Injection
Tesamorelin
A peptide that targets stubborn abdominal fat and supports a leaner body composition, prescribed and monitored by a licensed clinician.
Starting at $179/mo
Research peptideImmune
Thymosin Alpha-1
RxPrescription onlyInjected under the skin · Twice a week · 1.6 mg · Research peptide · Immune
Starting at $209/mo
A research peptide derived from the thymus gland, studied for immune function and recovery, used off-label to support immunity and healing.
Choose your plan
Real prices from our pharmacy. Longer plans cost less per month and are billed up front. Pause or cancel anytime.
- Naturally produced by the thymus, the gland that trains immune cells
- Early research in humans; most evidence is preclinical
- Subcutaneous injection, dosed by your physician
Every plan includes
- Personalized, physician-guided plan
- Monthly, 3-month and 6-month plans
- Dispensed by a US-licensed compounding pharmacy
- Unlimited protocol adjustments and messaging
- Ongoing support and check-ins
- Pause or cancel anytime
- Reviewed by our in-house physicians
- Physician-guided care
- Ongoing, expert support
- 100% online
- Free, discreet shipping
What is Thymosin Alpha-1?
(T-alpha-1; a thymic hormone)
Thymosin Alpha-1 is a peptide the thymus gland produces to train and activate immune cells, especially T-cells. Thymus function declines sharply with age. Thymosin Alpha-1 is prescribed off-label to support immune function and recovery, based on preclinical evidence and some clinical experience, not large approved trials.
- How it is taken
- Injected under the skin
- How often
- Twice a week
- Dose range
- 1.6 mg
- Form
- Research peptide · Immune
Thymic
hormone that declines with age, driving immune decline
Some clinical work in immune and infection contexts; most modern evidence is preclinical. Prescribed off-label at your physician's discretion.
How it works,
week by week.
Day 1
A US-licensed physician reviews your goal, health history and reasons to try this early-stage peptide. You discuss the evidence and the unknowns together.
Week 1
A small subcutaneous injection, usually in the abdomen or near the site you're treating. Most people find the routine comfortable within days.
Week 2–4
Signaling and recovery processes begin. Many report improved energy or easier movement, depending on the peptide.
Month 2+
Your physician checks in, adjusts dose if needed, and follows relevant labs (IGF-1, immune markers, etc.). Tell them everything you notice.
What you may notice,
and when.
Slower feedback
early-stage therapies take time and close monitoring
Individual response
outcomes vary widely because evidence is limited
Physician partnership
your role is to communicate closely at every check-in
Informed choice
you understand the evidence gap before starting
Individual results vary. Benefits reflect what Zepym Health members commonly report to their physician at check-ins; they are not the results of a clinical trial.
Safety first:
what to know before you start.
Important safety information and common side effects
Research peptides are prescribed off-label and carry more uncertainty than established therapies. Common, mild effects include redness, itching or a bump at the injection site, headache, or flushing in the first days. Because these peptides support cell growth or immune signaling, they are not prescribed with an active cancer, a cancer under evaluation, or during pregnancy or breastfeeding. Some (IGF-1) require careful glucose monitoring. Tell your physician about every medication you take, every supplement, and your complete health history, including any autoimmune conditions. Stop and seek care for hives, swelling of the face or lips, or trouble breathing.
The research behind
thymosin alpha-1.
A thymus-derived peptide that acts on immune cells. The largest human trial, in sepsis, found no mortality benefit. Its only approval we could cite is in some Asian countries, not the US.
- Sepsis trialno mortality benefit
In 1,089 adults with sepsis in 22 centres in China, 28-day deaths were 23.4% with thymosin alpha-1 and 24.1% with placebo, a difference that was not significant. Dosing was every 12 hours for seven days.
Wu et al., BMJ 2025 (TESTS) - Subgroupsexploratory only
In the same trial, the diabetes subgroup had a hazard ratio of 0.58 (0.35 to 0.99) and the under-60 group 1.67 (1.04 to 2.67). The authors describe these as potential differential effects, not confirmed benefits.
Wu et al., BMJ 2025 (TESTS) - Approvalslicensed in some Asian countries
The 2015 Asian-Pacific hepatitis B guideline says thymosin alpha-1 has been licensed in some Asian countries. We did not check current regulator records, so this page gives no count of approvals.
