Testosterone Subcutaneous Injection: How to Do It by Yourself

Last updated: August 30, 2026

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In a previous article, I showed you how to perform a testosterone injection into the muscle (intramuscular, IM). Today, I want to introduce you to a gentler, easier alternative that has been gaining popularity worldwide: the subcutaneous (SC) testosterone injection — injecting into the fat layer just under the skin rather than deep into the muscle.

Many of my patients on testosterone replacement therapy find the traditional IM injection uncomfortable, and some need a family member to help them reach the buttock or thigh muscle. The good news is that modern research shows the subcutaneous route is just as effective — and usually far more comfortable and easier to self-administer.

One thing to be clear about before the technique. This guide is written for men who are already under the care of a doctor for testosterone deficiency and who hold a prescription. Testosterone is a prescription-only medicine, and the decision to start it rests on symptoms together with blood tests taken on more than one morning — never on a description of how the injection is performed. If you are using testosterone, or a testosterone-like compound, obtained online, from a gym or from any source other than a pharmacy, technique is the smallest of the problems: those products are frequently mislabelled, and the reasons are set out in a separate article on unregulated men’s health products.

Why Consider the Subcutaneous Route?

For almost 8 decades, intramuscular (IM) testosterone injections have been the standard. They are inexpensive and produce predictable testosterone levels — but they are difficult to self-administer and are often associated with discomfort. Recently, the subcutaneous (SC) route has gained popularity because self-administration is much easier, and the available evidence supports its feasibility.

The key advantages of the SC route include:

• Easier self-injection: No need to reach deep muscle or ask for help.
• Less pain: Smaller needles and a shallower injection make it considerably more comfortable for most men.
• No risk of sciatic nerve injury: A known (though rare) risk with buttock IM injections.
• Stable hormone levels: SC injection produces smoother, more stable testosterone levels with smaller peaks and troughs.
• Better adherence: Because it is convenient and comfortable, patients are more likely to stay on therapy long-term.

A landmark 52-week clinical trial published in The Journal of Urology found that a weekly subcutaneous testosterone enanthate auto-injector produced steady testosterone levels with small fluctuations, and that more than 95% of patients reported no injection-related pain (Kaminetsky et al., J Urol 2019). Worth knowing what that figure describes: the trial used a licensed auto-injector device delivering a fixed dose, not a vial and a hand-held syringe. The comfort of the shallow route carries over; the exact percentage belongs to the device.

IM vs SC: What Is the Difference?

Feature	Intramuscular (IM)	Subcutaneous (SC)
Injection depth	Deep into the muscle	Into the fat layer under the skin
Common site	Buttock or outer thigh	Abdomen (belly) or thigh
Needle size	Longer, larger gauge	Shorter, smaller gauge (23-25G)
Pain level	Moderate discomfort	Usually mild
Self-administration	Difficult; may need help	Easy to do alone once taught
Testosterone levels	Larger peaks and troughs	Smoother, more stable

Things You Need to Prepare

• Alcohol swabs
• Your prescribed testosterone vial (e.g., testosterone enanthate or cypionate) — always check the expiry date
• A 1 mL Luer-Lok syringe (preferred to prevent the needle from disengaging due to the oil’s viscosity)
• A drawing-up needle (18-21G) to draw the testosterone from the vial
• A fine short injection needle (23-25 gauge, 5/8-inch) for the subcutaneous injection
• A sharps disposal container — a rigid, puncture-proof container kept for needles only, never the household bin

Where to Inject: The Landmark

The two recommended sites for subcutaneous testosterone injection are:

• The abdomen (belly): Inject into the fatty tissue 3 to 5 cm to the side of the belly button (umbilicus). Avoid the area too close to the navel.
• The thigh: The fatty tissue of the front or outer thigh is also a suitable site.

Gently pinch a fold of skin and fat to lift it away from the muscle. This helps ensure the injection goes into the subcutaneous layer and not the muscle. Move the spot every week — injecting repeatedly into the same patch of fat leaves firm lumps that absorb the oil unpredictably, so the dose stops behaving the way your blood tests suggest it should.

Step-by-Step: How to Do a Subcutaneous Testosterone Injection

⚠️ Important: Do not attempt your first injection by yourself. You must be taught and supervised by a health professional until you are fully competent. Reading a sequence of steps is not the same as having done it once with someone watching, and the steps below are a reminder for men who have already been trained — not a substitute for that training.

