Forzinity prescribing information describes a daily elamipretide injection for improving muscle strength in people with Barth syndrome, a rare inherited energy disorder. The label covers people weighing at least 30 kilograms, about 66 pounds. The usual labeled amount is 40 mg under the skin once daily. Reactions where the injection goes in are the most common side effects.
Elamipretide is also called SS-31. A compounded medicine is prepared by a pharmacy for an individual prescription. Forzinity's label describes the branded product.
Which Forzinity prescribing information is current?
As of September 30, 2026, the day this article was written, the current DailyMed prescribing information reads “Revised: 9/2025”. That is the prescribing document's revision date, rather than the date someone last refreshed a webpage.
Section 1: The indication and required follow-up trial
An indication is the use listed on a medicine's label. Forzinity's covers adults and children with Barth syndrome, an inherited condition affecting mitochondria, the parts of cells that make usable energy. The weight threshold is 30 kilograms, about 66 pounds.
It received accelerated approval, a pathway allowing earlier access based on a measure reasonably likely to predict patient benefit. Here, that measure was strength in the muscles that straighten the knee. A required confirmatory trial must verify whether that finding translates into clinical benefit. The approval-anniversary account covers the decision's history.
As of September 30, 2026, the day this article was written, the 4TAZPower registry record, updated September 17, 2026, lists the confirmatory study as recruiting. Its planned enrollment is 48 males with Barth syndrome. Over 72 weeks, it measures walking, rising from a chair, and getting up and moving. Recruitment is progress toward an answer; it isn't a trial result.
Section 2: Forzinity dosing and administration
The label describes 40 mg subcutaneously, meaning under the skin, once daily at the same time each day. Its missed-dose rule is to skip that dose and resume at the scheduled time, without doubling.
Kidney function changes the labeled amount in adults. The label uses eGFR, an estimate of kidney filtering measured in milliliters per minute:
| Adult kidney function | Labeled daily amount |
|---|---|
| eGFR at least 30 mL/minute | 40 mg |
| eGFR below 30 mL/minute, without dialysis | 20 mg |
Dialysis is treatment that filters blood when kidneys cannot. The label lacks enough information to recommend a regimen for adults on dialysis or children with kidney impairment.
It names the abdomen or outer thigh, daily rotation of injection spots, and training for adults or caregivers. It also rules out mixing other medicines in the same syringe. These amounts describe Forzinity; the prescriber sets the actual compounded SS-31 dose.
Section 4: Contraindications
A contraindication is a reason a medicine must not be used. Forzinity lists a serious allergic reaction to elamipretide or any other ingredient. Its exclusion includes the inactive ingredients, not just the active drug.
Section 5: The two warnings
Benzyl alcohol toxicity in newborns. Benzyl alcohol helps keep germs from growing in Forzinity's solution. Serious and fatal poisoning has occurred in premature or low-birth-weight newborns receiving other medicines containing it through a vein. Forzinity is not labeled for newborns or intravenous use, meaning delivery into a vein.
Hypersensitivity, meaning an allergic reaction. Reported reactions included rash, raised bumps, eczema-like inflamed skin, and cough. Some required emergency medical treatment. They could appear within minutes or months after treatment began.
The label calls for stopping Forzinity and emergency treatment after a serious allergic reaction. It says the medicine must not be restarted afterward. Persistent or severe skin reactions are also a reason for the clinician to consider stopping treatment.
Section 6: Forzinity side effects in Table 2
Adverse reactions are side effects recorded in the studies. The label's safety group included 12 males aged 12 to 35. Each received Forzinity and placebo, an inactive comparison treatment, in separate periods.
Table 2 combines those periods. These are the same 12 people under each treatment, rather than two separate groups:
| Reaction where the injection went in | Forzinity | Placebo |
|---|---|---|
| Any local reaction | 12 of 12 (100%) | 8 of 12 (67%) |
| Redness | 12 of 12 (100%) | 3 of 12 (25%) |
| Firm or hardened spot | 8 of 12 (67%) | 2 of 12 (17%) |
| Itching | 8 of 12 (67%) | 2 of 12 (17%) |
| Pain | 9 of 12 (75%) | 5 of 12 (42%) |
| Bruising | 3 of 12 (25%) | 0 |
| Raised itchy welts (hives) | 3 of 12 (25%) | 0 |
| Bleeding | 0 | 1 of 12 (8%) |
One person represents about eight percentage points here. Those rates describe this small study, not the odds for every person using elamipretide.
The label also reports eosinophilia, a rise in white blood cells involved in allergic responses. Counts usually peaked around 90 days. They returned to their starting levels after six to 12 months of continued treatment or after treatment stopped. The rise wasn't associated with symptoms or other laboratory changes. The broader SS-31 side-effects guide covers other trial populations.
Section 8: Pregnancy, breastfeeding, children, and older adults
There are no human pregnancy data establishing Forzinity's risks. The label's animal studies found no adverse developmental outcomes at the doses tested. Those findings don't establish safety in a human pregnancy.
There are also no data on the medicine in human milk, effects on a breastfed infant, or milk production.
For children, the indication uses weight rather than a minimum age. Evidence included seven children aged 12 or older; safety and effectiveness haven't been established below 30 kilograms. The Barth syndrome studies enrolled nobody aged 65 or older. Kidney-dose gaps for children and adults on dialysis remain separate questions.
Section 14: What the studies actually established
TAZPOWER's randomized phase, where treatment order was assigned by chance, missed both main outcomes: walking distance and fatigue. The 2021 paper in Genetics in Medicine reports that result.
Strength increases appeared during the open-label extension, when everyone knew they were receiving elamipretide and there was no simultaneous placebo group. The 2024 extension paper in Genetics in Medicine reports that 10 people entered and eight reached week 168. Injection-site reactions remained the most common unwanted effects. This explains why longer follow-up and a required controlled trial both matter.
Sections 3 and 16: The vial and storage limits
Forzinity is a ready-made solution, not a powder needing added liquid. Each single-patient vial contains 280 mg in 3.5 mL, a concentration of 80 mg/mL. Section 16 describes a carton of four vials.
The label's unopened-vial storage range is 2–8°C (36–46°F), without freezing. After first use, its allowed ranges are that refrigerator range or 20–25°C (68–77°F). It calls for discarding a vial eight days after first opening, even if medicine remains. These limits belong to the branded container and solution.
What this label says about compounded SS-31
SS-31 is coming soon to Promise — add me to the list. It will be dispensed as a compounded medication, which is different from an FDA-approved product: the formulation Promise will offer is not FDA-approved. Forzinity is the branded elamipretide product for the narrow Barth syndrome indication described above.
Its label can inform a clinical conversation. It doesn't establish a compounded preparation's concentration, ingredients, storage limits, or results. The FDA's compounding explanation describes why those preparations have a different review status.
A licensed provider may still prescribe a compounded formulation; that decision is between you and your doctor. At Promise, a licensed provider reviews every request and may prescribe or decline; not everyone qualifies.
