence, further research is needed before firm conclusions can be made.
Supplementation with inositol may also help support weight loss: some evidence shows it can reduce body mass index (BMI) in people with overweight or obesity. Supplementation with inositol may also reduce blood pressure, triglycerides, total cholesterol, and LDL cholesterol. However, the confounding effects of dietary intake and physical activity — factors that independently influence weight loss, blood lipids, and blood pressure — have not been clearly controlled in many studies. Consequently, there is a need for further randomized controlled trials examining the direct effect of inositol on these outcomes.
Inositol shows promise for the management of polycystic ovary syndrome (PCOS), a condition characterized by high androgen levels, infertility, and abnormalities in glucose metabolism in women. However, given the small number of studies, the small sample sizes of these studies, and the general low quality of the evidence, further research is needed before firm conclusions can be made.
Supplementation with inositol may also help support weight loss: some evidence shows it can reduce body mass index (BMI) in people with overweight or obesity. Supplementation with inositol may also reduce blood pressure, triglycerides, total cholesterol, and LDL cholesterol. However, the confounding effects of dietary intake and physical activity — factors that independently influence weight loss, blood lipids, and blood pressure — have not been clearly controlled in many studies. Consequently, there is a need for further randomized controlled trials examining the direct effect of inositol on these outcomes.
Fertility
Inositol has many uses, including but not limited to:
Myo-inositol is not just suggested for or prescribed for people that are wishing to get pregnant and for general health. But myo-inositol is often recommended for people that want to improve egg and sperm quality because of the way that it can positively impact insulin sensitivity. Insulin sensitivity might sound like a bad thing to people out there. But it turns out that you want to be insulin sensitive. The last thing you want is to be insulin insensitive.
Insulin insensitivity is associated with type 2 diabetes, with obesity, and even for people who are not challenged with obesity, you want your cells to be insulin sensitive. You don't want a lot of insulin floating around in your system with your cells unable to use that insulin. That's really what insulin insensitivity is about.
Myo-inositol, at dosages of 1 to 5 grams per day - keeping in mind that 1,000 milligrams is 1 gram - has been suggested to improve egg quality and sperm quality. Now, one point of note is that myo-inositol can reduce anxiety, and it can be a slight sedative, which is why some folks take almost a gram, 900 milligrams, prior to sleep. If you're going to take 5 grams of myo-inositol, you would want to restrict that to the late evening or second half of your day. And it is not suggested to start that high - start with 1 or 2 grams and then working your way up, seeing what you can tolerate in terms of the level of anti-anxiety and drowsiness that it produces.
1 to 5 grams per day of myo-inositol is what's suggested for both men and women wishing to improve egg health and sperm health. But for women, it's also often suggested to take myo-inositol and D-chiro inositol. D-chiro inositol has elements in it that can be both pro and anti-androgenic. Androgens are things like testosterone and related molecules. There are a number of different causes of infertility and disruption to egg quality, age being the most significant factor. But another significant and very common factor, even among young women who are of fertile age, is having too many androgens and as it relates to something called polycystic ovarian syndrome. 1-5 grams of inositol can balance androgens and offset some of the negative effects of polycystic ovarian syndrome or even for women who do not have polycystic ovarian syndrome because of the ways that D-chiro inositol can balance androgens in ways that are beneficial.
The dosages of D-chiro inositol that are recommended tend to be 1/25 to 1/40 of the myo-inositol dose. So you'll have to get out your calculator. Remember, 1,000 milligrams equals 1 gram. So figure out, if you're taking 1 gram of myo-inositol per day or 2 grams, you're going to want to convert that to milligrams. So let's say you're taking 2 grams of myo-inositol per day. That's 2,000 milligrams. Then you'd want to divide that by 25. And that's how many milligrams of D-chiro inositol you would want to take, as well. Or you could go with the lower end dose and divide it by 40 and take that number of milligrams of D-chiro inositol along with the inositol.
Again, probably taking it later in the day is going to be good. And it's not clear at all that taking it with food or without food makes any difference whatsoever. Keep in mind, these are recommendations. And of course, you should always discuss any supplements that you're planning to take or stop taking, for that matter, with your physician for your protection. Any time you're going to add or change something in your overall health regimen, you want to discuss that with your trusted health care professional.
