Damage Caused by Infidelity Reagents/Testing Services Sold Online

Rewrite date: May 23, 2025

Many "infidelity reagents" and "sperm test kits" sold online are unreliable products that react to substances other than semen. In Korea, a seller of such products was even arrested, and an accurate semen test requires examination by a specialized laboratory.

The Dangers of "Infidelity Reagents" and Cheating-Detection Services Sold Online

"Sperm test kits," "infidelity checkers," "cheating tests," "cheating search kits" — these are reagents and services for investigating a partner's infidelity that can be easily purchased on online shopping sites such as Amazon, Yahoo Shopping, and Rakuten Ichiba. If you suspect your partner of cheating and have been troubled by it, you have probably come across these in search results at least once.

Because these products are affordable, priced at only a few thousand yen, many people buy them without fully checking their reliability or scientific basis. However, some of these commercially available reagents and kits lack scientific grounding to the point of being almost fraudulent, so great caution is needed when using them. In particular, when a test result becomes a critical basis for a decision that could change someone's entire life, relying on an unreliable product risks causing irreversible harm.

The Truth About "Infidelity Reagents" — Arrest Cases in Korea and the Real Composition

In neighboring Korea, there has actually been a case in which a seller of products marketed as "infidelity reagents" was arrested and detained by police [ref:1]. Despite this, in Japan almost identical products continue to be openly sold on online shopping sites today.

The product descriptions for these items typically claim that "if male semen is on the underwear, simply applying the semen test reagent will turn it red in about an hour, allowing you to confirm your spouse's infidelity." At first glance this sounds scientific and credible, but when investigative authorities analyzed the ingredients, the reality turned out to be surprisingly simple.

Specifically, it was found to be nothing more than a solution made by mixing commercially available phenol red powder with ethyl alcohol [ref:1]. Phenol red is a chemical widely used as a pH indicator (a reagent that determines acidity or alkalinity). Since semen is mildly alkaline (roughly pH 7.2 to 8.0), phenol red does indeed react with semen and change color [ref:2]. The problem, however, is that it reacts in the same way to other alkaline substances besides semen.

According to investigations by law enforcement, this "infidelity reagent" was confirmed to also turn red in reaction to the following substances.

• Urine (especially alkaline urine)
• Milk
• Soap (residual detergent components)
• Egg white
• Water (alkaline mineral water or tap water)
• Sweat (which can be alkaline under certain conditions)

In other words, there is an extremely high likelihood of "false positives" (incorrectly identifying something as semen when it is not) for a variety of substances that commonly get on clothing in everyday life. Many products and services distributed under the name "semen test reagent" are based on the same ingredients and principle, so particular caution is needed when considering a purchase.

The Serious Harm Caused by False Positives — Real Cases of Family Breakdown

Among the customers who come to seeDNA for semen testing, there are many who have seen the bond with their loved ones broken by a mistaken result from a reagent they bought online.

In one actual case, even though the partner had not actually been unfaithful, a phenol-red-based reagent reacted to residual urine, milk, egg, or soap on underwear or clothing, and the result was presented as "proof of infidelity." In the end, seeDNA's accurate semen test proved the partner's innocence, but rebuilding the trust within a family once it has been lost requires considerable time and effort.

Cases like this are far from rare. In matters as sensitive as suspected infidelity, relying on a testing kit with uncertain scientific grounding carries the risk of hurting an innocent partner and destroying a family. When resolving an issue that could affect the rest of your life, testing accuracy is what matters most, and we strongly recommend having the analysis done by a trusted specialized testing institution.

Three Reasons seeDNA's Semen Testing Is Trustworthy

The seeDNA Genetic Medicine Research Institute offers a scientifically grounded, highly accurate semen testing service that is clearly distinct from simple over-the-counter kits. Below are three main reasons seeDNA's semen testing is trusted.

1. The Latest and Most Accurate Semen Testing Technology

seeDNA's semen testing employs the latest forensic science methods, which are also used by the FBI (Federal Bureau of Investigation) and CSI (Crime Scene Investigation) units in the United States [ref:3]. Most simple kits and other companies' semen testing services sold online use low-accuracy methods, like the phenol red mentioned earlier, that broadly react to substances other than human semen.

seeDNA's semen testing, on the other hand, uses the latest molecular biological methods, allowing us to accurately determine whether trace amounts of semen (as little as 0.001 ml) present on an item such as clothing or tissue paper are truly human semen. Because molecular biological methods detect protein markers specific to semen (such as PSA — prostate-specific antigen — and semenogelin), there is no reaction to unrelated substances such as urine, milk, or soap [ref:4].

