The first anabolic steroid successfully synthesized was testosterone. Often given to treat male hypogonadism, or low testosterone levels, and their many symptoms is testosterone propionate, a quick acting, shortester, oil based testosterone injectable molecule.

Schering AG in Germany made it available for medicinal use two years hence. It was sold under the name Testoviron and combined with testosterone enanthate. Before 1960, this kind of testosterone was the first commercially available one there and controlled the market for prescription drugs in the United States.

Testicular, ovarian, and adrenal cortex cells all generate intrinsic testosterone. Therapeutic use of testosterone helps to treat congenital or acquired hypogonadism. Testosterone is the most potent exogenous option for postmenopausal women with breast cancer. Androgen for palliative treatment was first utilized in 1939, following FDA approval in 1938. Anabolic steroids—which are testosterone derivatives—are today regarded controlled substances because of their past unauthorized use. Testosterone was given restricted drug status in 1991 with a number of anabolic steroids. Both conventional and delayed-release (depot) dose versions of testosterone are injected intravenously. Originally authorized by the FDA in September 1995, testosterone transdermal patches (Androderm); many transdermal forms and brands including implants, gels, and topical solutions are now available. The FDA approved an intranasal gel preparation (Natesto) in May 2014. A transdermal patch (Intrinsa) for hormonal replacement in women is being investigated; the daily Women’s dosages are far less than for items used in men. Regarding heart and breast health.

Endogenous testosterone causes sexual growth throughout life across all phases of development. It is created synthetically from cholesterol. From the moment males are fetuses till adulthood, androgens play a crucial role in their development. They are absolutely necessary throughout puberty. The adrenal cortex’s production of androgens cannot support male libido.

High androgen plasma levels block luteinizing hormone, follicle-stimulating hormone, and gonadotropin-releasing hormone (which lowers endogenous testosterone) through a negative feedback mechanism. Furthermore influenced by testosterone are erythropoietin synthesis, calcium equilibrium, and blood sugar levels. Because of their great lipid solubility, androgens can reach target tissue cells swiftly. Testosterone binds with cytolic receptors to form a weakly bound complex when it enters cells enzymatically transformed to 5alpha- dihydrotestosterone. The steroid-receptor complex initiates transcription and causes nuclear cellular changes, therefore triggering androgen activity.

Usually, endogenous androgens excite RNA polymerase, therefore boosting protein production. These proteins control the growth and maturation of the prostate, seminal vesicle, penis, and scrotum as well as other components of normal male sexual development. During puberty, androgens foster a great rise in muscle growth and development as well as a redistribution of body fat. The conclusion of puberty is indicated by beard development and body hair growth. The androgens also guide the fusion of the epiphyses, the termination of development, and the maintenance of spermatogenesis. Exogenous androgens must be used in the absence of endogenous androgens to support normal male development and growth.

Before starting testosterone treatment, it’s very important to tell your doctor if you have any of the following conditions: breast cancer, sleep apnea, diabetes, heart disease, kidney or liver problems, lung disease, prostate cancer or an enlarged prostate, or if you’ve had any unusual or allergic reactions to testosterone or other medications. Also, if you’re pregnant, trying to get pregnant, or breastfeeding, make sure your doctor knows. While you’re on testosterone, your doctor will want to do regular blood tests to keep an eye on your health. Keep in mind that most sports organizations ban testosterone use in athletes.

Some testosterone products like AndroGel and Striant contain soy ingredients, so if you’re allergic to soy or soy lecithin, you should avoid these. Also, testosterone gels and solutions can be flammable, so avoid using them near open flames, fire, or while smoking. The injectable form called testosterone undecanoate (Aveed) contains ingredients like castor oil and benzyl benzoate, so it’s not recommended for people allergic to these substances.

If you use testosterone patches (like Androderm), be sure to remove them before having an MRI scan.

Testosterone injections should always be given into a muscle, never into a vein. Some forms, like testosterone undecanoate and enanthate, have been linked to breathing problems right after injection, so it’s important that the injection is given slowly and deeply into the buttock muscle.

Because testosterone can encourage the growth of certain cancers, men with prostate or breast cancer should not use it. Men with an enlarged prostate need to be monitored carefully, as testosterone might worsen symptoms or increase cancer risk. Older men or those at higher risk for prostate cancer should be checked before starting testosterone therapy. Regular prostate exams and PSA blood tests are important during treatment.

Testosterone therapy is generally not recommended for older men who have low testosterone just because of aging, as there isn’t enough evidence about its safety and benefits in this group. Some guidelines suggest avoiding testosterone in elderly men unless they have moderate to severe testosterone deficiency.

