Testosterone and Surgery

By Nick Peplow·Gender-affirming surgery coordinator

Last reviewed 27 September 2026· How this site is researched

Whether to stop testosterone before surgery is one of the questions I get asked most, and surgeons disagree about it.

Two people decide this: the surgeon who is operating and whoever prescribes your testosterone. Ideally they talk to each other. If they do not, make sure each knows what the other has said. None of this is medical advice.

The short version

• A stop-T instruction was routine when I started coordinating patients. Many surgeons no longer ask for one for top surgery or hysterectomy.
• Some still ask for a pause of two to four weeks, usually citing clot risk, and a few ask for longer, most often before long operations like phalloplasty.
• Whatever your surgeon asks, follow it, and arrange it through your prescriber rather than by skipping doses. Then ask when you restart, and get the answer written on your discharge instructions.

Why some surgeons ask you to stop

The concern is venous thromboembolism: a clot in a leg vein (DVT) that can break off and lodge in the lungs (a pulmonary embolism, PE). Surgery raises clot risk; so do long operations and lying still afterwards. Testosterone raises haematocrit, the proportion of your blood made up of red cells, and the worry is that thicker blood stacks on top of the rest.

The published studies on trans men who stayed on testosterone through top surgery and hysterectomy have not found more clots. They are small and mostly look back at records, and clots after these operations are rare enough that small studies cannot rule a modest increase in or out. There is even less data for long genital surgery. The clot figures many people have in mind come from oestrogen in trans women, which works differently. Surgeons who dropped the pause read that evidence as reassuring; those who kept it read it as incomplete. I would be wary of anyone calling the question closed.

Caution counts for more if:

• your haematocrit is already high (see below)
• the operation is long, with days of limited movement after, as with phalloplasty
• you have had a clot before, have a close relative who has, smoke, have a high BMI or a known clotting disorder
• you will be flying long-haul soon after; see travelling for surgery

What a pause does, by preparation

How much a pause changes your levels depends on what you take. Your prescriber works out the detail.

• Gels and creams wear off within a day or two of stopping. A two-week pause is a real two weeks without testosterone.
• Weekly or fortnightly injections (enanthate or cypionate) fall away over one to two weeks after the last dose. The pause usually means skipping one or two injections.
• Long-acting undecanoate (given every ten to fourteen weeks) is the awkward one. Levels fall slowly over months, so a surgeon asking for a two-week pause is not asking for anything you can deliver by missing a date. Tell the surgeon which preparation you are on, and when your last injection was, at the consultation.

If you have no pause, think about timing anyway. On a weekly or fortnightly schedule, ask your prescriber whether to move an injection so it is not due on the day of surgery or while you are in hospital, and bring your own supply if you will be away for more than a week. Testosterone is a controlled drug in many countries, including the US and UK. If you are travelling for surgery, carry it in its original packaging with a copy of the prescription and a prescriber's letter, and check the destination's rules before you go.

A pause of a few weeks rarely brings periods back. Longer pauses can, and can hit mood hard right before something already stressful. If that is likely for you, say so to both the surgeon and the prescriber. Sometimes the pause can be shortened; sometimes the surgeon has a reason to hold to it. Ask.

If your ovaries are coming out

With an oophorectomy, the ovaries stop being a background source of oestrogen, which the procedure page covers. The planning point is the pause: if you are off T around the operation, you will spend those days with very little of any sex hormone, and hot flushes, night sweats and a flat mood can arrive while you are still recovering. It settles once testosterone is back.

Tell your prescriber before surgery if the ovaries are coming out, so they can plan the restart and your dose. Levels are usually checked a few months afterwards and the dose adjusted; some people need a little less. From then on testosterone, or another prescribed hormone, is what protects your bone density, so any future long break from it is a conversation to have with your prescriber first. See testosterone requirements for the bone question if you are not on T at all.

Haematocrit

Ask for a full blood count at your pre-op bloods, and ask what number your surgeon wants to see. Thresholds vary by lab and by surgeon. For men on testosterone, the level at which prescribers commonly act is around 54%, and some surgeons want it lower before a long operation.

If it comes back high, the levers are all your prescriber's: the dose, the preparation, the injection interval, a pause, or occasionally taking blood off (venesection). Adjusting your own dose to hit a number tends to create a different problem. Raise it at your consultation, months out, so there is time to act on the result.

Does T affect healing or results?

• Healing: testosterone is not generally considered a wound-healing problem. Nicotine, diabetes and weight are what surgeons watch; see smoking and nicotine.
• Bleeding: some surgeons feel patients on T bleed a little more in theatre; others see no difference. It is an impression rather than a settled finding, and part of where the older stop-T rules came from.
• Top surgery: time on T can reduce chest tissue slightly and shift fat, which can affect technique choice. It is not a reason to delay if you are not on T.
• Metoidioplasty: T matters a lot, because growth is what makes the operation possible. Surgeons usually want a year or more on T, until growth has plateaued. See metoidioplasty.

Clot prevention, whatever you do about T

• Walk as soon as you are allowed, and get up every hour you are awake
• Wear compression stockings if you are given them
• Drink enough water, and do not smoke
• Take any prescribed blood-thinning injections exactly as directed, for the full course
• Know the warning signs: a swollen, painful or warm calf, chest pain, or sudden breathlessness. These need emergency care, not a message to the clinic. See complications

How to have the conversation

Ask: "Do you want me to stop testosterone before surgery? If so, why, for how long, and when do I restart?" A surgeon who says "four weeks, that is our protocol" is giving you a policy. One who says "your haematocrit is fine and this is a short operation, stay on it" is giving you an assessment of you. Both are legitimate. What you are listening for is whether there is a reason behind it and whether it is about your body. In the hospitals I have coordinated for, two surgeons in the same department have given different answers, so ask yours rather than going by what a friend was told.

Then tell your prescriber what was said, and take the plan from the two of them together.