Can silicone irritate genital skin? | The maker reports comfort, but also injury [OK Prostate Chip]

This page is based on entries from "ok-lab's diary" (https://ok-lab.hatenablog.com/), the Japanese development diary written by Mr. Okada, founder of OK Lab, a small company in Japan (Okada Comfortable Life Laboratory). Only the entries about "silicone comfort outside the urethra" are summarized here, in order of publication. Past prices and sizes are as written at the time. Current prices come from the official product list (retrieved September 4, 2026). Quotations are translated from Japanese.

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Note: This page is a personal reading log by someone with no connection to the maker or the seller. It reflects the source entries as of their publication dates and makes no guarantee of accuracy or safety. The product is not a medical device; talk to a doctor about any health decision. Check the official site for current information. This page contains advertising.

In short

Mr. Okada reports comfort from external silicone parts, alongside injury from an elastic ring.

His design choices address skin contact, tightening, and pressure from rigid parts.

Two related garments remain listed; the historical silicone designs have no confirmed current match.

If you see blood in your urine, even a small amount or for the first time, do not wait and see. See a urologist right away. If you suddenly cannot urinate, or the device cannot be removed, do not try to fix it yourself. Go to a medical facility, including emergency care, immediately.

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About this product

The OK Prostate Chip is a small device that is placed in the urethra (the urine passage) so that it acts on the prostate; the maker sells it in several shapes, sizes and materials. It is made and sold by OK Lab (Okada Comfortable Life Laboratory), a small company in Japan, through its own online store, and prices are in Japanese yen (JPY). The maker's development diary, "ok-lab's diary", is written in Japanese. This page is an English summary of it, and every quotation is translated. OK Lab ships internationally, so readers outside Japan can order (see "Buying from outside Japan" below). Product names on this page are plain-English descriptions. The official Japanese product name is shown once in the product table so you can find the same item in the store.

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Before you read: key terms

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What happens: silicone on genital skin

The OK Prostate Chip is a device placed in the urethra (the urine passage) to act on the prostate. The external silicone parts discussed here contact the glans (penis head), nearby skin, or skin beneath supporting garments. They include a thread stopper, an external ring, tubing underwear, and coatings on gatekeepers (retainers connected to the chip). Mr. Okada discusses their comfort alongside separate problems involving tightening, pressure, and friction.

An early stopper test shaped the maker's view of silicone on genital skin

In an entry published in March 2018, Mr. Okada introduced an external stopper for the separate-chip device with two threads. He described silicone as harsh inside the urethra, yet gentle against the glans outside it. He reported no discomfort when the stopper moved around near the glans.

An added correction said the stopper's material and shape had changed, with the following entry showing the official version. Mr. Okada points readers to that following entry for the finalized design.

(Source: ok-lab's diary, published March 2018)
https://ok-lab.hatenablog.com/entry/20180324/1521875816

An elastic ring injury limited reassurance about silicone on genital skin

In an entry published in October 2022, Mr. Okada described repeatedly leaving an elastic silicone ring on because it felt pleasant. He reported purple discoloration that he described as almost reaching tissue death. The diary does not record a medical assessment of that episode.

His proposed alternative was reinforced cord (silicone surrounding nylon), made into an external ring with a loop fitting. The 20cm ring and loop fitting cost ¥2,000 (about $13 at ¥156 = $1, rate as of 2026-09-04) excluding tax as published in October 2022. Mr. Okada cautions that an elastic ring can tighten, making prolonged wear difficult.

(Source: ok-lab's diary, published October 2022)
https://ok-lab.hatenablog.com/entry/2022/10/01/122944

Personal tubing tests informed the maker's claims about silicone on genital skin

In an entry published in October 2022, Mr. Okada described making T-shaped underwear from silicone tubing. It followed a girdle experiment he abandoned because he found its pressure intolerable. He based his confidence partly on tubing already touching his bare skin in parts supporting stockings and other accessories.

He reported that this prolonged skin contact had gone well. The connected retainer design remained unfinished, with its shape and the attached chip assembly awaiting further testing. On the basis of his experience, Mr. Okada suggested that silicone tubing underwear would probably cause no skin problems.

(Source: ok-lab's diary, published October 2022)
https://ok-lab.hatenablog.com/entry/2022/10/22/122828

A retainer coating reflected the maker's preference for silicone on genital skin

In an entry published in November 2022, Mr. Okada chose silicone for contact with scrotal skin (around the testicles). The retainer's body was epoxy resin (a rigid shaping material), with silicone coating the areas that touched that skin. He wrote that silicone seemed gentlest during prolonged contact, linking his choice to the skin's changing shape with body and outside temperatures.

An uncoated epoxy version was also discussed as a possible simpler product because the coated version took considerable work to make. Mr. Okada favored silicone for prolonged contact but considered epoxy acceptable for shorter use.

(Source: ok-lab's diary, published November 2022)
https://ok-lab.hatenablog.com/entry/2022/11/12/122932

Belt bleeding prompted another proposed role for silicone on genital skin

In an entry published in October 2023, Mr. Okada discussed bleeding around the glans rim after prolonged wear of a traction belt. He attributed these reports to friction and said he had sometimes experienced the same problem. His proposed buffer was silicone tubing around the glans rim as part of a side-entry retainer.

