How to Specify Active Ingredient Concentration in Cosmetic OEM
When developing a custom cosmetic formula with an OEM, one of the most critical decisions is specifying the concentration of active ingredients. This determines efficacy, safety, and regulatory compliance. Whether you're a brand founder or procurement buyer, understanding how to set active percentages, navigate regulatory limits, and manage formula iterations will save you time and money. In this guide, we'll walk you through the process step by step, with practical insights for working with manufacturers in China and beyond. For a broader overview of the OEM process, see our custom formula development guide.
1. Setting Active Percentages in Your Brief
Your product brief should clearly state the desired concentration of each active ingredient, along with the intended benefit and target consumer. For example, you might specify 2% salicylic acid for an acne treatment or 10% vitamin C for a brightening serum. However, simply picking a number isn't enough—you need to consider the form and delivery system of the active, as these affect bioavailability and stability. Work with your OEM's formulator to determine the optimal percentage based on clinical studies, supplier recommendations, and sensory goals. Be transparent about your budget and timeline, as higher active concentrations may require more expensive raw materials or additional testing.
2. Regulatory Maximum Limits: EU vs. US
Active ingredients are subject to different regulations depending on the market. In the EU, cosmetics are governed by Regulation (EC) No 1223/2009, which lists restricted substances in Annex III. For example, salicylic acid is restricted to 2% in leave-on products (except body lotion) and 3% in rinse-off hair products. The US FDA does not have a pre-market approval system for cosmetics, but ingredients must be safe under intended use conditions. However, if your product makes drug claims (e.g., acne treatment), it may be regulated as an OTC drug, which imposes active ingredient monographs (e.g., 0.5–2% salicylic acid). Always confirm the regulatory status in your target market. For more on quality control, see our quality control guide.
3. Stability and Compatibility Testing
Once you've set the active concentration, your OEM will conduct stability testing to ensure the formula remains effective and safe over time. This typically includes accelerated stability (e.g., 40°C for 3 months) and real-time stability. Compatibility testing checks interactions between the active and other ingredients, packaging, and preservatives. For instance, vitamin C is prone to oxidation and may require a low pH, which can affect the stability of other components. Your OEM should provide a stability protocol and report. At 8OEM, we conduct stability testing in-house and can share results during the development process.
4. Lab Testing and Verification
Beyond stability, your OEM should perform microbiological testing, challenge testing for preservative efficacy, and analytical testing to confirm active concentration. High-performance liquid chromatography (HPLC) is commonly used to verify actives like vitamins or acids. Depending on claims, clinical or consumer studies may be needed. Ensure your OEM has a documented testing plan and can provide certificates of analysis for raw materials. For a deeper dive into testing, refer to our quality control guide.
5. Iterating Your Formula: Rounds and Feedback
Formula development is iterative. After initial samples, you'll likely need 2–4 rounds to refine texture, scent, efficacy, and stability. Each round should be based on clear feedback: what you liked, what you didn't, and any new requirements. Provide specific comments (e.g., "too sticky," "absorption too slow") rather than vague impressions. Your OEM should document changes and adjust the formula accordingly. Keep regulatory limits in mind—if you increase an active, ensure it stays within allowed levels. At 8OEM, we typically provide samples within 7–10 days per round, with detailed formulation sheets.
6. Working with 8OEM on Active Concentration
8OEM offers OEM/ODM services with custom formula development, sampling, and regulatory support for markets including the EU, US, China, and the Middle East. We can help you set realistic active percentages, source compliant raw materials, and navigate stability and testing. Our team is experienced in halal, vegan, and clean beauty positions. To discuss your project, contact us or learn more about our cosmetic OEM services.
Ready to develop a custom formula with the right active concentrations? Contact 8OEM today to discuss your project and receive a tailored proposal.
Frequently Asked Questions
What is the maximum concentration of salicylic acid allowed in the EU?
In the EU, salicylic acid is restricted to 2% in leave-on products (except body lotion) and 3% in rinse-off hair products, according to Annex III of Regulation (EC) No 1223/2009.
Can I make acne claims with salicylic acid in the US?
In the US, salicylic acid is recognized as an OTC monograph active for acne treatment at 0.5–2%. If you make acne claims, your product must comply with the OTC drug monograph, which includes specific labeling and testing requirements.
How many formula iterations are typical?
Most custom formulas require 2–4 iterations to refine sensory properties, stability, and efficacy. The exact number depends on complexity and your feedback.
Does 8OEM provide stability testing?
Yes, 8OEM conducts stability testing in-house and can provide reports as part of the development process. We also perform microbiological and analytical testing to ensure quality and compliance.