Thymosin beta-4

What Thymosin beta-4 does

Thymosin beta-4 is a natural 43-amino-acid peptide studied as sterile eye drops, skin gels and injections into a vein. No approved dose or controlled human evidence supports tendon-repair injections. Large dry-eye trials and overall ulcer results showed little benefit. One recombinant product contains 44 amino acids. It differs from the seven-amino-acid TB-500 fragment.

• In a small uncontrolled study, eye drops with it improved some slow-healing sores on the surface of the eye. (Studied in a trial)
• In a small randomized study, a scalp gel with it helped scalp dermatitis. (Studied in a trial)
• People report less pain and easier rehab after shoulder surgery, though surgery and age may explain some of it. (Reported by users)

Uses in the sources

• RGN-259 eye drops were studied for dry eye and neurotrophic corneal defects. Primary results were mixed or negative. (Studied in a trial) (source)
• Skin gels were studied for chronic ulcers, fragile-skin wounds and scalp dermatitis. These findings do not establish injected recovery dosing. (Studied in a trial) (source)
• IV products were studied for safety and after heart attacks. The published cardiac trial did not show an overall infarct-size benefit. (Studied in a trial) (source)
• Community users inject products called TB4 for injury recovery. Reliable controlled human tendon-repair evidence is missing. (Reported by users) (source)

Thymosin beta-4 dosage

Typical reported dose: 500 mcg every other day

• Synthetic Tβ4: 42 mg IV: 42 mg IV once; after safety review, 42 mg IV once daily for 14 days single dose; then daily for 14 days after safety review, into a vein. Studied in a trial. Studied in: Healthy adult volunteers. (source)
• Synthetic Tβ4: 140 mg IV: 140 mg IV once; after safety review, 140 mg IV once daily for 14 days single dose; then daily for 14 days after safety review, into a vein. Studied in a trial. Studied in: Healthy adult volunteers. (source)
• Synthetic Tβ4: 420 mg IV: 420 mg IV once; after safety review, 420 mg IV once daily for 14 days single dose; then daily for 14 days after safety review, into a vein. Studied in a trial. Studied in: Healthy adult volunteers. (source)
• Synthetic Tβ4: 1260 mg IV: 1260 mg IV once; after safety review, 1260 mg IV once daily for 14 days single dose; then daily for 14 days after safety review, into a vein. Studied in a trial. Studied in: Healthy adult volunteers. (source)
• NL005: 0.05 mcg/kg once: 0.05 mcg/kg IV once one dose, into a vein. Studied in a trial. Studied in: Healthy Chinese adults. (source)
• NL005: 0.25 mcg/kg once: 0.25 mcg/kg IV once one dose, into a vein. Studied in a trial. Studied in: Healthy Chinese adults. (source)

These are doses reported in labels, trials or user reports, not a personal plan. Check the source behind each one.

Work out syringe units with the dosing calculator

How to mix Thymosin beta-4

Comes as: Investigational sterile ophthalmic solution, Investigational skin gel and IV product, Community: lyophilized powder and blends.

Mixed with: Community powder reports use bacteriostatic water. Trial eye drops were supplied sterile and ready to use..

Common vial sizes: 5, 10 mg. Common water amounts: 2 mL.

• Amounts and water volumes describe TB-labelled community products; full-length identity was not confirmed.
• A 5 mg/5 mg BPC/TB blend in 2 mL contains two separate ingredient amounts.
• Home-reconstituted powder is not the sterile RGN-259 eye formulation.
• Trial concentrations must not be converted to mg per dose without the drop volume or applied gel mass.

Before mixing: No universal storage instruction applies across trial formulations and unregulated powder vials.

After mixing: Community users refrigerate mixed powder vials. No validated home-mixed Tβ4 shelf life was found.

Thymosin beta-4 side effects and risks

Reported side effects

• Eye-drop pain: ARISE 3: 23/350 active versus 16/349 vehicle had instillation site pain., mild. Persistent pain or reduced vision needs eye assessment. (source)
• Eye-drop irritation: ARISE 3: 5/350 active versus 2/349 vehicle had instillation site irritation., mild (source)
• Reduced visual acuity during eye trials: ARISE 3: 12/350 active versus 7/349 vehicle. This does not establish drug causation., serious. New vision loss needs urgent eye care. (source)
• IV trial laboratory or ECG changes: NL005 repeat dose study: events in 16/24 active versus 5/6 placebo; one ECG related withdrawal in each group., moderate. Research infusions included ECGs and lab monitoring; these are not home-injection safety data. (source)
• Immune reactions from unregulated injections: Long term subcutaneous immune risk is not quantified. Product impurities and identity uncertainty add risk., serious (source)
• Itching after topical skin application: A review describes drug related pruritus in the 250 mcg skin cohort; complete primary safety counts were unavailable., mild (source)

Stop and get help if

• Throat or tongue swelling, breathing trouble, collapse: Stop use and call emergency services now.
• Spreading injection-site redness, heat, pain, pus or fever: Stop injections and get urgent same-day assessment. Confusion, fast breathing or fainting needs emergency care.
• New loss of vision, severe eye pain or a worsening corneal wound: Stop the eye product and get urgent ophthalmic care.
• Chest pain, collapse or persistent new palpitations: Stop use and seek emergency assessment.