If you have liver or kidney problems, testosterone should be used cautiously because it can build up in the body and cause fluid retention, which might worsen heart, kidney, or liver conditions. There’s ongoing research about whether testosterone increases the risk of heart attacks or strokes. Some studies have shown a higher risk in older men or those with heart disease, but the FDA has not confirmed this. Doctors will carefully weigh the benefits and risks before prescribing testosterone.

Testosterone can also worsen sleep apnea, especially in people who are overweight or have lung disease. If you have these conditions, your doctor will monitor you closely.

High doses of testosterone can increase red blood cell counts, which thickens the blood and may increase the risk of blood clots. Your doctor will check your blood regularly to watch for this.

Testosterone should never be used during pregnancy because it can harm the baby. Women who could become pregnant should use reliable birth control while on testosterone. It’s also not recommended for breastfeeding women, as it may affect the baby and reduce milk supply.

Some testosterone products are not approved for use in women because they can cause unwanted male characteristics like deepening of the voice, excess hair growth, acne, and changes in menstrual cycles. Women using testosterone should be closely monitored, and treatment should be stopped if these side effects appear.

Accidental exposure to testosterone gels or creams can happen if others touch the treated skin. This is especially risky for children and women, who may develop unwanted effects like early puberty signs or masculinization.

Nasal testosterone sprays are not recommended for people with recent nasal surgery, nasal injuries, or chronic nasal conditions. Nasal congestion or allergies can reduce how well the medication works, so treatment should be delayed until symptoms improve.

Testosterone products are generally not approved for use in children and teenagers under 18, except under strict medical supervision. In young boys, testosterone can speed up bone growth but may also cause early closure of growth plates, potentially limiting adult height. Doctors will monitor bone development closely if testosterone is used in children.

In rare cases, testosterone injections can cause serious allergic reactions or breathing problems right after the shot. Doctors usually observe patients for a short time after injections to manage any reactions.

Some medicines can interact with testosterone, so it’s important to tell your doctor about all the medications, supplements, or herbs you’re taking. Also, let them know if you smoke, drink alcohol, or use recreational drugs, as these can affect how testosterone works.

Here are some common medicines that might interact with testosterone:

Diabetes medications: Testosterone can affect blood sugar levels, so your doctor will want to monitor your diabetes closely.

Blood thinners like warfarin: Testosterone can make blood thinners work stronger, increasing the risk of serious bleeding.

Other drugs like oxyphenbutazone, propranolol (a heart medicine), and steroids such as prednisone or cortisone: These can also interact with testosterone, so your doctor will watch for side effects.

Testosterone is processed in the liver by an enzyme called CYP3A4 and is involved with a protein called P-glycoprotein that helps move drugs in and out of cells. Because of this, some medicines that affect these systems can change how testosterone works or how much stays in your body.

For example:

Testosterone can increase the effects of warfarin, so bleeding risks go up.

Some steroids and testosterone together can cause swelling, especially if you have heart or liver problems.

Drugs like goserelin or leuprolide, which lower hormone production, don’t work well with testosterone and usually shouldn’t be taken together.

Testosterone can increase the risk of liver damage if taken with other liver-harming drugs, so your doctor will monitor your liver health.

In boys who are still growing, too much testosterone can speed up bone growth but might stop height growth early, so doctors watch bone development carefully.

Testosterone can boost red blood cell production, which might help some anemia treatments but can also thicken the blood too much, increasing clot risks.

Some medications that block testosterone’s effects, like finasteride or dutasteride, don’t make sense to take with testosterone because they work against each other.

Herbal supplements like saw palmetto may also block testosterone’s effects, so it’s best to avoid using them together.

Certain antifungal drugs like fluconazole (especially at higher doses) can increase testosterone levels by slowing its breakdown in the liver. A similar effect might happen with voriconazole.

Testosterone’s effect on blood sugar can vary. In men with low testosterone and diabetes, testosterone treatment often improves blood sugar control. But in some cases, it might cause low or high blood sugar, so close monitoring is important.

Some natural compounds found in soy may reduce testosterone’s activity by blocking its conversion to a more potent form.

Other drugs like ranolazine or ambrisentan may have their levels affected by testosterone because of interactions with drug transport proteins.

If you’re taking dabigatran (a blood thinner) and testosterone together, especially if you have kidney problems, there’s a higher risk of side effects, so this combination should be avoided or closely monitored.

Nasal testosterone sprays shouldn’t be used with other nasal medications because their interactions aren’t well understood.

