Testosterone Test

What this test actually measures

Most of the testosterone circulating in your blood is not available to do anything.

It is bound, mostly to a carrier protein called sex hormone binding globulin, and some more loosely to albumin. Bound tightly to SHBG means it cannot enter a cell and act.

So there are three numbers worth knowing. Total testosterone is everything in circulation. Free testosterone is the small unbound fraction that can act directly. Bioavailable is the free fraction plus the loosely albumin-bound portion, which is also reasonably accessible.

That matters because anything shifting your SHBG level changes your total without changing what your body can use. Thyroid disease shifts it. Insulin resistance lowers it. Ageing raises it. Oral oestrogen raises it substantially, which is why hormonal contraceptives lower free testosterone even when the total looks unremarkable.

This test uses mass spectrometry, which is more accurate than the immunoassay methods, and that difference matters most at the lower concentrations relevant to women.

Why the timing and the fractions both matter

Testosterone follows a strong daily rhythm, peaking in the early morning and falling through the day. That is not a small effect, and it is why the convention is a morning draw, generally before about 10am.

Turn up in the afternoon and you may measure your schedule rather than your physiology. If you are comparing to a previous result, drawing at a similar time each occasion removes a variable that otherwise looks like a change.

Now the fractions. If total testosterone comes back in the lower half of the range, the immediate question is what your SHBG is doing, because a raised SHBG will produce exactly that with normal underlying production. That is why this panel measures the fractions rather than only the total, and why SHBG is worth having alongside.

There is a second question worth asking before you interpret any result, and it will save some people a wasted test.

Sleep. A 2021 randomised double-blind crossover study in the Journal of Clinical Endocrinology and Metabolism opened by stating the established position plainly: sleep loss in men increases cortisol and decreases testosterone. That study went on to clamp both hormones during four nights of four-hour sleep and found doing so cut the resulting insulin resistance roughly in half.

The practical consequence is that testing testosterone during a stretch of poor sleep risks measuring your sleep debt. Where you can, sort the sleep for a few weeks first, then draw.

Finally, and I want to be plain about it: the relationship between testosterone level and symptoms is looser than the advertising around this hormone implies. Plenty of men in the lower part of the range have normal libido and energy, and plenty in the middle do not. Levels are read alongside symptoms by a good clinician, not instead of them.

Test details

What is measured: total, free and bioavailable testosterone by mass spectrometry.

Sample: blood draw.

Provider: Quest Diagnostics, ordered through Jess's practitioner dispensary.

Fasting: not generally required, though a morning draw is, since testosterone peaks in the early hours and falls through the day.

Turnaround: results typically within a few business days of the sample reaching the lab.

Order this test.

How the pricing works

I want to be straightforward about this, because lab pricing in the wellness industry frequently is not.

Jess takes no markup on the test itself. The lab cost is passed through exactly as it comes. What you pay is the test cost, the dispensary's service fee, the authorization fee, the collection fee where one applies, a flat handling fee for placing and managing the order, and the card processing cost. The handling fee is the part that is Jess's, and it is flat regardless of how expensive the test is.

That structure is deliberate. A percentage markup on labs creates an incentive to recommend expensive tests, and this way there is not one.

Because every blood test in one order shares a single draw fee, adding a second or third test to the same order costs considerably less than ordering them separately. The full lab menu shows what shares a draw with this one, and the order page itemises every fee before you pay.

Who this test is worth running for

Men with low libido, persistent fatigue, loss of morning erections, reduced muscle mass or strength despite training, low mood, or difficulty concentrating.

Women too, and this is the more neglected case. Testosterone matters for libido, energy and muscle in women and is measured far less often, so someone can go through an entire workup without anyone checking the hormone most directly tied to what they came in about. It is also part of assessing polycystic ovary syndrome, where it runs high rather than low, alongside DHEA sulfate and SHBG.

Worth pairing with a thyroid panel and ferritin, since thyroid disease shifts SHBG and low iron produces overlapping symptoms. All three share one draw.

Ordering restrictions

The lab network cannot issue orders to residents of New York, New Jersey, Rhode Island, or Hawaii. New York, New Jersey, and Rhode Island prohibit direct-to-consumer lab testing outright, requiring a treating provider's signature on every requisition. Hawaii is excluded by the network. This is tied to where you live, not where the sample is collected, so it applies to kits as well as draws.

If you live in one of those four states, your doctor can order the same test.

What to do with the result

If the total is low but free is normal, look at SHBG before concluding anything, since the fractions are what your tissues actually experience.

If it is genuinely low in a man, that belongs with a physician rather than a clinic that advertises. Testosterone therapy is a real medical decision with real trade-offs including fertility, and it needs the cause investigated rather than only the number corrected.

If it is high in a woman, particularly with irregular cycles, unwanted hair growth or acne, that is worth taking seriously as a possible polycystic ovary syndrome picture, which is common and treatable.

Check your sleep before drawing conclusions. If you have been sleeping badly, retest after a few weeks of proper sleep before deciding what the number means.

Read the result alongside symptoms and the rest of the panel. A number in isolation, in either direction, is not a plan.