What are the primary uses of HCG injections. How do HCG injections affect male and female patients differently. What are the most common side effects of HCG injections. How should patients prepare for and administer HCG injections. What precautions should be taken when using HCG injections.

Understanding HCG Injections: Purpose and Applications

Human Chorionic Gonadotropin (HCG) injections serve multiple medical purposes, primarily in the realms of reproductive health and hormonal therapy. These injections contain a hormone that plays a crucial role in both male and female reproductive systems.

HCG in Male Patients

For male patients, particularly young boys before puberty, HCG injections serve a specific purpose. How do these injections benefit male patients? HCG stimulates the testicles to descend into the scrotum, a process crucial for normal sexual development. In some cases, it’s also used to promote the production of testosterone and support overall sexual maturation.

HCG in Female Patients

In female patients, HCG injections are primarily used to address fertility issues. How does HCG support female fertility? The hormone is typically administered after a course of menotropins to trigger ovulation – the release of an egg from the ovary. This makes HCG a valuable tool in fertility treatments and assisted reproductive technologies.

It’s important to note that HCG injections are not recommended for weight loss purposes, despite some misconceptions. The use of HCG for weight loss is not only ineffective but can also lead to serious side effects.

Administration and Dosage of HCG Injections

The proper administration of HCG injections is crucial for their effectiveness and safety. These injections are typically given intramuscularly, often by a healthcare professional. However, in some cases, patients may be instructed to self-administer the medication at home.

Dosage Considerations

How is the dosage of HCG determined? The appropriate dose varies based on several factors, including:

• Age of the patient
• Weight
• Specific medical condition being treated
• Individual response to the treatment

For male patients, particularly boys, the typical regimen involves injections three times a week or as prescribed by the physician. Female patients undergoing fertility treatment usually receive a single dose of HCG following their menotropins treatment.

Self-Administration Guidelines

When patients are required to self-administer HCG injections at home, what precautions should they take? Here are some key guidelines:

1. Receive thorough training from a healthcare professional on proper injection techniques
2. Always check the medication for particles or discoloration before use
3. Follow strict hygiene protocols to prevent infection
4. Properly dispose of needles and medical supplies
5. Maintain a consistent injection schedule as prescribed

Common Side Effects of HCG Injections

While HCG injections are generally well-tolerated, they can cause various side effects. Understanding these potential reactions is crucial for patients and healthcare providers alike.

Mild Side Effects

What are the most common mild side effects of HCG injections? Patients may experience:

• Headache
• Restlessness
• Fatigue
• Pain or discomfort at the injection site

These side effects are usually temporary and often resolve on their own. However, if they persist or worsen, it’s important to consult a healthcare provider.

Serious Side Effects and Complications

While less common, HCG injections can sometimes lead to more serious side effects that require immediate medical attention. What are these severe reactions, and when should patients seek help?

Ovarian Hyperstimulation Syndrome (OHSS)

One of the most significant risks associated with HCG injections in women is Ovarian Hyperstimulation Syndrome (OHSS). This condition can occur during or after treatment. What are the symptoms of OHSS?

• Severe pain or swelling in the lower abdominal area
• Severe nausea or vomiting
• Sudden and rapid weight gain
• Decreased urination

In rare cases, OHSS can lead to fluid buildup in the stomach, chest, and heart area, which requires immediate medical intervention.

Other Serious Side Effects

Patients should be aware of other potential serious side effects and seek immediate medical help if they experience:

• Chest pain, jaw pain, or left arm pain
• Sudden severe headache
• Confusion or weakness on one side of the body
• Difficulty speaking
• Sudden vision changes
• Pain, redness, or swelling in the legs

Allergic Reactions to HCG Injections

While rare, allergic reactions to HCG injections can occur and may be severe. How can patients recognize an allergic reaction? Symptoms may include:

• Rash or hives
• Itching or swelling, especially of the face, tongue, or throat
• Severe dizziness
• Difficulty breathing or shortness of breath

Any signs of an allergic reaction should be treated as a medical emergency, requiring immediate attention.

