Body fat isn't distributed randomly. Where you carry it is a signal — about cortisol, insulin, estrogen, testosterone, growth hormone. The question is whether anyone measuring you knows how to read it.
TL;DR: The Poliquin BioSignature system maps 14 skinfold measurement sites to hormonal patterns established in endocrinology literature. It's not a diagnostic tool — it's a pattern-recognition layer. When the suprailiac skinfold is disproportionately thick, the clinical literature says to look at insulin. When the umbilical is the outlier, look at cortisol. The data informs where to intervene. That's the point.
Why Where You Store Fat Matters
Adipose tissue isn't passive storage. Different fat depots behave differently because they respond to different hormonal signals. Visceral fat (around the organs) is highly responsive to cortisol. Abdominal subcutaneous fat (around the belly button) is driven partly by cortisol and partly by insulin. Chest fat in males is associated with estrogen dominance. Lower-body fat in females tracks with estrogen and progesterone cycling.
These relationships are documented in endocrinology research — not invented by biosignature practitioners. What Charles Poliquin's BioSignature system did was organize them into a structured measurement protocol that a coach can run in a training environment with skinfold calipers.
The 14-site assessment takes approximately 20 minutes. The result is a body fat distribution map — and a set of hypotheses about which hormonal systems might be driving the pattern.
The 14 Sites and What They Signal
Biosignature measures skinfold thickness at 14 specific anatomical locations. The sites are standardized: same location, same angle, measured three times and averaged. The thickness at each site — and more importantly, the ratio between sites — forms the pattern.
Umbilical (belly button) — cortisol signal. Elevated umbilical skinfold relative to the rest of the body, particularly if the client has high training load, poor sleep, and a high-stress job, points toward chronic cortisol elevation as a driver. This site responds well to sleep quality intervention before nutrition adjustment.
Suprailiac (love handle, above the hip crest) — insulin sensitivity. Disproportionate fat at this site suggests glycemic dysregulation. Diet composition (refined carbohydrate load, meal timing, fasting patterns) is the primary lever. This is the site that often shifts fastest with a low-GI nutrition intervention.
Subscapular (under the shoulder blade) — also insulin-sensitive, often paired with suprailiac as an insulin panel. When both are elevated relative to other sites, the clinical picture points clearly toward blood sugar management.
Chest (males) — estrogen. In males, disproportionate chest fat alongside other anterior sites points toward elevated estrogen relative to testosterone. Interventions focus on reducing xenoestrogen exposure, optimizing sleep (testosterone is primarily synthesized during deep sleep), and dietary fat quality.
Knee and calf — growth hormone. These two sites, when they're the outliers, suggest growth hormone deficiency or chronic growth hormone suppression. Growth hormone is suppressed by elevated insulin, poor sleep, and high refined carbohydrate intake. The knee and calf sites are typically the last to move because growth hormone is the slowest variable to normalize.
Triceps and subscapular combined — overall body fat set point, with a secondary read on estrogen in females. Triceps is one of the most gender-variable sites — females typically carry significantly more here than males at the same total body fat percentage.
Chin, cheek, pectoral, axilla, quadricep, hamstring — these complete the map and provide comparison data for the ratios. The absolute thickness matters less than how each site compares to the others and to expected values for the client's age and sex.
What Biosignature Is and Isn't
It is a pattern-recognition tool. Poliquin developed it from clinical observation across thousands of clients combined with what the existing endocrinology literature said about hormonal fat distribution. The site-hormone connections are grounded in peer-reviewed research — the fat distribution patterns themselves aren't controversial. What biosignature did was translate them into a coaching protocol.
It is not a diagnostic medical test. A trained practitioner running a biosignature assessment cannot tell you your serum cortisol level, your insulin sensitivity index, or your testosterone-to-estrogen ratio. Those require blood work. What biosignature can do is flag which systems look like they might be worth investigating clinically — and give you a body fat distribution target to track as you intervene on nutrition, sleep, or stress.
And it is not standardized with the same rigour as InBody or DEXA. Skinfold measurement requires a trained assessor using consistent technique. Inter-rater reliability varies. Jay Arzadon is a Level 2 BioSignature practitioner — the measurements are performed to protocol — but you should understand the tool's limits before interpreting the results.
How Biosignature Combines With InBody 770
The two tools answer different questions. InBody 770 tells you total body composition and segmental lean mass distribution with high precision. Biosignature tells you where the fat is concentrated and suggests which hormonal systems to look at.
Used together: InBody gives you the tracking metric (body fat %, lean mass, visceral fat area), and biosignature gives you the pattern hypothesis (why the fat distribution looks the way it does, and where to intervene first).
For a client with elevated visceral fat on InBody and a disproportionate umbilical skinfold on biosignature — the picture is: cortisol load, likely driven by poor sleep and high-stress work. The intervention priority is sleep quality and recovery management before food volume. Without biosignature, the default intervention would be to cut calories. With biosignature, you know that cutting calories on top of elevated cortisol tends to make the hormonal situation worse before it gets better.
The Practical Protocol
A biosignature assessment at intake takes about 20 minutes alongside the InBody scan. We record all 14 sites, build the distribution map, and identify the two or three sites that are most disproportionate relative to total body fat.
Those outlier sites guide programme design: nutrition emphasis, sleep protocol priority, supplement strategy (where relevant), and training time-of-day recommendations. They also set expectations. A client with an elevated growth hormone panel (knee and calf disproportionate) should expect slower fat loss than average — not because the programme isn't working, but because the growth hormone axis takes longer to normalize.
We retest biosignature every 8 weeks alongside the InBody data. What we're looking for: are the outlier sites moving proportionally faster than the overall body fat reduction? That would confirm the hormonal hypothesis and the intervention is targeting the right system.
FAQ
What is BioSignature Modulation? BioSignature is a body fat analysis system developed by Charles Poliquin that maps 14 skinfold measurement sites to hormonal patterns in the endocrinology literature. Each site has documented associations with specific hormones — cortisol, insulin, estrogen, testosterone, growth hormone — and the site-ratio pattern guides nutritional and lifestyle intervention priorities.
Is biosignature scientifically validated? The fat distribution patterns biosignature is built on are documented in peer-reviewed endocrinology research. The assessment-to-intervention protocol hasn't been tested in randomised controlled trials as a system, so it should be understood as a structured clinical-observation tool, not a validated diagnostic method. The cortisol-umbilical and insulin-suprailiac connections are established physiology; the biosignature protocol organizes those findings into a coaching framework.
How does biosignature compare to a DEXA scan? They measure different things. DEXA gives you total body composition with high accuracy — body fat %, lean mass, bone density. Biosignature gives you body fat distribution and hormonal pattern hypotheses. Neither replaces the other. We use InBody 770 for composition tracking and biosignature for hormonal pattern identification.
How many sessions does it take to see biosignature site changes? It depends on which sites are the outliers and which hormonal systems are involved. Insulin-sensitive sites (suprailiac, subscapular) can respond in 6-8 weeks with a significant nutrition intervention. Cortisol-sensitive sites (umbilical) often shift meaningfully in 8-12 weeks if sleep and stress management improve. Growth hormone sites (knee, calf) typically take 3-6 months to shift.
Can I get a biosignature assessment without a full coaching programme? Yes. Biosignature is included in the Transformation Blueprint assessment ($167), which also includes InBody 770, metabolic rate profiling, and a custom blueprint. You'll leave with the distribution map, the pattern analysis, and specific interventions to prioritize.
