Inositol is a sugar found in food that comes in nine forms. The two most common of which are Myo-inositol and D-chiro-inositol. Inositol isoforms are useful for preventing and treating metabolic and reproductive disorders, like polycystic ovary syndrome (PCOS), gestational diabetes, and male fertility issues.^[1]Dinicola, S., Unfer, V., Facchinetti, F., Soulage, C.O., Greene, N.D., Bizzarri, M., Lagana, A.S., Chan, S.Y., Bevilacqua, A., Pkhaladze, L., Benvenga, S., Stringaro, A., Barbaro, D., Appetecchia, … Continue reading Inositol is used in many cosmetic products including those marketed toward hair growth.

In this article, we will explore the science behind inositol and whether supplementation with inositol might benefit those with hair loss.

Key Takeaways

• What is it?  Inositol is a sugar that comes in 9 isoforms, with the two most common being myo-inositol and D-chiro-inositol. Inositol can be found in fruits and beans as well as being synthesized within the body. Inositol contains properties that may be beneficial to human hair growth including: facilitating nutrient delivery and potentially reducing dihydrotestosterone (DHT) through reduced testosterone levels. Due to its hormone-balancing properties inositol is commonly used in the treatment of PCOS, and some studies have suggested that it may be beneficial for those with PCOS – induced hair loss or excessive unwanted facial hair growth (hirsutism). ^[2]Lumezi, B.G., Berisha, V.L., Pupovci, H.L., Goci, A., Hajrushi, A.B. (2018). Grading of hirsutism based on the Ferriman-Gallwey scoring system in Kosovar women. Postepy Dermatologii I Alergologiii. … Continue reading
• Evidence Quality: The evidence quality is 5/100 based on our metrics.
• Clinical Data: There is very little evidence to suggest that inositol by itself can improve hair loss outcomes. 
  • One study conducted with 46 women with PCOS who were given myo-inositol daily for 6 months, showed a significantly reduced hirsutism score, indicating that it may be able to treat excessive hair growth in women. Myo-inositol treatment also led to a decrease in testosterone and total androgen levels indicating a potential further effect on improving hair loss outcomes in those with androgenetic alopecia.^[3]Lumezi, B.G., Berisha, V.L., Pupovci, H.L., Goci, A., Hajrushi, A.B. (2018). Grading of hirsutism based on the Ferriman-Gallwey scoring system in Kosovar women. Postepy Dermatologii I Alergologiii. … Continue reading
  • Another study investigated the effects of two inositol treatments on improving hair loss outcomes in women over 6 months. Unfortunately, because only the conference proceedings were published we have limited data about this study. However, it was found that both treatments were able to reduce testosterone levels and induce a 20-70% reduction in hair loss. ^[4]Kandarakis, E.D., (2015). Novel strategies in the management of polycystic ovary syndrome. Endocrinology & Metabolic Syndrome. 4(4). Available at: https://dx.doi.org/10.4172/2161-1017.C1.012 … Continue reading

Inositols are sugars of which there are nine forms. Present in fruits and beans and synthesized within the body, inositols are incorporated into cells as precursors of inositol triphosphate (InsP3). InsP3 is a second messenger for many hormones including insulin. Defects in this pathway can lead to impaired insulin signaling, causing insulin resistance.^[5]Kalra, B., Kalra, S., Sharma, J.B. (2016). The inositols and polycystic ovary syndrome. Indian Journal of Endocrinological Metabolism. 20(5). 720-724. Available at: … Continue reading As insulin resistance is linked to hyperandrogenism (excessive androgen production) which is a key factor contributing to hirsutism (excessive facial hair in women) and alopecia. It is thought that inositol may relieve these symptoms, by enhancing insulin sensitivity.

But is there any evidence that inositols can have any effect on hair follicles?

Is There Evidence for an Effect of Inositol on Hair Follicles?

Unfortunately, there do not appear to be any studies directly examining the effect of inositol on hsair follicles. However, inositol does have some properties that might benefit hair growth, so let’s take a look at a couple of these.

Nutrient Delivery

The inositol phosphate system plays a key role in the efficient transportation of nutrients to cells. For example, inositol helps to facilitate cell-cell communication which is vital for nutrient uptake and utilization. Additionally, insulin enhances insulin sensitivity, particularly in individuals with insulin resistance or PCOS. As insulin plays a role in nutrient metabolism, inositol may help to optimize the utilization of glucose and other nutrients by cells. Furthermore, inositol has been shown to regulate the activity of specific nutrient transporters in cells. These transporters are proteins that facilitate the movement of nutrients across cell membranes. By influencing the expression and activity of these transporters, inositol can enhance the uptake of essential nutrients, such as amino acids, vitamins, and minerals.^[6]Tu-Sekine, B., Kim, S.F. (2022). The Inositol Phosphate System – A Coordinator of Metabolic Adaptability. International Journal of Molecular Science. 23(12). 6747. Available at: … Continue reading

