What is pain sensitivity? The science behind your pain threshold

Pain sensitivity isn’t just about how much something hurts - it’s about how your brain decides something is painful in the first place. Two people can go through the exact same experience - a period cramp, a muscle injury, post-run soreness - and one might barely register it while the other is doubled over.

That difference isn’t about being “tough” or “weak.” It’s about how your nervous system and brain process and interpret pain signals, shaped by biology, hormones, emotions, past experiences, and even your expectations of pain.

How your pain threshold is measured

Scientists often measure pain sensitivity using something called the pressure pain threshold (PPT) - the exact point where pressure stops feeling like pressure and starts feeling like pain. Imagine pushing a dull object towards your skin. Initially, you’ll just sense it touching, then you’ll sense it pushing and then, suddenly, it will become painful. That limit is different for everyone, and is your individual ‘pain threshold’.

In a large study of 617 healthy, pain-free young adults, researchers tested 16 different points on the body, from the neck to the shin, to create a kind of pain sensitivity map. They found that women generally had lower thresholds than men, meaning their bodies registered pain at lower levels of pressure, and that factors like mental health, smoking, and even waist–hip ratio also played a role. Pain is never just in the body - your threshold is set by a whole-body, whole-brain network.

Example of pressure pain threshold measurement on the upper trapezius muscle with an algometer, as described in Firmani et al. (2014) Acta Odontologica Scandinavica.

Menstrual pain sensitivity and your cycle

For some people, pain sensitivity is turned up across the entire body. In menstrual health, this is especially visible in conditions like primary dysmenorrhea (painful periods without another underlying condition) and endometriosis. Research shows that women with dysmenorrhea (period pain) often have a lower pain threshold throughout their entire menstrual cycle - not just during menstruation. This state, known as hyperalgesia, can sometimes progress into central sensitization, where the brain and spinal cord become so used to processing pain that they stay “on alert” even when the original cause is gone. The volume dial for pain gets stuck on high, and sensations that wouldn’t usually be painful start to hurt. For some, pain thresholds vary across the menstrual cycle, or are altered by the perimenopause.

When hyperalgesia becomes central sensitization

If you’ve noticed pain in parts of your body not directly linked to your condition, discomfort from light touch, or flare-ups with no obvious trigger, those can all be signs that your central nervous system is amplifying pain signals. For people living with chronic menstrual pain, this amplification can make work, exercise, intimacy - and daily life in general - harder than it needs to be.

Why brain-based treatments matter for pain sensitivity

Traditional pain relief tends to focus on the source: reducing inflammation with painkillers or regulating hormones with contraception. But if the brain’s pain-processing networks are already overactive, these local fixes might only address part of the problem.

Instead, we start with the brain. Nettle™ is a safe, non-invasive brain stimulation wearable designed to target the areas responsible for pain perception and emotional regulation. The goal is not just to quiet pain in the moment, but to retrain the brain, raise the pain threshold, and reduce overreaction to incoming signals.

In our double-blind randomized controlled trial, participants reported up to a 53% reduction in menstrual pain symptoms after just one cycle of Nettle™ use (recommended use of at least three cycles). Because we’re targeting pain at the command centre, the benefits can extend beyond pain - into mood, energy, and overall daily functioning.

Pain is never just in your muscles, pelvis or uterus. It’s a conversation between your hormones, your nervous system, and your brain. When you understand that pain is processed centrally - and that your brain can be retrained - you open the door to new ways of managing it, without relying on drugs or hormones.

References

1. Bazzari, A.H. and Bazzari, F.H. (2022) ‘Advances in targeting central sensitization and brain plasticity in chronic pain’, The Egyptian Journal of Neurology, Psychiatry and Neurosurgery, 58(1), p. 38.

2. Firmani, M., Miralles, R. and Casassus, R. (2015) ‘Effect of lidocaine patches on upper trapezius EMG activity and pain intensity in patients with myofascial trigger points: A randomized clinical study’, Acta Odontologica Scandinavica, 73(3), pp. 210–218.

3. Iacovides, S., Avidon, I. and Baker, F.C. (2015) ‘What we know about primary dysmenorrhea today: a critical review’, Human Reproduction Update, 21(6), pp. 762–778.

4. Quintas-Marquès, L. et al. (2023) ‘Central sensitization in patients with deep endometriosis’, Pain Medicine (Malden, Mass.), 24(8), pp. 1005–1007. Available at: https://doi.org/10.1093/pm/pnad002.

5. Waller, R. et al. (2016) ‘Pressure and cold pain threshold reference values in a large, young adult, pain-free population’, Scandinavian Journal of Pain, 13(1), pp. 114–122.

6. Zhi, Y. et al. (2025) ‘Variability in Pain Traits Among Young Individuals with High and Low Pain Sensitivity’, Journal of Pain Research, 18, pp. 3439–3450.