"Free" versus "bioavailable" testosterone

[Charlie67]

Just thinking out loud...

Question:
How valuable is it knowing SHBG numbers mid-cycle? seems it would be more helpful to know between cycles, right?


Current Cycle:
wks 1-5 anadrol
wks 1-12 500 testE / wk
wks 1-12 aromasin ED
wks 1-12 HCG


Mid-cycle blood taken at week 6, 1 week since last anadrol, and one day after Test injection (so its likely inflated a bit, but...):

From Bloodwork:
Albumin 4.1 g/dL
SHBG 7 nmol/L
Testosterone: 3408 ng/dL (Mid-cycle)


As calculated at, issam(dot)ch
Free Test: 145 ng/dL
Bioavailable Test: 3244 ng/dL


As I understand it:

“A high SHBG level means that it is likely that less free testosterone is available to the tissues than is indicated by the total testosterone test. A low SHBG level means that more of the total testosterone is bioavailable and not bound to SHBG.” ... Given that I am in the middle of a cycle.... this should be obvious.

What are free testosterone and bioavailable testosterone?

"Testosterone is present in the blood as "free" testosterone (less than 4%) or bound testosterone (~98%). The latter may be loosely bound to albumin (about one-third), the main protein in the fluid portion of the blood, or bound to a specific binding protein called sex hormone binding globulin or SHBG (about two-thirds). The percentages in the three fractions varies greatly. The binding between testosterone and albumin is not very strong and is easily reversed, so the term bioavailable testosterone (BAT) refers to the sum of free testosterone plus albumin-bound testosterone. It is suggested that bioavailable testosterone represents the fraction of circulating testosterone that readily enters cells and better reflects the bioactivity of testosterone than does the simple measurement of serum total testosterone."

Question:
How valuable is it knowing SHBG numbers mid-cycle? seems it would be more helpful to know between cycles, right?


It seems obvious that during a cycle, assuming legitimate gear, your bioavailable test would be elevated. Paying for the extra SHBG would be unnecessary. BUT, very helpful in thinking about TRT or something between cycles. Thoughts?

Best,
C-

[kelkel]

Really not valuable at all when on. More test = more suppression of shbg. When you come off it will rise to whatever it's norm is. So, more valuable off than on.

[Charlie67]

Thanks Kel, always appreciate your fine advice.

[kelkel]

Twas a short answer but to the point. There's also really no issue with lower shbg either unless you have issues relating to metabolic syndrome.

[Charlie67]

I guess I didn't realize that more Test = suppressed SHBG. Rather than Test suppressing anything, I guess I was thinking about it more like having lower SHBG left more Test available for other endeavors, So low SHBG would actually be beneficial.

What is the best way (between cycles) to determine free test levels?

[kelkel]

It can be beneficial yes, barring any symptoms of metabolic syndrome. Google that instead of me regurgitating it.
Just simply blood work. Discounted labs has a post pct lab option that's cheap and I believe covers what you need if your state allows it.