Precautions and Contraindications for HCG Injections

Before starting HCG injections, it’s crucial for patients to discuss their full medical history with their healthcare provider. What conditions or factors might affect the safety or efficacy of HCG treatment?

Medical Conditions to Disclose

Patients should inform their doctor if they have a history of:

• Blood clots
• Heart disease or high blood pressure
• Kidney or liver disease
• Lung problems, including asthma
• Migraines or seizure disorders
• Thyroid or adrenal gland problems
• Cancer of the reproductive organs
• Brain tumors

Pregnancy and HCG

HCG injections should not be used during pregnancy. If a patient becomes pregnant while using HCG or suspects pregnancy, they should contact their healthcare provider immediately.

Interactions with Other Medications

HCG injections can interact with various medications, potentially altering their effectiveness or increasing the risk of side effects. What types of medications might interact with HCG?

• Hormonal contraceptives
• Certain fertility medications
• Testosterone replacement therapies
• Some medications used to treat endocrine disorders

Patients should provide their healthcare provider with a complete list of all medications, including over-the-counter drugs, supplements, and herbal products, to avoid potential interactions.

Monitoring and Follow-up During HCG Treatment

Regular monitoring is essential during HCG treatment to ensure its effectiveness and minimize risks. How should patients be monitored during HCG therapy?

For Male Patients

Boys receiving HCG for testicular descent or sexual development may require:

• Regular physical examinations
• Hormone level tests
• Monitoring of sexual development milestones

For Female Patients

Women undergoing fertility treatment with HCG may need:

• Frequent ultrasounds to monitor ovarian response
• Blood tests to check hormone levels
• Close monitoring for signs of OHSS

How often should follow-up appointments occur? The frequency of monitoring will depend on the individual treatment plan and the patient’s response to the medication. Typically, patients should expect regular check-ins with their healthcare provider throughout the course of treatment.

Long-term Considerations and Outcomes of HCG Treatment

While HCG injections can be highly effective for their intended purposes, it’s important to consider the long-term implications of this treatment. What should patients and healthcare providers keep in mind regarding extended use or repeated courses of HCG?

Fertility Outcomes

For women undergoing fertility treatment, what are the typical success rates with HCG injections? Success rates can vary widely depending on individual factors, including:

• Age
• Underlying cause of infertility
• Overall health
• Treatment protocol

It’s important for patients to have realistic expectations and discuss potential outcomes with their fertility specialist.

Long-term Effects in Male Patients

For boys receiving HCG for testicular descent or sexual development, what are the long-term outcomes? Most patients experience positive results, including:

• Successful testicular descent
• Normal sexual development
• Improved fertility potential in adulthood

However, long-term follow-up may be necessary to monitor ongoing hormonal balance and reproductive health.

Potential for Repeated Treatments

In some cases, patients may require multiple courses of HCG treatment. How does this impact long-term health? While HCG is generally safe for repeated use under medical supervision, considerations include:

• Cumulative risk of side effects
• Potential changes in hormone responsiveness
• Need for ongoing monitoring of reproductive health

Patients should discuss the implications of repeated treatments with their healthcare provider to develop a comprehensive long-term care plan.

Alternative Treatments and Complementary Approaches

While HCG injections are effective for many patients, they may not be suitable or successful for everyone. What alternatives exist for patients who cannot use HCG or who have not achieved desired results?

Alternatives for Male Patients

For boys with undescended testicles or delayed sexual development, alternative approaches may include:

• Surgical intervention for testicular descent
• Other hormonal therapies to stimulate development
• Watchful waiting in some cases of mild delay

Alternatives for Female Patients

Women seeking fertility treatment have several options beyond HCG, including:

• Other ovulation induction medications
• Intrauterine insemination (IUI)
• In vitro fertilization (IVF)
• Egg or embryo donation
• Adoption or surrogacy

How do patients decide which treatment option is best for them? The choice of treatment should be made in consultation with a reproductive specialist, taking into account factors such as age, medical history, cause of infertility, and personal preferences.

