Some human trialsIn clinical trials

Thymosin beta-4 side effects

Also known as: Thymosin beta 4 · Tβ4 · TB4 · TB-4 · Full-length thymosin beta-4 · TMSB4X · RGN-259 · RGN-137 · NL005

Updated Oct 24, 202626 sources

7 side effects reported for Thymosin beta-4: 3 from studies and labels, 4 from users and guides. 1 come with the ways people manage them.

Healing & recovery

Thymosin beta-4 overview

Side effects reported in studies and labels

Rates as each trial or label states them. A rate from one trial does not carry over to research-grade vials or other doses.

From trials and regulators3

Clinical studies and regulatory documents.

Adverse events in IV trials
Infrequent, mild or moderate at 42 to 1,260 mg IV; mild to moderate with recombinant Tβ4. No dose-limiting toxicity or serious events in either.
Adverse events with topical gel
Safety of all gel strengths acceptable and comparable to placebo in 73 venous ulcer patients
Adverse events with eye drops
Safe and well tolerated in dry eye; no significant adverse effects in neurotrophic keratopathy

Side effects users and guides report

What people post and what dosing guides list. These are reports, not measured rates.

From users and guides4

Community reports, competitor and vendor guides, media.

Injection-site redness or irritation
Typically mild, per one guide
How people manage it
- Rotate injection sites
Fatigue or mild headache
Transient; reported by some users of the peptide class
Flu-like feeling
Occasional, temporary
Eye stinging with drops
Transient, on application

Who should avoid it, and what not to combine

Active or past cancerCondition
Thymosin beta-4 drives cancer cell migration and metastasis in lab and tissue studies, and guides advise caution with any history of cancer. No human data.
Tested sportCondition
Prohibited by WADA at all times under S2.3.
Pregnancy or breastfeedingCondition
No safety data; guides say check with a clinician first.

How much is known

Some human trials

Real human trials, mixed results, none subQ. Two IV Phase 1 safety studies were clean. A venous ulcer gel Phase 2 showed a signal at 0.03%. Eye drops: a small dry-eye Phase 2 and a small keratopathy Phase 3 trended positive; a second keratopathy Phase 3 is recruiting. Recombinant IV Phase 2 trials in heart attack have completed without published results.