Furthermore, because testing is carried out at our own laboratory in Tokyo, if you need results urgently, you can receive a clear result in as little as one day. You do not need to keep worrying for a long time — the truth can be determined quickly.

2. DNA Testing That Can Identify Whose Semen It Is

seeDNA's strength goes beyond simply determining whether something is human semen. By combining our DNA testing technology, we can also identify whose semen was detected.

Specifically, in the course of semen testing, DNA is extracted from the semen and its DNA profile is compared with the DNA profile of the partner. This allows us to scientifically confirm the identity of the person to whom the semen belongs [ref:5].

Even if it is difficult to conduct DNA testing right away, the extracted DNA can be stored under appropriate conditions. This makes it possible to carry out comparative analysis again if testing becomes necessary in the future, which offers a major advantage from the standpoint of evidence preservation.

* If 0.005 ml or more of semen is present, DNA testing using the stored DNA can be carried out.

3. Easy Test Application Process

Applying for semen testing is simple and can be done through the following steps.

1. Apply anytime, 24 hours a day, by phone (Mon–Sun, 9:00 AM–6:00 PM) or through our company website
2. We will deliver a testing kit to your home
3. Send us the clothing or underwear with the suspected semen stain as is, or cut out the stained section and mail it to us
4. If cutting is difficult, use the dedicated swab included with the kit to rub the stained area and mail it back to us
5. We analyze the sample at our own laboratory and report the results

* If you would like the clothing or underwear used in the test returned to you, please let us know in advance when requesting the test.

See details on semen testing here

Apply for semen testing

Differences Between Over-the-Counter Kits and Professional Semen Testing

There is a large gap between over-the-counter infidelity testing kits and seeDNA's semen testing in terms of testing accuracy, what is actually detected, and scientific basis. The table below summarizes the main differences.

As shown above, over-the-counter kits merely "react to alkaline substances" and have no ability to specifically detect semen. When making an important decision that could affect your life, it is crucial to choose a test whose scientific reliability is guaranteed.

seeDNA's Quality Management System and Reliability

seeDNA is the only DNA testing institution in Japan to hold both ISO 9001, the international quality management standard, and the Privacy Mark (P-Mark) for privacy protection [ref:1]. ISO 9001 is an international standard for quality management systems, ensuring standardization and continuous improvement of the testing process. In addition, holding the Privacy Mark means that customers' personal information and sensitive test data are strictly protected.

If you are troubled by suspected infidelity or feel uncertain about a parent-child biological relationship, please feel free to consult seeDNA. Our specialized staff will assist you courteously.

[Free consultation with specialized staff]
[Toll-free number]
　0120-919-097
[Business hours]
　Mon–Sun 9:00 AM–6:00 PM (excluding holidays)

Frequently Asked Questions

Q1. Can I trust over-the-counter "sperm test kits" or "infidelity checkers"?

A. Many over-the-counter kits use pH indicators such as phenol red, which react not only to semen but also to a wide range of alkaline substances including urine, milk, soap, and water. The risk of false positives is very high, and their scientific reliability must be considered extremely low. When making an important decision, we recommend getting an accurate test from a specialized institution.

Q2. What testing method does seeDNA use for semen testing?

A. seeDNA uses the latest molecular biological methods, which are also adopted by the FBI and CSI. By detecting protein markers specific to semen (such as PSA and semenogelin), we can accurately identify human semen alone. Unlike over-the-counter kits, there is no risk of a false reaction to other substances.

Q3. How long does it take to get semen test results?

A. Because seeDNA conducts testing at our own laboratory in Tokyo, results can be confirmed in as little as one day for urgent requests. We have also set up our system to deliver results quickly even in standard cases.

Q4. Can you identify exactly whose semen it is?

A. Yes, this is possible. By extracting DNA from the semen detected during testing and comparing it with the DNA of the partner or other subject, we can scientifically identify whose semen it is. If DNA testing cannot be done right away, the extracted DNA can be stored and tested at a later date (at least 0.005 ml of semen is required).

Q5. Will the clothing or underwear used for testing be returned to me?

A. Yes. If you let us know that you would like your clothing or underwear returned when you request the test, we will send it back to you after testing is complete. If you do not notify us in advance, the items may not be returned, so please be sure to let us know when you place your request.

Q6. Is seeDNA's personal information protection thorough?

A. seeDNA holds the Privacy Mark (P-Mark) and strictly manages and protects customers' personal information and sensitive test data. We have also obtained the ISO 9001 international quality management certification, establishing a quality assurance system that covers the entire testing process.

[References]