What is testosterone?

Testosterone is a hormone primarily produced in the testes in males and in smaller amounts in the ovaries in females, as well as in the adrenal glands of both sexes. Its purpose is to develop male reproductive tissues, such as the testes and prostate, and is crucial for promoting secondary sexual characteristics like increased muscle mass, body hair, and a deeper voice during puberty. In both males and females, testosterone also contributes to bone density, red blood cell production, mood regulation, and libido (sex drive). While it is commonly associated with masculinity, maintaining balanced testosterone levels is important for overall health in all genders.

Effects

When undergoing HRT with testosterone, you can expect a range of physical changes, outlined below along with an approximate timeline. However, the exact pace and extent of these changes vary depending on factors like age and dosage. It’s important to note that testosterone tends to be more effective when started before or during female puberty. Once female puberty is complete and the bones have fused, certain skeletal changes such as increased height and widened shoulders are unlikely to occur.

Irreversible effects:

• • • Deepening of the voice

    • Increased body hair growth

    • Facial hair growth

    • Clitoris growth

    • More masculine hairline

Reversible effects:

• • • Rougher and oilier skin

    • Change in body odor

    • Vaginal atrophy

    • Ending of menstruation

    • Masculine fat redistribution

    • Increased libido

    • Increased muscle mass

    • Decreased breast size

    • Increased red blood cell count

Added irreversible effects if you have not yet finished female puberty:

• • • Lengthened face

    • Increased height

    • Broader rib cage

    • Broader shoulders

    • More angular appearance

    • Increased limb size

How female puberty affects success with testosterone

Female puberty generally begins around the age of nine and lasts until the ages of 15 to 17. The longer an AFAB (assigned female at birth) person waits to begin HRT, the more their growth plates fuse, making it impossible for their skeleton to change and become more masculine as well as giving more time for their breasts to fully develop. AFAB trans people who start testosterone at an earlier age generally have a better chance of passing as male, if that is their goal. By the age of 15 to 17, there is a very low chance that your bone structure will change with HRT.

Risks

As with any medication, taking testosterone comes with some potential risks. However, these risks are minimal and can easily be avoided. The most important aspect to be aware of is the danger that comes with overdosing. There is no risk associated with underdosing (other than not experiencing its full effects, of course).

Taking too much testosterone can lead to side effects such as chest pain, mood swings, and unexplained weight gain. Long-term use may also involve additional complications. If you experience any of these issues, consider lowering your dosage. Testosterone usage generally requires more careful monitoring than estrogen, so we strongly recommend reaching out for support.

General risks that come with taking testosterone include loss of fertility, cardiovascular disease, and fluid retention, while minor risks include obstructive sleep apnea, high red blood cell concentration, and acne. However, it is important to note that these risks (not including loss of fertility) apply to anyone with high levels of testosterone in their body, not just transmasculine people.

How to inject

There are a few different methods of taking testosterone. While some people have success with gels or patches, it is extremely difficult to find a reputable source for these while DIYing. The common consensus in the DIY community is that gels only work when prescribed by a doctor, since many online suppliers sell fake gel with no testosterone in it. For this reason, the only reliable way to take testosterone is to inject it via needle and syringe.

There are two methods of injection that you can use: intramuscular (IM) or subcutaneous (subq).

• IM needles inject directly into the muscle. These needles are around 1 inch long and with a wider diameter than subq needles. The pros of this type of injection are that the needle’s larger size makes the injection process fairly quick. The cons are that it can be intimidating and slightly painful when you start out, and the wider size of the needle makes your testosterone vial more susceptible to coring (more on that later).

• IM injection video: https://youtu.be/IrHgX-2qrjs 

• IM injection written instructions: https://fenwayhealth.org/wp-content/uploads/MG-6_TransHealth_InjectionGuide.pdf

• Subq needles inject right beneath the skin into fatty tissue. They are around ½ to ⅝ inches long and much narrower and finer than IM needles. The pros of this type of injection are that it is easier, less intimidating, less susceptible to coring, and almost always painless. The cons are that due to the small size of the needle, it can take longer to draw and inject the testosterone.

