Frequently Asked Questions

90gut features an adaptive engine. It analyzes your answers in real-time, and once a clear tendency is detected on an axis, remaining questions for that axis are skipped.

Conversely, additional verification questions may be inserted for axes with uncertain answers. In other words, changing question counts is "proof that we're taking your answers seriously."

Yes. Questions are shuffled using an interleave method. Questions from the same axis are never consecutive, reducing response bias and yielding more accurate results.

The reliability shown after diagnosis is the result of cross-validation. It checks consistency between related axes (e.g., brain-spine, gut-heart). If contradictions are few, it shows "High"; if many, "Low".

If "Low," retaking the quiz in a relaxed state may improve it.

About 3 minutes. It can be even shorter if the adaptive engine skips questions. Easy to get started.

90gut is based on 6 physiological axes. Each axis estimates body-based tendencies supported by neuroscience and physiology research.

This is not a genetic test. It's an approach that estimates physiological tendencies from behavioral patterns. Our philosophy is "Estimate, test, learn."

Genetic tests directly analyze DNA (cost: tens of thousands of yen, weeks for results). 90gut estimates constitutional tendencies from self-reported behavioral patterns.

Like noticing wheat sensitivity from "I feel bad when I eat it" without a formal test. Quick, immediate, and free to start.

Each of the 6 axes is classified as High/Low, and from the combination patterns, 8 base characters × 2 variations (A/B) = 16 archetypes are determined.

The A/B difference represents how secondary axis strengths create different behavioral traits within the same base character.

Body and mind are deeply connected. For example, gut bacteria produce about 90% of serotonin (the happiness hormone), and gut health is known to affect mental well-being.

The autonomic nervous system directly influences stress tolerance and emotional stability.

90gut focuses on this relationship between physical constitution and personality, estimating "what tendencies your body has" through 6 physiological axes. Understanding your constitution means understanding the roots of your personality.

The gut and brain are connected through the vagus nerve, constantly exchanging information. This is called the gut-brain axis.

Research shows that changes in gut environment can affect brain function, altering mood, focus, and stress responses.

The "Digestion (Gut-Flora)" axis in 90gut focuses on this gut-brain connection. People who notice their mood shifting with digestive changes may see distinctive patterns in this axis score.

MBTI and 16Personalities classify personality types based on psychological self-reports ("Are you a planner?" etc.). 90gut, on the other hand, is based on physiological constitution.

It explores "why you have that personality" from the body's mechanisms, offering insights from a different angle than psychological tests.

If MBTI is a "map of the mind," 90gut is a "blueprint of the body." It's not about which is correct — combining both gives you deeper self-understanding.

People with a high "Empathy (Ion-Gate)" axis score tend to be sensitive to surrounding emotions and atmospheres.

While they naturally pick up on others' feelings, they may also tire easily in crowds or when exposed to intense emotions. This overlaps with HSP (Highly Sensitive Person) traits. High empathy isn't a weakness — properly understood, it becomes a significant strength.

Knowing your empathy profile helps you choose the right environments and self-care strategies.

This refers to a high score on the "Sensitivity (Qualia-Depth)" axis. It means you tend to process sensory information deeply — sounds, light, temperature changes, subtle facial expressions.

If you're easily moved by art or music, cry at movies, or feel captivated by beautiful scenery, you may have high sensitivity.

High sensitivity is also the source of creativity and empathic ability. Understanding and leveraging your sensory richness is key.

Here is what each plan includes.

See report details →

5 detailed sections + column articles generated based on your 6-axis balance.

Career — Specific suggestions for jobs, environments, and team roles suited to your constitution.

Growth Path — 3-stage roadmap: current you → next stage → aspired state.

Health Wisdom — Nutrition, exercise, gut health. A wellness plan tailored to your constitution.

Compatibility Trends — Compatibility scores with all 16 archetypes and best match analysis.

Relationships — Romance, friends, family. Deep-dive advice for each relationship type.

In-depth Column — A 2,000+ word expert article explaining the scientific mechanisms of your type.

Credit card via Stripe Checkout. Payment is securely processed on Stripe's encrypted page, and no card information is stored on our servers.

Results are saved only in your browser (localStorage). If you sign in with Google, data also syncs to Firestore, enabling cross-device result sharing and retake history management.

Personal diagnostic data is never shared with third parties.

No. Both the quiz and free results are available without registration.

Google sign-in is optional and enables: result saving, cross-device sync, change tracking across retakes, and premium purchase linking.

Local data: Clear site data (localStorage) from your browser settings.

Firestore data: Contact us via the Contact page. A self-service deletion feature is planned for the future.

Yes. You can share on X (Twitter). The compare feature also lets you check compatibility scores and complementary strengths with friends.

Your archetype is updated with the new results. If logged in, past results are also saved, and the change tracking feature (sparklines and timeline) lets you visually track profile changes over time.

Yes! The original Japanese version is available at 90gut.com.