SHBG: what it is, what it tells you and when it’s tested

SHBG is a protein made by your liver. The full name is sex hormone-binding globulin. It carries testosterone and oestrogens in your blood. While they are bound to it, these hormones do not act: so SHBG decides how much testosterone stays free to work.

When it’s tested

Almost always together with testosterone. In men with symptoms of low testosterone, it is used to work out free testosterone. In women with excess hair, acne or irregular periods, it shows how much androgen is really active.

On its own it says little. It is not a prevention test for people who feel well.

That is why Rosa does not test it. Instead it looks at what often shifts it: insulin and blood sugar, your thyroid through TSH, and your liver through ALT and AST.

What it tells you, and what it does not

If SHBG is high, it binds more testosterone and leaves less free. A normal total testosterone can then hide too little active testosterone.

If it is low, the opposite happens: there is more free testosterone, even with a low total. A low SHBG is common with excess weight, insulin resistance and diabetes.

On its own it does not make a diagnosis. Your doctor uses it to read testosterone correctly.

That is why it is read together with other tests:

Normal SHBG levels

The lab decides what is normal. It differs a lot between men and women: it is higher in women. In men it rises with age.

So there is no single number for everyone. The range on your own report counts, read together with testosterone.

If your SHBG is high or low

SHBG and blood sugar

A low SHBG is linked to a higher risk of type 2 diabetes, in women and in men. It is often a sign of insulin resistance.

SHBG itself is not what gets treated. What lowers it is: excess weight, too little movement, high blood sugar. When they improve, it usually comes back up too.

What can change the result

A few things shift it without any disease. It helps to tell your doctor.

When to worry

SHBG on its own is rarely a worry. Talk to your doctor if:

Frequently asked questions

What does a high SHBG mean? It binds more testosterone and leaves less free. The most common causes are age, the pill, an overactive thyroid and some liver diseases.

What does a low SHBG mean? There is more free testosterone. It often goes with excess weight, insulin resistance or diabetes, and in women with polycystic ovary syndrome.

Does the pill raise SHBG? Yes. The oestrogens in the pill push it up, so free testosterone falls. Do not stop the pill on your own: talk to your gynaecologist.

How do you lower or raise SHBG? It is not treated on its own: the cause is. If it is low because of extra weight or high blood sugar, losing weight and moving more usually bring it back up.

Does Rosa test SHBG? No. Rosa measures insulin, blood sugar, TSH and liver enzymes, which say a lot about what shifts it. If your doctor wants SHBG, they order it separately, usually with testosterone.

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