
Tests
Which tests offer strong actionable insights? What do practitioners use? Why use tests at all?

Value of Functional Testing within Health Optimisation
For myself, before beginning practice as a nutritional therapist, I simply always wanted more data, more potential insights. Any test which gave me new information appealed. I was a dedicated n=1 quantified self enthusiast.
Now, for my clients, I am far more selective. If a client is not cost constrained I will happily recommend a basket of potentially useful tests, For most others when I recommend a test I do so with explicit rationale for what actionable insights it can bring us & what the alternative is, enabling the client to make a truly informed choice.
I also consider the potential downside effects of tests. The experience of extracting the various bodily excretions can be unpleasant. For some, having knowledge of unfavourable metrics is anxiety inducing rather than empowering, even with an expert practitioner ready to support them.
Generically, purposeful functional testing offers the following benefits
1, Establish *your* personal norms
Comparison against statistical norms can be useful, sometimes, but can also be misleading if and when *your* natural norms are naturally lower or higher than others with no negative impact.
Sometimes the statistical norms are just not helpful. If the population you are being plotted against has a high incidence of metabolic dysfunction, being average is not a great sign.
Building up your own history with regular testing enables you to be informed of change over time and connect this with your health and vitality and context at the time, giving the result meaning. For example, if you see a low or high anomaly in contrast to your personal history, it suggests there has been a significant change, prompting further investigation and action.
2. Highlight root causes and opportunities
Functional testing can reveal or suggest the root causes of problems and in doing so, inform focused action.
Some tests, such as Hormone panels, Organic Acid Tests and 24-Hour Cortisol Tests, deliver information which cannot be intuited or inferred from subjective experience and experimentation, thus adding a lot of value within a health optimisation plan.
3. Create baselines for test-retest comparison
To complement your own sense of wellbeing you may find it very powerful to be able to quantify the impact of changes you make to your diet, lifestyle and supplements. This is exactly what a test-retest approach can do.
4. Provide validation and motivation
Seeing positive changes within test results can offer objective validation that interventions are working.
Receiving this clear signal can reinforce commitment and help you stay consistent with the choices that progress you towards your health goals.
5. Novel Personalised Insights
Using the examples of Continuous Glucose-Monitoring (CGM) and Heart Rate Variability (HRV) some tests can make available real-time biofeedback on metrics which could otherwise be entirely unknowable to you. These novel insights can enable you to grow your awareness of problems and opportunities and even support your natural sense of interoception.
6. Trade off between cost and speed
If a food intolerance or sensitivity is suspected then an elimination and managed reintroduction diet is a fantastic tool to identify the problems and has no direct cost. It does however take weeks of thorough planning and effort to provide clarity and certainty.
Using something like an IgG food sensitivity test cannot give you certainty but can highlight potentially problematic foods, enabling a simpler and shorter elimination and reintroduction approach.
Link goes to a full size image, on Instagram, where you are welcome to connect and ask me anything.

Optimising Natural Testosterone: Key Functional Tests
Why test at all? I have a separate post dedicated to that, and in brief, the value includes establishing your own personalised norms, highlighting potential root causes, creating baselines for test-change-retest protocols, validating intervention outcomes, and offering novel personalised insights.
These are the tests and biomarkers I would often consider for a client seeking to improve their natural testosterone:
1. Total and Free Testosterone
The ‘free’ testosterone is critical, since only this is actually available for active use, and knowing both provides two signals. One on testosterone production, and the other on testosterone availability.
2. Sex Hormone-Binding Globulin
If total testosterone is okay but free testosterone is low, this is often a root cause. SHBG binds to testosterone, making it unavailable for active use. If this is true, interventions to reduce SHBG may be high value.
3. Luteinizing Hormone (LH) & Follicle-Stimulating Hormone (FSH)
These hormones regulate testosterone production within the male testes, so if their levels are exceptionally lower or higher in the presence of low testosterone they are suggestive of a root cause, and a target for intervention.
4. Estrogen
Males and females both produce and need estrogen(s) and testosterone, whilst the levels of course are very different. Testosterone may be converted to estrogen via aromatisation, and if the fraction being converted is excessive it can result in too little of the former and too much of the latter.
5. DHEA-Sulfate
DHEA-S is a precursor building block for both testosterone and estrogen. Just as with testosterone, normal levels decline with age and low levels can indicate issues, and opportunities, with diet, lifestyle and body composition.
6. 24-Hour Cortisol
Used to inform whether the daily oscillating pattern of cortisol has peaks and troughs at the appropriate times, and whether its activity may be suppressing testosterone production
7. Vitamin D3, Magnesium & Zinc
By no means the only essential micronutrients, but those for which insufficiency may be common, and with strong links to testosterone production.
8. Omega-3 Index
Omega-3 fatty acids are essential (hence essential fatty acids) for cellular activity including hormone production. If this is below optimal, it is very easily addressed via diet and supplementation.
9. Inflammatory Markers
Chronic inflammation, regardless of source, can impair endocrine organ function, including and not limited to testosterone production. If present, identifying and addressing the root cause is a high priority.
10. HbA1C Blood Glucose
Poor blood glucose regulation, leading toward prediabetes and diabetes, can impair testosterone production, with the good news being that insulin sensitivity is highly manageable, for most people, via diet and lifestyle practices.
Link goes to a full size image, on Instagram, where you are welcome to ask me anything
Work in progress!
Working on it, coming soon :-)