Yinbai

What is SP1?

SP1 (Yinbai) is the first point of the Spleen channel, sitting at the inner corner of the big toenail.

Its Pinyin name, Yinbai, is usually translated as "Hidden White". In classical Chinese medicine it is a jing-well point, the place where the channel is said to begin. Jing-well points sit at the fingers and toes and were traditionally reserved for sudden, dramatic problems.

Texts link SP1 to heavy uterine bleeding, nosebleed, restless sleep with vivid dreaming, and agitation. Old sources often paired it with heat applied over the toe rather than pressure alone. This page covers finger pressure only.

Two honest points before you read on. A point being famous in tradition is not evidence that it works, and it is not evidence that it is safe for you. Both have to be checked separately, and that is what the rest of this page tries to do.

The evidence verdict is short. We found no controlled human trials testing finger pressure at SP1 for any condition. What exists is classical description, case reports and clinical custom, which cannot tell you whether an effect is real or whether it is expectation and the passage of time.

That does not make SP1 useless to press. Gentle pressure on a sensitive toe point is calming for some people, costs nothing, and carries little risk if the skin is intact. It does mean you should treat any confident claim about SP1 stopping bleeding or curing insomnia with real caution, and never let it replace care for a symptom that needs a diagnosis.

Where is SP1 and how do you find it?

SP1 sits on the inner edge of the big toe, roughly 2 to 3 mm behind the corner of the toenail, towards the second toe side of the foot.

• Sit so you can reach the foot. Cross one ankle over the opposite knee, or sit on the floor with the knee bent. You need to see the big toenail clearly.
• Find the inner corner of the nail. That is the corner on the side facing your other foot, not the outer edge. SP1 is on this inner side only.
• Step back from the corner. Move about the width of a matchstick head behind the nail corner, towards the toe joint. In classical terms this is 0.1 cun, which is a couple of millimetres on most adults.
• Feel for the junction. The spot lies where the hard nail edge, the soft nail fold and the skin of the toe meet. It usually feels slightly tender under a fingernail tip, more so than the skin either side.
• Check both feet. SP1 is a paired point, one on each big toe. Tradition treats the pair together rather than choosing a side.

Use the nail corner as your anchor, not a measurement from the joint. The distal phalanx of the big toe is short, and a few millimetres either way changes which point you are on.

If your toenail is thickened, ingrown or curling into the fold, do not dig for the exact spot. Press the flat skin just behind the nail fold instead, or skip the point entirely until the nail is sorted out.

How do you apply pressure to SP1?

1. Clean the toe first. Wash and dry the foot and your hands. You are pressing right at a nail fold, which is a common entry point for infection.
2. Use a fingertip or thumb tip. Place the pad of your thumb or index finger on the spot. A short, smooth fingernail edge can be used to find it, but press with the pad.
3. Press lightly. Aim for about 3 out of 10 pressure, enough to feel a dull ache. Toe tips are nerve-rich and bony, so this point needs far less force than a fleshy point like the calf.
4. Hold or circle. Hold steady for 20 to 60 seconds, or make small circles at the same pressure. Breathe slowly and keep the foot relaxed.
5. Do both feet. Repeat on the other big toe for the same length of time.
6. Repeat sparingly. Two or three short sessions a day is plenty. There is no benefit in grinding away at it for ten minutes.
7. Stop at any sharp signal. Stop if you feel sharp or shooting pain, numbness, or pins and needles, or if the skin reddens, splits or stings afterwards.

Never break the skin. Some traditional descriptions of jing-well points involve pricking or burning herb over the toe. Neither belongs in self-care, and neither is described on this page.

A warm foot responds better than a cold one. A few minutes in warm water before you start makes the spot easier to find and the pressure more comfortable.

Give any approach a fair but limited trial. If a week or two of regular pressure changes nothing, the honest conclusion is that it is not helping you, and it is time to look at other options.

What is SP1 traditionally used for?

• Heavy menstrual or uterine bleeding. This is the headline classical use, with old texts naming SP1 for flooding-type bleeding. There are no controlled human trials of finger pressure at SP1 for this. Heavy or unexpected bleeding needs a medical assessment, not a toe point.
• Nosebleed. Tradition lists SP1 for bleeding from the nose, on the idea that jing-well points act on bleeding anywhere. Human evidence is absent. First aid for a nosebleed is pinching the soft part of the nose and leaning forward.
• Restless sleep and vivid dreaming. Classical sources describe SP1 for agitation, excessive dreaming and night-time restlessness. No trial has tested it. Some people find any slow, repeated self-touch before bed settling, which is a real but non-specific effect.
• Anxious agitation. Tradition frames SP1 as calming a disturbed mind. The evidence here is anecdote only. If anxiety is affecting daily life, talking therapy and medical advice have far stronger support.
• Abdominal fullness and poor appetite. As the start of the Spleen channel, SP1 is linked to digestion in theory. Nothing in the human literature tests this at SP1 specifically.
• Fainting and collapse in old texts. Jing-well points as a group appear in classical first-aid descriptions. This is historical context, not guidance. Anyone who collapses and does not come round quickly needs emergency help.

