Understanding Sex Hormone Binding Globulin

Understanding Hormones Series

Sex hormone binding globulin, commonly known as SHBG, is a protein that plays a crucial role in regulating hormone levels in the bloodstream. In this article, we will delve deep into understanding what SHBG is, its normal levels, and why it matters. We will also explore the factors that can influence SHBG levels and ways to increase or decrease them naturally.

What is SHBG?

SHBG is a protein produced mainly in the liver that binds to certain sex hormones, including testosterone, dihydrotestosterone (DHT), and estradiol (an estrogen). It carries these hormones throughout your bloodstream, regulating hormone levels in the body. Hormones in this bound state aren't available for your cells to use. Generally speaking, when your SHBG levels are low, your body has more unbound sex hormones available for use. When your SHBG levels are high, your body has fewer free sex hormones at its disposal.

Normal SHBG Levels

The normal SHBG range varies according to gender and age. In males, normal SHBG levels range from 13.3-89.5 nmol/L, while in non-pregnant females, the range is 18-144 nmol/L. It's important to note that reference range values may vary from lab to lab depending on where you have the test performed. 

Why SHBG Levels Matter

SHBG is an important marker in understanding hormone levels in the body. In men, SHBG levels play a critical role in regulating testosterone, which affects mood, energy, and sex drive. In women, SHBG levels can indicate potential symptoms of polycystic ovary syndrome (PCOS), which can lead to weight gain, increased body hair growth, and menstrual cycle problems. SHBG levels can also be associated with conditions affecting the liver, thyroid, or pituitary gland.

Factors Influencing SHBG Levels

SHBG levels can vary due to several factors, such as age, gender, pregnancy, weight, and other underlying health conditions. In men, SHBG levels typically increase with age as testosterone levels drop. Pregnancy usually raises SHBG levels, and they typically return to normal after childbirth. In women, conditions like PCOS can lead to a reduction in SHBG levels, resulting in increased levels of free testosterone in the blood. Other factors that can influence SHBG levels include liver cirrhosis, hyperthyroidism, hypothyroidism, and nephrotic syndrome.

How to Increase SHBG Levels

Treatment of low SHBG levels depends on the underlying cause. However, research has found that certain lifestyle changes may help increase SHBG levels naturally. Here are some ways to increase SHBG levels:

Regular Exercise

A randomized clinical trial of sedentary men aged 40 to 75 found that a year-long program of moderate aerobic exercise increased SHBG and DHT. The exercise program had no effect on other androgens in this group. Another study found that women who were postmenopausal, mostly overweight, and previously sedentary saw an increase in SHBG levels after a year-long exercise intervention.

Dietary Changes

Studies have found that increasing fiber intake and decreasing sugar intake can increase SHBG levels. A 2000 study involving men between the ages of 40 and 70 found that fiber intake increased SHBG levels, while protein intake lowered levels. A recent study of postmenopausal women looked at the links between diet and SHBG. The findings indicated that low glycemic load or glycemic index diets with low sugar and high fiber could be associated with higher SHBG concentrations.

Coffee Consumption

Research on women over age 60 indicates that having two or more cups of regular caffeinated coffee a day is associated with higher SHBG concentrations.

Certain Oral Contraceptives

A meta-analysis of women with PCOS found that SHBG levels increased after three months to one year of treatment with certain combined oral contraceptives.

Weight Loss

Research shows that when children who are obese lose weight, SHBG levels can rise significantly

SMBG and Supplements

Certain supplements claim to help lower SHBG levels to boost testosterone. While some may have merit, it's difficult to know for sure. Supplements aren't regulated by the Food and Drug Administration (FDA), so manufacturers are free to make claims that may not be true. We are currently working on a research series on so called testosterone booster supplements. Unfortunately very few actually contain clinically studied doses of there ingredients. So far from the 100 or so we've looked at around 7-10 seem to have some reasonable claims. One that we currently recommend is TestoFuel.

Some supplements contain ingredients that can cause unwanted side effects and interact with prescription medications or aggravate underlying health conditions. It's essential to consult with your doctor before adding any new supplements to your routine.

Wrap Up of Sex Hormone Binding Globulin

SHBG is a critical protein in regulating hormone levels in the body. Understanding SHBG levels can help diagnose underlying health conditions, such as PCOS, and may indicate potential symptoms of low testosterone in men. Natural ways to increase SHBG levels include regular exercise, dietary changes, coffee consumption, certain oral contraceptives, weight loss, and supplements. However, it's essential to consult with your doctor to determine the underlying cause of low SHBG levels and develop a treatment plan that works best for you.