Sarin et al., Hepatology International 2016 (APASL 2015 update)
What the studies found
- Sepsis: no clear fall in deaths at 28 days in a placebo-controlled trial of 1,106 adults (TESTS, BMJ 2025).
- Sepsis, people with diabetes: a lower risk of death in a prespecified subgroup (hazard ratio 0.58, 0.35 to 0.99), an exploratory finding not confirmed as a benefit (TESTS, BMJ 2025).
- Hepatitis B: the 2015 Asian-Pacific guideline describes it as an immune modulator with a modest antiviral action; the trials behind that are not quoted here (APASL 2015 guideline).
- No human trial we checked shows a benefit for immunity, longevity or general wellness.
The sepsis trial gave seven days of injections in adults with sepsis, not the schedule of any hepatitis or wellness use. No trial of injections for healthy adults, immunity or longevity was found.
What this does not say
- The largest human trial, in sepsis, did not show a mortality benefit.
- No human trial we checked shows a benefit for immunity, longevity or general wellness.
- Approval in some countries is not evidence of benefit for an individual.
The research
behind it.
In laboratory and animal studies, thymosin alpha-1 activates and expands T-cell populations, enhancing immune response and reducing excessive inflammation.
Human evidence is limited and older. Your physician explains this and uses it based on clinical judgment, with close attention to immune markers if appropriate.
Getting started
takes a few minutes.
- 1
Connect with a physician
Answer a few questions online and a US-licensed physician reviews your health, history and goals to make sure treatment is right for you. 100% online. No in-person visit required.
- 2
Get your discreet shipment
If approved, your treatment is compounded by a US-licensed, LegitScript-certified pharmacy, inspected for quality, and shipped discreetly to your door.
- 3
Receive continuous support
Start with one goal, then keep building over time. Unlimited physician messaging, easy refills and dose adjustments, all from the Zepym Health app.
Frequently asked questions
Contact supportHow do I use Thymosin Alpha-1?
Injected under the skin, twice a week. The starting prescription is 32 units (1.6 mg) each time. Your physician sets your own dose and it is printed on your label.
How much arrives in each shipment?
1 vial at the starting strength, shipped to your door from a licensed US pharmacy.
When is thymosin alpha-1 used?
For immune support in people recovering from illness or looking to strengthen immunity with age. It is not a substitute for vaccines or standard immune care. Your physician decides whether it fits your history and goals.
Why are these off-label?
Off-label means not FDA-approved for these specific uses, but prescribed by physicians based on preclinical evidence and clinical experience. It is common in medical practice; your physician explains the evidence and the gaps.
How often do I take it?
Usually a small subcutaneous injection once daily or a few times a week, depending on the peptide. Your physician sets the schedule and adjusts it as needed. The kit includes everything.
What is the evidence really like?
Honest answer: early. Preclinical and animal data are promising; human data are limited or absent. Your physician explains this plainly and monitors you closely. If you prefer established therapies, tell them.
Thymosin Alpha-1 educational content reviewed by our physician
Scott Nass, MD Doctor of Medicine, board-certified in Family Medicine
Charles R. Drew University and David Geffen School of Medicine at UCLA. Family Medicine residency at Ventura County Medical Center.
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References
- 1.Mechanisms of IGF-1-Mediated Regulation of Skeletal Muscle Hypertrophy and Atrophy. Cells, 2020
- 2.Unique features of human cathelicidin LL-37. Biofactors, 2015
- 3.Regeneration or Risk? A Narrative Review of BPC-157 for Musculoskeletal Healing. Curr Rev Musculoskelet Med, 2025
- 4.Metabolic effects of a growth hormone-releasing factor (tesamorelin) in patients with HIV. N Engl J Med, 2007
- 5.Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol, 1998
- 6.Thymosin alpha 1: A comprehensive review of the literature. World J Virol, 2020
Prescription products require an online evaluation with a licensed medical professional who will determine if a prescription is appropriate. Products are compounded by a licensed pharmacy. The FDA has not reviewed or approved compounded products for any use for safety, efficacy, or quality. Compounded medications are not FDA-approved brand-name products.