- reducing anxiety or improving mood
- fertility
- treatment of depression
- sleep optimization
Myo-inositol is not just suggested for or prescribed for people that are wishing to get pregnant and for general health. But myo-inositol is often recommended for people that want to improve egg and sperm quality because of the way that it can positively impact insulin sensitivity. Insulin sensitivity might sound like a bad thing to people out there. But it turns out that you want to be insulin sensitive. The last thing you want is to be insulin insensitive.
Insulin insensitivity is associated with type 2 diabetes, with obesity, and even for people who are not challenged with obesity, you want your cells to be insulin sensitive. You don't want a lot of insulin floating around in your system with your cells unable to use that insulin. That's really what insulin insensitivity is about.
Myo-inositol, at dosages of 1 to 5 grams per day - keeping in mind that 1,000 milligrams is 1 gram - has been suggested to improve egg quality and sperm quality. Now, one point of note is that myo-inositol can reduce anxiety, and it can be a slight sedative, which is why some folks take almost a gram, 900 milligrams, prior to sleep. If you're going to take 5 grams of myo-inositol, you would want to restrict that to the late evening or second half of your day. And it is not suggested to start that high - start with 1 or 2 grams and then working your way up, seeing what you can tolerate in terms of the level of anti-anxiety and drowsiness that it produces.
1 to 5 grams per day of myo-inositol is what's suggested for both men and women wishing to improve egg health and sperm health. But for women, it's also often suggested to take myo-inositol and D-chiro inositol. D-chiro inositol has elements in it that can be both pro and anti-androgenic. Androgens are things like testosterone and related molecules. There are a number of different causes of infertility and disruption to egg quality, age being the most significant factor. But another significant and very common factor, even among young women who are of fertile age, is having too many androgens and as it relates to something called polycystic ovarian syndrome. 1-5 grams of inositol can balance androgens and offset some of the negative effects of polycystic ovarian syndrome or even for women who do not have polycystic ovarian syndrome because of the ways that D-chiro inositol can balance androgens in ways that are beneficial.
The dosages of D-chiro inositol that are recommended tend to be 1/25 to 1/40 of the myo-inositol dose. So you'll have to get out your calculator. Remember, 1,000 milligrams equals 1 gram. So figure out, if you're taking 1 gram of myo-inositol per day or 2 grams, you're going to want to convert that to milligrams. So let's say you're taking 2 grams of myo-inositol per day. That's 2,000 milligrams. Then you'd want to divide that by 25. And that's how many milligrams of D-chiro inositol you would want to take, as well. Or you could go with the lower end dose and divide it by 40 and take that number of milligrams of D-chiro inositol along with the inositol.
Again, probably taking it later in the day is going to be good. And it's not clear at all that taking it with food or without food makes any difference whatsoever. Keep in mind, these are recommendations. And of course, you should always discuss any supplements that you're planning to take or stop taking, for that matter, with your physician for your protection. Any time you're going to add or change something in your overall health regimen, you want to discuss that with your trusted health care professional.
