To Freeze or Not To Freeze: Lyophilized Peptides

Peptides should be stored in solution only for short periods of time. For long-term storage the peptide should be lyophilized from a volatile buffer or solvent and stored desiccated at -20 °C.

Grant, Gregory A. (2002). Synthetic Peptides: A Users's Guide. p 283.


The best storage and handling conditions will depend on peptide sequence. However, despite the individuality of peptide sequences, some general recommendations for peptide handling can be made (Table 7).
Table 7:
Duration of storage

Concentrated stock solution (0.5–2 nmol/μL): storage duration depends on peptide

Short-term (≤3 months): high concentration (1–100 pmol/μL) liquid solution at 4 °C or frozen solution at −20 °C to −80 °C

Medium-term (3 months to 1 year; peptide-dependent): frozen solution at high concentration

Long-term (>1 year): lyophilized at −20 °C to −80 °C
 
Grant, Gregory A. (2002). Synthetic Peptides: A Users's Guide. p 283.



Table 7:


Tl;dr: so you're on the pro-freezer side of the debate?

I'm fridge but really fridge/freezer seems minutiae compared to either vs. room temperature.
 
Tl;dr: so you're on the pro-freezer side of the debate?

I store mine in the freezer, but my main point is that the people who are saying the freezer is bad are wrong and using bro science to justify it. There is nothing to debate. The science on this has been known for decades. In general if you want to store lyophilized peptides for > 3 months, the freezer is the best place.

I'm fridge but really fridge/freezer seems minutiae compared to either vs. room temperature.

Like the above study says, it depends on the peptide. If you go read the study that ghoul grabbed graphs from but didn't link the source, it shows that the bilirubin actually degraded quite a bit in the refrigerator (4%) but not in the freezer.
 
There is nothing to debate. The science on this has been known for decades. In general if you want to store lyophilized peptides for > 3 months, the freezer is the best place.

We're talking about only lyophilized peptides (not reconstituted). And yeah, fridge or freezer. Not room temperature.
 
Like the above study says, it depends on the peptide. If you go read the study that ghoul grabbed graphs from but didn't link the source, it shows that the bilirubin actually degraded quite a bit in the refrigerator (4%) but not in the freezer.

Bilirubin is not a good example. Not a peptide.

Was it reconstituted? If so, kinda interesting (light exposure conditions?), but doesn't provide insight into the questions being asked here.
 
BTW, I was lazy in referencing the example. It was bivalirudin that degraded 4% at 4C. Bivalirudin Is a peptide.

My guess is it’ll be different for each individual peptide. Phizer says explicitly not to freeze Lyophilized HGH powder and to store it under refrigeration.

GENOTROPIN® (somatropin) How Supplied/Storage and Handling | Pfizer Medical Information - US

Edit: Omnitrope also says to refrigerate before and after reconstitution.

 
My guess is it’ll be different for each individual peptide.

For sure. The study I referenced earlier explicitly says it depends on the peptide, but then says the general advice is to store at -20C.

Phizer says explicitly not to freeze Lyophilized HGH powder and to store it under refrigeration.

HGH is s tough one. Definitely, as you've pointed out, some say refrigerate rather than freeze. There a bunch of other manufacturers, though, who say store their's at -20C. Fortunately, I'm in a test of UGL HGH that has been stored for 6 months in the freezer. We already have a before test of the batch so the after test should give us some insight on whether this UGL HGH is best stored in the freezer.
 
For sure. The study I referenced earlier explicitly says it depends on the peptide, but then says the general advice is to store at -20C.



HGH is s tough one. Definitely, as you've pointed out, some say refrigerate rather than freeze. There a bunch of other manufacturers, though, who say store their's at -20C. Fortunately, I'm in a test of UGL HGH that has been stored for 6 months in the freezer. We already have a before test of the batch so the after test should give us some insight on whether this UGL HGH is best stored in the freezer.

Hope you come back here and report the findings! I’d be very interested.
 
I had the owner of Canada Peptide tell me me years ago, unreconstituted peptides (with vacume) are recommended to be stored in a non "frost free" freezer.
I have an old tank GE freezer that fits the bill perfectly.
 
我不会。家用冷冻室与实验室冷冻室完全不同,不会变得那么冷,但更糟的是,会受到很大的温度波动的影响。如果肽的水分含量高于实验室标准,则最终可能会导致晶体在肽内膨胀和收缩,从而破坏蛋白质链。

我个人认为暗冷是最好的环境。许多重组肽在这种环境中可以使用多年,包括 Sema 和 Tirz。
我认为它应该在 8 摄氏度以下冷藏,而不是低于 0 摄氏度
 
I wouldn't. Household freezers are nothing like lab freezers, not getting nearly as cold, but worse, subject to wide temp fluctuations. If moisture content of the peptide is higher than lab standards, you could end up with crystals expanding and contracting within the peptide breaking the proteins chains apart.

Personally, I think dark refrigeration is the best environment. Many reconstituted peptides are good for years in that environment, including Sema and Tirz.
I throw everything in the freezer that i know im not using. The peps are lyophilized so they shouldnt contain any moisture. Ive never seen moisture in any of them.

I think it should be refrigerated below 8 degrees Celsius, not below 0 degrees Celsius
 
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