May Reduce DHT Levels

Dihydrotestosterone (DHT) is made through the conversion of testosterone by the enzyme 5α-reductase.^[7]Kinter, K.J., Anekar, A.A. (2023). Biochemistry, Dihydrotestosterone. NIH. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. Available at: … Continue reading It has been suggested that inositol might reduce DHT levels because of its hormone-balancing properties. Particularly examined in the context of PCOS, it has been shown that inositol may reduce testosterone levels, leading to a subsequent decrease in dihydrotestosterone. Results from a double-blind study on the use of myo-inositol in 42 women aged 18-40 with PCOS showed that after 16 weeks, total testosterone decreased from 99.5 ng/dl to 34.8 ng/dl (normal range = 15 – 70 ng/dl).^[8]Constantino, D., Minozzi, G., Minozzi, F., Guaraldi, C. (2009). Metabolic and hormonal effect of myo-inositol in women with polycystic ovary syndrome: a double-blind trial. European Review for … Continue reading Unfortunately, there are no studies to tell us whether this reduction in testosterone will lead to improvements in hair loss outcomes in individuals with androgenetic alopecia.

So, while these properties might help hair follicle growth, is there any clinical evidence?

Clinical Data

There is unfortunately very little evidence supporting the use of inositol in the treatment of hair loss. However, there is a small amount of evidence to suggest that inositol might both reduce hirsutism and improve hair loss outcomes in those with PCOS.

Hirsutism

A prospective clinical study was conducted with 46 women (mean age of 24.2) with mild to moderate hirsutism.^[9]Minozzi, M., Andrea, G.D., Unfer, V. (2008). Treatment of hirsutism with myo-inositol: a prospective clinical study. Reproductive BioMedicine Online. 17(4). 579-582. Available at: … Continue reading Participants were treated with 2 g of myo-inositol twice daily in the form of sachets mixed with water for 6 months.

The researchers used a modification of the Ferriman-Gallwey score to evaluate the level of hirsutism by counting terminal hair numbers in nine areas of the body. The score ranged from zero (no excessive terminal hairs) to 4 (presence of terminal hairs). The score for each area on the body is then added together to make a total score.^[10]Lumezi, B.G., Berisha, V.L., Pupovci, H.L., Goci, A., Hajrushi, A.B. (2018). Grading of hirsutism based on the Ferriman-Gallwey scoring system in Kosovar women. Postepy Dermatologii I Alergologiii. … Continue reading The researchers also measured androgen, glucose, insulin, and cholesterol levels.

The average hirsutism score dropped from 13.1 – 10.8 (Figure 1) after 6 months of treatment with myo-inositol indicating that the treatment was reducing excess unwanted facial hair. The other factors measured also showed improvements with reductions in testosterone, total androgens, and total cholesterol, as well as normalized insulin concentrations in all participants that showed elevated levels in the initial measurements.

So to summarize, myo-inositol can reduce excessive hair regrowth, as well as reduce the concentration of testosterone and total androgens. This indicates a potential for myo-inositol to be able to improve hair loss outcomes in patients with androgenetic alopecia. But is there any evidence for this?

Alopecia

There were no articles published in peer-reviewed journals that used inositol alone, however, we did find a conference abstract examining the effects of inositol treatment on androgenetic alopecia. Unfortunately, the information is very limited. The study was completed on patients with androgenetic alopecia related to PCOS, who were treated with either: 550 mg of myo-inositol, 13.8 mg D-chiro-inositol, and 200 mg of folic acid in soft gel capsules or 2 g of myo-inositol plus 200 mg of folic acid in a soluble powder twice daily for 6 months.^[12]Kandarakis, E.D., (2015). Novel strategies in the management of polycystic ovary syndrome. Endocrinology & Metabolic Syndrome. 4(4). Available at: https://dx.doi.org/10.4172/2161-1017.C1.012 … Continue reading The researchers found that both treatments led to a reduction in PCOS symptoms and a 20-70% reduction in hair loss without side effects.

Unfortunately, because we do not have access to all of the data involved in this study it is not possible to determine the effects of each treatment or determine which treatment might have been more effective at treating PCOS-related hair loss.

Is Inositol Supplementation Safe?

According to the European Review for Medical and Pharmacological Sciences, doses of up to 12 g/day can be well-tolerated, with potential side effects including mild gastrointestinal side effects, like nausea, gas, and diarrhea.^[13]Carlomagno, G., Unfer, V. (2011). Inositol Safety: Clinical Evidences. European Review for Medical and Pharmacological Sciences. 15(8). 931-936. Available at: … Continue reading

Who might benefit from Inositol Supplementation?

The data is very limited for the use of inositol supplements to treat hair growth. However, from this limited data, it is possible that inositol may benefit people with PCOS who are experiencing either excessive facial hair growth or androgenetic alopecia. Regardless, we do not recommend using this ingredient by itself, as further research needs to be conducted.