01
Cell Communication
Inositol derivatives participate in intracellular signaling pathways, helping cells respond to external signals.
Ingredient Deep Dive
Inositol
Deep Dive
A closer look at an important cellular messenger, the differences between myo-inositol and D-chiro-inositol, and why researchers continue to study its roles throughout the body.
Start Here
What Is Inositol?
Inositol is a naturally occurring, vitamin-like carbohydrate compound found in the body and in a variety of foods.
It is sometimes casually called vitamin B8, but inositol is not officially classified as a vitamin because the human body can produce it.
Inositol compounds participate in cell membranes and cellular signaling pathways, helping explain why they are studied across several areas of human physiology.
What It Is
Naturally occurring compound
Forms
Multiple stereoisomers
Key Role
Cellular signaling
Two Names You'll See Often
Myo-Inositol & D-Chiro-Inositol
Inositol exists in several forms. Two of the forms most often discussed in nutritional research are myo-inositol and D-chiro-inositol.
Myo-
Inositol
Inositol
Myo-Inositol
The most abundant inositol form in the human body and the form most commonly encountered in foods and supplements.
↔
D-Chiro-
Inositol
Inositol
D-Chiro-Inositol
Another naturally occurring form that participates in signaling pathways and has been studied both independently and alongside myo-inositol.
↔
The Cell Signaling Connection
Inositol-containing compounds are components of cell membranes and participate in signaling systems that allow cells to respond to messages.
These signaling pathways are involved in many biological processes, including pathways related to hormones, metabolism, and neurotransmission.
Research
What Do Researchers Study?
Inositol has been investigated in several areas, although evidence and clinical relevance differ depending on the population and outcome studied.
Insulin Signaling
Myo-inositol and D-chiro-inositol participate in signaling pathways related to insulin action and glucose metabolism.
Reproductive Health
A substantial portion of supplemental inositol research has examined reproductive and metabolic outcomes, including research involving women with PCOS.
Nervous System
Inositol signaling also has biological relevance within the nervous system, leading to research across several neurological and psychiatric areas.
Metabolic Research
Researchers continue to investigate relationships among inositol signaling, insulin sensitivity, metabolic health, and hormone-related physiology.
The Bigger Picture
Why Inositol Is Interesting
02
Metabolic Signaling
Some inositol-derived signaling molecules are involved in pathways associated with insulin signaling and glucose metabolism.
03
Reproductive Biology
Myo-inositol and D-chiro-inositol have attracted particular research interest in reproductive and metabolic physiology.
MYO
+
D-CHIRO
+
D-CHIRO
Understanding Combination Products
Why Are They Often Paired?
Some supplements combine myo-inositol and D-chiro-inositol rather than supplying only one form. The two compounds are biologically related, but they are not interchangeable in every pathway.
When comparing products, look beyond the front label and check the actual amount of each form supplied per serving.
On the Label
Common Supplement Forms
Powder
A common format, especially when products provide larger amounts per serving.
Capsules
Convenient and pre-measured, although serving sizes may require multiple capsules.
Combination Formulas
Products may combine myo-inositol and D-chiro-inositol in specified amounts or ratios.
Choosing a Product
What to Look For
- Clearly identified form or forms of inositol.
- Amount of each form listed per serving.
- A clearly disclosed ratio when myo-inositol and D-chiro-inositol are combined.
- Appropriate identity, purity, and contaminant testing.
- Clear serving-size instructions.
- Transparent ingredient and manufacturing information.
Good to Know
Understanding Inositol
Good to Know
"Vitamin B8" Isn't Quite Accurate
Inositol is sometimes marketed as vitamin B8, but it is not considered an essential vitamin because the body can synthesize it.
Good to Know
Your Body Already Contains It
Inositol occurs naturally in human tissues and is incorporated into biologically important membrane and signaling compounds.
Good to Know
Food Contains Inositol
Inositol and related compounds occur naturally in foods including fruits, grains, beans, and nuts.
Good to Know
Form Matters
"Inositol" is not a single-form story. Myo-inositol and D-chiro-inositol are distinct forms with related but different biological roles.
Important
Before Taking Inositol
Possible Side Effects
Inositol can cause gastrointestinal symptoms such as nausea, gas, abdominal discomfort, or diarrhea in some people.
Medical Considerations
If you have a medical condition or take medications, discuss supplementation with an appropriate healthcare professional.
Pregnancy & Fertility Care
Anyone using inositol as part of fertility, pregnancy, or medical care should discuss the product and serving amount with their healthcare professional.
Key Takeaway
The Inositol Story
Inositol is much more than a name on a supplement label. It is part of an intricate cellular signaling story. Myo-inositol and D-chiro-inositol are two important forms, and their roles in insulin signaling, metabolism, reproductive physiology, and cell communication continue to make them subjects of scientific research.
Continue Exploring
Discover more ingredients in our Deep Dive library