Complementary Approaches

In addition to medical treatments, what complementary approaches can support reproductive health and fertility? Some patients may benefit from:

• Lifestyle modifications (e.g., diet, exercise, stress reduction)
• Acupuncture or other traditional medicine practices
• Nutritional supplementation under medical guidance
• Psychological support and counseling

It’s important to note that while these complementary approaches may support overall health and well-being, they should not replace medically prescribed treatments without consultation with a healthcare provider.

Patient Education and Support During HCG Treatment

Successful HCG treatment relies not only on proper medical administration but also on patient understanding and adherence. How can healthcare providers ensure that patients are well-informed and supported throughout their treatment journey?

Comprehensive Patient Education

What key information should be provided to patients starting HCG treatment?

• Detailed explanation of how HCG works and what to expect
• Clear instructions on administration techniques and schedules
• Information on potential side effects and when to seek medical attention
• Guidance on lifestyle factors that may impact treatment success
• Resources for additional information and support

Ongoing Support and Communication

How can healthcare providers maintain open lines of communication with patients undergoing HCG treatment?

• Regular check-in appointments or telemedicine consultations
• Provision of contact information for urgent questions or concerns
• Patient support groups or online forums moderated by healthcare professionals
• Follow-up care to address any ongoing issues or concerns

By ensuring that patients are well-informed and supported, healthcare providers can improve treatment adherence, reduce anxiety, and potentially enhance treatment outcomes.

Future Developments in HCG Treatment

As medical research continues to advance, what potential developments might we see in the use of HCG for reproductive health and hormonal therapy?

Emerging Research Areas

Current and future research in HCG treatment is focusing on several key areas:

• Improved delivery methods to enhance efficacy and reduce side effects
• Personalized treatment protocols based on genetic and hormonal profiles
• Combination therapies that may enhance the effectiveness of HCG
• Extended applications of HCG in treating other hormonal disorders

Technological Advancements

How might technology impact the future of HCG treatment? Potential developments include:

• Smart injection devices for more precise dosing and easier self-administration
• Advanced monitoring systems to track treatment response in real-time
• AI-assisted treatment planning to optimize dosage and timing
• Improved diagnostic tools to identify patients most likely to benefit from HCG therapy

As research progresses, patients and healthcare providers can look forward to potentially more effective, personalized, and less invasive HCG treatments in the future.

HCG Intramuscular: Uses, Side Effects, Interactions, Pictures, Warnings & Dosing

Uses

This medication is a hormone used in boys (before puberty) to cause the normal dropping of the testicles into the scrotum. It is also used in certain boys to help with normal sexual development. It works by causing the testes to release male sex hormones (such as testosterone).This medication is also used in women to treat fertility problems. It is given after finishing another medication (menotropins) to cause the release of an egg (ovulation). It should not be used in women whose ovaries no longer make eggs properly (primary ovarian failure).This medication has not been shown to be effective for weight loss and should not be used for this purpose due to risk of serious side effects.

How to use HCG Solution, Reconstituted (Recon Soln)

This medication is given by injection into a muscle, usually by a health care professional.

The dosage is based on your age, weight, medical condition, and response to treatment.

For boys, use this medication usually 3 times a week or as directed by your doctor. For women, use this medication usually for 1 dose after finishing your menotropins treatment.

Use this medication regularly to get the most benefit from it. To help you remember, mark the day(s) on the calendar when you need to receive the medication.

If you are using this medication at home, learn all preparation and usage instructions from your health care professional. Before using, check this product visually for particles or discoloration. If either is present, do not use the liquid. Inject this medication into a muscle as directed by your doctor. Learn how to store and discard needles and medical supplies safely.

