Free vs Total Testosterone: What Your Blood Test Won’t Show

 

A lot of men come to TESTO after the same experience. They’ve been to the GP, had a blood test, been told their testosterone is ‘in the normal range’, and walked out more confused than when they went in. They still feel flat. Still slow to recover. Still not quite themselves. And now they’ve been told there’s nothing wrong.

There often is something worth looking at. It’s just not always visible in a standard panel.

The number most GPs report is total testosterone. But total testosterone is the sum of bound and unbound hormone. It’s the bound portion, the testosterone that’s been locked up by a protein called sex hormone-binding globulin (SHBG), that doesn’t do the work. It’s the free, unbound fraction that actually reaches your muscle, brain, and reproductive tissue.

And SHBG tends to rise as men age. That means even as your total number holds steady, the usable portion can quietly shrink. Which is exactly why you can look fine on paper and still feel off.

Total vs Free: Why the Distinction Matters

Imagine you've got $1,000 in your account but $900 is locked in a term deposit you can't touch. You're technically a thousand-dollar man. But you've only got $100 to spend.

SHBG works similarly. It binds to testosterone during transport in the bloodstream, which is useful, but it also means that bound testosterone can’t interact with cell receptors. Only the free fraction can. And the free fraction is what influences energy, mood, recovery, drive, and physical vitality.

 

 

The distinction between total and free testosterone is getting more attention in men’s health research. It helps explain a pattern that GPs increasingly hear: men whose labs are technically normal, but who don’t feel like themselves.

 

What This Looks Like in Practice

 

SHBG doesn’t just rise with age. It also increases with certain lifestyle factors including high-fibre diets, excess alcohol, low protein intake, and elevated cortisol from chronic stress. Any of these can push SHBG higher, which in turn reduces the proportion of testosterone that’s actually available to your body.

The result can feel a lot like what people loosely call ‘low testosterone’, even when the lab numbers say otherwise:

 

•        Persistent fatigue that doesn’t resolve with sleep

•        Slower recovery after training

•        Reduced motivation and drive

•        Mood that’s harder to regulate

•        Reduced confidence and physical vitality

 

If you’ve described any of these to a GP and been told your testosterone is fine, it may be worth asking specifically about free testosterone, or SHBG levels. Not every standard panel includes it.

 

What TESTO Was Built Around

 

TESTO was formulated with this in mind. Rather than trying to push total testosterone higher, the focus was on supporting the balance between bound and free, and creating the right environment for the testosterone you already have to be as usable as possible.

Jenni Lane, who leads product development at TESTO, describes the approach directly:

 

 

The formula contains 7 ingredients selected for their specific roles in this process:

 

Fenugreek extract (saponins)

 

Fenugreek extract has been studied for its potential to support a more favourable hormonal balance by influencing SHBG binding activity. A 12-week double-blind randomised placebo-controlled trial involving 120 healthy men aged 43 to 70 found that 600mg of standardised fenugreek extract daily improved symptoms of androgen decline, sexual function, energy, and self-reported wellbeing. TESTO uses 600mg of fenugreek seed extract, standardised to 50% saponins, the same dose and specification used in that trial.

 

View the published trial (PubMed) [LINK: https://pubmed.ncbi.nlm.nih.gov/26791805/]

 

Zinc (as zinc glycinate)

 

An essential mineral involved in normal immune function and overall wellbeing. Zinc deficiency is one of the more common nutritional gaps in NZ men. TESTO includes zinc at 15mg as zinc glycinate, a chelated form with significantly better absorption. 15mg is the maximum daily dose permitted under NZ natural health product regulations.

 

Vitamin D3

 

Supports hormonal regulation, mood, and general wellbeing. Most NZ men have adequate vitamin D through the summer months, but levels often dip in winter when sun exposure is lower. Vitamin D3 in supplement form supports levels all year round. TESTO uses D3 (cholecalciferol), the form identical to what your body makes from sunlight, at 1,000 IU daily, the NZ permitted maximum.

 

Korean Ginseng (ginsenosides)

 

An adaptogen traditionally used to support stamina, resilience, and the body’s response to stress. Elevated cortisol from chronic stress directly suppresses free testosterone, so supporting a healthier stress response has a meaningful secondary effect on hormonal balance. Korean Ginseng also supports healthy nitric oxide levels and blood flow. TESTO uses a 15:1 extract standardised to 20% ginsenosides.

 

Selenium (as selenomethionine)

 

A key mineral in the glutathione antioxidant defences in the body. The Leydig cells in the testes are high-energy cells and at risk of oxidative damage. Population studies show a link between low selenium levels and reduced vitality markers in men. Selenium also supports normal thyroid function, which has an indirect but meaningful effect on overall hormonal balance. TESTO uses selenomethionine, the organic form found naturally in food, at the NZ-regulated maximum dose.

 

Horny Goat Weed / Epimedium (icariin extract)

 

Traditionally used in herbal medicine to support healthy blood flow and physical vitality. Icariin, the active compound in Horny Goat Weed, is one of the more well-documented herbal extracts in men’s health research. TESTO uses a 50:1 extract standardised to 10% icariin.

 

Black Pepper (piperine)

 

Included specifically to improve absorption. Piperine supports the bioavailability of the other 6 ingredients, meaning more of each active compound reaches your system rather than passing through unused. It’s a small but important part of why the formula works as a system rather than just a collection of individual ingredients.

 

A note on doses

 

Vitamins and minerals in NZ natural health products are subject to regulated daily maximums. Zinc is capped at 15mg, Vitamin D3 at 1,000 IU, and selenium at its permitted level. TESTO includes all three at their NZ-regulated maximums, in the most bioavailable forms available. The herbal ingredients, fenugreek, ginseng, and horny goat weed, are not subject to the same caps and are included at doses that reflect the evidence behind them.

 

All batches are manufactured in a GMP and MPI-compliant facility in New Zealand. The label reflects what’s in the capsule.

 

Four Things Worth Doing Before (or Alongside) Any Supplement

 

TESTO works best as part of a reasonably healthy daily routine, not as a substitute for one. If you’re taking it seriously, these four foundations make a real difference to how quickly and clearly you’ll feel results:

 

•        Prioritise sleep. Most testosterone production happens during deep sleep, specifically slow-wave sleep in the first half of the night. Even one extra hour of quality sleep per night has a measurable effect on hormonal health.

•        Train and eat protein. Resistance training is one of the most effective natural drivers of testosterone activity. Pair it with adequate protein and you give your body the raw material to respond.

•        Watch the alcohol. Alcohol raises SHBG and lowers free testosterone directly. You don’t have to quit but keeping it in check makes a difference.

•        Manage stress. High cortisol is not your friend. Chronic stress directly suppresses free testosterone. Meditation, quality time out, and genuine recovery all help.

 

Supplements aren’t a substitute for looking after your body. TESTO is designed for men who are already doing the basics, and want a natural, well-formulated addition to their daily routine.

 

Common Questions

 

Will TESTO raise my total testosterone?

TESTO isn’t designed to push total testosterone beyond your normal range. It’s built to support a more favourable free-to-bound balance, with the emphasis on the usable, active portion. If your total is already in range, that’s often where the real work is anyway.

 

How soon might I notice a difference?

Some men notice changes in the first week, particularly in energy and drive. The fuller picture, recovery, body composition, confidence, typically shows at 60 days and beyond. Consistency is what gets you there.