If you have allergies or nasal congestion, testosterone absorption through the nose might be reduced, so treatment may need to be delayed until symptoms improve.

Possible Side Effects and Safety Information About Testosterone Therapy

When men use testosterone for a long time, some may experience feminizing effects. This happens because testosterone can partly turn into estrogen, the female hormone. Men with liver problems are more likely to notice this. Symptoms include breast tenderness and enlargement. The good news is these effects usually go away if testosterone treatment is stopped.

Testosterone therapy can also reduce the body’s own testosterone production by signaling the brain to slow down hormone release. At high doses, it may also reduce sperm production, which can affect fertility.

Sexual side effects vary. Some men notice an increase in sex drive, while others may experience a decrease. Rarely, men—especially older men—may have prolonged or unwanted erections.

Testosterone can cause the prostate gland to enlarge, especially in older men. This may lead to urinary problems like frequent urination, difficulty starting or stopping urine flow, or a weak stream.

Women who use testosterone may develop male-like features such as acne, excess facial or body hair, a deeper voice, and changes in menstrual cycles. These effects often improve if treatment is stopped early, but long-term use can cause permanent changes. Testosterone can also disrupt the menstrual cycle, causing missed or irregular periods.

Because testosterone can harm a developing fetus, pregnant women or women who may become pregnant should avoid exposure, including accidental contact with topical testosterone products.

Testosterone gels, patches, and topical solutions can cause skin irritation where applied. Many people experience redness, itching, or irritation. Sometimes, blisters or more severe skin reactions can occur, especially if the patch is placed on bony areas or areas under pressure during sleep or sitting. Using mild steroid creams after removing the patch can help reduce irritation. Acne and oily skin are also common side effects.

Testosterone can cause the body to retain fluid, leading to swelling and weight gain. This is usually mild but can be more serious in people with heart, kidney, or liver problems. Testosterone may also raise blood pressure in some men, so regular monitoring is important.

There is ongoing research about whether testosterone increases the risk of heart attacks, strokes, or other serious heart problems. Some studies suggest a higher risk, especially in older men or those with existing heart disease. However, the FDA has not made a final conclusion. Doctors carefully weigh the benefits and risks before prescribing testosterone.

Liver problems are rare but possible, especially with certain types of testosterone or when abused.

Some men report headaches, mood swings, irritability, anxiety, depression, or difficulty sleeping while on testosterone. These symptoms vary and should be discussed with your healthcare provider.

Testosterone can cause nausea, diarrhea, back pain, and fatigue in some people. Other less common effects include dizziness, increased sweating, and changes in taste or mouth irritation, especially with buccal (gum) testosterone products.

Testosterone can affect bone health. In some cases, it may cause bone loss or worsen high calcium levels, especially in patients with certain cancers. Regular monitoring may be needed.

Symptoms of thickened blood include dizziness, headaches, unusual bleeding, or redness of the skin. Your doctor will monitor your blood regularly to avoid complications.

If you receive testosterone injections, you may experience pain, redness, swelling, or irritation at the injection site. Rarely, serious allergic reactions or breathing problems can occur shortly after injection, especially with certain formulations. Doctors usually monitor patients for a short time after injections to manage any reactions.

Testosterone therapy may worsen sleep apnea, a condition where breathing stops briefly during sleep. This is especially a concern for men who are overweight or have lung disease.

Testosterone is not recommended during pregnancy because of the possible harm it could cause to the developing fetus (FDA pregnancy risk category X). When getting testosterone therapy, women able to conceive should use reliable birth control. Since testosterone is not utilized throughout pregnancy, there should be no specific cause to give the products to women undergoing labor or experiencing an obstetrical delivery; effectiveness and safety under these circumstances have not been demonstrated.

Nursing moms are not advised to use testosterone topical creams, transdermal patches, or gels. Other testosterone preparations should also be avoided while nursing. The allocation of testosterone in breast milk is unknown, and it is uncertain whether exposure will increase levels beyond those usually found in human milk. Important nursing exposure to this androgen might have negative androgenic effects on the baby; the medicine also prevents the mother from beginning her milk supply correctly. Testosterone and androgens were formerly used together to suppress lactation. For breastfeeding women on testosterone treatment, alternative techniques are advised.

Store this medication at 68°F to 77°F (20°C to 25°C) and away from heat, moisture and light. Keep all medicine out of the reach of children. Throw away any unused medicine after the beyond use date. Do not flush unused medications or pour down a sink or drain. NOTE: Warming and shaking the vial should redissolve any crystals that may have formed during storage temperatures lower than recommended.