• Subq injection video: https://youtu.be/APSPbpqefKw

• Subq injection written instructions: https://www.med.umich.edu/1libr/NursingUnits/Giving_Subcutaneous_Injection.pdf

(Author’s note: I personally recommend subq injections, especially for people with a fear of needles. I was very nervous when I performed my first injection, but the small size of the needle and the lack of pain helped ease my fears. If you mess up your first injection, it’s totally fine - in fact, most people do! The more injections you perform, the less scary the process will be.)

To prevent bleeding and oil leakage, keep the needle in your skin for 30 seconds after you finish injecting, while maintaining pressure on the plunger. Apply firm pressure to the injection site with toilet paper or a similar material for about 10 seconds after removing the needle. This same technique also helps prevent oil leakage from the injection site.

All injection supplies can be found in our supplies list.

When it comes to injection risks, there are three main things you need to watch out for.

1. Injecting into a vein (IM only): If you notice any blood leaking out or entering your syringe while doing an IM injection, it means you’ve hit a vein. This is not common if you inject in the correct area, but if it does happen it’s important not to panic. Simply remove the needle, apply pressure onto the injection site with toilet paper or a similar material, and then redo the injection with a new spot. The bleeding will quickly stop, so you shouldn’t be worried about bleeding out.

2. Vial contamination/coring: This can occur when drawing testosterone from your vial into the syringe. To draw from the vial, you need to stick the needle through the rubber seal on the vial. If your needle is large enough, it can break the rubber seal and cause rubber to break off into the oil. This is called coring, a major safety risk to DIYers.

• • • If you’re doing subq injections and using a small needle, coring is extremely rare. However, if you are using a larger and wider IM needle, specifically between 18G and 25G, it may be a good idea to eliminate the risk of coring by using a small needle to draw and then switching to a larger needle to inject.

    • If your rubber seal breaks or you see suspicious-looking particulates floating in your vial, you will unfortunately have to dispose of it and purchase another. Saving money on vials is not worth the risk of severely damaging your health. If you have questions about the quality of your vial, consult the r/TransDIY reddit forum.

3. Finally, please make sure to cycle through different injection spots. If you inject into the same spot every week, you can develop scarring and become unable to inject there in the future.

After injections, needles become a biohazard and must be placed in a container that keeps them safely stored until they can be disposed of. In hospitals, these are known as sharps containers. It is not necessary to buy an official medical sharps container to store your syringes and needles; simply keep them in a single container such as an empty bleach/detergent jug, milk carton, or plastic tupperware. When the container gets full, throw it away in a trash can or dumpster that you are sure your parents will not check the contents of, preferably not near your home. Do not attempt to recycle used needles and/or syringes.

Storing vials

Testosterone vials can last up to three years when placed in standard room temperature. Storing them in cold temperatures or refrigerating them can cause the testosterone to crystallise. Crystallised testosterone is cloudy and contains small needle-like crystals that cause pain when injected. If you suspect your vial has crystallised, place it in a plastic bag and then submerge it in a bowl of water. Gently heat the water to around 90 - 100°F (32 - 38°C), and you should see the oil inside begin to clear. Avoid overheating the water, and do not use a microwave. It’s fine to keep your vial in slightly warm conditions over time, such as inside a backpack, but not too warm (for example, outside in 80°F weather).

Where to buy

Please only purchase testosterone in the form of Testosterone Cypionate or Testosterone Enanthate. The only difference between the two forms is that cypionate lasts about a day longer in the body than enanthate; both work equally well. Additionally, make sure to buy testosterone in vial form, not ampules. Ampules are small glass containers that must be broken open by hand, which makes them inconvenient, messy, and wasteful. They're designed for single use, so you'd need to discard one after every injection, which results in significant loss of testosterone oil over time.