He claimed this tubing eased irritation there and that the retainer could also reduce slippage when a belt would not stay put. He described only a few days of testing of the retainer with downward support. Mr. Okada cautions that this combination is not a recommendation for everyone.

(Source: ok-lab's diary, published October 2023)
https://ok-lab.hatenablog.com/entry/2023/10/21/123054

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The maker's answer to silicone on genital skin

Mr. Okada changes the contact material, connector flexibility, and retainer shape according to the problem he is addressing.

Reinforced cord addressed tightening concerns about silicone on genital skin

In an entry published in October 2022, Mr. Okada explained why his reinforced cord behaved differently from an ordinary elastic ring. Nylon inside the silicone limited stretching; he described the cord as barely stretching at all. He claimed this combination avoided digging into skin and was gentler than a silicone ring.

He also claimed it could not form a very tight knot and would always come undone easily. Unlike the internal cord's stretch-limiting safety knots every 10cm, the external ring had an uninterrupted 20cm length. Mr. Okada proposes the reinforced cord as an alternative to an elastic silicone ring.

(Source: ok-lab's diary, published October 2022)
https://ok-lab.hatenablog.com/entry/2022/10/01/122944

Connector pricing added another consideration beyond silicone on genital skin

In an entry published in November 2022, Mr. Okada presented silicone tubing as a lower-cost connection between the retainer and chip. It replaced the thread's connecting role; the alternative was a 4-wire connector (a wire assembly joining the retainer and chip). He described the silicone connection as effectively free; the 4-wire connection cost ¥6,000 (about $38 at ¥156 = $1, rate as of 2026-09-04) excluding tax as published in November 2022.

The higher price reflected manufacturing effort, according to Mr. Okada. He also reported a level junction between the tubing and ceramic chip, with no step or snagging point. Mr. Okada says both connections have advantages and drawbacks, leaving the choice to personal preference.

(Source: ok-lab's diary, published November 2022)
https://ok-lab.hatenablog.com/entry/2022/11/12/122932

Flexible tubing addressed internal pressure separately from silicone on genital skin

In an entry published in November 2022, Mr. Okada adopted a flexible-tubing retainer (Unicorn type). This design had silicone tubing extending on both the body-facing and outward-facing sides of the retainer. He wrote that an earlier, internally fixed design passed changes in the retainer's angle directly to the urethra.

According to him, the newer design's internal silicone could bend, substantially reducing that strain. He also removed the older design's locking key, describing a different tube-based locking arrangement. Mr. Okada favored the flexible connection because reducing strain on the urethra was his priority.

(Source: ok-lab's diary, published November 2022)
https://ok-lab.hatenablog.com/entry/2022/11/12/122932

Sideways arches addressed pressure alongside concerns about silicone on genital skin

In an entry published in October 2023, Mr. Okada described testing the side-entry retainer with the 2017 support stocking (an external support garment). He had expected the rigid retainer to burden the glans under pressure against a chair. After his test, he reported little apparent effect when the arch ran sideways across the glans.

Earlier requested arches had unequal 20mm and 35mm sides; he now discussed equal 30mm sides. Mr. Okada favored a symmetrical side-arch design for downward support because he believed it reduced pressure on the glans. He also cautions that beginners may not get the comfort he describes.

(Source: ok-lab's diary, published October 2023)
https://ok-lab.hatenablog.com/entry/2023/10/21/123054

If you see blood in your urine, even a small amount or for the first time, do not wait and see. See a urologist right away. If you suddenly cannot urinate, or the device cannot be removed, do not try to fix it yourself. Go to a medical facility, including emergency care, immediately.

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How silicone on genital skin changed over time

The diary does not say what the current state is.

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OK Prostate Chip products related to silicone on genital skin

The current list includes two garments from these discussions; neither listing confirms the historical silicone assemblies.

Products that appear in these entries

The traction belt is listed in OK Lab's own online store.

The 2017 support stocking is listed in OK Lab's own online store.

(Source: ok-lab's diary, published October 2023)
https://ok-lab.hatenablog.com/entry/2023/10/21/123054

Products the diary mentioned as alternatives

The diary names no alternative.

These entries also discuss an early stopper, a reinforced-cord ring, tubing underwear, and historical retainer assemblies with connector options. No matching product can be confirmed on the current list.

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Common worries about silicone on genital skin

(The material contains no questions from readers.)

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Buying from outside Japan

OK Lab ships internationally to countries covered by Japan Post's EMS courier service. Overseas orders are paid in advance by PayPal. Each order carries a ¥400 (about $3 at ¥156 = $1, rate as of 2026-09-04) handling fee, and EMS shipping is charged on top. These terms come from OK Lab's official sales-terms page (written here as plain text, not a link: ok-lab.net/docs/law), checked on September 7, 2026; confirm them on the official store before you order, because they can change.

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Summary of this article

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Source: ok-lab's diary (Okada Comfortable Life Laboratory). The original entries are in Japanese; quotations on this page are translated. Photos and videos are on the original entries.