Side Effects

Headache, restlessness, tiredness, or pain at injection site may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including: swelling of the hands/ankles/feet, mental/mood changes (such as depression, irritability), signs of early puberty in boys (such as facial/pubic hair, voice change, acne), pain/swelling of the breast (in boys), unusual vaginal bleeding (women).

This medication may cause a condition known as ovarian hyperstimulation syndrome (OHSS). This condition may occur during or after treatment. Rarely, serious OHSS causes fluid to suddenly build up in the stomach, chest, and heart area. Get medical help right away if you develop the following side effects: severe pain or swelling in the lower abdominal (pelvic) area, severe nausea/vomiting, sudden/rapid weight gain, or decreased urination.

Get medical help right away if you have any very serious side effects, including: chest/jaw/left arm pain, sudden severe headache, confusion, weakness on one side of the body, trouble speaking, sudden vision changes, pain/redness/swelling in the legs.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing, shortness of breath.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US – Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada – Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Precautions

Before using this medication, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: early puberty (in boys), blood clots, heart disease (such as chest pain, heart attack), high blood pressure, kidney disease, liver disease, lung problems (such as asthma), migraine, seizure disorder, stroke, unusual vaginal bleeding, problems of the uterus, unexplained ovarian cyst/enlargement, certain type of fertility problem (primary ovarian failure), thyroid problem, adrenal gland problem, cancer of the reproductive organs (breast, uterus, ovary, prostate), brain tumor.

This medication should not be used during pregnancy. If you become pregnant or think you may be pregnant, tell your doctor right away.

When this medication is used in women to treat infertility, it may cause multiple births (such as twins, triplets).

It is unknown if this drug passes into breast milk. Consult your doctor before breast-feeding.

Interactions

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor’s approval.

A product that may interact with this drug is: gonadorelin.

This medication may interfere with certain lab tests (including luteinizing hormone-LH/follicle stimulating hormone-FSH levels), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.

Does HCG Solution, Reconstituted (Recon Soln) interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.

Do not share this medication with others.

If you miss a dose, ask your doctor or pharmacist right away for a new dosing schedule.

Store the vials of powder at room temperature away from light and moisture. Store the mixed medication in the refrigerator. Write the date when the medication was mixed on the vial. The mixed medication must be used within 1 to 2 months, depending on the product. Check the product package for the storage time for your product. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

Selected from data included with permission and copyrighted by First Databank, Inc. This copyrighted material has been downloaded from a licensed data provider and is not for distribution, except as may be authorized by the applicable terms of use.

CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.

Testosterone, Weight Loss, Side Effects & More

The Food and Drug Administration (FDA) has approved hCG injections to treat specific medical conditions. In females assigned at birth (FAABs), they can help treat infertility. In males assigned at birth (MAABs), they can treat a type of hypogonadism.

Human chorionic gonadotropin (hCG) is sometimes called “the pregnancy hormone” because of its important role in maintaining pregnancy.

Pregnancy tests check hCG levels in the urine or blood to determine if a person is pregnant or not.

Read on to learn how it can be used for MAABs.

There are a variety of reasons why a doctor might prescribe hCG to a man.

To help address hypogonadism

In men, doctors prescribe hCG to help address the symptoms of hypogonadism, such as low testosterone and infertility. hCG can help the body increase its production of testosterone and sperm, which can help reduce infertility.

To improve testosterone deficiency

Injections of hCG are also sometimes used as an alternative to testosterone products in MAABs with testosterone deficiency.

Testosterone deficiency is defined as testosterone blood levels less than 300 nanograms per deciliter (ng/dL) along with symptoms of low testosterone. These include:

• fatigue
• stress
• a low sex drive
• depressed mood

According to the American Urological Association, hCG is appropriate for those MAABs with testosterone deficiency who also desire to maintain fertility.

Testosterone products boost levels of the hormone in the body but can have the side effects of shrinking the gonads, altering sexual function, and causing infertility.

hCG can help increase:

• gonad size
• testosterone levels
• fertility

Some doctors believe that using testosterone along with hCG may help improve symptoms of testosterone deficiency while preventing some of testosterone’s side effects.