We’ve organized a list of trusted testosterone sources by region, along with accepted payment methods. Be aware that not all sources ship to every country, particularly Scandinavian countries, so be sure to check shipping availability before placing an order. You can also explore or verify sources through forums such as Eroids, SteroidSourceTalk and ThinkSteroids. However, keep in mind that many forums accept paid advertisements, and some listed sources, such as GDroids or AnabolicSteroids, have scammed users.

(Author’s note: I have personally seen people get scammed by shady sellers/sites, so please proceed with caution.)

Ordering HRT from a domestic source will usually result in faster shipping and eliminates the risk of your package being seized by customs, though it may be more expensive than ordering internationally.

There are many scam websites impersonating legitimate sources. These fake sites often appear in search engine results (including Google), and they will take your money without delivering your order. Only use the links that have been listed below, and always triple-check the website URL and payment amount before completing a transaction.

Dosage

How to calculate dosage

When you receive a testosterone vial, you’ll see labels like "250mg/mL" or "2500mg/10mL." These indicate how much testosterone (in milligrams) is dissolved in the total volume of oil (in milliliters). For example, if the vial says "250mg/mL," it means there are 250 milligrams of testosterone in each 1 milliliter of oil. Most vials contain 10mL of liquid, so multiplying 250mg by 10 gives you a total of 2500mg of testosterone in the full 10mL vial, which is the same as a label that says "2500mg/10mL."

The formula for calculating how much testosterone you need to put in your syringe is [Dosage] / [Testosterone per mL] = [Syringe Millimeters]. For example, if you wanted to do a dose of 50 mg and your vial says “250 mg/mL”, you would divide 50 mg by 250 mg/mL to get 0.2 mL. This is how much testosterone oil you would draw up and inject to get 50 mg in your body.

One important term to understand is the concept of deadspace. Deadspace is the small amount of fluid that remains trapped between the syringe and the needle after an injection. This leftover fluid slightly reduces how long your vial will last, since a small extra amount is used with each shot. The lower the dead space, the longer your vial will last. It’s typically measured in microliters (μL), where 1 μL = 0.001 mL.

How long will your vial last?

If you want to calculate how many injections you can do with your vial, use this formula:

Make sure that for total deadspace you convert the microliters into millilitres (multiply the uL by 0.001)

Recommended dosage

The following dosages only work if you use testosterone cypionate or enanthate. Notice that there is dosage information for two different regimens: you can choose to inject once every 7 days or once every 10 days.

(Author’s note: I personally choose to inject every 10 days so that I have to do less injections. You can choose either option; both are equally effective.)

11 years or younger: There are currently no established HRT dosage guidelines for AFAB trans children aged 11 or younger. Because of this, we cannot ensure the safe use of hormone replacement therapy for individuals in this age group. If you are 11 years old or younger, please do not attempt DIY HRT.

If you live in a trans-affirming area, consider asking your primary care provider about puberty blockers if you wish to pause current or future feminizing changes and stop menstruation. If you’re in a location with limited access to gender-affirming care, you may want to ask your doctor about Depo-Provera as an option to stop menstruation. However, please note that it does not prevent other feminizing effects of puberty. This may be a more accessible option in areas where access to puberty blockers is restricted.

Self-care

To get the most out of taking testosterone, it's necessary to take care of your body and put in consistent effort. Simply taking HRT without supporting lifestyle changes won’t lead to dramatic results. One important factor is maintaining a lean physique. This is important not only for revealing your newly masculine muscle distribution, but also because of a process called aromatization.

Aromatase is an enzyme that converts excess testosterone into estrogen. Higher levels of body fat increase aromatase activity, meaning that more of your testosterone could be converted into estrogen rather than contributing to masculinizing effects. This is especially relevant for those who are overweight or obese. Staying lean can help minimize this conversion, improve your overall health, and boost the effectiveness of HRT. Reducing excess body fat also makes your muscles more visible and improves your overall physique, helping you appear more masculine.