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Thymosin Alpha-1 Info Sheet

May 1996

A note from The field of medicine is constantly evolving. As a result, parts of this article may be outdated. Please keep this in mind, and be sure to visit other parts of our site for more recent information!

NOTE: Thymosin is taken as an injectable drug. (You need to use a needle.)
  1. BEFORE taking thymosin, it is critical to have your doctor show you how to take this drug. If you are not comfortable giving yourself an injection, have your doctor help you out.
  2. You will need to get syringes (which requires a prescription in New York and several other states) and determine a way to safely dispose of your syringes.
  3. This product NEEDS TO BE REFRIGERATED. Do not leave it out more than a few hours.
  4. Thymosin comes as two doses in one small bottle. Once mixed with sterile water, the SECOND dose must be taken with TWO DAYS, or the drug will become too weak to be useful.
  5. Although thymosin is a singularly safe drug, injections can cause infections if the needle isn't sterile. Therefore we are asking all referring physicians to keep a list of adverse reactions for PWAs taking thymosin.

What Is It, Really?

Thymosin is a synthetic version of a naturally occurring hormone that circulates inside your thymus. Thymosin alpha-1 is an injectable synthetic hormone that is being studied for hepatitis B, lung and neck cancer, and as an immune-modulator in AIDS. Results from a very small Italian trial suggest that thymosin in combination with an anti-retroviral and low dose alpha-interferon may result in increased T cells.

The Thymus

The thymus is where T-cells mature and grow into functional CD4 cells or CD8 cells. How the four thymic hormones shape this process is not understood or agreed upon yet. Long overlooked by researchers, the thymus is in fact a critical part of your immune system: it's where individual T cells are tailored to respond to the millions of bacteria or fungi or viruses that could invade your body during your lifetime. Unfortunately, little is known about how the thymus works, or how it figures in HIV/AIDS.

The Theory Behind Thymosin Alpha-1

The mechanism of action for the use of thymic hormones with hepatitis B or HIV/AIDS is unknown. Interest in thymosin stems mostly from the results of a few small clinical trials and its strong safety profile. HIV/AIDS: The initial idea was to replace thymic hormones in PWAs to compensate for an increasingly atrophied thymus. Since then, taking thymosin has been reported to increase 1) IL- 2 and alpha interferon receptors on T cells, 2) thymic maturation of T cells and 3) production of IL-2, gamma interferon, and alpha interferon. It may increase the number and activity of NK (natural killer) cells. In the Italian study, 7 participants with 200-500 T cells took three drugs together: AZT, alpha-interferon (2 million units 2x/wk) and thymosin (1 mg 2x/wk). After a year, participants saw an average increase of 187 T cells, and improved T4/T8 ratios. Other participants who took AZT alone or AZT plusinterferon or AZT plus thymosin, did not experience similar T cell increases. Why AZT? The theory here is to take AZT (or another anti-retroviral) to lessen the chance that increasing T cells will result in increased HIV replication at the same time. How thymosin interacts with interferon is a mystery. One theory is that they synergize and work together to improve immune function. Others, noting similar viral load drops and T cell increases with high-dose alpha interferon and AZT, theorize that thymosin boosts interferon's antiviral activity. If that's true, it's good news given the side effects of alpha interferon. Hepatitis: The mechanism of action for treating hepatitis has yet to be spelled out. Small studies phase II studies abroad showed thymosin to be a much safer alternative to the standard treatment, alpha-interferon, with similar or better efficacy. A recent phase III trial (yet to be published) in people with chronic hepatitis B has reported disappointing results: an equal number of participants on drug and placebo cleared hepatitis DNA from their blood. Critics have suggested that the results are skewed from one site, and/or because chronic hep B was sloppily defined. It is interesting that twice as many people on placebo as expected cleared virus from their blood. Until we see the data or hear from other studies, we don't know much.

Side Effects and Toxicity

Thymosin appears to be quite well tolerated. No adverse drug interactions have been observed. No side effects, other than irritation or a burning sensation at the site of injection, have been seen to date.


The dose used in clinical trials for HIV/AIDS is: 1 mg twice a week. Hepatitis B or C doses used in the clinical studies have been either 1 or 1.6 mg twice a week. Once mixed, thymosin is only stable for two days. Suggested dosing schedule: Monday-Thursday or Tuesday-Friday. Keep it refrigerated at all times.

Thymosin Preparation

Preparation: Please ask your doctor for instructions and go over this process with him or her. Thymosin alpha-1 needs to be mixed before you can inject it. When you receive your order of thymosin, it should contain a small bottle with white powder (thymosin) and a glass vial of sterile water. Open the vial of sterile water and withdraw it via a needle. Gently pull off the aluminum cover to the thymosin bottle, and poke the needle through the rubber membrane in the top of the bottle. Inject the water into the bottle and swish it around to mix the thymosin and the water. If you are using your own sterile water, inject 1 ml of sterile water into the thymosin bottle.

Taking Thymosin

When the thymosin is mixed, use an insulin needle and withdraw 1/2 ml of the fluid. Thymosin is a subcutaneous injection, namely, just below the skin. After injecting the thymosin, store it in the refrigerator. Use a clean needle each time you inject thymosin. Re-cap the needles carefully and dispose of carefully - get a red hazardous waste basket for your needles. Ask your doctor or get one from a home care company (who will also pickup on a regular basis). Home care companies always provide hazardous waste baskets and pick them up.

What We Carry

The PWA Health Group imports Sclavo brand Thymosin-alpha-1 from Italy. Each unmixed bottle of thymosin contains 2 mg of drug.

On-Going Studies

At present, we know of no open studies in the US. We will keep you informed.

A note from The field of medicine is constantly evolving. As a result, parts of this article may be outdated. Please keep this in mind, and be sure to visit other parts of our site for more recent information!

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This article was provided by PWA Health Group.
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