To improve sexual function

hCG may also help improve sexual function in MAABs who don’t experience improvement while on testosterone.

To reverse steroid side effects

Bodybuilders who take anabolic steroids such as testosterone also sometimes use hCG to help prevent or reverse some of the side effects steroids cause, such as gonad shrinkage and infertility.

In men, hCG acts like luteinizing hormone (LH). LH stimulates Leydig cells in the testicles, which results in the production of testosterone.

LH also stimulates production of sperm within structures in the testicles called seminiferous tubules.

As hCG stimulates the testicles to produce testosterone and sperm, the testicles grow in size over time.

Very little clinical research has evaluated hCG in MAABs with low testosterone levels.

In a small 2002 study of older MAABs with partial hypogonadism, hCG increased testosterone levels compared to a placebo control. However, hCG had no effect on sexual function.

In one 2005 study, MAABs taking testosterone along with hCG were able to maintain testosterone production in the testicles.

In a 2013 study, MAABs taking testosterone along with hCG were able to maintain adequate sperm production.

According to a 2018 study, hCG can help MAABs with hypogonadism preserve their fertility, whether it’s used alone or in combination with testosterone. It can help restore sperm production as well.

A small 2019 study concluded that hCG was safe and effective for MAABs who experience the symptoms of hypogonadism but have testosterone levels above 300 ng/dL. Testosterone levels above 300 ng/dL are widely considered normal.

For men, the most common side effects of hCG injections include:

• gynecomastia, or the growth of male breasts
• pain, redness, and swelling at the injection site
• stomach pain
• nausea
• vomiting

In rare cases, people taking hCG have developed blood clots. Although also rare, allergic reactions can occur, including mild skin rashes and severe anaphylactic reactions.

hCG is sometimes used for weight loss. Several products are available that are marketed as over-the-counter (OTC) homeopathic hCG products for weight loss.

However, the FDA has warned that it hasn’t approved hCG products for the purpose of weight loss. Any OTC products claiming to contain hCG aren’t legally authorized, either.

The FDA has also advised consumers that there’s no substantial evidence that hCG works for weight loss.

These products are often used as part of an “hCG diet. ” This typically involves taking hCG supplements while following a low calorie diet of 500 calories per day.

Although this low calorie diet can help reduce weight, there’s no evidence that using hCG products helps.

Additionally, this extremely low calorie diet can be unsafe for many people. Possible side effects of extremely restrictive diets include:

• gallstones
• electrolyte imbalances
• arrhythmias

When used appropriately with the guidance of your doctor, hCG is safe.

It shouldn’t be used by MAABs with prostate cancer, certain brain cancers, or uncontrolled thyroid disease.

Talk with your doctor about other medical conditions you may have before using hCG.

hCG is produced from hamster ovary cells. People with an allergy to hamster protein shouldn’t take hCG.

You should avoid all OTC hCG products, since none of them have been FDA approved. The FDA warns against using these products or following the hCG diet.

hCG is an FDA-approved medication for treating specific conditions in both FAABs and men.

In men, it seems to have an important role as an alternative to testosterone for boosting testosterone levels and maintaining fertility.

Some doctors are prescribing it in conjunction with testosterone products for testosterone deficiency to help maintain fertility and sexual function.

Some people are also using hCG for weight loss, often as a component of the hCG diet. However, there’s no reliable evidence that hCG works for this purpose. Due to concerns about its safety, it should be avoided as a weight loss aid.

Choragon instructions for use: indications, contraindications, side effects – description of Choragon powder for injection. 5000 IU: amp. 3 pcs. in set with solvent (1798)

Estrogens and hCG ovarian stimulation during electrolysis

Last update:

11/15/2022

Any changes in the hormonal background can significantly affect the intensity of hair growth and the final results of electrolysis.

