When it comes to injectable treatments, clinicians often obsess over product choice, dosage, and technique—but what’s often overlooked is something just as vital: how we store and reconstitute botulinum toxins.
This article explores a common yet critical question I frequently receive in training and practice:
“How long can reconstituted botulinum toxin be stored, and does it matter whether we use preservative-free or preserved saline?”
Using current literature and best clinical practice, let’s explore the storage dynamics of reconstituted Botox, Dysport, Xeomin, Jeuveau, and Letybo—as well as the implications of using preserved vs. non-preserved saline.
The Fundamentals of Botulinum Toxin Formulations
There are currently five FDA-approved botulinum toxin type A products in the United States for glabellar lines:
- Botox® (onabotulinumtoxinA)
- Dysport® (abobotulinumtoxinA)
- Xeomin® (incobotulinumtoxinA)
- Jeuveau® (prabotulinumtoxinA)
- Letybo® (letibotulinumtoxinA)
Each of these arrives as a lyophilized (freeze-dried) powder and requires reconstitution with 0.9% sodium chloride. Here’s where technique—and evidence—become pivotal.
Reconstitution: Preserved vs. Non-Preserved Saline
Manufacturers universally recommend preservative-free (non-bacteriostatic) 0.9% saline for reconstitution. However, in clinical practice, bacteriostatic saline containing 0.9% benzyl alcohol is frequently used to improve patient comfort and extend usability of multi-dose vials.
So what’s the difference?
| Feature | Non-Preserved Saline | Preserved (Bacteriostatic) Saline |
|---|---|---|
| Manufacturer recommended | ✅ Yes | ❌ No |
| Contains antimicrobial agent | ❌ No | ✅ Yes |
| Stinging sensation | Moderate | ✅ Reduced |
| Off-label usage | ❌ No | ✅ Yes |
| Shelf-life post-reconstitution | Short | ✅ Potentially longer |
What Happens After Reconstitution?
Once reconstituted, botulinum toxin begins a gradual loss of potency—affected by temperature, handling, saline type, and time.
Here’s a breakdown of what the literature says.
Key Study Insights
1. Botox Stability with Time and Saline Type
A pivotal 2013 study (Vartanian et al.) in Dermatologic Surgery demonstrated that onabotulinumtoxinA (Botox) retained full clinical efficacy up to 6 weeks when stored at 4°C after reconstitution with preserved saline.
[Source: PubMed ID 23894239]
Clinical takeaway: Benzyl alcohol in preserved saline may help stabilize the toxin for extended use, although this remains off-label.
2. Toxin Stability in Unrefrigerated Conditions
A 2011 study published in Actas Dermo-Sifiliográficas showed that Botox retains clinical efficacy up to 24 hours at room temperature after reconstitution. However, protein degradation begins thereafter.
[Source: ScienceDirect: S2173508511000141]
Clinical takeaway: If you accidentally leave reconstituted toxin out overnight, efficacy may still be retained within 24 hours—but beyond that, assume degradation.
3. Preserved Saline and Long-Term Storage
The Journal of Cutaneous and Aesthetic Surgery (2015) confirms that using preserved saline at 4°C allows reconstituted toxin to maintain activity for up to 6 weeks, showing no loss of effect in clinical outcomes.
[Source: PubMed ID 25973563]
Clinical takeaway: A practical and common off-label solution, especially for low-volume clinics or mobile injectors.
4. Xeomin’s Unique Shelf-Stability
IncobotulinumtoxinA (Xeomin) lacks complexing proteins, which may enhance its resistance to degradation. According to Almeida et al. (2024), this may contribute to greater thermostability after reconstitution compared to other toxins.
[Source: ScienceDirect: S1130634324001946]
Clinical takeaway: Xeomin may offer a wider margin of safety in situations where refrigeration is disrupted, but it still requires cold storage as per guidelines.
Summary Table: Post-Reconstitution Stability
| Toxin | Manufacturer Reco. | Preserved Saline? | Stability at 4°C | Stability at Room Temp |
|---|---|---|---|---|
| Botox | ≤24h (official) | Off-label | ✅ Up to 6 wks | ⚠️ ≤24h only |
| Dysport | ≤24h | Off-label | ✅ Up to 30 days | ⚠️ <24h only |
| Xeomin | ≤24h | Off-label | ✅ Stable (likely >2 wks) | ⚠️ Possible stability, but not advised |
| Jeuveau | ≤24h | Off-label | ⚠️ Limited data | ⚠️ Not recommended |
| Letybo | ≤24h | ⚠️ No data | ⚠️ Assume ≤24h | ⚠️ Not recommended |
What Should You Do If You Leave It Out?
Let’s say you reconstitute your Botox or Dysport, and realize the next morning it wasn’t refrigerated:
- Check duration: If under 24 hours at room temp, most literature supports clinical efficacy.
- Consider product: Xeomin may tolerate brief temperature lapses better. Botox with preserved saline is your next best bet.
- Observe outcomes: Document, monitor for diminished clinical effect, and disclose to patients when appropriate.
- Don’t risk patient trust: If there’s any uncertainty, discard the vial. Reputation > cost.
Final Thoughts: Striking a Balance Between Evidence and Ethics
In aesthetic medicine, protocols are often written in absolutes—but real-world practice is rarely that clean. Evidence suggests preserved saline offers viable shelf-life extension, but it remains off-label and not manufacturer-endorsed.
As injectors, our job is to balance:
- Patient safety
- Product integrity
- Clinical outcomes
- Regulatory responsibility
My advice?
Use preserved saline when appropriate and safe—but document everything, and train your team rigorously.
Want to sharpen your aesthetic practice with clinical reasoning and ethical mastery?
Join me in training sessions that prioritize safety, evidence, and artistry, all grounded in real-world medicine. If you’re a doctor, nurse, PA, or dentist looking to master neurotoxin and dermal filler injections, my friends at Cosmetic Medical Training offer botox certification programs that go beyond the basics—so you can open or scale your aesthetic practice confidently.