1. Wash your hands thoroughly and sit in a comfortable chair with your supplies ready.
2. Decide on your injection site (abdomen 3-5 cm beside the navel, or thigh). Alternate sites with each injection.
3. Draw the prescribed testosterone dose from the vial using the larger drawing-up needle (18-21G) on your Luer-Lok syringe.
4. Remove all air bubbles from the syringe (air must not be injected).
5. Replace the drawing-up needle with the fine injection needle (23-25G).
6. Clean the injection site with an alcohol swab and let it air-dry.
7. Gently pinch a fold of skin and insert the needle at a 45 to 90-degree angle into the fatty tissue.
8. Slowly inject the testosterone over several seconds.
9. Remove the needle and gently press the site with a clean cotton ball or gauze. Do not rub.
10. Dispose of the needle and syringe safely in your sharps container.
11. Never reuse a needle or syringe, and never share them with another person — including a relative or friend on the same treatment. A reused needle is blunt and hurts; a shared one transmits blood-borne infection.

One important exception. The ultralong-acting ester testosterone undecanoate is not a formulation for self-injection at home. It is a large-volume oily preparation, given slowly in a medical setting, after which the patient is observed for a period — because it carries a small but recognised risk of pulmonary oil microembolism and of an anaphylactic reaction, which announce themselves as a sudden cough, tightness in the chest, breathlessness or dizziness during or just after the injection. If you are on testosterone undecanoate, your injections belong in a clinic rather than at your kitchen table.

Dose — and Why It Is Not Yours to Adjust

In the 52-week auto-injector trial, the starting dose was 75 mg once weekly, moved down to 50 mg or up to 100 mg according to blood levels. Those figures appear here because patients reasonably ask what is typical — not as a schedule to follow. Your own dose is set by your doctor from your symptoms and your blood results, and on-treatment testosterone is measured midway between injections.

The number that most often forces a change is not testosterone at all. It is the haematocrit — the proportion of your blood made up of red cells. Testosterone raises it, and if it climbs too far the blood becomes thicker, which matters for clotting risk. That is managed by lowering the dose, spacing the injections differently or, in some cases, donating blood — none of which anyone can judge without the test. Blood pressure and PSA are followed for the same reason. Taking more than you were prescribed does not produce a better result; it produces a higher haematocrit.

Possible Side Effects

Local reactions are usually mild and temporary, and may include:

• Minor redness, itching, or a small painless lump at the injection site
• Light bruising or bleeding
• Firm thickened patches of fat if the same spot is used repeatedly — the reason for rotating sites

Because testosterone levels achieved via SC are similar to IM, the general systemic effects of testosterone therapy still apply and require monitoring — a rise in red blood cell count (haematocrit), blood pressure and PSA, suppression of the body’s own production, worsening of untreated sleep apnoea, and breast tenderness or enlargement. This is why regular follow-up with your urologist is essential. Changing the route does not change any of it.

What Is Not Normal — and What Cannot Wait

Most injection-site reactions settle within a day or two. These do not, and should be looked at rather than waited out:

• Spreading redness, increasing swelling, warmth or any discharge at the injection site — particularly with fever or chills. That is an infection, and it needs to be seen the same day rather than at the next appointment.
• Pain that is worse on day three than it was on day one, or a lump that keeps growing.

Separately, testosterone therapy itself has a short list of symptoms that are not for the next appointment either. Chest pain, sudden breathlessness, pain or swelling in one calf, or a sudden severe headache with weakness or difficulty speaking are emergencies — go to hospital and tell the team you are on testosterone. The same applies to a cough, chest tightness or dizziness during or just after an injection of testosterone undecanoate.

What Injections Do to Fertility

This is the part most often missing from an article about technique. Testosterone given from outside switches off the signal from the brain that drives the testicles, and sperm production falls with it. In many men on weekly injections the sperm count drops to zero. Testosterone is not a fertility treatment — for as long as you are on it, it does the opposite.

It is usually reversible after stopping, but recovery is measured in months rather than weeks and is not guaranteed in every man. If children are a possibility — now or in a few years — say so before you start, because there are ways of raising testosterone that do not suppress sperm production, and because azoospermia discovered later is very often the treatment itself rather than a separate problem. This is set out in more detail on the male fertility and microsurgery service page.

