ICH Stability Zones: Which Long-Term Condition Your Market Needs

The ICH stability zones set the long-term test condition for each climate (up to three options in some zones), with 40°C/75% RH as the accelerated condition for products stored at room temperature. The table below follows Table 3 of the 2025 ICH Q1 draft, which was released for comment on 11 April 2025.

Long-term studies run at least 12 months before submission. The guideline currently in force, ICH Q1A(R2), covers zones I and II only: 25°C/60% RH or 30°C/65% RH long-term, 30°C/65% RH intermediate, 40°C/75% RH accelerated. WHO Technical Report Series No. 1010, Annex 10 covers all climatic zones, including III and IV, and lists 25°C/60% RH, 30°C/65% RH and 30°C/75% RH as long-term options.

As of 14 October 2026 the consolidated ICH Q1 is still a Step 2 draft; ICH's work plan anticipates final adoption (Step 4) in November 2026. Until then, ICH Q1A(R2) and WHO Annex 10 apply.

Most markets list 30°C/65% RH (115 of 193 states), and 30°C/75% RH is listed by 36. This is our tally of the 193 member-state rows in WHO's March 2021 stability-conditions table, counted as of October 2026.

Counting any state that lists the condition, 30/65 appears for 115 states (60%), 25/60 for 74 (38%) and 30/75 for 36 (19%). WHO's table marks 92 of the 193 entries (48%) in square brackets as supplied by the International Federation of Pharmaceutical Manufacturers and Associations (IFPMA) rather than by regulators. Confirm bracketed entries with the destination regulator.

For markets we commonly discuss with buyers:

Take the market with the highest humidity and use its condition. A study for the USA, Brazil and Peru runs at 30°C/75% RH. A study for the USA and Mexico can run at 25°C/60% RH or 30°C/65% RH. Our recommendation is to treat 30°C/75% RH data as covering India's 30°C/70% RH too, because it is the more severe condition. The ICH Q1 draft supports the principle: data generated under a more severe zone condition is acceptable in the others, provided labelling follows regional requirements. Some regions set stricter requirements, so check each regulator.

If a product fails at 30°C/75% RH, the draft lists the options: an alternative long-term condition for the intended zone, a modest cut to the retest period or shelf life, a different container-closure system, or reformulation. Retest period is the interval an API is expected to stay within specification; shelf life is the equivalent for a finished product.

Common zone tables mislead in three places: the Zone I condition, the status of ICH Q1F, and the idea that a country has one tidy zone.

Zone I is not tested at 21°C/45% RH. ICH Q1A(R2) addresses zones I and II together and names 25°C/60% RH or 30°C/65% RH as the long-term condition. None of the 193 entries in WHO's table lists 21/45. Using it in a protocol would put your data below the condition any regulator in the table asks for.

ICH withdrew Q1F. Q1F had set 30°C/65% RH for zones III and IV. Some countries wanted a larger safety margin, so ICH withdrew Q1F and left zone III and IV conditions to regions and WHO. ICH therefore does not decide the IVb condition for a given country; the national regulator does.

A country does not have one tidy zone. India is listed by WHO at 30°C/70% RH, which sits between the IVa and IVb conditions. Brazil and Peru list 30°C/75% RH. Use the country's own listed condition, not a zone label.

Data at 25°C/60% RH supports "Do not store above 25 °C" and nothing warmer. WHO Annex 10, Appendix 3 says a product approved in zone II on zone II data should carry "Do not store above 25 °C. Protect from moisture" when distributed in zone IV. A 30 °C statement needs 30/65 or 30/75 data.

The statements below come from WHO Annex 10, Appendix 2, Tables A10.1 (APIs) and A10.2 (finished products), which are identical in this respect:

WHO adds that a storage statement should not be used to compensate for inadequate or inferior packaging. It also notes that 30/65 may be acceptable in place of 30/75 where humidity is not an issue, for example storage in glass containers.

Worked example, using WHO's water-loss method for semi-permeable packs. The ratio between humidity conditions at the same temperature is (100 − low RH) ÷ (100 − alternative RH). For 30/35 against 30/75, that is 65 ÷ 25 = 2.6. If a hypothetical oral solution bottle loses 0.4% of its weight per month at 30°C/75% RH, the expected loss at 30°C/35% RH is 0.4 × 2.6 = 1.04% per month. WHO's own table gives 1.9 for 30/35 against 30/65 and 3.0 for 40/NMT 25 against 40/75. The loss figure is our illustration, not a measured value.

Test a supplier's stability package with five checks, each of which has a pass or a fail result. Run them on the report before you rely on a retest period for your market. A COA (certificate of analysis) is the batch-specific certificate a supplier issues; see how to read a steroid API COA for that document.

The stability program that sits behind a retest date is also an expectation of good manufacturing practice, covered in ICH Q7 explained.

When you request an API quote from us, tell us the destination market and the long-term condition you need, and ask whether stability data for that condition exist for the specific product. We supply steroid, peptide, hormone and general pharmaceutical APIs as bulk raw material to business buyers, and documentation is confirmed product by product.

Our quote request asks for the product name or CAS number (the Chemical Abstracts Service registry number), quantity, destination, grade or purity, documents, payment terms and Incoterms (the international shipping terms). Available documentation may include the COA, specifications and SDS/MSDS (safety data sheet) where applicable. We support evaluation quantities for qualified business buyers, so you can test a batch against your own protocol before committing to bulk. We discuss requirements in English, and in Spanish for Latin American customers. Prices are quoted per product on request.

For more on how we test materials, see our pharmaceutical API quality testing guide. To start a request, contact us with your product, destination and the stability condition you need.