Especially great changes in the body occur during pregnancy or during artificial stimulation of the ovaries to increase the likelihood of conception.

Estrogens are a large group of female sex hormones. They belong to the steroid and are quite close in structure to the male – androgens.

Moreover, the structure of the molecules is so similar that part of the estrogens produced by the woman’s body (or coming from outside) are then converted into androgens. This is a normal process of self-regulation of the internal environment of the body.

Estrogens directly affect the condition of the hair follicles.

Under the influence of these hormones, hair growth is accelerated. But the most noticeable effect is the stimulation of the transition of follicles from a dormant state to an active one. After all, most of the follicles are in a “sleeping” state, under the influence of estrogen, they leave it earlier than physiological norms.

HCG, used to stimulate ovulation, has a similar effect. It enhances the effect of other sex hormones and in itself is also a stimulator of hair follicle cells.

Chorionic gonadotropin (hCG) is a hormone that is normally produced by the body of a pregnant woman.

It is usually produced by the corpus luteum of the follicle and is needed to prepare a woman’s body for implantation and carrying a fertilized egg.

Also, this hormone is used to artificially activate the maturation of follicles, that is, the treatment of infertility. HCG therapy is also carried out before IVF: the introduction of the hormone allows you to activate several follicles at once, from which eggs are then taken for in vitro fertilization.

With the introduction of hCG, a wide variety of side effects can occur. The most common include:

1. Ovarian hyperstimulation syndrome. Accompanied by excessive production of estrogen, heavy and painful periods.
2. Increased blood clotting. May cause thrombosis and embolism.
3. Formation of ovarian cysts. These are benign tumors filled with fluid.

HCG also affects the condition of the follicles, stimulating hair growth and facilitating the transition from telogen (rest) to anagen – the phase of active growth.

Although the effect of the hormone itself on the follicle is not great, it significantly enhances the effects of estrogens and androgens, which is especially noticeable when combining hCG therapy with the introduction of sex hormones.

Should electrolysis be performed during hormone therapy

Against the background of infertility treatment with estrogen and hCG injections, overactive hair growth does not always occur.

Most patients note an increase in the density of the hairline and an improvement in the condition of the hair on the head, but without extreme bursts of hair growth.

But the situation can change dramatically when exposed to external stimuli, which lead to “violent” activation of dormant follicles.

One of the reasons for this situation may be electrolysis. The method involves the complete destruction of the follicle by introducing the thinnest electrode into it and applying direct or alternating current.

In this case, the cells of the hair follicle, including the growth zone, are completely destroyed, that is, the hair in this place will never grow again.

However, after the procedure, many micro-wounds remain in place of the destroyed bulbs. In a normal situation, this is nothing to worry about, they will heal without a trace after a few days.

But in women undergoing estrogen therapy (especially in combination with hCG), even minimal stress on the skin can lead to “explosive” activation of the follicles.

This is due to the fact that after the electrolysis procedure, the remains of destroyed cells are released into the surrounding tissues, to which the body reacts with a slight inflammation and activation of regenerative processes.

If their effect is superimposed on the hormonal enhancement of hair growth, the activation of the hair follicles located on the treated area also occurs.

An additional factor that shifts the balance of hair growth towards stimulation can also be an electric current. Under its influence, there is a local increase in blood circulation and metabolic processes in tissues, which will also contribute to the activation of hair follicle cells.

Summing up

Although treatment with estrogens and hCG is not a direct contraindication to electrolysis, it is better to refuse to use the technique during the period of administration of hormonal drugs.

It should be carried out only after consultation and obtaining the permission of the attending physician.

In addition to relatively harmless reactions, such as the activation of the remaining follicles, more serious consequences can occur, such as increased pigmentation or hematomas.

Article prepared by:

Author: Sergey Uzyakov, general practitioner
Published by: Olesya Smagina, Assistant Director of Beauty Universe Hair Removal Centers

Sources:

1.