The pattern is consistent across these uses: a long and specific tradition, and almost no modern testing. Read the claims as what a system of medicine believed, not as results.

Are there tips for using SP1 effectively?

• Trim the nail first. A long or ragged big toenail makes the inner corner hard to reach and easy to catch. A clean, short nail edge makes the point obvious.
• Warm the foot. Two minutes in warm water relaxes the toe and makes the tender spot easier to locate without pushing hard.
• Let tenderness guide you. SP1 usually feels slightly sore compared with the skin on either side. Mild soreness is your landmark; sharp pain is your stop sign.
• Keep the foot supported. Rest the foot on the opposite thigh or a cushion. Holding the leg up in mid-air tightens the hip and makes you press harder than you meant to.
• Use it at a consistent time. If you are trying it for restless evenings, do it at the same point in your wind-down routine. Consistency makes it easier to judge whether anything changed.
• Keep a short note. Write down the date and what you noticed. Two weeks of notes will tell you more than a month of vague impressions.
• Pair it with the basics. For sleep, a dark cool room and a regular bedtime have strong evidence behind them. Use SP1 alongside those, never instead of them.
• Stop if the skin reacts. Redness that lasts, stinging or a split at the nail fold means you pressed too hard or too often. Leave it alone until it is fully settled.

One general point about expectations. Short, gentle, regular pressure is the safest way to use any toe point, and it is also the way most likely to feel pleasant rather than irritating.

What do people get wrong with SP1?

• Expecting a cure. No acupressure point cures heavy bleeding, insomnia or anxiety. Treating SP1 as a fix delays care that actually works.
• Pressing the outer corner. SP1 is on the inner side of the big toenail, the side facing the other foot. The outer corner is a different channel entirely.
• Digging with a nail. People use a thumbnail edge and press until it hurts sharply. The skin here is thin and the nail fold tears easily. Use the finger pad and light pressure.
• Confusing it with BL67. BL67 (Zhiyin) sits at the outer corner of the little toenail and is the point studied for breech presentation. SP1 is not that point and has no such research behind it.
• Using it on damaged skin. An ingrown nail, a blister, athlete's foot between the toes or a healing cut all rule the point out until the skin is intact again.
• Ignoring reduced foot sensation. If you cannot feel your feet well, you cannot judge how hard you are pressing. That is how small injuries go unnoticed.
• Copying needle or heat videos. Clips showing pricking or burning herb over the toe are not self-care. Pressure with a fingertip is the only method described here.
• Overdoing the first session. Ten minutes of hard pressure on a toe tip leaves it sore for days and tells you nothing. Short sessions, repeated, are the sensible test.

The biggest mistake is the first one on the list. SP1 may be worth a calm trial for comfort, but the symptoms tradition links it to are exactly the ones that need a doctor's eyes.

What does the research on SP1 actually say?

There is essentially nothing. We found no controlled human trials testing finger pressure at SP1 for menstrual bleeding, nosebleed, sleep, anxiety or digestion.

The modern literature that mentions SP1 at all is mostly Chinese-language clinical reporting, often describing heat applied over the toe rather than pressure, and usually as case series without a control group. Case series can describe what happened to a handful of people, but they cannot separate a real effect from natural recovery, expectation or the attention of a practitioner.

This matters most for the bleeding claim. Heavy menstrual bleeding varies a lot from cycle to cycle on its own. Any uncontrolled report of improvement after treatment is extremely hard to interpret, which is why uncontrolled reports do not change what we can say.

It is worth naming the point SP1 is often confused with. BL67, at the outer corner of the little toenail, has been studied in randomised trials for turning a breech baby, with mixed results. That research says nothing about SP1, and the two points are not interchangeable.

The wider acupressure evidence base follows a pattern. Most trials are small, short, and cannot blind participants to whether they were pressed. The clearest exception is PC6 at the inner wrist for nausea and vomiting, which has repeated controlled trials behind it. SP1 has nothing comparable.

What this means for you is simple. Absence of evidence is not proof that SP1 does nothing, but it does mean no one can tell you honestly that it works. Try it if you like, keep it gentle, keep it brief, and judge it on your own notes rather than on claims made for it.