The route of administration is largely a matter of preference; the monitoring schedule is not optional. See what structured long-term follow-up looks like under our testosterone therapy service.

If you would like to discuss whether subcutaneous testosterone therapy is appropriate for you, or to be taught the injection technique properly, Dr. Soarawee Weerasopone consults at Bangkok Hospital Headquarters and at Samitivej Sriracha Hospital, Chonburi — 088-022-1445.

Bangkok Hospital Telemedicine is available for patients who cannot attend in person, including international patients — arrange it in advance by email to the Urology department at bhquro@bdms.co.th. It suits reviewing blood results or discussing a change of route; the first injection, however, has to be taught face to face. Samitivej Sriracha is in-person only.

Frequently Asked Questions

Is subcutaneous testosterone injection as effective as intramuscular?

Yes. Multiple studies show that subcutaneous (SC) injection of testosterone enanthate or cypionate produces serum testosterone levels comparable to the intramuscular (IM) route. In fact, SC injection often produces smoother, more stable hormone levels with smaller peaks and troughs, while being easier to self-administer and less painful.

Where do I inject subcutaneous testosterone?

The two recommended sites are the abdomen — 3 to 5 cm to the side of the belly button — and the fatty tissue of the thigh. Gently pinch a fold of skin and fat, then insert the fine needle at a 45 to 90-degree angle. Always rotate injection sites, both to avoid irritation and to prevent firm patches of fat that make absorption unpredictable.

What size needle should I use for subcutaneous testosterone?

Clinical studies typically use a 1 mL Luer-Lok syringe with a fine 23 to 25-gauge, 5/8-inch needle for the injection itself, and a larger 18 to 21-gauge needle to draw the oil-based testosterone from the vial. A Luer-Lok syringe is preferred because the oil’s viscosity can otherwise cause the needle to detach. Needles are single-use and must never be shared.

Is subcutaneous testosterone injection painful?

For most men it is mild. In a 52-week clinical trial of a licensed weekly auto-injector, more than 95% of patients reported no injection-related pain; that figure describes the device rather than every syringe technique, but the smaller needle and shallower injection do make the SC route considerably more comfortable than the traditional intramuscular one.

Can I switch from intramuscular to subcutaneous injections?

Often, yes. Many patients successfully switch from IM to SC injection while maintaining stable testosterone levels. Studies in patients who switched routes found no significant change in hormone levels, and most preferred not to return to IM injection. Always make this change under the guidance of your urologist. One formulation is excluded: testosterone undecanoate is given in a medical setting, not self-injected at home.

Will testosterone injections affect my fertility?

Yes, and it is important to know this before starting rather than afterwards. Testosterone from outside suppresses the brain signal that drives sperm production, and in many men on weekly injections the sperm count falls to zero. It usually recovers after stopping, but over months rather than weeks, and not in every man. If you may want children, raise it at the first consultation — other ways of raising testosterone exist that do not suppress sperm production.

What should I do if the injection site becomes red and swollen?

A small area of redness or a painless lump for a day or two is ordinary. Redness that spreads, swelling that increases, warmth, any discharge, or fever and chills point to infection and should be seen the same day rather than at your next appointment. Pain that is worse on day three than on day one is the other sign worth acting on.

Can I be started on testosterone by teleconsultation?

Bangkok Hospital Telemedicine is available and suits reviewing results, discussing a change of route or planning follow-up — arrange it in advance by email to the Urology department at bhquro@bdms.co.th. Starting therapy is different: it needs an in-person assessment and morning blood tests, and the first injection has to be taught face to face. Samitivej Sriracha is in-person only.

Disclaimer: This content is written and reviewed by Dr. Soarawee Weerasopone, a board-certified urologist at Bangkok Hospital Headquarters. It is intended for educational purposes only, does not constitute medical advice, and is not a substitute for being taught in person before you inject yourself. No advice, diagnosis or prescription is given through personal messaging channels or social media. Always consult a qualified healthcare professional before starting or changing any medical treatment. If you develop chest pain, sudden breathlessness, swelling in one calf, or spreading redness and fever at an injection site, seek emergency or same-day care rather than waiting for an appointment.