References
Parthasarathy, L.K., Ratnam, L., Seelan, S., Tobias, C., Casanova, M.F., Parthasarathy, R.N. (2006). Mammalian Inositol 3-phosphate Synthase: Its Role in the Biosynthesis of Brain Inositol and its Clinical Use as a Psychoactive Agent. In: Majumder, A.L., Biswas, B.B. (eds) Biology of Inositols and Phosphoinositides. Subcellular Biochemistry, vol 39. Springer, Boston, MA . https://doi.org/10.1007/0-387-27600-9_12
Motuhifonua SK, Lin L, Alsweiler J, Crawford TJ, Crowther CA. Antenatal dietary supplementation with myo-inositol for preventing gestational diabetes.Cochrane Database Syst Rev.(2023-Feb-15)
Mashayekh-Amiri S, Mohammad-Alizadeh-Charandabi S, Abdolalipour S, Mirghafourvand M. Myo-inositol supplementation for prevention of gestational diabetes mellitus in overweight and obese pregnant women: a systematic review and meta-analysis.Diabetol Metab Syndr.(2022-Jul-06)
Wei J, Yan J, Yang H. Inositol Nutritional Supplementation for the Prevention of Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.Nutrients.(2022-Jul-09)
Unfer V, Facchinetti F, Orrù B, Giordani B, Nestler J. Myo-inositol effects in women with PCOS: a meta-analysis of randomized controlled trialsEndocr Connect.(2017 Nov)
Showell MG, Mackenzie-Proctor R, Jordan V, Hodgson R, Farquhar C. Inositol for subfertile women with polycystic ovary syndrome.Cochrane Database Syst Rev.(2018-12-20)
Greff D, Juhász AE, Váncsa S, Váradi A, Sipos Z, Szinte J, Park S, Hegyi P, Nyirády P, Ács N, Várbíró S, Horváth EM. Inositol is an effective and safe treatment in polycystic ovary syndrome: a systematic review and meta-analysis of randomized controlled trials.Reprod Biol Endocrinol.(2023-Jan-26)
Zarezadeh M, Dehghani A, Faghfouri AH, Radkhah N, Naemi Kermanshahi M, Hamedi Kalajahi F, Mohammadzadeh Honarvar N, Ghoreishi Z, Ostadrahimi A, Ebrahimi Mamaghani M. Inositol supplementation and body mass index: A systematic review and meta-analysis of randomized clinical trials.Obes Sci Pract.(2022-Jun)
Hashemi Tari S, Sohouli MH, Lari A, Fatahi S, Rahideh ST. The effect of inositol supplementation on blood pressure: A systematic review and meta-analysis of randomized-controlled trials.Clin Nutr ESPEN.(2021-Aug)
Tabrizi R, Ostadmohammadi V, Lankarani KB, Peymani P, Akbari M, Kolahdooz F, Asemi Z. The effects of inositol supplementation on lipid profiles among patients with metabolic diseases: a systematic review and meta-analysis of randomized controlled trials.Lipids Health Dis.(2018-May-24)
Motuhifonua SK, Lin L, Alsweiler J, Crawford TJ, Crowther CA. Antenatal dietary supplementation with myo-inositol for preventing gestational diabetes.Cochrane Database Syst Rev.(2023-Feb-15)
Mashayekh-Amiri S, Mohammad-Alizadeh-Charandabi S, Abdolalipour S, Mirghafourvand M. Myo-inositol supplementation for prevention of gestational diabetes mellitus in overweight and obese pregnant women: a systematic review and meta-analysis.Diabetol Metab Syndr.(2022-Jul-06)
Wei J, Yan J, Yang H. Inositol Nutritional Supplementation for the Prevention of Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.Nutrients.(2022-Jul-09)
Unfer V, Facchinetti F, Orrù B, Giordani B, Nestler J. Myo-inositol effects in women with PCOS: a meta-analysis of randomized controlled trialsEndocr Connect.(2017 Nov)
Showell MG, Mackenzie-Proctor R, Jordan V, Hodgson R, Farquhar C. Inositol for subfertile women with polycystic ovary syndrome.Cochrane Database Syst Rev.(2018-12-20)
Greff D, Juhász AE, Váncsa S, Váradi A, Sipos Z, Szinte J, Park S, Hegyi P, Nyirády P, Ács N, Várbíró S, Horváth EM. Inositol is an effective and safe treatment in polycystic ovary syndrome: a systematic review and meta-analysis of randomized controlled trials.Reprod Biol Endocrinol.(2023-Jan-26)
Zarezadeh M, Dehghani A, Faghfouri AH, Radkhah N, Naemi Kermanshahi M, Hamedi Kalajahi F, Mohammadzadeh Honarvar N, Ghoreishi Z, Ostadrahimi A, Ebrahimi Mamaghani M. Inositol supplementation and body mass index: A systematic review and meta-analysis of randomized clinical trials.Obes Sci Pract.(2022-Jun)
Hashemi Tari S, Sohouli MH, Lari A, Fatahi S, Rahideh ST. The effect of inositol supplementation on blood pressure: A systematic review and meta-analysis of randomized-controlled trials.Clin Nutr ESPEN.(2021-Aug)
Tabrizi R, Ostadmohammadi V, Lankarani KB, Peymani P, Akbari M, Kolahdooz F, Asemi Z. The effects of inositol supplementation on lipid profiles among patients with metabolic diseases: a systematic review and meta-analysis of randomized controlled trials.Lipids Health Dis.(2018-May-24)