Who should avoid it

• pregnant: Precaution: human fetal safety is unknown. Trial pregnancy exclusions do not establish safety.
• breastfeeding: Precaution: infant exposure and effects are unknown.
• tryingToConceive: Precaution: reproductive safety is not established.
• under18: Adult self-use only. Limited pediatric skin-trial eligibility does not establish an injection dose.
• activeCancer: Precaution: Tβ4 affects angiogenesis and cell migration. Whether dosing promotes human cancer is unknown.
• cancerHistory: Discuss prior cancer before exposure; long-term recurrence risk is unknown.
• other: A prior serious reaction to this peptide or an excipient should stop further exposure.
• kidneyDisease: No validated impairment dose adjustment is established for community injections.
• liverDisease: No validated impairment dose adjustment is established for community injections.
• heartCondition: Investigational cardiac use required hospital care. ECG changes occurred in healthy-volunteer trials.
• diabeticRetinopathy: Eye disease needs specialist review. Corneal trial results do not establish retinal safety of injections.
• surgeryPlanned: Tell the surgical team. Pain improvement does not prove structural healing or readiness for activity.
• immunosuppressed: Unregulated injections increase infection concerns; approved eye or wound care should not be delayed.
• bleedingDisorder: Injection-related bleeding is a concern, particularly intramuscularly.
• testedAthlete: WADA 2026 prohibits Tβ4 and derivatives at all times.

Interactions

• TB-500 and duplicate Tβ4 products: Products may duplicate exposure or contain different molecules despite similar names.
• Anticoagulants: Injection-related bruising or bleeding, especially with intramuscular injections. No specific Tβ4 interaction was established.
• BPC-157 and other repair peptides: No controlled human trial establishes a routine recovery stack. A tiny knee series cannot show added Tβ4 benefit.
• ACE inhibitors: ACE breaks down Ac-SDKP, a Tβ4 fragment; ACE inhibitors raise endogenous Ac-SDKP. Clinical effects with added Tβ4 are unknown.

Product quality risks

• In a 2018 study, all three sampled TB-labelled products contained full-length Tβ4; two claimed TB-500 fragment.
• Mass spectrometry detected Tβ4-related modifications despite no quantifiable impurity peaks by UV in those samples.
• The wider 27-product study found dose variation and some toxic-metal contamination. Its 5–75% purity range concerned cysteine-containing peptides, not Tβ4.
• Unauthorized injections have no assurance of sterile contents, correct dose or reliable expiry.

What to expect

Large dry-eye trials and ulcer results combining gel strengths showed no clear benefit. No controlled human trial supports routine tendon-repair injections.

Key studies

• Synthetic Tβ4: IV dose finding: Short-term IV tolerability does not establish a subcutaneous recovery dose. (source)
• NL005: single IV doses: Early IV safety and PK only; not an efficacy or subcutaneous-dose trial. (source)
• NL005: 10 daily IV doses: Early IV safety and PK only; not an efficacy or subcutaneous-dose trial. (source)
• Corneal defects: four compassionate-use cases: Uncontrolled corneal observations; likely overlap with the nine-case report. (source)
• Corneal defects: nine compassionate-use cases: Small uncontrolled series with improvement in some corneal defects. (source)
• Severe dry eye: six doses daily: Promising but extremely small; eyes are not independent participants. (source)

Thymosin beta-4 FAQ

• Is Thymosin beta-4 FDA-approved? No. RGN eye, skin and IV products remain investigational. No FDA-approved product or label dose was identified.
• How do people take it? Under the skin, every other day. 12 weeks. Source: reported by users, not an established dose.
• What's the difference between Thymosin beta-4 and BPC-157? Thymosin beta-4: a peptide studied for eye conditions and skin wounds; tendon-repair injections lack controlled human evidence. BPC-157: an experimental repair peptide with mostly animal evidence and a few small human reports. Why people pair them: reported for injury recovery. Four knee cases used intra-articular Tβ4 with BPC-157; no controlled trial establishes added benefit.
• Can I take it with BPC-157? Reported for injury recovery. Four knee cases used intra-articular Tβ4 with BPC-157; no controlled trial establishes added benefit. Community subcutaneous use differs from the uncontrolled knee series. Source: reported by users. Ask a doctor before combining anything.
• Is it banned in sport? Yes. It is banned in and out of competition (WADA 2026). Tβ4 and derivatives, including TB-500, are named.
• How long does a mixed vial last? Community users refrigerate mixed powder vials. No validated home-mixed Tβ4 shelf life was found.