This article in 30 seconds
- You can hold stock without a freezer. Freeze-dried products are stored in a dark place at room temperature (up to 40°C) — and even a room with no cooling on an extreme heat day measures just 34.5°C.
- Room temperature applies to storage only. Because the temperature in transit is ours to manage, all shipments go by refrigerated courier (2–8°C) year-round.
- Choose the format by equipment and frequency of use. Freeze-dried suits facilities without freezer equipment; liquid-frozen suits facilities with a −20°C freezer and frequent use.
1. How much headroom does “up to 40°C” leave?
The short answer: an air-conditioned room will almost never exceed this limit. Our freeze-dried products can be stored at room temperature, protected from light (up to 40°C); liquid-frozen products require frozen storage (−20°C or below).
The number 40°C by itself does not tell you whether the condition is strict or lenient. So let us place the two storage conditions on the same axis as temperatures that are actually being measured.
In observations by the Japan Weather Association, a room left without heat countermeasures on an extreme heat day measured 34.5°C at 2 p.m. [1] Even under those unfavorable conditions — a mid-summer room with the cooling off — the temperature stays short of 40°C. An air-conditioned room or storage area stays lower still.
In a user test by JAF (the Japan Automobile Federation), meanwhile, a car with its windows closed at an outside temperature of 35°C reached 57°C [2]. It is closed spaces like these that cross the 40°C line.
In practice, then, “up to 40°C” is hardly a constraint at all for ordinary storage inside a facility. The places to avoid are limited: window sills, the vicinity of heating equipment, and closed storerooms or vehicles.
The key point
The 40°C limit is drawn above even a mid-summer room with the cooling switched off (34.5°C). An ordinary room will almost never cross that line — what does is a sealed space in a “steam bath” state, such as a car interior at the height of summer.
2. Room-temperature storage, not room-temperature shipping
Let us first clear up a point that is often confused. Room temperature applies to storage after arrival — not to shipping. We deliver our freeze-dried products by refrigerated courier (2–8°C).
Freeze-dried products could, in themselves, also be shipped at ambient temperature. During transit, however, the environment can exceed 40°C, and that temperature is not something we can control. To guarantee quality, we standardized on refrigerated courier year-round from April 7, 2026 (see the notice on product storage conditions).
Shelf-stable foods, too, are sometimes sent by refrigerated parcel at the height of summer. The idea is the same: during transit, when the environment cannot be chosen, we fix the temperature on our side.
After arrival, the product can be stored at room temperature as long as it stays below 40°C. There is no need to conclude that “it arrived refrigerated, so it must require refrigeration equipment.”
3. What changes for inventory operations
The point is this: with freeze-dried products, a storage shelf is all you need to hold stock. Here are the conditions for the two formats (the physical forms of the product), compared from the perspective of the party holding the stock.
| Item | Freeze-dried | Liquid-frozen |
|---|---|---|
| Storage temperature | At room temperature, protected from light (up to 40°C) | Frozen (−20°C or below) |
| Required equipment | Storage shelf | −20°C freezer |
| Shelf life | 2 years from manufacture | 1 year from manufacture |
| Recommended use period | Within the expiration date on the label | Within 6 months of delivery |
| Shipping | Refrigerated courier (year-round) | Frozen shipping with ice packs |
| Best suited for | Facilities without freezer equipment, or holding stock long term | Facilities with a −20°C freezer and frequent use |
Both formats contain 1 mL per vial and are manufactured to the same quality standards. The products contain no preservatives; handle them under aseptic conditions and use them as soon as possible after opening.
What not needing a freezer means
Installing a freezer brings management overhead beyond the equipment itself: floor space and power, temperature logging, and the risk of losing the entire stock at once if the unit fails or the power goes out.
Put another way, a freezer is also a device that gathers your stock into a single basket. If the basket breaks, everything in it is exposed to danger at the same time.
Freeze-dried products sit on a storage shelf. A power outage has no effect as long as the room stays below 40°C. Facilities without freezer equipment can adopt them, and splitting stock across multiple sites becomes straightforward.
The key point
Shelf life differs as well. Freeze-dried keeps for 2 years from manufacture; liquid-frozen for 1 year from manufacture (with use within 6 months of delivery recommended). The slower your pace of use, the more the longer freeze-dried shelf life lowers the risk of having to discard stock.
4. When we still recommend refrigeration or freezing
The bottom line: if you have an environment that can store the product at a lower temperature, use it — there is no downside. Being storable at room temperature is not the same as room temperature being optimal. We recommend refrigerated (2–8°C) or frozen (−20°C or below) storage in the following cases:
- When the storage environment could exceed 40°C
- When longer-term quality stability is a priority
The value of room-temperature storage is that facilities without freezer equipment can still adopt the product. Facilities that already have the equipment have no reason to switch to room temperature.
5. Choosing between the two formats — equipment and frequency of use
The conclusion is simple: it comes down to equipment and frequency of use.
When freeze-dried is the better fit. Facilities without freezer equipment, facilities with relatively infrequent use, and cases where stock is split across multiple sites. Before use, the product is reconstituted by adding about 1 mL of purified water or physiological saline per 1 mL.
When liquid-frozen is the better fit. Facilities that have a −20°C freezer and use the product frequently. It contains no cryoprotectant (an additive that prevents damage during freezing) and thaws at room temperature in about 5 minutes. Because the protein components it contains can gradually denature even in the frozen state, we recommend use within 6 months of delivery.
Detailed specifications are on the product page. Feasibility often hinges on what storage equipment a facility has, so please contact us if you are unsure.
The principles of the freeze-drying (lyophilization) process itself are covered in our note on freeze-drying technology (in Japanese), and how to read per-mL pricing by format in why “¥X per mL” is not a useful comparison metric (in Japanese).
Frequently Asked Questions
If it can be stored at room temperature, why does it arrive by refrigerated courier?
Because storage conditions and shipping method are decided separately. Freeze-dried products could also be shipped at ambient temperature, but transit environments can exceed 40°C, and that temperature is not something we can control. Since April 7, 2026, all shipments have been standardized on refrigerated courier year-round. After arrival, the product can be stored at room temperature as long as it stays below 40°C.
Where in our facility should we keep it?
Any dark location below 40°C is fine — an ordinary storage shelf works. Please avoid window sills, the vicinity of heating equipment, and closed storerooms or vehicles. An air-conditioned room will almost never reach 40°C, even at the height of summer.
Sources
- [1] Indoor temperature observation by the Japan Weather Association. On an extreme heat day, a room without heat countermeasures was reported at 34.5°C as of 2 p.m. (noted in Figure 1).
- [2] User test by JAF (Japan Automobile Federation) verifying in-car temperatures. With an outside temperature of 35°C and the windows closed, the car interior reached 57°C (noted in Figure 1).
This article explains product storage conditions and inventory management. Our stem cell secretome is supplied for research use only and is not intended to demonstrate efficacy against any specific disease.
Shelf life is counted from the date of manufacture. The time remaining on delivery is shorter by however long has passed since manufacture. For the actual usable period, check the expiration date printed on the vial label. If you require a minimum remaining shelf life, let us know when placing your order.
View Stem Cell Secretome specifications Notice on product storage conditions